GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: PakProtector on August 22, 2015, 08:06:07 PM
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I got to see my first main air tube failure today. The rifle was charged to 1k5 psi. Upon loading it into the truck for its return home it blew up. Air tube is MIA. I hope my neighbor does not find it with his 96" mop mower. Mostly because I want to take a picture of it. Nobody was hurt, entirely due to luck IMO.
This was a near-new example, and was un-modified. I believe our resident expert( well, one of the top 2 or 3) Bob Sterne raised some questions about their construction topology and warned against high pressure operation.
cheers,
Douglas
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Glad to hear there was no injuries. That had the potential to be catastrophic.
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Scary stuff!!! good to see no one was harmed. I really hope you can find the tube it needs to go back to FD to find out if it was a bad tube or a flaw in all of the tubes. Its a popular low budget gun that many have. Differently shows that all manufactures need to incorporate a burst disk in to our rifles like on a scuba valve. Was the sun beating down on the rifle when it happened?
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Scary stuff!!! good to see no one was harmed. I really hope you can find the tube it needs to go back to FD to find out if it was a bad tube or a flaw in all of the tubes. Its a popular low budget gun that many have. Differently shows that all manufactures need to incorporate a burst disk in to our rifles like on a scuba valve. Was the sun beating down on the rifle when it happened?
The rifle was not left in the sun. It was charged, and then put back in its case. It blew up whilst being moved around in the truck. As you said, very scary...just a matter of luck as to where it was pointed when it let go.
cheers,
Douglas
and yes, I want very much to find it. A thorough search was conducted up to the edge of the woods/brush line and it has not turned up yet.
cheers,
Douglas
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Any idea as to where the failure point was? Was the threads on the receiver end? Or did it burst? How about a picture of the rest of the rifle? I'm very interested as I have a couple of these.
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I would really like to state my opinion here and I know I will get bashed and will probably loose some business over it but Im ok with that. There are Many cheap china replica knock offs and cheaply made originals to boot that I wouldnt use as door stops let alone fill with high pressure air!!! I know people like a good deal but Im telling you your life is worth more than a $200 pcp. And one last thing and this is the most important part of my rant , If you live in this country why not support it instead of sending your money over seas and if you do please buy from companys that have been around awhile and support us airgunners. I have worked on a few of the better chinese guns for customers but no more..Im so glad Douglas your ok that certainly could have turned out much much differently(scary).
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I would love to see a pic of the rest of the rifle.... In a complete lack of knowledge or evidence, I would bet that it failed where the tube is threaded where it screws into the receiver....
Bob
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Douglas post a pic of the remains or shoot me a pic from your phone ill post it. Bob I also believe thats where it let go. I bet that air tube is 200 yards from your truck at least.
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Douglas, MAN you are a very lucky unlucky person. luckily you were not hurt and I'm so glad to here that. Unlucky because you just lost a air rifle. Just glad all is well with you.
We do indeed need to see the remains and hopefully the tube can be recovered.
Bob Well.....some times the sky does fall after all I suppose. Ever been caught in a hailstorm in Kansas. ;D
Bill
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REALLY GLAD no one was injured!
There are too many unknowns here, so any speculation would be nearly irrelevant...BUT Bob is quite likely correct regarding the failure point. WHY is the question (was there ANY mishandling--however slight-- or some other information we might use?). As a Fusion-to-HPA owner I am very interested in this incident.
I will wait in the wings and listen eagerly for any information !
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Scary stuff. Glad no one got hurt! Scary just reading about it.
I bulked my fusion, but only will fill with co2.
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I also own a FDPCP I dont like to see a panic until we get the facts. Other airguns have failed and to me it seems it may be an isolated event. I am certainly glad no one was hurt. Mike has sold alot of these guns and I would hate to see his reputation belittled before the facts have come in. I think we need to hear from Mike before we pass judgement
Tom
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Very well stated Tommy.
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At this point, it is much more important to assess HOW the part failed, and WHY it failed.... If the pressure was 1500 psi, that is well within what CO2 can develop on a hot day (it is 1900 psi at 120*F if the tube is properly filled by weight).... I would not have expected a failure at 1500 psi on a stock XS-60c, as they SHOULD be engineered to be safe at that pressure.... Mike assured us that his PCP version was checked by engineers, so I am sure he will want to get to the bottom of it....
Douglas, I'm really glad you weren't hurt....
Bob
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Not the first tube to fail. The other IIRC was the wall of the cylinder was thin and failed. If it was a poor manufactured tube I would think they all should be recalled. I would think at 1500 psi the threads would not be a factor. But if so then even on CO2 there should be a concern on storing it like in a trunk on a hot day. JMO
Sorry Mr. Sterne got in late but posted anyways.
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I also own a FDPCP I dont like to see a panic until we get the facts. Other airguns have failed and to me it seems it may be an isolated event. I am certainly glad no one was hurt. Mike has sold alot of these guns and I would hate to see his reputation belittled before the facts have come in. I think we need to hear from Mike before we pass judgement
Tom
I've got two of these gun myself, so I've a vested interest in this as does anyone who owns one. I also used to be a White Muzzleloader Dealer and had an opportunity to know a gentleman who had one of our rifles fail catastrophically and on top of that, had a myriad of problems on the warranty replacement... sights broken off in shipping, and a few other snoballed errors on top of that. Then Savage had one of their gun REALLY LET GO.... There is a reason that things fail... I'm hoping this becomes clear in time.
Aloha... 8)
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I disagree, in a factory rifle designed for CO2, there should be NO concern about storing it at up to 120*F because that is the maximum temperature marked right on CO2 cartridges.... A company should design for a MSWP (maximum safe working pressure) of 1800 psi for CO2 and then allow a sufficient safety margin to allow a hydrotest to 5/3rds of that pressure, which is 3000 psi, exactly as it done for CO2 tanks, which are fitted with a 3K burst disc.... There is no way that any CO2 gun should fail before a 3K burst disc pops, IMO.... Is this practice followed universally?.... I would have to say no, because I know of one QB79 that failed at 2600 psi when the regulator bypassed and dumped the tank pressure into the tube.... The screws mounting the tank block sheared off, and in addition nearly ripped out of the tube as well, and the tank/regulator/tank block combination went spinning across the shop floor.... Now to be fair to Industry Brands (the QB manufacturer), the action was out of the stock at the time, so the extra two screws that mount the tank block to the stock were not in place, so maybe it would have survived 3000 psi, maybe not....
Bob
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If it was the threads may have to trash the four that I have bought. Three first gen and one second gen. One was modified with a Ninja reg and bottle. I hope Douglas can shed more light on the matter.
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I form one will not worry. My gun sits over nite with 1800psi I have checked the threads numerous times. I hope people dont start bashing Mike and his guns. He has helped me numerous times and from what I read I am not the only one. Strange that we have not seen pictures yet
Tom
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Got in late again on previous post.
So I am guessing it may be a defect on the aftermarket tube. And I should be safe running a 1100 psi regulator.
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I form one will not worry. My gun sits over nite with 1800psi I have checked the threads numerous times. I hope people dont start bashing Mike and his guns. He has helped me numerous times and from what I read I am not the only one. Strange that we have not seen pictures yet
Tom
There was a picture posted in the Flying Dragon vendors gate of the defective tube some time back.
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An HPA failure of any kind is not good. Douglas, first and foremost, we are VERY glad no one was injured. I will say to everyone, do not jump to conclusion or start throwing anyone under the bus. There are MANY variables that can come into play here so let's see if the evidence can be presented, examined and the failure correctly identified. With hundreds of these out there and in use, and the reports of previous failures almost no-existent, let's not start a panic. We ARE about member safety and we take that serious. If the product is in fact deemed unsafe, you can bet we will be announcing that!!!
Again Douglas, we are very glad no one was injured. When you find the rest of the airgun, we most definitely need detailed pictures and possibly the whole airgun to have examined.
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A voice of reason.
Thank you Dez
Tom
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The weak spot is pretty much where you describe the failure: where the air tube screws into the receiver. That section is under pressure, and the thickness of the air tube is actually the thickness from the bottom of that thread. Not much metal there.
(http://i157.photobucket.com/albums/t50/ribbonstone/XS%2060C/7dbcd153-57cc-4cd2-bc49-53660b23083f.jpg) (http://s157.photobucket.com/user/ribbonstone/media/XS%2060C/7dbcd153-57cc-4cd2-bc49-53660b23083f.jpg.html)
It would also be the spot where any excess force to the tube (or barrel as the barrel band would transfer the force to the tube) would collect.
So a lot of things could have lead to that failure. Over pressure, stress cracking of the thin metal, fatigue from flexing, or a little bit too deep of a thread (or a combination of any of those).
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I think DEz said all the needs be said at this time.
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I form one will not worry. My gun sits over nite with 1800psi I have checked the threads numerous times. I hope people dont start bashing Mike and his guns. He has helped me numerous times and from what I read I am not the only one. Strange that we have not seen pictures yet
Tom
Just to clear up a few details. The rifle was not mine. I didn't take pix of it, and the truck also was not mine(follows that since it wasn't mine it would not be loaded into my truck), and the person who narrowly missed being skewered by the air tube wasn't me.
I will make sure that y'all get to see pix of what ever remains( air tube is still missing ). As far as bashing Mike goes, that shouldn't happen either; it( bashing ) is a far different thing than reporting details of a failure.
cheers,
Douglas
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At this time all of the information concerning the failure needs to be gathered before an intelligent conclusion can be reached . Please lets not speculate about what has happened. Lets wait for all the information to be gathered
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Not for nothing but, reporting details of a failure should include all details. If not, people are left to draw their own conclusions and innocent people can suffer. I too am glad that nobody got hurt..... yet. It's quite possible that all the fallout has not hit the ground. I'm greatful for this warning but I will continue to use my 3 FD-PCP guns as I have until I see evidence of no human error. I'm constantly checking my guns for things loosening up... including the air tube. I believe Mike would not put the gun out there if he thought the was any danger beyond reason. His knowledge and abilities are time tested. I am the one I don't trust. As for buying American.... I think it might be difficult to find a gun today that is 100% forged, stamped, smelted, rolled, molded, shaped, threaded, honed and assembled in America. BTW... I've seen some pretty shady products produced in America.
Again.. thanks for this warning. I will think about it every time I shoot my FD-PCPs.
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Glad everyone is okay. Also glad the truck is okay. You could have had a flying dragon shaped hole in your truck.
I look forward to resolution.
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Yes! TBTG Douglas and his neighbor are OK.
PICS of what's left, please!
Rod
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I would be nice to hear from the owner of the gun. There are now some pictures of the gun over on the Yellow forum.
Nathan
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I will say to everyone, do not jump to conclusion or start throwing anyone under the bus. There are MANY variables that can come into play here so let's see if the evidence can be presented, examined and the failure correctly identified.
Apparently, according to pics on another website, the gun was filled with a tank. The possibility also exists that whoever was shooting the gun, was also shooting other PCP's which were likely being filled to 3K, and very easily could have filled the gun with 3K. Don't rule that out.
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I will say to everyone, do not jump to conclusion or start throwing anyone under the bus. There are MANY variables that can come into play here so let's see if the evidence can be presented, examined and the failure correctly identified.
Apparently, according to pics on another website, the gun was filled with a tank. The possibility also exists that whoever was shooting the gun, was also shooting other PCP's which were likely being filled to 3K, and very easily could have filled the gun with 3K. Don't rule that out.
Can you attach a link?
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I will say to everyone, do not jump to conclusion or start throwing anyone under the bus. There are MANY variables that can come into play here so let's see if the evidence can be presented, examined and the failure correctly identified.
Apparently, according to pics on another website, the gun was filled with a tank. The possibility also exists that whoever was shooting the gun, was also shooting other PCP's which were likely being filled to 3K, and very easily could have filled the gun with 3K. Don't rule that out.
At this time all of the information concerning the failure needs to be gathered before an intelligent conclusion can be reached . Please lets not speculate about what has happened. Lets wait for all the information to be gathered
If it is manufacturing or user error I do not know, but what I do know it is a scary situation either way. I think safety & caution should be our top concern.
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Can you attach a link?
http://www.network54.com/Forum/79537/thread/1440284787/last-1440350522/Expand+Thread (http://www.network54.com/Forum/79537/thread/1440284787/last-1440350522/Expand+Thread)
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Here's one of the pix put up by critter99 on the YF. The reservoir from this airgun is missing as well.
(http://i941.photobucket.com/albums/ad257/critter99/11903705_882570078445312_2287482977316507828_n_zpsyiec6jc9.jpeg)
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One failure of this kind is already to much.
if I owned one of them guns I would immediately degas it and put it away for good.
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So it looks like so far that two of the testimonies are that the threads on the tube or receiver gave out. Curious to know if Douglas can inspect the threads on the receiver that he originally posted.
I am looking to someones opinion if I should epoxy the tube in and if it would help or solve the problem if it exist. I think the valve can be removed from the rear if need to.
Not trying to bash the airgun. But if trying to be safe is bashing then I apologize.
If anyone has an opinion I would appreciate a personal message on the matter.
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I have received some info from the owner of the gun.... He won the gun a couple years ago at the GTA shoot, and has never used it, so the gun is new, and he has never had it apart.... He took it to Douglas' to shoot a short Chrony string, shot 3 shots, refilled it to 1450 psi and put it in the case and then in the truck and it went bang and the air tube nearly hit his wife in the head as it departed the scene.... The photo I have seen of the inside of the left side of the receiver shows the threads in good shape, but unfortunately the photo of the inside of the right side of the receiver is blurred.... The air tube blew out of the receiver, and has not been found.... There was no stub of it left in the receiver, so we must assume that the threads either stripped or were mismatched with insufficient area to hold against the end force when filled.... Since the tube is 7/8" OD, at 1450 psi the end force is about 870 lbs.... That is all I know for now, if I see any more photos of the threads in the receiver I will share that information....
Bob
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They are attempting to get in contact with Mike to send the carcass to for examination.
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Here are the photos I have received, published with the permission of the gun owner....
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FD_PCP%201_zpschzzuoy7.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/FD_PCP%201_zpschzzuoy7.jpg.html)
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FD_PCP%202_zpsplevswwz.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/FD_PCP%202_zpsplevswwz.jpg.html)
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FD_PCP%203_zpsynpbzyc9.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/FD_PCP%203_zpsynpbzyc9.jpg.html)
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FD_PCP%204_zpseefbxyhz.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/FD_PCP%204_zpseefbxyhz.jpg.html)
He will take more photos of the right inside of the receiver and forward them.... He says that running his fingernail over the threads that part of them seems to be missing....
Bob
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Yikes. What causes that?
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One would have to assume that either the threads inside the receiver were oversize.... or (and/or) the threads on the tube were undersize.... so that there was insufficient material in shear to withstand the end force.... If someone else has a better explanation, I would like to hear it....
Again, no blame here, just working logically with the evidence presented so far....
Bob
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At this point, I'd pay to see a quality tap run into the receiver, and the fit checked. It's SOP here.
Given what is left inside the receiver, I wouldn't be surprised if both factors are involved here.
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Could it have been a cross thread issue?
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The valve in mine is flat across not countersunk like that. David
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Could it have been a cross thread issue?
Unlikely, since the gun was never apart.... and if it was, you should be able to see evidence of that in the good photos....
Bob
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Here is a picture of my valve One or the other was modified You all can be the judge
Tom
ps. I did not do anything to mine
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You are assuming that all the FD-PCPs produced were made exactly the same way.... something only the manufacturer knows for sure....
Bob
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Is there some of the threads from the tube still in the housing in that first close up pic?
They may have cracked right at the beginning and uncoiled right out of the housing. If the tube is found with a coil of metal on the end of it then that's where the weak point was.
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You see the pics the way I received them.... The description from the owner is that there was NO part of the tube inside the case, just the seal.... no threads, no tube, nothing....
Bob
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I am not assuming anything I am just presenting evidence before someone comes to the wrong conclusion
Tom
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The missing peice holds the truth. Key player here.
Near miss has stirred the pcp world up and for a good reason. SAFETY🚨ALERT🚀
Just glad no one was hurt. I know the parties involved are still rattled and for a good reason.
FANG
JUNKYARD AIRGUN'S
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Very scary situation,most important thing is everyone's ok! This rifle has been modified from CO2 to use compressed air?hmmm Wonder what exactly is modified?
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I have 2 and they will be getting bored thru and the valve secured to the tube, before they are used again. 2024 or 4130.
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I've seen thread failure like this before, and it's an over/under size and thread, and failure (breakage) starts in a very small section of the threads.
If you follow the logic you would think that maybe the over/undersize of the thread would cause a leak, but the pressure is too high, sealing it, until it fails.
It's not any fun or to be taken lightly, a complete tube failure like that could have caused severe damage. Very fortunate that no one got hurt, like everyone else, data is key to figure out the root cause.
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Could it have been a cross thread issue?
It could definitely contribute to that type of failure, but I am having difficulty imagining that... but definitely can cause the threads to loose!
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I am looking for a XS60 receiver that I can use for a jig. If anyone now wants to dump one let me know. If you want to saw the top only so it won't fire I am fine with that also.
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As more details unfold, (albeit very slowly). That was a very close call (wife & tube flying past her). Scary scary stuff.
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I will say to everyone, do not jump to conclusion or start throwing anyone under the bus. There are MANY variables that can come into play here so let's see if the evidence can be presented, examined and the failure correctly identified.
Apparently, according to pics on another website, the gun was filled with a tank. The possibility also exists that whoever was shooting the gun, was also shooting other PCP's which were likely being filled to 3K, and very easily could have filled the gun with 3K. Don't rule that out.
This is a very serious point and not one to be dismissed.
I'll also say, Bob's great help providing pics and suggestions really does make things tougher to call. Personally, I feel the threads we CAN see look pretty decent for a pressure failure where you would expect much more thread damage. Albeit, we can't see much of the other side of the tube wall, but what I CAN see doesn't look a lot like multiple threads ripping past each-other. I would expect a lot more thread damage, particularly flattening and material removal of the thread peaks where shearing would take place. As it stands, those threads look nearly undamaged.
I'd also question the ability of the rifle to hold pressure in the first place if the threads were so ill fitting as to allow catastrophic failure without significant thread damage.
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I am looking for a XS60 receiver that I can use for a jig. If anyone now wants to dump one let me know. If you want to saw the top only so it won't fire I am fine with that also.
So, what's the plan?
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PMed.
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The bottle had to be put on at some point. Could the bottle have been cross threaded during the build? I suppose there are several possibilities, however, there has to be a solution. Hopefully this is an isolated incident and no one will be hurt. Regardless, the solution needs to be found and if it's a design issue, certainly fixed. If this all comes down to one act of carelessness on the behalf of one person, hopefully that person is no longer working on air guns or has anything to do with them whatsoever.
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I dunno I may be biased some but I call BS.
So the dude filled it to EXACTLY 1450 right before... Sure. Nobody ever says they fill their gun to 1450 unless they want YOU to know "dang" sure they didn't 'overfill' it. All we know is that this happened in the summer in some guy's vehicle while it was banging around in one of those thin fabric cases.
You see that damage and you've all seen what 1500 psi is capable of. Could that have been caused by 1500 psi? It's certainly possible but I don't think its probable.
I'm willing to accept all the hate and discontent that this will generate but please understand that there is more going on here just based on the descriptions.
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It had to have blown straight out without deforming the tube, which kind of leads you to think the thread engagement too shallow to hold pressure.
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I dunno I may be biased some but I call BS.
So the dude filled it to EXACTLY 1450 right before... Sure. Nobody ever says they fill their gun to 1450 unless they want YOU to know "dang" sure they didn't 'overfill' it. All we know is that this happened in the summer in some guy's vehicle while it was banging around in one of those thin fabric cases.
You see that damage and you've all seen what 1500 psi is capable of. Could that have been caused by 1500 psi? It's certainly possible but I don't think its probable.
I'm willing to accept all the hate and discontent that this will generate but please understand that there is more going on here just based on the descriptions.
Really, who doesn't know what psi fill they JUST used. ::) If you do a little reading on the forum, there are quite a few guys that fill these to 2kpsi., which by the way, I would hope this would make them reconsider.
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I have received some info from the owner of the gun.... He won the gun a couple years ago at the GTA shoot, and has never used it, so the gun is new, and he has never had it apart.... He took it to Douglas' to shoot a short Chrony string, shot 3 shots, refilled it to 1450 psi and put it in the case and then in the truck and it went bang and the air tube nearly hit his wife in the head as it departed the scene....
I understand the owner would not want to be the one at fault for say overfiling, but the above just does not make total sense to me.
Who takes a gun they have never used, loads it into the car, along with the wife, and drives to a neighbors house to shoot the gun just 3 times (unless something happened to it)? And then fill the gun, to 1450psi (which I'm sure would have taken just a blip of air, right? Would 3 shots have even taken the pressure down 100psi), and drive back home? Not me. I mean why just 3 shots?
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The thread depth an XS-60c / FD-PCP is over 3/4".... Even in soft aluminum, a third of that depth should be overkill for strength.... If the threads were engaged to full thread form height, and since the aluminum isn't as strong as the steel, if the tube pulled out you would expect the threads in the receiver to be missing / torn / severely damaged.... We will have to await better pics of the right inside to determine that.... Finding the tube would tell us exactly what happened, I sure hope that occurs....
Soooooooooooooo.... here come all the conspiracy theories.... and the end of this thread, for it will shortly be locked or end up in the Non-Productive Gate.... ::)
Bob
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Dave and DEz have both said they want to hold off on any final word until all the facts are in. All I ask as one of the Moderators for the PCP Gate is to not rush to judgement on either case, Mike M at Flying Dragons has stated to DEz that he wants to know what caused the failure more than anyone. Please refrain from speculation or blame placing and lets let the facts speak for themselves :-X
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I really will plead that folks refrain from all of the conspiracy theory stuff. All attempts are being made by all parties concerned to find out EXACTLY what happened in this case. This thread will NOT find it's way to the NP Gate or deleted. It is needed information and serves as a reminder to all that play with HPA to never get complacent. Use care at ALL times!!!!
Anything can happen to ANY airgun, there is always a possibility of something unusual happening, as in this case. Please keep the conjecture out of this thread and let's stick to the KNOWN facts. As the airgun gets closer examination by Mike, we will hopefully get an answer.
This thread will stay intact and may even become a sticky if necessary. We take safety issues seriously!!!!
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Did anyone else notice the barrel band did not even move?
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Yes...several including Mike. Again, he needs the reservoir if possible to see EXACTLY how to reconstruct the events.
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Dave and DEz have both said they want to hold off on any final word until all the facts are in. All I ask as one of the Moderators for the PCP Gate is to not rush to judgement on either case, Mike M at Flying Dragons has stated to DEz that he wants to know what caused the failure more than anyone. Please refrain from speculation or blame placing and lets let the facts speak for themselves :-X
I agree. Locking this thread would be a huge diservice to those of us who own these guns, and there are quite a few of us. I would hope that we can all act as the grown men and women that we are and let the facts tell the story. Especially those that don't own the guns.
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The thread depth an XS-60c / FD-PCP is over 3/4".... Even in soft aluminum, a third of that depth should be overkill for strength.... If the threads were engaged to full thread form height, and since the aluminum isn't as strong as the steel, if the tube pulled out you would expect the threads in the receiver to be missing / torn / severely damaged.... We will have to await better pics of the right inside to determine that.... Finding the tube would tell us exactly what happened, I sure hope that occurs....
Soooooooooooooo.... here come all the conspiracy theories.... and the end of this thread, for it will shortly be locked or end up in the Non-Productive Gate.... ::)
Bob
My thoughts exactly Bob. Even without full engagement, I would think there would be very clear thread damage. The barrel band remaining intact is certainly weird. I too would love to have that tube found and some good close ups of the both the tube threads and receiver threads posted.
I am beginning to wonder if that tube was fully engaged within the receiver. It LOOKS like it would have to have been threaded on only a quarter of the way at the most to come out like that. Right now, that's the only way I can see a tube blowing out this way without damaging the threads.
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I have been extremely careful to try and present only the facts that have been given to me, and to try and analyze those logically to the best of my ability.... If indeed the threads did pull apart, it would have been about the least likely mode of failure that could be expected.... I only have a sample of one to base my opinions on (my son's FD-PCP), and although the threads are a bit loose, I have every confidence this would not happen to it.... However, there are reports of much looser samples circulating, even in the XS-60c which the FD-PCP is based on.... That may be part of the story, I hope we eventually get to the bottom of it....
Calculations of thread strength are based on the assumption of a proper overlap and fit between the male and female parts.... This insures a shear plane of very nearly 50% of the material threaded together.... The shear plane is the pitch diameter (roughly the mid-point between inner and outer diameters) times PI, times the length of thread engagement, divided by two, because half the area in shear is in each part, male and female.... The weaker material in shear should fail first, in this case the aluminum receiver instead of the steel tube.... It the threads are not fully engaged, because the female threads are cut too deep (too large an ID), or the thread on the tube too deep (too small an OD), or both, then only the tops of the triangular threads are touching instead of the full face of the thread.... Think of a pyramid, with an inverted pyramid pressing to the side of it.... Now slide the inverted pyramid up, and draw a line through the mid point of the overlap.... The area providing the strength is reduced.... Since the strength of the material is the area in shear times the shear strength of the material, it is now weaker.... Eventually, the weaker material will fail....
Explaining this failure (and assuming the threads pulling out is what we are dealing with, still undetermined but it seems likely) is difficult.... It is possible that the tube was only threaded in a thread or two, although you would expect to see the last thread in the receiver missing in that case.... However, considering that the seal between the tube and the receiver is located 3/4" inside the receiver, where the end of the tube compresses a square-section O-ring against a shoulder, it would be very difficult to get it to seal at all if the tube were only threaded in a turn or two.... The air should have literally poured out nearly as fast as you put it in.... I would point out that even a few threads, properly engaged, should be plently for strength.... even with a soft aluminum receiver.... Finding the missing tube would certainly help a lot....
Bob
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WHich is why I simply can't get an understanding of this failure. If not in fully, no decent seal. If in fully, thread damage should be very obvious...
???
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So the tube left in one piece (nothing remains in the breech) Finding the tube will reveal details, however you would expect the threads on the steel counterpart to have even less damage than the receiver (aluminum) being the weaker part.
I have seen separation of two parts where there was barely any damage to the threads on both parts (pressure was in the 1200psi realm). I was shocked to find no sheared threads, and could only conclude that the outside part expanded to the point of letting go of the inserted part.
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... Since the tube is 7/8" OD, at 1450 psi the end force is about 870 lbs.... That is all I know for now, if I see any more photos of the threads in the receiver I will share that information....
Bob
Bob,
Based on the shape of the tube, the approx weight of the tube and using the 870lbs of force can you "estimate" the max distance the tube could have flown giving an "optimum" angle and discounting the unknown resistance of tearing thru the gun case?
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Even very experienced people can make mistakes when filling.....so you can never really rule out that sort of thing. I saw a very experienced shooter dump 4500psi into one of my guns. He was borrowing someones tank because his was too low. It had a fill setup that he wasn't used to. It can happen.
I'm editing this to say that I'm not suggesting that this may have been the case.....just mentioning it.
Mike
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... Since the tube is 7/8" OD, at 1450 psi the end force is about 870 lbs.... That is all I know for now, if I see any more photos of the threads in the receiver I will share that information....
Bob
Bob,
Based on the shape of the tube, the approx weight of the tube and using the 870lbs of force can you "estimate" the max distance the tube could have flown giving an "optimum" angle and discounting the unknown resistance of tearing thru the gun case?
I don't think so...but I will invite any and all ov youse out to look. As has been mentined, finding it will be very useful, and the downrange cone is poorly defined, and very large in area. Some of it underwater( SCUBA folks welcome, and we won't drain your tanks for filling PCP's either ). the tube is also stick-sized, and not coloured to stand out....though I doubt we'd find it even if it were orange.
cheers,
Douglas
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Based on the mass and force, (and assuming the threads parted/failed) the tube was subjected to an initial acceleration of over 1000 g.... :o
Bob
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Maybe someone should (if they haven't already) plan out a methodical search grid of the area using at least one metal detector. The tube could be obscured by vegetation and you could possibly walk right past it more than once. I don't know how much effort the owner of the gun is willing to put into finding the tube to help (possibly) identify the cause of the failure... or if this will be just another in a long line of unsolved mysteries, generating a fair share of opinions, suggestions and even a few conspiracy theories.......
Nathan
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Thanks Douglas. I know you guys are trying your best to recover the tube!!!
Since you must know the approximate flight direction, since it came very close to Nancy, that you have an area of probability to search. any chance it is lodged in nearby tree? I have had launched items settle in a tree before which made it hard to find. And the water also makes for interesting recovery. Maybe someone close with a waterproof metal detector.
Please keep us informed and pass along to Nancy and David that we are VERY thankful no one was injured!!!!!
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Thru all of this it is important that we do say how happy no one was hurt. This should be an example to all that we need to be very careful of all we do in life
Dave and Nancy I wish you the good health you deserve
Tom
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I dunno I may be biased some but I call BS.
So the dude filled it to EXACTLY 1450 right before... Sure. Nobody ever says they fill their gun to 1450 unless they want YOU to know "dang" sure they didn't 'overfill' it. All we know is that this happened in the summer in some guy's vehicle while it was banging around in one of those thin fabric cases.
You see that damage and you've all seen what 1500 psi is capable of. Could that have been caused by 1500 psi? It's certainly possible but I don't think its probable.
I'm willing to accept all the hate and discontent that this will generate but please understand that there is more going on here just based on the descriptions.
If I fill my disco to 2k psi she shoots under 500 fps in 22 cal .. at 1950 PSI she shoots at 800 fps, so I know what I fill mine to and generally stop where 1975 would be on the tank gauge (which happens to align with the aftermarket gauge on my disco).
I imagine quite a few GTA members know what they fill to for best performance and it isn't 3k psi in a 3k psi gun in quite a few cases.
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I imagine quite a few GTA members know what they fill to for best performance and it isn't 3k psi in a 3k psi gun in quite a few cases.
Quite so, the .30 pellet Marauder I have in hand now loves a 2000 psi fill. This with a 3k6 psi bottle. Its huge valve lets it shoot efficiently( at 950 fps ) at very low pressure.
cheers,
Douglas
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Thought much about ALL of the details. I failed to mention that the tube, depending on the soil, did a submarine dive and is barried? Many posiblities.
I will not point or assume any fault.
This is ROOT CAUSE investigation only.
I will say this from an Inspector of metal materials, pressure piping and vessels?
All things given, no different than when you buy a new PCP that is factory tested, or you have your fill tank certed?
The test and paperwork are only good for that test. After inspection and it leaves the inspectors eyes it becomes another thing.
All factors of miss use, damaged l, material defect and all other things come to Play.
In theory ever time you fill your gun or tank, you are conducting a self performed test but the below the standard which the manufactures used.
My testing for the most is 1 1/2 times the max operating service.
Test for a 3000 psi bottle advertised operations would be 4500 psi testing set point.
You can do the math. I have no clue to the standard testing of the pcp tube or bottles. But I have seen videos of testing and they used water pressured. The end of the tube let go and all stored energy was released as a cut in a pressured water hose. Not like an air hose being cut.
The safest medium for testing without catastrophic damage is just water no heat.
Pneumatic testing can result in a slight leak found by a leak test using a solution applied to the area. I call it a bubble 0 test. As a leak in a tire is found. Or as this indication a sudden release of stored energy. Most times catastrophic.
Jmo and hope made some Since and shed some light on this topic.
I'LL GO HOME NOW.💀
FANG
JUNKYARD AIRGUN'S
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After reading this I am glad I AS AN INSPECTOR that name is not on the paper work and all test data was recorded as Material data sheets and much more is in hand.
Because if and when the findings ever surface, that Inspector will be under fire! This could get really bad.
But the best thing about this case,no life was taken. No one injuried or property damage.
FANG
JUNKYARD AIRGUN'S
HOME bound!!✌
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I have been extremely careful to try and present only the facts that have been given to me, and to try and analyze those logically to the best of my ability.... If indeed the threads did pull apart, it would have been about the least likely mode of failure that could be expected.... I only have a sample of one to base my opinions on (my son's FD-PCP), and although the threads are a bit loose, I have every confidence this would not happen to it.... However, there are reports of much looser samples circulating, even in the XS-60c which the FD-PCP is based on.... That may be part of the story, I hope we eventually get to the bottom of it....
Calculations of thread strength are based on the assumption of a proper overlap and fit between the male and female parts.... This insures a shear plane of very nearly 50% of the material threaded together.... The shear plane is the pitch diameter (roughly the mid-point between inner and outer diameters) times PI, times the length of thread engagement, divided by two, because half the area in shear is in each part, male and female.... The weaker material in shear should fail first, in this case the aluminum receiver instead of the steel tube.... It the threads are not fully engaged, because the female threads are cut too deep (too large an ID), or the thread on the tube too deep (too small an OD), or both, then only the tops of the triangular threads are touching instead of the full face of the thread.... Think of a pyramid, with an inverted pyramid pressing to the side of it.... Now slide the inverted pyramid up, and draw a line through the mid point of the overlap.... The area providing the strength is reduced.... Since the strength of the material is the area in shear times the shear strength of the material, it is now weaker.... Eventually, the weaker material will fail....
Explaining this failure (and assuming the threads pulling out is what we are dealing with, still undetermined but it seems likely) is difficult.... It is possible that the tube was only threaded in a thread or two, although you would expect to see the last thread in the receiver missing in that case.... However, considering that the seal between the tube and the receiver is located 3/4" inside the receiver, where the end of the tube compresses a square-section O-ring against a shoulder, it would be very difficult to get it to seal at all if the tube were only threaded in a turn or two.... The air should have literally poured out nearly as fast as you put it in.... I would point out that even a few threads, properly engaged, should be plently for strength.... even with a soft aluminum receiver.... Finding the missing tube would certainly help a lot....
Bob
IIRC someone did post that there their tube would leak even after tighten it down into the receiver. I am trying to picture this in my head. If the installer felt there was enough torgue used after screwing the tube in and it still leaked. If having thread that were loose still cause a leak. I am sure there may be other reasons for a leak (bad or dirty seal etc.) but if not can loose fitting threads be a reason for a leak?
I am not making any conclusions on what happened but just asking for my personal info. All I know if Douglas said it happened it happened and trying see what signs or alarms that I should look for personally.
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Who takes a gun they have never used, loads it into the car, along with the wife, and drives to a neighbors house to shoot the gun just 3 times (unless something happened to it)? And then fill the gun, to 1450psi (which I'm sure would have taken just a blip of air, right? Would 3 shots have even taken the pressure down 100psi), and drive back home? Not me. I mean why just 3 shots?
There are lots of folks who pursue this hobby/obsession differently. That rifle got handed to me to play with, and never even left the case. Just couldn't bring myself to look at it. As mentioned this gun was a prize at the GTA fun shoot raffle some years back. A large pile of tickets was bought with the primary purpose of supporting the GTA. So the result was Dave got this rifle, and a pile of other prizes, such was his ticket buy qty...:)
The goal as I understand it was to gather a rough idea of what it shoots in order to sell it. I would not need more than 2 shots to do that...:)
cheers,
Douglas
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Leaks between the tube and receiver are relatively commonplace, I have one that I have been unable to stop leaking.... It is not the threads that seal, but a square-sectioned seal, inboard of the threads, between the end of the tube and a shoulder in the receiver.... Whether it leaked or not really has NOTHING to do with this failure, however, as air that leaks out slowly cannot then create a force to propel the tube as apparently happened in this case....
Bob
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Just a reminder, we don't attack our members and question their integrity on the GTA. Let's keep our focus on the facts presented not speculate on what isn't. Safety and safe practices are the number one concern for all our members; please keep this thread on track!
Reminder:
13- Personal attacks on individual airgunners, dealers, tuners or other airgun forums are strictly forbidden. If you have issues with them, then they should be addressed one on one. Do not create a “war zone” on your forum. Take your issues up directly with them and do not launder them here on the GTA forums.
tom
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The goal as I understand it was to gather a rough idea of what it shoots in order to sell it. I would not need more than 2 shots to do that...:)
cheers,
Douglas
Now this makes even less sense. If I'm selling a gun (with an expected shot string between 15-30 pellets) would I want to shoot 3 times to get the velocity? or 30 times to get a string? I mean why take 3 shots if you could spend another 5 minutes and get a shot string?
If I'm buying and seller says it does "x" fps, and when I ask how many shots he doesn't know, that throws up a flag.
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The total ejection of the tube surprises me. Not sure how that happened. IF that exposed thread had let go, then I'd have expected the rear threaded portion of the tube to still be in the receiver. It's not, seems like the tube was totally ejected like a harpoon.
Didn't totally screw the threads in the receiver and I'd suspect that Al. receiver would have shown some cracking/swelling to let the tube go that cleanly if the tube's threads were fully seating.
So best guess is that the missing tube was at fault.
Just a couple of odd thoughts:
Over pressure seems easier with tank filling; have to be real inattentive to over fill with a pump. Not saying it is definitely what happened, just the waiting potential of 3K (or 4.5K) pressure with just a turn of a knob is more likely to over fill.
The fill caps are often on so tight that taking them off or on turns the tube.
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IMO some are getting pretty close here to calling other GTA members liars.... and down,down,down the rabbit hole we go, Alice....
If one were a conspiracy theorist, it might make one wonder if the goal is to get the thread locked or pushed into the Non-Productive Gate.... How about one more plea for people to stick to the FACTS as they have been presented.... unless you have other FACTS that dispute them?.... Would that be too much to ask?....
Bob
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IMO some are getting pretty close here to calling other GTA members liars....
I don't see that as the gun owner has not even posted, has he? Seems like everything is hearsay to this point
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The gun owner is no longer a member here but that is not the point at all. I made a plea above (see reply #69) and I advise everyone to take a moment and reread.
This thread will NOT go away. It's not the kind of subject we enjoy seeing but it has a purpose and will remain. Now, if I HAVE to lock it to prevent it from being polluted any further, I will do that. And I'll review every request for post and allow only pertinent information be added. Please let's work as a concerned community and not force us to take such actions.
This thread is needed and we should see it to the end for the entire airgun communities good.
This is a very serious subject but we have to handle it appropriately and not with an angry mob mentality.
Thank you for understanding!!!!
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And if you take the time to really read this entire thread, you would discover that this is not hearsay. The event actually took place at the home of this thread OP's home. All they were interested in is shooting this airgun to see if it shot in the advertised power range before offering it up for sale. And they needed to make certain since they had never shot it in the two years of it being a closet queen.
Yes, they could have spent a hour or so doing a string or two as well as checking accuracy. But I understand he just wanted to move out an airgun he had no use for.
Enough said about that, so let's please stick to the facts and getting to the bottom of this failure.
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And if you take the time to really read this entire thread, you would discover that this is not hearsay. The event actually took place at the home of this thread OP's home. All they were interested in is shooting this airgun to see if it shot in the advertised power range before offering it up for sale. And they needed to make certain since they had never shot it in the two years of it being a closet queen.
Yes, they could have spent a hour or so doing a string or two as well as checking accuracy. But I understand he just wanted to move out an airgun he had no use for.
Enough said about that, so let's please stick to the facts and getting to the bottom of this failure.
I DID read the entire thread, and since you use the same word (hearsay) as I did I would presume you are talking to me. I know it's not a good idea to tell a moderator that he is wrong but the below quote coming from Douglas is HEARSAY
The goal as I understand it was to gather a rough idea of what it shoots in order to sell it. I would not need more than 2 shots to do that...:)
cheers,
Douglas
an hour to shoot a string? For velocity #'s? on a MAX 30 shots per fill gun? Come on, 2 minutes per shot? not even with one of KO's pumpers.
With a single shot PCP would take 10 seconds max to shoot, write number and then reload.
If you want to find out the answer, but then do not question anything that is said, how do you know it's the truth? Ever see a trial where the defense does not get to cross examine the witnesses?
Unless the OP actually filled the gun then the "fact" presented that it was filled to 1450psi is also HEARSAY.
The fact that the gun had NEVER BEFORE BEEN SHOT, unless in the possession of the OP, is also HEARSAY.
please remember that the job of a Moderator is to "Moderate", not take sides
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This is an excellent thread, and hopefully a positive one. Facts and conclusions can't be that far off.
Despite all of the excitement, if it works out that mods or new operating procedures are recommended by Mike, rsterne or any or our other experts, it will be easy to comply and move on.
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looking up the history of the XS60 PCP rifles i come to only this instance of catastrophic failure. There are literally hundreds of this guns in our hands (i still have mine) and have not had anything similar happen. is it possible that we are jumping the gun by feeding this panic? i mean, there is gotta be instances of other rifles (costing a lot more) that have failed similarly, but i dont see a witch hunt started for that... is it because it is a 100$ gun? that does mean that obviously it has to be weak?. I have filled mine to 2k and now im back to 1550 psi, and it still just as solid as when it got to me. I dont think filling to 1450 would have cause that, but i also dont think that it was overfilled to bursting pressure (as it was shot 3 times before it was put away) and if it would have been filled way too much valve lock would have forbidden any shooting through the chrony. the story seems to hold as much water as a seive... something is missing...
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The bottom line is that we don't have all the information. Until the remains are inspected by Mike or someone with the experience to do so, we will only have what we have been told. Additionally, the tube is missing, which unless found will cause further difficulty in determining the definite cause. At this point, all we are doing is engaging in guesswork and conjecture and to go any further would be foolish. There are several possibilities, and perhaps possibilities we have yet to think of. Until all the information is available and the gun inspected, I would suggest we refrain from attempting any conclusions.
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Let me add this simple fact to those who are convinced that an overfill to 3,000 or even 4,500 psi would be fatal to the average PCP.... The Disco has a recommended fill pressure of 2,000 psi.... The first part to fail, and this has been tested, is the valve retaining screws, at about 7,000 psi.... The tube is good for over 10,000 psi.... IMO, no single fill from a 4500 psi tank should cause a PCP rated at 1,500 psi, or for that matter a gun designed to work on CO2 (which can reach 1900 psi at 120*F) to fail in a catastrophic manner.... Does this mean you can overfill a PCP with impunity, of course not.... You will be driving the gun past the point where metal fatigue becomes a problem, and doing so repeatedly is asking to receive the Darwin award.... However, if the gun is designed with the usual 3:1 safety margin, even a ham-fisted fill from a 4,500 psi tank shouldn't cause what happened, IMO....
Is this a one-time incident, or a symptom of a deeper problem, I have NO idea, that's not my responsibility.... I'm just interested in finding out what happened so that hopefully it will never happen again.... If some of you want to argue what pressure the gun was filled to, go right ahead.... but don't try and convince me that an overfill, intentional or otherwise, from the equipment being used (a Joe B setup) is justification for the tube parting company with the gun.... If your attitude about safety is that close to disaster, then please never shoot around me....
Bob
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And if you take the time to really read this entire thread, you would discover that this is not hearsay. The event actually took place at the home of this thread OP's home. All they were interested in is shooting this airgun to see if it shot in the advertised power range before offering it up for sale. And they needed to make certain since they had never shot it in the two years of it being a closet queen.
Yes, they could have spent a hour or so doing a string or two as well as checking accuracy. But I understand he just wanted to move out an airgun he had no use for.
Enough said about that, so let's please stick to the facts and getting to the bottom of this failure.
I DID read the entire thread, and since you use the same word (hearsay) as I did I would presume you are talking to me. I know it's not a good idea to tell a moderator that he is wrong but the below quote coming from Douglas is HEARSAY
The goal as I understand it was to gather a rough idea of what it shoots in order to sell it. I would not need more than 2 shots to do that...:)
cheers,
Douglas
an hour to shoot a string? For velocity #'s? on a MAX 30 shots per fill gun? Come on, 2 minutes per shot? not even with one of KO's pumpers.
With a single shot PCP would take 10 seconds max to shoot, write number and then reload.
If you want to find out the answer, but then do not question anything that is said, how do you know it's the truth? Ever see a trial where the defense does not get to cross examine the witnesses?
Unless the OP actually filled the gun then the "fact" presented that it was filled to 1450psi is also HEARSAY.
The fact that the gun had NEVER BEFORE BEEN SHOT, unless in the possession of the OP, is also HEARSAY.
please remember that the job of a Moderator is to "Moderate", not take sides
Well Rob, you have been here long enough to know what is acceptable and what is not on GTA Forums. And you are correct, it's not a very good idea to tell the Executive Administrator and registered owner of this forum that he is wrong. Especially when I probably have a bit more of the fact and background than most. The event in discussion happened at Douglas' home, so hearsay? How about eye witness.
The airgun was won by David at a GTA event two years ago and was a closet queen since. He won it by supporting GTA and buying massive amounts of raffle tickets. He has no use for a $100 PCP, just look at the arsenal he shoots on a routine basis. So yes, he pulled it out to shoot a couple of rounds across the chrony to make certain it performed before parting with it. Nothing wrong with that.
I may be the Executive Administrator for this forum and have a lot of management duties, as in keeping this thread on track, but I am also a member and have the right to my opinion too.
My opinion is not in this, I am managing it to keep JUST the facts flowing and to reach a conclusion to this incident. And for the final time we will not tolerate anyone polluting this thread with conjecture and argumentative posts. The outcome of this is very important to a lot of folks and to the entire airgun community. And I do appreciate your corporation in keeping this thread on track. I believe I have also made it clear what the alternative actions are for keeping this thread intact.
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"The outcome of this is very important to a lot of folks and to the entire airgun community."
Absolutely.
It has been suggested, on another forum, that this is being covered up (huh??) because of bias. Nothing could be further from the truth.
I submit that if there is a better qualified group to solve this, given the wide base of expertise, here, in every field even remotely connected, it exists on another planet.
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Well, I certainly hope that wherever this is being said has some of our members there to defend our position on this. And I certainly hope that none of that totally wrong information is not being projected by those directly involved in this incident. As you said, nothing can be farther from the truth. GTA, it's staff and the great family members have not let this subject lie dormant since it first came to our attention. I have personally made several calls and sent many messages to help solve this, definitely not coving anything up. The only thing I'd like to cover up is kitty litter over folks that make those kinds of statements.
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Gentlemen this thread has gone farther than any thread of this nature ever has in the history of the GTA and for a purpose. I have read every comment from the start and some of it for the most part is ridiculous, we have conspiracy we have negligence we have people calling others liars and a host of other things just plain wrong. What we want is facts of why this happened reason being for the safety of others that own this gun. Could it happen again?? No persons safety is worth the price of a airgun.
I am asking that the posters please respect others opinions, this thread is a prime example of why we send them to the NP gate. HPA is dangerous and we certainly do care about the well being of others regardless of what some think. After all a tornado can drive a drinking straw through a tree so ponder that for a while. David
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On my 13xxs I bore out the nose of the valve to .4 from .36 and then pump to about 1300-1500 psi, well if not done right it can go off...
I linked to a thread about one such happening when a guy got one side a bit to thin... cant find the link now though.
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There are many different dynamics that were involved in the failure of the rifle and as many of the posts my own included have asked unless you have specific knowledge please refrain from speculation . The administrators have asked for cool heads so in this instance please let the facts speak for themselves and end the foolishness.
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Just replying so I can keep up with this thread. I own two of these rifles and I'm still quite please with both.
Casey
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Hey Casey, not a problem. But for future reference, or for anyone else, all you have to do is look to the right side of the page for the Notify tab. Clicking on that for any thread will notify you when there is an update. A bit easier than having to post to follow a thread.
:)
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That is precisely why caution is warranted. To date, we have a single failure, with no conclusive reason.
GTA puts safety first, so you can be assured as soon as more information is available, it will be produced.
Till then, without any clear indications of definite issues, I personally, and not on behalf of GTA, would recommend you simply maintain normal vigilance and attention to safety when using your FDPCP.
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Ok, I am going to fail my own advice in this reply. How about the admin's delete the superfluous entries not pertaining to facts from the involved parties.
Edit: Ezman604, I get that, no problem.
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I'll give you one reason why I'll not edit this thread. We have already been accused of covering up this incident. I can't for the life of me understand anyone saying that? My gosh, we're up to 6 pages of discussion already and NO posts have been removed. I want it to stay intact but ON POINT so the detractors and the rest of the airgun community can see those statements made elsewhere are pure BUNK!!!
I. and other staff, have pleaded and warned folks to keep the junk out and leave this very important thread to facts and results.
Thanks all for your cooperation!!!
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Still no tube recovery. My neighbor cut the grass and did not find it with the mower, and given my description of the event is curious too, to the point of going out to look himself. I hope one of us finds it. Further discussion with Dave points toward the rifle not being at a high angle of elevation...but with Bob's calculation of 1k g's that thing would have been going trans-sonic with only a third of a second worth of thrust.
cheers,
Douglas
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Taking into consideration the dampness/dryness and the composition of the ground, it may very well have buried itself nearby. A metal detector would certainly help if you haven't tried that already.
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Taking into consideration the dampness/dryness and the composition of the ground, it may very well have buried itself nearby. A metal detector would certainly help if you haven't tried that already.
No metal detector. it is possible, but IMO unlikely to have burried itself w/no visible disturbance. If it is in the woods, swinging a metal detector will be problematic.
Douglas
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You'll find it some day....probably in the fall, in that time frame between the leaves/plants dieing off and snow covering the ground (unless you live where there is no real fall/winter). Didn't evaporate, so you'll find it when least expected and looking for something else.
Only one reported failure, but it's an important failure even if it a one-off. Lot of these in use, often with new-to-PCP shooters, so it's worth investigation.
Don't find anything wrong with supposition, it's probably healthy to think of ways any PCP could fail. We tend to get use to the idea of high pressure air and lose some caution though familiarity.
Think I'll go fill my 1st generation and give her a work out.
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Hi just a thought
What are the odds that the air tube landed on the roof of the house and rolled into a gutter?
Had it happen when I was a kid with a water rocket.
Just an idea
Dave
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Still no tube recovery. My neighbor cut the grass and did not find it with the mower, and given my description of the event is curious too, to the point of going out to look himself. I hope one of us finds it. Further discussion with Dave points toward the rifle not being at a high angle of elevation...but with Bob's calculation of 1k g's that thing would have been going trans-sonic with only a third of a second worth of thrust.
cheers,
Douglas
I too think it could be buried. Were you near any buildings such that the tube could be on a roof?
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Really do like my FDPCP (xs 60c) and do use it more often than most of the expensive toys.
(http://i157.photobucket.com/albums/t50/ribbonstone/XS%2060C/409c2fff-840f-4064-90b9-b5798a971809.jpg) (http://s157.photobucket.com/user/ribbonstone/media/XS%2060C/409c2fff-840f-4064-90b9-b5798a971809.jpg.html)
There are reasons for that.
1. Shoots 20 “good” shots per fill (about 1500 – 900/850psi). Energy is between 18 and 19 foot pounds per shot (depending on pellet weight, with heavier earning more than lighter).
2. Shoots cheap tinned 14.3gr. Crosman pellets well (which are not only chap, but locally available).
3. Running pretty efficiently and with the home-brew LDC, it is very quiet.
4. Accuracy has been quite good. Not “match” good, but much better than the price would lead you to believe.
5. Been a bit over a year and the Chinese pump still works fine. Call it 23-24 pump strokes to fill it back up to 1500psi (and 2-3 of them just go to pressurizing the hose before the tube starts filling).
Mods?
1. Striker adjustment backed out to “zero” in order to run well on a 1500psi fill.
2. A barrel/tube spacer ahead of the barrel band to keep the barrel from touching the end cap.
(http://i157.photobucket.com/albums/t50/ribbonstone/XS%2060C/6039b0d6-1da4-45a9-97c1-1e3bba9e80c9.jpg) (http://s157.photobucket.com/user/ribbonstone/media/XS%2060C/6039b0d6-1da4-45a9-97c1-1e3bba9e80c9.jpg.html)
3. LDC
4. Transfer port on the barrel slightly reduced in order to slow it down/extend 4% shot count to 20 shots.
Tested it today with 3 fills/ 20 shots per fill.
(http://i157.photobucket.com/albums/t50/ribbonstone/XS%2060C/36374ba1-66d8-4b5d-8677-55d9d7c8e845.jpg) (http://s157.photobucket.com/user/ribbonstone/media/XS%2060C/36374ba1-66d8-4b5d-8677-55d9d7c8e845.jpg.html)
Shot 20 little (about ¼”) circles once each (and missed one). Not sure what I did for the miss, but the odd shape of the hole indicates a tumble. I might have managed to load that pellet backwards (honestly, with the scope mounted that low, that kind of thing can happen).
Shot the same circles 5 shots each (4 5-shot groups)
Shot the same circles 20 times each (2 10-shot groups
So out of 60 shots at 20yards, can consider just 1 miss out of 60 shots. This will certainly do the job .
Now if the blown-off-tube shows a weakness that can be improved, I’m going to improve it (even to the point of a new, ticker walled/less volume) air tube and keep on shooting. It is seems to be a one-off happenstance, then will just take care.
Caution and familiarity are opposing forces. Am comforted that this 1st generation hasn’t had any problems from day one, but if something seems to need improvement, I’ll find a way to improve it.
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Worse case senario... I think I read back in the thread that there was a body of water nearby. That would be tuff to locate and recover.
Whether it be found or not.... whether the root cause is uncovered and proven or not.... this needs to be a wake up to all of us that it can and DID happen. PLEASE BE CAREFUL WITH ANY AIRGUN !!! The less threads I read like this the better.
And once agian... soooo glad nobody was hurt.
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Hi just a thought
What are the odds that the air tube landed on the roof of the house and rolled into a gutter?
Had it happen when I was a kid with a water rocket.
Just an idea
Dave
Oh, was that you? STAY OFF MY LAWN!!! ;)
Shot the same circles 5 shots each (4 5-shot groups)
Shot the same circles 20 times each (2 10-shot groups
So out of 60 shots at 20yards, can consider just 1 miss out of 60 shots. This will certainly do the job .
Excellent shooting there sir! I wouldn't have even guessed they were 5 shot groups unless you pointed it out. Some looked hole in hole.
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Good advice Avator
I am thinking without the tube there is noways to say what happened. My wondering mind was thinking it could be user error. We or I will never know. Being that the FDPCP had no fill pressure gauge could be if filled from a tank user may have miss read the fill pressure. Even the most experienced may make a careless mistake (talking from personal experience). Anyways Happy Shooting JMO :)
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http://www.network54.com/Forum/275684/message/1440511558/MWP+Of+Chinese+PCP%27s (http://www.network54.com/Forum/275684/message/1440511558/MWP+Of+Chinese+PCP%27s) This is well worth reading
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Curious WHY the post wasn't made HERE.
Hmmm.....
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Boy ..............,
I'd sure like to hear Bob (rsterne) thoughts regarding the QB Air Cylinder/Tank Block & Valve Integrity, relative to a 1300/1500 PSI Ninja HPA tank set-point. Yikes ............ :o
Kirk
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JMO, but if you're going to re-post something...at least take a couple minutes to make it moderately more legible. I typically ignore large, rambling "block" posts..kind of doubt I'm alone in that. ;)
Curious about "which" hydrotest standard is 8/5 MWP. 1.5x and 1.3x design are common with vessels and piping systems while paintball, scuba, scba seem to employ a 5/3 standard.
(C&P was deleted due to not getting permission FIRST. We're not in the habit of copy & paste something but editing it also. It's called plagiarism?)
Might I inquire permission from whom? If by editing, you mean "separating paragraphs"...guilty. Left the content of the post intact, including Tims signature. Certainly wasn't claiming Tims thoughts/words as my own. ???
Be that as it may, will let it be.
Al
https://www.google.ca/search?q=plagarism&rlz=1C1CHWA_enCA599CA599&oq=plagarism&aqs=chrome..69i57l2j69i59j69i65l3.2302j0j8&sourceid=chrome&es_sm=122&ie=UTF-8#q=plagiarism (https://www.google.ca/search?q=plagarism&rlz=1C1CHWA_enCA599CA599&oq=plagarism&aqs=chrome..69i57l2j69i59j69i65l3.2302j0j8&sourceid=chrome&es_sm=122&ie=UTF-8#q=plagiarism)
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Most of the comments are directed at QBs, and my only comment would be that I agree with Tim @ Mac1 that running a CO2 rifle on HPA without a 1.8K burst disc (which limits the pressure to ~1500 psi) isn't a good idea.... unless you rework the weak points to survive a higher pressure.... The standard hydrotest pressure I am familiar with is 5/3rds of the Maximum Safe Working Pressure.... but pressure reservoirs under 2" diameter and 2' long don't require that, so they are typically designed with a MUCH higher safety margin of 3:1 or greater.... One of the reasons for that is metal fatigue, which on steel becomes a concern if the stress is greater than 50% of the yield strength.... That means that if the safety margin is less than 2:1 of the yield strength, fatigue may eventually bite you.... Hence the 3:1 figure, to avoid that.... If a gun has a 1500 psi MSWP, and a 3:1 safety margin, it should not fail until the pressure exceeds 4500 psi, IMO.... As Tim says, if you make a mistake, you should allow for whatever pressure is in the tank to end up in your gun.... without catastrophic failure....
Bob
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I'm wondering if the receiver could have cracked longitudinally allowing the air tube to exit and the receiver threads not to be stripped due to an air cushion while the tube was leaving then snapped shut afterwards. Cracks can be very hard to see it you aren't specifically looking for them. I would suggest the owner try to gently pry the receiver threads open in a few different ways and see if a crack shows up. Something to try. Regards, Tom
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Well my offer still stands as when the rifle first came out. I will throw in a few bucks into a pot to buy and test one of these rifles if any will take the lead. :)
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(C&P was deleted due to not getting permission FIRST. We're not in the habit of copy & paste something but editing it also. It's called plagiarism?)
Might I inquire permission from whom? If by editing, you mean "separating paragraphs"...guilty. Left the content of the post intact, including Tims signature. Certainly wasn't claiming Tims thoughts/words as my own. ???
Be that as it may, will let it be.
Al
https://www.google.ca/search?q=plagarism&rlz=1C1CHWA_enCA599CA599&oq=plagarism&aqs=chrome..69i57l2j69i59j69i65l3.2302j0j8&sourceid=chrome&es_sm=122&ie=UTF-8#q=plagiarism (https://www.google.ca/search?q=plagarism&rlz=1C1CHWA_enCA599CA599&oq=plagarism&aqs=chrome..69i57l2j69i59j69i65l3.2302j0j8&sourceid=chrome&es_sm=122&ie=UTF-8#q=plagiarism)
[/quote]
Hey Al, was not speaking about you. :)
The post was copied and pasted here before getting the authors permission. Was not talking about you doing the C&P. And I would not edit anything in a C&P, even the grammar errors.
Must keep things like that original.
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Just a thought.
We had a 1/2" thick 20" pipeline rupture and fling sections of pipe over 200yrds in three directions that was transporting methane. It was idle at the time and only had 600 psi contained. It was a 2200 psi rated line. After gathering and analyzing the pieces we found , it was determined that a corrosion pit that reached 70% of the thickness was the intitial cause of failure. Since the pipe contained a gas the rupture was many times more violent than one containing liquid. A Chevron pattern pointed to the intial point of failure.
Sooo. What if the gun had moisture in the tube and sat long enough in one place to start the corrosion and when it failed it failed so dramatically that the section of threads were not "pulled free" but instead simply deformed enough to loose contact.
And looking for one piece is why you are not finding multiple pieces instead? We found 13 individual pieces.
Very interesting 7 pages of info here. Just haven't seen this line of thought.
The pieces we found looked like torn paper and it was 1/2" steel.
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:-[ My apologies for the copy and paste of the authors post without his permission I was just attempting to provide further safety information . Unfortunately I engaged my fingers before my brain
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Don, I don't see the problem at all. It is an internet posting in the public domain and you made no claim that it was your original material.
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Interesting thought there ronbeaux. The gun was unused for quite a while.
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Has anyone thought of doing a magniflux on the receiver? The pics that we have seen don't have enough resolution to be nearly as good as in person and in person, a fine crack in the aluminum could be very hard to detect. That same, nearly undetectable crack, could also flex enough to allow escape of components with out much damage to threads. Its a thought although it doesn't seem likely since the gun had no real service. Anyway, at this point, any avenue of discovery is worth while especially since parts are missing. I would imagine, from the view point of the manufacturer, I'd want to have that test done.
Bill
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Thanks Bob for the clarification ;),
Even though he briefly mentioned the 1.8K burst disc in his post, I missed that "it" was the Trump Card for all his (TimmyMac1) QB concerns? His tone was pretty foreboding :P
Whew .................. I was starting to have Other thoughts ;D
Kirk
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Just a thought.
We had a 1/2" thick 20" pipeline rupture and fling sections of pipe over 200yrds in three directions that was transporting methane. It was idle at the time and only had 600 psi contained. It was a 2200 psi rated line. After gathering and analyzing the pieces we found , it was determined that a corrosion pit that reached 70% of the thickness was the intitial cause of failure. Since the pipe contained a gas the rupture was many times more violent than one containing liquid. A Chevron pattern pointed to the intial point of failure.
Sooo. What if the gun had moisture in the tube and sat long enough in one place to start the corrosion and when it failed it failed so dramatically that the section of threads were not "pulled free" but instead simply deformed enough to loose contact.
And looking for one piece is why you are not finding multiple pieces instead? We found 13 individual pieces.
Very interesting 7 pages of info here. Just haven't seen this line of thought.
The pieces we found looked like torn paper and it was 1/2" steel.
Just thinking out loud here, no real experience in this type of work, but wouldn't the fact that it was in a gun case and the hole in the case shows that a single point of exit was made indicate your idea that it fragmented not logical. ps without searching all of this thread, I may have seen the photo of the gun case from the yellow link.
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Ronbeaux may have hit the nail on the head. Nothing like personal experience to provide useful information that can be generalized to another situation. My experience with Crosman parts (A US company that also has some parts made overseas) is that not all parts have the same quality or condition. For example Gas tubes of the same part number come with different color and quality of craftmanship. What is to say that one part could have a flaw that 100,000 parts would not share. EG: A small pinhole rust spot that could grow over time.
And this is really off topic but has filled a lot of the discussion:
As for the discussion on plagerism... might want to include a discussion on liable (falsely accusing someone of something that causes damage to their reputation). As stated by the accused party he did give the source of the quote and is not plagerism. Is it a violation of copyright? Probably not, even though electronic publication is protected by copyright a violation is determined by quantity of material copied and the intent of the copying and the damage to the author. Peace is the answer! 8)
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Borrow a magnetic rake for roofing nail pickup and try that to locate the tube, or a strong magnet on a rope in the water..
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So this is the bottom line for me and correct me if I am wrong or add any thoughts.
This incident did happen but probably will never be solved.
If threading in the tube and tolerances feel adequate (not to much wobble 1/4" in) and the ends are square (no taper). As mentioned through mass production there may be a bad apple in the bunch. So with a little checking of part or parts on hand. I will feel confident on using this rifle as designed under 1500 psi. JMO
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I don't own one of these rifles, so I have "no dog in the fight" as they say. If you feel, after some inspection of your rifle(s) that they're safe to use at a given fill PSI, great. Shoot and enjoy your rifle. Some people may never trust this gun design at any pressure even after an inspection and get rid of them. If they feel that is the safest thing to do, great. Do it.
One gun failed, we know that. One gun out of maybe dozens, hundreds or many more converted so far. There may never be another failure like this or any other type in one of these guns, ever. The missing airtube may never be found and even if it is, they may not be enough information to conclusively determine that cause(s) of the failure.
Each individual is going to have to choose. If they own one or more of these rifles, if they want to continue pressurizing and shooting it/them. If they don't own one, if they want to purchase a new or used model or not.
If someone makes a choice different from yours or what you think they should, so be it. Don't say anything negative about them.
Just my $0.03 (adjusted for inflation) and not directed at any one poster/person.
Nathan
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Has anyone thought of doing a magniflux on the receiver?
Bill
That won't work best I understand how magniflux works .... Part must be Steel, Ferris iron able to be magnetized by current applied which then shows breaks in the magnetic field created along fractures of part edges.
The Iron particles then get attracted to where this field gets broken etc ...
Cast or billet aluminum I don't think can be subjected to a magnetic field and test the same as irons ??
Could be wrong tho ::)
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https://www.pegasusautoracing.com/productdetails.asp?RecID=1207 (https://www.pegasusautoracing.com/productdetails.asp?RecID=1207)
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I have checked iron, aluminum, titanium just about everything on a racing engine, different dust for different type metals. David
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Very interesting, can't wait to see what comes of it, I will be shooting my FDPCP this weekend, only fill to 1500 psi, lets see what happens....
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Just a thought.
We had a 1/2" thick 20" pipeline rupture and fling sections of pipe over 200yrds in three directions that was transporting methane. It was idle at the time and only had 600 psi contained. It was a 2200 psi rated line. After gathering and analyzing the pieces we found , it was determined that a corrosion pit that reached 70% of the thickness was the intitial cause of failure. Since the pipe contained a gas the rupture was many times more violent than one containing liquid. A Chevron pattern pointed to the intial point of failure.
Sooo. What if the gun had moisture in the tube and sat long enough in one place to start the corrosion and when it failed it failed so dramatically that the section of threads were not "pulled free" but instead simply deformed enough to loose contact.
And looking for one piece is why you are not finding multiple pieces instead? We found 13 individual pieces.
Very interesting 7 pages of info here. Just haven't seen this line of thought.
The pieces we found looked like torn paper and it was 1/2" steel.
Just thinking out loud here, no real experience in this type of work, but wouldn't the fact that it was in a gun case and the hole in the case shows that a single point of exit was made indicate your idea that it fragmented not logical. ps without searching all of this thread, I may have seen the photo of the gun case from the yellow link.
The pic I saw here showed tearing of the material inside of the gun case and not a 'clean' exit hole. The case is layed open and there are tears on each side of it and there is not evidense that the zipper still works. It could have ruptured into pieces, tore the inside material, and broke the zipper evenly along the threads. Once the threads of the plastic zipper failed it would just lay open.
Sure would like to see the tube
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It could have ruptured into pieces, tore the inside material, and broke the zipper evenly along the threads. Once the threads of the plastic zipper failed it would just lay open.
If this happened, I wonder how the alum barrel band was apparently untouched? Did the tube just break apart on each side of it?
(http://i941.photobucket.com/albums/ad257/critter99/11903705_882570078445312_2287482977316507828_n_zpsyiec6jc9.jpeg)
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It could have ruptured into pieces, tore the inside material, and broke the zipper evenly along the threads. Once the threads of the plastic zipper failed it would just lay open.
If this happened, I wonder how the alum barrel band was apparently untouched? Did the tube just break apart on each side of it?
(http://i941.photobucket.com/albums/ad257/critter99/11903705_882570078445312_2287482977316507828_n_zpsyiec6jc9.jpeg)
+1 on the barrel band.
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here is 1 image that Bob posted where I cropped, lightened and sharpened the image
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here is 1 image that Bob posted where I cropped, lightened and sharpened the image
(http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=96148.0;attach=133104;image)
So not being able to see the opposite side of threads...what if the tube to receiver threads where on the "loose" side and when the gun was put into the vehicle the tube was "knocked" against something on it's right side? (or if it was sitting still and something else was dropped or shoved against it?) causing the end of the tube to move to the left and "disengaging" the threads we can see. Could the tube then get ejected from the receiver only damaging the threads we can't see?
In this pic the threads we can see do not look "damaged", but some look to have some pieces of "debris" on them.
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Can we get a pic of the other side of the threads?
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Can we get a pic of the other side of the threads?
Didn't realize one had been posted towards beginning of thread, but looks like the other side is in "decent" shape. Hard to tell from the quality of pic (a bit blurry), but it doesn't seem like much of the Alum threads are damaged on either side. I would think it would look quite a bit different if the tube had "scraped" along any of the threads while "exiting".
The receiver separating (expanding) , via a possible crack, seems like the most plausible explanation at this point.
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FD_PCP%204_zpseefbxyhz.jpg)
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I saw that pic but it is not very clear or telling.
Does Grumpy still have the gun or is it on its way to Mike?
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It is obvious that the threads gave out, could have been tube to small/receiver hole too big/ or badly cut threads. That receiver did not crack, it would be obvious if it was, due to as the threads on the tube forced their way out, it would have spread open the breach and a crack would be obviously seen.
I have seen a lot of threads give out on tubing and other types of threaded items, that picture shows the same thing, threads not holding for some reason.
I'm no expert but anyone should be able to look at that and tell what happened and it was not from over filling.
William
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WOW that's the first picture of the stock I've seen. That shows some energy that I didn't have a mental image of before.
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My understanding is that the tube went straight out through the end of the case, and therefore straight out through the barrel band, which is why it wasn't damaged.... The damage to the stock and the sides of the case are presumably from the sudden air blast when the tube parted company from the receiver.... There was no parts of the air tube found inside the truck, nor was it damaged, so I think it extremely unlikely that the tube fragmented.... If I get any more details or photos, you can rest assured I will post them....
Bob
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Partial information and minimal photos lead the masses to speculate. That doesn't help anyone. It doesn't help the owners of the fdpcp and it sure doesn't help Mike.
Mike is a good guy and does a lot for the airgun community and the GTA!
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IMHO the photos and other evidence point to a spiral failure of the thread root. The tube is quite possibly hanging in a tree, the threads having turned into a Slinky(Tm). I have seen this type of failure in low pressure steam and HP water piping, the pipe corrodes and erodes from the inside until only the threads are left. The pipe is then removed simply by pulling on it( if it hasn't already removed itself) The damaged thread tops is the main indicator for my diagnoses.
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IMHO the photos and other evidence point to a spiral failure of the thread root. The tube is quite possibly hanging in a tree, the threads having turned into a Slinky(Tm). I have seen this type of failure in low pressure steam and HP water piping, the pipe corrodes and erodes from the inside until only the threads are left. The pipe is then removed simply by pulling on it( if it hasn't already removed itself) The damaged thread tops is the main indicator for my diagnoses.
. There is no room for anything but the tube to go through the barrel band. If its not on the threads it won't make it out of the gun case. A crack in the receiver would crack the paint.
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Actually, the idea of a spiral thread failure makes some sense if the thread in the tube was, for example, cut way too deep, leaving too thin a wall to survive the tensile load.... Imagine if you will the thread turning into what looks like a spring, or as said, a slinky.... It wouldn't have to be any larger than the barrel band.... What doesn't make sense is that not even a small piece of the spiral broke off and remained behind, or inside or caught up in the case.... but I suppose it is possible.... Remember, one of the statements is that no metal fragments were found inside the case.... I have removed damaged screws by drilling them out until all that is left is the thread, and sometimes they collapse and pull partially out of the threaded hole.... but usually break off in pieces.... They can, however, leave the female thread perfectly intact if you drilled straight and carefully....
Here is a possible failure mode, typed as I work my way through it.... The stress in the steel remaining below the root of the tube thread would be the highest right where the threads on the tube enter the receiver.... a failure at that point would logically result in a crack, starting there, that would follow the root of the tube thread in a spiral as the tube rocketed away from the receiver.... As the thread became progressively detached from the stub of threaded tubing still in the receiver, it would wedge up along the ramp of the female (receiver) thread outboard of it, collapsing slightly, and leaving a "spring", still attached to the tube, that was smaller in OD than the barrel band, and small enough to only damage the tops of the female threads as it was yanked out of the hole.... Yes, I think this is entirely possible.... That it could happen and leave NO trace behind boggles my mind, however....
Bob
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Similar failures have been seen when tapered fittings are used in normal threads not ment for those.
Marko
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IMHO the photos and other evidence point to a spiral failure of the thread root. The tube is quite possibly hanging in a tree, the threads having turned into a Slinky(Tm). I have seen this type of failure in low pressure steam and HP water piping, the pipe corrodes and erodes from the inside until only the threads are left. The pipe is then removed simply by pulling on it( if it hasn't already removed itself) The damaged thread tops is the main indicator for my diagnoses.
This is exactly what I was saying in my post #49.
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sixshooter, I completely missed/misunderstood that about it uncoiling.... Checking the trees is definitely a good idea....
Bob
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another edited angle ... enlarged photo, lightened and sharpened
click on it to see larger
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Could it be a defective tube? Where the wall of the tube was too thin (edited) at the threaded end.
http://www.gatewaytoairguns.org/GTA/index.php?topic=83461.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=83461.0)
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I guess no new photos or additional info pertaining to the guns whereabouts are available. I think it was petroleum based lubes used on one of the fittings. Those lubes then worked their way into the tube. The fill which occurred just prior to detonation caused the oils to be pressurized, vaporized, and ultimately ignited causing the tube to shoot off like a scud missile.
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I guess no new photos or additional info pertaining to the guns whereabouts are available. I think it was petroleum based lubes used on one of the fittings. Those lubes then worked their way into the tube. The fill which occurred just prior to detonation caused the oils to be pressurized, vaporized, and ultimately ignited causing the tube to shoot off like a scud missile.
So you are saying this can happen in storage?
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Highly unlikely but I suppose anything is possible.
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How would you go about checking tube fitment in the receiver? Degas first, then?
1. Wiggle it as is?
2. Unscrew (to break red thread locker) then tighten down again then wiggle it?
I understand that the rifle failure is pending investigation. As a precautionary measure, I'm degassing and grounding my rifles. NOT blaming anyone at this point, just playing it safe.
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I guess no new photos or additional info pertaining to the guns whereabouts are available. I think it was petroleum based lubes used on one of the fittings. Those lubes then worked their way into the tube. The fill which occurred just prior to detonation caused the oils to be pressurized, vaporized, and ultimately ignited causing the tube to shoot off like a scud missile.
THIS is the thoughts of several of us. Supposedly the remains are on the way to Mike how will examine it himself but says he will also take it to the university for forensic metallurgy examination. Will make sure ANY new information is posted.
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THIS is the thoughts of several of us. Supposedly the remains are on the way to Mike how will examine it himself but says he will also take it to the university for forensic metallurgy examination. Will make sure ANY new information is posted.
It's nice to hear he's doing his due diligence to investigate. He has a good reputation.
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What I'd like to do is examine a fresh off the boat set of rifles. Measure thread pitch both external and internal and see what the spread is. As mentioned by vigilandy, re-assemble them with clean threads and see what sort of clearance exists between the biggest internals and smallest externals. Likely pressure test the worst-case examples...perhaps with air from behind an appropriate blast shield.
It is quite unlikely the missing tube will show up. Knowing what we're dealing with on tolerance stack up will allow us to decide just how bad the situation is.
Has anybody asked Mike, or other experienced builders just what they have seen so far?
cheers,
Douglas
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What I'd like to do is examine a fresh off the boat set of rifles. Measure thread pitch both external and internal and see what the spread is. As mentioned by vigilandy, re-assemble them with clean threads and see what sort of clearance exists between the biggest internals and smallest externals. Likely pressure test the worst-case examples...perhaps with air from behind an appropriate blast shield.
It is quite unlikely the missing tube will show up. Knowing what we're dealing with on tolerance stack up will allow us to decide just how bad the situation is.
Has anybody asked Mike, or other experienced builders just what they have seen so far?
cheers,
Douglas
Douglas, do you know if the FDPCP in question had an air tube the was painted flat black or glossy black? I have both but am unsure if there are any differences other than paint color.
Since the Gen 1 have been sold out for a while, Mike probably won't have any around to measure variations in the manufacturing. However if enough of us got together, we could probably get together a decent sample size. Is there a relatively simple way to take measurements of the threads in the receiver? The airtube itself I assume can be measured with simple calipers.
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You guys do realize that the gen I is an aftermarket tube right? So getting one "off the boat" ain't gonna tell you nothing. Please correct me if I'm wrong.
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You guys do realize that the gen I is an aftermarket tube right? So getting one "off the boat" ain't gonna tell you nothing. Please correct me if I'm wrong.
Alright, could some of the experienced mechanics( Mike I am at a bare minimum talking to you ) who have worked on these things please step up and tell us what their experience with that particular joint fit is?
cheers,
Douglas
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How would you go about checking tube fitment in the receiver? Degas first, then?
1. Wiggle it as is?
2. Unscrew (to break red thread locker) then tighten down again then wiggle it?
I understand that the rifle failure is pending investigation. As a precautionary measure, I'm degassing and grounding my rifles. NOT blaming anyone at this point, just playing it safe.
I have a Gen 1 that I purchased for my son, and it happens to still be sitting here because it is leaking.... When this happened, I checked and found no pressure in it, and with the tube screwed home against the seal there was very little movement sideways at the front end of the tube.... When I unscrewed it 1 turn, the front end would move about 1/10" side to side, which dividing the tube length (15") by the thread engagement in the receiver (3/4"), a ratio of 20:1, means that the tube threads have a clearance of roughly 0.005" in the receiver threads (0.0025" per side).... I then unscrewed the tube and looked at both the receiver and tube threads under magnification, and both appear reasonable in quality, no missing chunks or obvious problems.... I felt confident that they were within safe tolerances and reassembled the gun....
To the best of my knowledge, no Loctite is used on the tube to receiver threads in the FD-PCP, and it makes no sense to do so, as it is sold as a "tinkerer's gun", so numerous assembly/disassembly cycles could be reasonably expected.... I cannot speak for the parent gun, the XS-60c, but I do know that Mike replaces the original (shorter) tube with one made of larger tubing.... The original is 22 mm OD x 1.5 mm wall (0.866" x 0.059" - ID 0.748"), and the FD-PCP tube is 7/8" OD x 0.065" wall (0.875" OD x ID 0.745").... However, the threads are still Metric, 22 mm x 1 mm, so Mike is obviously having those made somewhere.... While checking the fit of XS-60c tubes in XS-60c receivers is a good idea, it won't tell us what the tolerance is on the tubes that Mike is making / having made.... Shortly after I got my son's gun (early 2014?) I asked Mike what material he was making the tube of, and he declined to tell me, stating that was Proprietary information.... Without that information, doing the math to determine safety factors is not possible.... I heard that Mike was considering having the longer tubes for the FD-PCP made offshore (by Xisico?) but have no knowledge if that happened or not, nor have I ever seen a Gen 2 gun.... Only Mike can supply us with that information, should he choose to....
I cannot recommend what each individual owner of an FD-PCP do since this incident.... All I can do is tell you what I did and the results I found.... I agree with Douglas that anyone who has had one of these apart has the right to comment on the fit of the tube to receiver that they have found, and would value that information considering what has happened.... This should be done in a factual manner, with no blame assessed, but we have a right to the information, one way or the other, IMO....
Bob
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I cannot recommend what each individual owner of an FD-PCP do since this incident.... All I can do is tell you what I did and the results I found.... I agree with Douglas that anyone who has had one of these apart has the right to comment on the fit of the tube to receiver that they have found, and would value that information considering what has happened.... This should be done in a factual manner, with no blame assessed, but we have a right to the information, one way or the other, IMO....
Bob
Well said!
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No new information...no new theories.
Am going to assume the simplest explaination is the best.
Loose tube threads, probably just a confluence of minimum/maximum variation.
Tube likely took off in one chunk. Nothing left in the receiver, so not likely a radial separation. Stock shattering does show a pressure release right about at the receiver/air tube junction.
Barrel band doesn't have anything to do with holding the air tube in place. Doesn't have a cross screw, the tube can slide in and out of it a will, so it being in place doesn't indicate much.
No evidence of soot/detonation on the bright face of the valve or breech, so am going to rule out lube detonation.
LEt go while in a nylon case...so not likely that purely an over pressure.
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As you are probably aware, there are tolerances for the Minimum and Maximum dimensions for every thread.... Here are the tolerances for 22 mm x 1 mm threads, as used in the XS-60c and the FD-PCP.... I don't know the fit class, so I will give both classes for External threads (there is only one for Internal).... I will give the dimensions in both Metric and Inch, for your convenience.... The source is a website called "Engineers Edge"....
Internal Threads (class 6H):
Minor Diam:
Min. 20.917 mm 0.8235"
Max. 21.153 mm 0.8328"
Pitch Diam:
Min. 21.350 mm 0.8406"
Max. 21.510 mm 0.8469"
Major Diam:
Min. 22.000 mm 0.8661"
Max. 22.304 mm 0.8781"
External Threads (Class 6g):
Major Diam:
Max. 21.974 mm 0.8651"
Min. 21.794 mm 0.8580"
Pitch Diam:
Max. 21.324 mm 0.8395
Min. 21.206 mm 0.8349"
Minor Diam:
Max. 20.891 mm 0.8225"
Min. 20.590 mm 0.8106"
External Threads (Class 4g6g): Slightly tighter tolerances than class 6g for the dimensions in red - ie not cut as deep
Major Diam:
Max. 21.974 mm 0.8651"
Min. 21.794 mm 0.8580"
Pitch Diam:
Max. 21.324 mm 0.8395"
Min. 21.249 mm 0.8366"
Minor Diam:
Max. 20.891 mm 0.8225"
Min. 20.633 mm 0.8123"
The original tube for the XS-60c uses a 22 mm OD x 1.5 mm wall tube, and is threaded 22 mm x 1mm pitch.... I just pulled my FD-PCP tube and measured the OD of the tube threads, and the ID of the receiver threads.... The dimensions in blue are the ones that are easy to measure with Digital Calipers.... The receiver I have, was within the stated tolerance on Minor Diameter, the ID measures 0.829-0.830" .... The tube I have, measured 0.8575 to 0.8585" for the back end that threads into the receiver (right on the minimum for the Major Diameter).... and I got 0.8565-0.8575" (slightly under the minimum allowable) for the front end.... Therefore, the tube on my rifle was right at the minimum allowable dimensions.... I did not measure the ID of the front nut/sleeve that holds on the fill fitting.... Remember, this is a sample of ONE....
Bob
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Hey Bob,
Is the calculator on Engineers edge for thread strength what you use? basically, I am wondering which formula/ method to use to decide what thread and pitch to use for a reservoir. Obviously the remaining wall thickness it paramount to containment and is likely the weakest aspect of a reservoir. I'm undecided on threading vs the shear on the bolt head method. The threads sure make for a cleaner look on a rifle. It would seem to me, that the method of using bolt heads under shear, would be better at producing a soft failure than a threaded end cap. Although, proper design and fit should leave both methods completely safe.
Bill
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Not really the place for this discussion.... but there are three failure methods possible with a threaded plug.... If the threads are under pressure (as in the FD-PCP), the thinner wall below the threads weakens the tube, and you must use that thinner wall in your tube strength (hoop strength) calculations, instead of the full tubing thickness.... If the O-ring is inboard of the threads (eg. Disco fill fitting), then the thinner tube wall where the threads are is not under pressure, it is only in tension, resisting the end force on the cap or tube trying to pull the threaded portion away from the reservoir axially.... To calculate the strength of that you use the cross sectional area of the remaining tube wall and the end force.... The third type of failure would be the threads shearing.... The strength of that is calculated using the circumference of the pitch diameter, times the engagement length, divided by two (half that area is in the tube and half in the plug).... using the shear strength of the weaker material, which is 60% of the tensile strength.... This calculation is only valid if the threads are full depth.... the less engagement you have, the less material you have in shear (axially), because the two pitch diameters are different, so where they touch the other half of the thread is not full thickness.... If the threads are on the low side of the tolerance, you need additional length of thread engagement to make up for the lack in shear area of each individual thread.... Properly fitted threads (ie at the maximum tolerances) are incredibly strong and need little length of engagement (only a few threads, generally)....
Bob
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Yea my question was off topic some what. I realized this when I found the thread on end caps that you had replied to some time back. :-[
Thanks for the reply
Bill
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Any updates? Does Mike have the gun in hand? No luck finding the tube I assume?
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When I saw this it made me glad my Hatsan at44 is built like a tank. I am not saying these guns are Not as I have no experience with them. I am not here to try and get my kick in as I hate seeing this. Mike has always been courteous and answered any of my questions regarding his products. Hope its a just fluke situation though.
With the band still intact I wonder if it might have been a valve failure?
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Curious if anything has been resolved/discovered.
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Not to my knowledge, and I see that nobody else has even measured the OD of their tube threads or the ID of the receiver threads to see if they meet the standard tolerances I posted.... pretty complacent considering your safety is at stake if there are guns out there that don't meet those tolerances.... JMO....
Bob
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Bob, the one I just took apart to inspect and tune measures as follows:
tube thread major diameter: 0.859" - 0.860"
receiver thread minor diameter: 0.825"
Which puts them both within tolerance though on the low side. There is just the tiniest bit of play perceptible when the threads are engaged just 2-3 turns.
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Not to my knowledge, and I see that nobody else has even measured the OD of their tube threads or the ID of the receiver threads to see if they meet the standard tolerances I posted.... pretty complacent considering your safety is at stake if there are guns out there that don't meet those tolerances.... JMO....
Bob
I've taken one apart and with my cheapie calipers (only accurate to two decimal points) I can see that the one I took apart is close to the minimum requirements. Bought a better caliper but haven't remeasured. Subjectively, there seems to be quite a bit of play when the tube is screwed in but not tightened. In the meantime, my three have been grounded pending resolution of this issue. Not being complacent and trying to be safe.
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Jason, yours is a good one, for sure, I wish mine was like that....
Bob
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Bob, the one I just took apart to inspect and tune measures as follows:
tube thread major diameter: 0.859" - 0.860"
receiver thread minor diameter: 0.825"
Which puts them both within tolerance though on the low side. There is just the tiniest bit of play perceptible when the threads are engaged just 2-3 turns.
Jason, can you clarify what you mean by "tiniest" bit of play? Is this on the one I sent you? I appear to have two versions. One with the matte black tube like the one I sent you and two with gloss black tubes. The one I had apart was one of the glossy models. At 2-3 threads engagement the tube has enough play that I would never use the word "tiny."
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If this is helpful, perhaps measuring the maximum and minimum positions at the end of the tube using a standard number if turns of the tube would make for a standard point of comparison? Say 5 turns in?
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If you are going to do that, I would use fully installed and backed off so that it JUST doesn't touch the seal.... That is the condition the rifle is in when filled.... The end of my tube moves about 0.1" sideways when so installed.... I have heard of much worse, but apparently the owners don't want to post in this thread for fear of criticism....
Bob
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If you are going to do that, I would use fully installed and backed off so that it JUST doesn't touch the seal.... That is the condition the rifle is in when filled.... The end of my tube moves about 0.1" sideways when so installed.... I have heard of much worse, but apparently the owners don't want to post in this thread for fear of criticism....
Bob
How would this work Bob? Screw the tube till you feel it tightening up, then back off a half turn? And measure movement at the fill end? I'm having trouble feeling when exactly it starts touching the seal.
It would be nice to have a sample from various owners, but honestly that wouldn't help me in figuring out the safety margin of my own guns. Seems like there is a bit of variation in manufacturing.
I'm not one to criticize Mike either. He's been nothing be nice and helpful to me. At this point I'm just being paranoid. I've got no evidence that these guns are out of spec. Since Mike has sold all his supply he probably can't take measurements himself.
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Your description is what I had in mind.... Since the engagement is about 3/4", whether it was backed off 1/4 turn or 1 turn would make no difference to the sideways play at the fill end, which is where mine moves about 0.1".... Perhaps it would be almost impossible to relate this to whether or not the gun was safe, however.... if in fact any of them besides the one that let go have a problem, which we don't know for sure....
Measuring the OD of the tube and the ID of the receiver isn't perfect either, because it doesn't address the depth of the threads in the two parts.... All it tells you is the amount of interference to prevent the tube from pulling out of the threads.... On my gun that is about 0.0275-0.0295", or about 0.014" per side.... If you use the minimum tolerance on the tube OD (0.8580") and the maximum tolerance on the receiver ID (0.8328"), that gives a minimum overlap of 0.0252", or 0.0126" per side.... The maximum overlap, if the threads were as tight as allowed by the tolerances, would be 0.0416" (0.0208" per side).... Obviously, the more overlap the stronger the joint....
If the failure of the tube in this event was, indeed, a spiral failure with the tube cracking at the bottom of the threads and unravelling out of the receiver like a spring.... the critical dimension is not the OD of the tube threads, but the diameter at the bottom of the threads, minus the ID of the tube.... or more to the point the thickness of the tube at the bottom of the threads at the thinnest point....
Bob
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Andy, the measurements are from one of the glossy-tubed rifles. I didn't get a measurement of the play before I reassembled, sorry. It was just barely enough that I could feel it. All I can say is it felt like the parts were well engaged.
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Ok, here's my measurements. I gotta say that this type of work makes me really wish I had something fancier than a $20 digital caliper from Harbor Freight. That's something to add to the Christmas list.
The calipers are supposed to be accurate to 0.001" but I have no way of verifying.
The threads were measured in terms of overall min/max readings.
Air tube threads at receiver end measure 0.853" to 0.855"
Threads inside receiver measure 0.820" to 0.822"
Amount of wobble (at the tube cap) was significant but difficult to measure. I basically marked a piece of paper at the start and stop points using the shadow cast from a light almost directly overhead. The receive and tube were lying directly on the table. I would give these a plus/minus 0.05" error.
After three turns in from thread engagement: 0.198"
After backing off 1/2 turn from contacting seal (started tightening up): 0.132"
I can see that my measurements are less than what Bob posted as the minimum. How does a that translate into the tube's ability to hold XXXX psi?
As you all can probably tell, I'm not fully confident in my tools and measurements. I would be happy to send the parts out to someone for verification. Preferably someone who is properly equipped and knowledgeable.
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Andy, the measurements are from one of the glossy-tubed rifles. I didn't get a measurement of the play before I reassembled, sorry. It was just barely enough that I could feel it. All I can say is it felt like the parts were well engaged.
My measurements are also from a glossy tubed model. Clearly there's production variation here because mine has a definite wobble until tightened down.
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I can see that my measurements are less than what Bob posted as the minimum. How does a that translate into the tube's ability to hold XXXX psi?
The only one who can determine that is Mike.... it's his responsibility, IMO.... If my tube was 0.003-0.005" under tolerance, I would send it back.... The good thing is that your receiver is also on the small side, so the interference on the sizes (worst case) is (0.853 - 0.822) = .031", or 0.0155" per side.... I would be more concerned about the thickness of the tube below the bottom of the threads....
Bob
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Thanks for your analysis Bob. This one will remain dismantled pending further information. I have two others to measure when I can find the time - for now I've got them degassed.
When I purchased these FDPCP I knew they were homebrew tinker guns. I didn't expect catastrophic failure, but was open to the possibility that they could be poor shooters and/or mechanicaly flawed. If it turns out I need to scrap all three guns, I'm okay with that. Them's the breaks.
I do hope others will share their own measurements. I'm no Snowden but in this case I do believe additional information and open communication will be helpful to all involved.
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Andy, just FYI that in the next day or two I intend to measure the matte-tubed FD PCP that you sent me. I'll report back when I do.
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I've not measured mine, but I did take the extended tube off and go back to the original shorter factory tube. ( this is due to I bottled mine using a custom machined block).
My factory tube, ( originally for the Co2 carts), fit the receiver very well with no noticible sloppy/wobbly thread engagement.
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Thanks Jason. I really miss shooting my .22 FDPCP -- that's the one with the matte black tube (ordered at the same time as the one you have Jason) and will try to find the time to inspect it. It's one of my favorites. I took many Starlings with it last winter. I have a .22 Disco as well. You would think that's comparable, but I for some reason the FDPCP just feels better in my hands.
@Ron- I like the idea of bottled FDPCP. Could run it at low pressure and still get pretty good power.
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@Ron- I like the idea of bottled FDPCP. Could run it at low pressure and still get pretty good power.
I guess it might not be exactally correct or right to still call mine a "FD-PCP"... since I have removed the longer tube installed by Mike, and replaced it with Block and Bottle now. I suppose it might be more accurately described as a "Baby Bottled PCP XS60C" now.
either way, I'm did find that the original tube fit the receiver a bit better than the extended tube did, so I got lucky in that aspect. then toss on the bottle and we end up with a 1800psi fill that is giving a fairly decent spread in the 900-920 fps range, pushing 14'3's for around 35-40 shots. Yay !
Can't wait to see what it will do with a little bigger bottle,... and may even try a regged 13/3000 Ninja later on, but for now, I'm pretty happy with the results.
Here's how it is currently set up.
(http://i979.photobucket.com/albums/ae274/ronsnewemailis/Airguns/IMG_0264_zpsjuwfej0b.jpg) (http://s979.photobucket.com/user/ronsnewemailis/media/Airguns/IMG_0264_zpsjuwfej0b.jpg.html)
(http://i979.photobucket.com/albums/ae274/ronsnewemailis/Airguns/IMG_0256_zpsxytqz8dp.jpg) (http://s979.photobucket.com/user/ronsnewemailis/media/Airguns/IMG_0256_zpsxytqz8dp.jpg.html)
(http://i979.photobucket.com/albums/ae274/ronsnewemailis/Airguns/IMG_0265_zpsduxv49z0.jpg) (http://s979.photobucket.com/user/ronsnewemailis/media/Airguns/IMG_0265_zpsduxv49z0.jpg.html)
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Hi all,
I have two of these rifles. I have one rifle apart that I wanted to refinish. For what it's worth I am using a $20 digital caliper also. The receiver measures .8305 and the glossy reservoir tube seems to have tapered threads. At the end of the tube I measure .8480 and not counting the last two threads I measure .8585. I do have wobble all the way till the tube is either hitting the washer seat, no washer installed, inside of the receiver or the unthreaded part of the tube is seating against the receiver.
I've had the rifle apart many times and the receiver tube wobble has always been disconcerting but I thought that's how it was supposed to be.
Is my rifle safe?
Thank you all in advance.
I will post the second rifle's measurements as soon as I have it apart.
Taso
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Your tube is barely within tolerance at the big end, and way undersize at the small end.... The receiver measures within the tolerance range.... I would contact Mike and give him the dimensions and ask him if it is safe to use or not.... and what you should do about it....
Bob
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So I pulled apart rifle #2. Receiver measures .841 and the tube measures .849 on the end and .8575 towards the center of the tube measured two threads in from last.
I will shoot these numbers over to Mike and see what he says. God knows I've bugged him with a million questions and he has been more than patient and helpful. I have 5 of his rifles and am very happy with all of them.
Thanks,
Taso
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The tube is once again undersized, and the receiver seems oversized as well (assuming that 0.841" isn't a typo).... I definitely wouldn't use that combination, that is only 0.008" difference in diameters, or only 0.004" per side.... Seems a VERY loose fit to me....
Bob
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Yeah, I double checked the measurements before I posted them. I haven't used that rifle a lot. I bought it after I liked the first one. I detuned it to around 500fps with 7.4gr pellets at an 1100 psi starting fill. Power adjuster all the way out and coils cut off striker spring. It shot forever almost and was quiet. So I left it at that and wanted to strip the first rifle's receiver and reservoir tube and paint with Aluma Hyde II. I haven't been able to decide on clear coat or natural aluminum for the receiver. So it's all apart in a box.
Thanks,
Taso
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The remains of the rifle are at the Iowa State testing lab, would be nice if the tube was included but that appears to be lost. Initial tests shows that the rifle had what apprears to be a hard hit during shipping...waiting on futher testing of metal to confirm if that is what happened or not...when the tube shows up that will tell what happened...I think there is more to this than meets the eye
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Thanks Mike!
Taso
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the rifle had what apprears to be a hard hit during shipping
Mike, thanks for joining the discussion.... It is nice to see that you are striving to get to the bottom of this incident....
Bob
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the rifle had what apprears to be a hard hit during shipping
Mike, thanks for joining the discussion.... It is nice to see that you are striving to get to the bottom of this incident....
Bob
I will second what Bob just posted
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From what I have seen and heard, I like the AirForce airguns that have the tank as a butt stock. I really don't want that tank right against my face, let alone the tube PCP mentioned in this thread is more than a cause for concern. But most all hobbies have their dangers.
Glad your ok and hope you have or will get it figured out.
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Well, I, for one, will be sticking with the major manufacturers. Not high-end, necessarily, but major, like Benjamin and Hatsan, which are what I have now.
I think I will also be investigating tunes at no more than 180 bar, or about 2600 psi.
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while I am sorry for the loss of your Air Rifle, I am sitting here wondering why anyone would charge a thin wall air chamber to "1K5" and then transport it in any conveyance other than a slow moving ATV or some such, which is NOT going highway speeds or driven in or near any place where there is any other people. You indicated you hope your neighbor does not find it with his mower so I think I can safely assume you were not in some heavily driven roadway. I am just concerned that we sometimes take things for granted and that we as a group of enthusiast should exercise more caution. I do not know this OP or anything about them, I can and do assume they are quite the responsible user and follows all safety precautions, and more then likely have never had another incident with this rifle or with any other rifle of this sort. I just come at this from an understanding of how air pressure can and does effect things, having worked with air pressure systems before, namely in Trucking industry. I do not trust any container unless it has been checked out completely. Repeated pressurizations can and do weaken metals, and though I am not familiar with this PCP rifle, I am leery of using any pressure close to what it is rated for...just my cautionary nature.
Well, all this being said I would like to stress that this is not a criticizing of the OP at all, and if it sounds as such I beg forgiveness as this was not my intent, I am just stating my opinions here.
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My FD PCP recently developed a slow leak, and I only filled it when I wanted to shoot it. It has been an accurate shooter, and my son and I have had fun with it. However, I am going to err on the side of caution, and neither of us will be using it. After reading through this topic from beginning to end, I think that I will release the air and put this up on a shelf for long term storage. I won't have a hard time scrapping it if more safety issues turn up.
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THIS IS NOT AGAINST MIKE- HE do not make the guns might get stuck with some lawyers on his door step-
Not worth the hassle to sell these 'Me thinks' but I am wrong much, and often according to the masses
just another reason why I would not buy cheap china made guns-
WOW this could have ended up sooo bad and maybe deadly to wife- in the car just sitting there-
makes me want to go back to PB weps. after hearing and seeing the things that pass for GOOD enough in PCP air guns, WOW so glad no one was KILLED or hurt
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Need to find a metal detectorist in the area.. Post for help doing that on treasurenet or findmall and I'm sure some locals will help no charge...
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AlanB.... with all due respect, the tubes supplied with the FD-PCPs were NOT the original tubes supplied on a XS-60c, they are longer, and made from a different tubing.... What Mike is using in the current production FD-PCPs is unknown to anyone but Mike.... I certainly have no idea if they are still the same material, made to the same specifications, or not.... He will not answer our questions about that.... I would refer any FD-PCP owners to the following thread.... http://www.gatewaytoairguns.org/GTA/index.php?topic=99476.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=99476.0)
Bob
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Everyone who knows of the problem has choices to make. Not using the rifle would be a safer choice and have the right to do so. But what about the owners who are not aware of this problem. Should there be an greater effort to inform them on that choice? JMO
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No respect needed towards me- I feel for any one that has to source goods from 'there' for any reason-
'Dealt' with them before - over sea suppliers- and never had good outcome, even to the point that they wanted to replicate and steal our products to make there and retail here-- they are sneaky that way...
MANY parts failed early or made out of spec but we (the co) got stuck with the junk and lost money just to go back to a US source for those components-
Just think how all this would have turned out had the wife been hit??
WHY do "we" accept cheap good from there?? Because they are 'cheap' and WE are want it even cheaper??
I hope Mike does not take a big hit for this- or at all, but folks in this world love lawyers and love to blame any one but them selves - even when they choose cheap over GOOD.
not worth life or limb
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Correct me if I am wrong. But this may not be the result of a poorly made Chinese product. But a poorly manufactured American aftermarket part.
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I think we would better serve the group if we knew facts before we added more controversy to the thread. The XS-60c GenI was manufactured as a C02 ONLY rifle. They were discontinued by the Chinese for quality issues. The remaining stock was exiled to a warehouse. Mr. Mellick was able to purchase these guns, repair the leaking issue, convert them to bulk HPA and offer them as a tinkerer's gun with no warranty for $100. Anyone who bought these guns was fully aware of this. It was clearly posted on the website and spoke of quite often here on the GTA. It's unfortunate that this has happened... quite honestly, I can believe it's the only major incident... you all might remember one individual that had no business even owning one.. he went after a charged pressure tube with vise grips and a hammer. I have 3 of them and I have degassed and checked the "slop" in mine. I ust have hit the FD-PCP lotto because mine fell pretty snug once they are threaded in. I feel confident that if I stay within the 1500psi recommended fill pressure. And I still think it just might be the best $100 i've spent on an airgun. I don't have any death wish... I ain't jumping out of a perfectly good air plane but, I'm gonna shoot my FD-PCP guns and periodically break them down and see if things are deteriorating. And I will refrain from posting any of my plinking, hunting or tuning of this rifle on the GTA until the "all clear" is posted. Will you read about me in the obits one day? Probably but, the odds of it being due to ahead on collision with some drunk are probably greater than death by the mysterious exploding FD-PCP. That being said... I think it's awesome that the GTA makes the recommendation to degas and cease to use these guns. It's a great way to get the word out that there has been an incident. I feel like I'm part of a fellowship that truley cares about me. I appreciate folks like Bob Sterne enlightening me. He is a wealth of knowledge and is more than willing to share. But what I don't like is mud slinging and unfounded statements from people who don't know the facts and like to read what they wrote.
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Going to break my 90 year old Father In Laws heart to take away the 60c PCP loaned to him for wood pecker control.
He just loves that rifle !! and giggles every time asked "Well .. hows it shootin ?"
It gets filled to 1350# off a Crosman 3k regulated bottle set up also loaned to him.
:P :P have to get back out to his place and break the sad news :P :P
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Going to break my 90 year old Father In Laws heart to take away the 60c PCP loaned to him for wood pecker control.
He just loves that rifle !! and giggles every time asked "Well .. hows it shootin ?"
It gets filled to 1350# off a Crosman 3k regulated bottle set up also loaned to him.
:P :P have to get back out to his place and break the sad news :P :P
Just to be clear.... I would do the same thing. Shooting it myself is one thing.....
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Going to break my 90 year old Father In Laws heart to take away the 60c PCP loaned to him for wood pecker control.
He just loves that rifle !! and giggles every time asked "Well .. hows it shootin ?"
It gets filled to 1350# off a Crosman 3k regulated bottle set up also loaned to him.
:P :P have to get back out to his place and break the sad news :P :P
Just loan him your S410. :) If he doesn't want it I will take it on loan. ;)
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I will continue to shoot mine. I have been in it more times than I can count and will keep inspecting it as I do it and my Disco. I agree with Bill that we will make our own decisions based on our knowledge of the guns. Thanks to the GTA we are aware of a failure but I seem to recall a failure of a gun that uses a rear tank and someone was injured. These guns are still sold with the rear tank.
I hope all are safe with whatever gun they use
Tom
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What did the inside of the barrel band look like? If the threads on the tube end did fail and unravel like a spring I would expect to see evidence of this inside the barrel band. Looking at what little we can actually see of the treads in the receiver the scrapes look consistent with something being drug across them. I am only guessing obviously, but have seen pressure related failures of this type in person with the female threads having a serrated appearance.
On a side note: In dive school we teach to never empty tanks completely as a completely depressurized cylinder is more likely to corrode inside than one with even 100 psi remaining. Especially when dealing with dissimilar metals.
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That is an excellent contribution Wood Boats, thanks man. I've always maintained at least a few hundred PSI in my PCPs just feeling that the seals will stay sealed better that way. Now I have another reason. So far my inspections of each tube I've opened has shown zero corrosion, perfectly smooth surfaces whether steel or aluminum, while I've only ever used an FX pump, in a damp climate. I'm careful to properly vent the hose and pump at the end of each fill and leave the pump vents open at base and top for evaporation of moisture between uses. I also pace my pumping carefully so as not to unduly increase condensation.
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interesting thread.
I have a FDPCP gen1.5 and was a little concerned about the soft receiver material. But seems like it was not the source of failure here.
Took mine out and check the pressure in the tube. It is seating at 600 psi now so probably low enough to not be a concern. The reason for such a low pressure is that I drained it down a bit last time in preparation for installing a push-to-connect fitting ( I do not like the possibility of hooking my 2.5K output air bottle to the foster-nipple on the FDPCP by mistake. Using a different fitting basically prevents such possibility).
One question about the tube thread: is it a tapered "pipe" thread? Is the thread in the receiver tapered? Since the sealing is done by the flat seal just ahead of the valve, there is probably no need for pipe thread.
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Just got the "official notice" from GTA regarding the decese and desist order.
Though I don't have one of the identified problems. I will NEVER entrust the "Vast wisdom" of some group to decide my fate. I will use my own good sense and observations.
I do have a very enjoyable other airgun from MM, and have not troubles reading and understanding the "conditions of use".
I suggest the entire whoopla "grow a pair!" No one looks out for you like you will!
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Id never keep a fully charged rifle in such a flimsy case. I keep my synthetics breaks in socks.. (gun socks) but all powder and wood stays in a hard case. I wonder if that had anything to do with it.
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if it looks like a duck , I feel fortunate that the threads of the receiver and of the tube on my gen 2 mesh snugly and smoothly , any one that has run a die head and chasers to cut threads on an OD , know that the die head can be adjusted to small , and that all parts don't get inspected when running an order , I think its quite possible the tube threads were undersized , and the tube left the receiver with minimal damage to the receiver threads , the barrel band remaining intact is a little bit of a head scratcher , I have tried removeing the tube on my gen 2 through the barrel bands , it don't work , the tube drags on the bands and gets bound up , the bands have to come off first , but I haven't tried blasting the tube thru the bands with 1450 pounds of HPA , glad no one got hurt
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The threads in the receiver and on the tube are NOT tapered pipe threads, they are 22mm x 1mm straight thread.... The seal is against the end of the tube....
Bob
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So are there any firm conclusions in this case? The topic starter hasn't posted in this topic for months, so apparently he's not that interested any more and without further information there are really no lessons to be learned, except "Be carefull with HPA.", which is pretty obvious. Untill a second one of the FD rifles fails in a better documented manner no reason to be especially worried about those rifles i would say. :-\
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Die heads are used in high production manufacturing and can cut any thread required. Tapered and straight.
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So are there any firm conclusions in this case? The topic starter hasn't posted in this topic for months, so apparently he's not that interested any more and without further information there are really no lessons to be learned, except "Be carefull with HPA.", which is pretty obvious. Untill a second one of the FD rifles fails in a better documented manner no reason to be especially worried about those rifles i would say. :-\
While I somewhat agree on this well discussed failure being the ONLY ONE and not having the offending tube to inspect does raise some doubt on it being an OVER FILL failure.
But then again worse case scenario having another failure than may actually hurt someone or worse !! is NOT a safe or sane perspective to have IMO :o
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So are there any firm conclusions in this case? The topic starter hasn't posted in this topic for months, so apparently he's not that interested any more and without further information there are really no lessons to be learned, except "Be carefull with HPA.", which is pretty obvious. Untill a second one of the FD rifles fails in a better documented manner no reason to be especially worried about those rifles i would say. :-\
As you may have read in the announcement post I sent out to all members, no conclusions as of yet. The missing reservoir hinders any conclusive evidence in my opinion.
As for the OP, please understand this was NOT his airgun. He was in the vicinity of the event. The persons that actually own this airgun are not members here and therefore cannot post in the thread. It certainly isn't that they no longer care. Just to let you know.
I have not heard the outcome of the U of I forensic examination. That's all of the information I have available at this time. The more important issue is to get all of these airguns checked and verified to be safe. If not, taken out of service or retrofit to BE safe.
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Correct me if I am wrong. But this may not be the result of a poorly made Chinese product. But a poorly manufactured American aftermarket part.
No correction needed. The evidence seen so far indicates no failure of a Chinese part.... unless you can reasonably expect a wood stock to take that kind of blast pressure.
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orphaned post... pls remove?
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I've asked before and will do so one last time ask that this thread stay on track with FACTS. Not conjecture, accusations, what would you do and so forth.
There is a problem...we have seen it and there is enough evidence available that we took the step of giving out a warning to all. Rest assured, there is more than one airgun involved here. These need to be checked....plain and simple.
We offer our knowledge on the subject for YOUR benefit. ONE person getting hurt is too many. People are going to have their opinions on our warning...on their use of any airgun...and what THEY choose to do we have no control over.
GTA has only stepped out once or twice with warnings of this type. The only other one I can recall at the moment was issued by the manufacturer and was a recall.
You and everyone else are absolutely free to do what you wish. Take whatever risks you want but we as a leader in the airgun community have an obligation to bring a potential issue to your attention.
We have done that...and I have no regrets in doing so and feel we are doing what we HAVE to do for the airgun community.
Now, let's get and keep this thread going where it was intended to go.
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Need to find a metal detectorist in the area.. Post for help doing that on treasurenet or findmall and I'm sure some locals will help no charge...
I like this idea. Finding the tube might answer a lot of questions.
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That was one of the very first suggestions given directly to the participants.
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No doubt that any of us could make any PCP self-destruct if we put our minds to it. Wouldn’t have to purposely weaken any parts, just maladjusted a few things, loosen a few screws, loosen the tube, over pressure the tube, and bang it around for a while.
They don’t come with flight data recorders, so may never know what actually leads to the failure, but am pretty sure I could make any of them do something equally horrific.
Normally, would examine all the parts of the failed unit for what physical evidence is available. Busted parts do have a tale to tell about how they became busted. Without all the parts, may never know what lead to that particular failure.
Even though it is just one failure being discussed (out of how many rifles that didn’t fail…haven’t a clue how many were made/sold) it SHOULD lead to thoughts about safety. The only thing the pictures can prove is the point of failure. From there, we have to speculate about the mechanics of that failure.
But it is just speculation without substantiation...and like lower body orifices, we all have one.
Personally, think Elvis impersonating aliens did it. Has just as much validity as any other speculation.
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I've asked before and will do so one last time ask that this thread stay on track with FACTS. Not conjecture, accusations, what would you do and so forth.
There is a problem...we have seen it and there is enough evidence available that we took the step of giving out a warning to all. Rest assured, there is more than one airgun involved here. These need to be checked....plain and simple.
We offer our knowledge on the subject for YOUR benefit. ONE person getting hurt is too many. People are going to have their opinions on our warning...on their use of any airgun...and what THEY choose to do we have no control over.
GTA has only stepped out once or twice with warnings of this type. The only other one I can recall at the moment was issued by the manufacturer and was a recall.
You and everyone else are absolutely free to do what you wish. Take whatever risks you want but we as a leader in the airgun community have an obligation to bring a potential issue to your attention.
We have done that...and I have no regrets in doing so and feel we are doing what we HAVE to do for the airgun community.
Now, let's get and keep this thread going where it was intended to go.
Well said.
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Simpler:
Let a "one off" evet get your attention, but not form a firm conclusion.
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Simpler:
Let a "one off" evet get your attention, but not form a firm conclusion.
I like it
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The fact is several have been measured for correct tolerance and are well outside safe limits and not listening to warnings posted here is plain crazy. Don't use your gun just because it hasn't happened to me attitude or because you might believe this is a isolated event. A repair or recall will happen I'm sure of it but for now please be safe and cautious its your life or someone else's that may be affected. Please pass along the very thoughtful email from Dez to anyone you know who may have one.
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Well put.
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They say a picture is worth a 1000 words. In this case, these speak volumes. I hope you choose to listen.
Please remove your FD-PCP airguns from service until they can be properly inspected.
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0323_zpshyfuyg5o.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0324_zpsq5ertpcp.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0325_zpsghuxdxlv.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0326_zps1zntxcwo.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0327_zpss7gad9dn.jpg)
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Enough said.
Thank you.
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They say a picture is worth a 1000 words. In this case, these speak volumes. I hope you choose to listen.
Please remove your FD-PCP airguns from service until they can be properly inspected.
Done.
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I tried to drain the tube earlier today, but my usual method didn't seem to work (connect to the hill pump and pump until the check valve opens, then open the bleed screw a tiny bit so a tiny amount of air leaks out). Probably have something to do with the gun's spring loaded intake valve.
Will go to the range tomorrow and fire some pellets to empty the tube, and do some measurement tomorrow night.
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Dez, did someone find the tube from the failed gun? Or is this a second sample? I hope I didn't miss an explanation somewhere. Been following this thread and not seen anything.
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AFAIK the "explosion" tube has not been located...or at least reported. This one was purchased in February.
I offer it as backup for the warnings I have given. I do not need to add more details...or shouldn't need to.
Those that have been around here very long or know me personally can attest I have no agenda besides the safety of our family!!!
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Yup Guys,
Brains over Brawn every time 8)
Risk vs. Reward just not worth it, unless your gun has been inspected carefully.
We don't want to find out who is holding the "short stick" by accident.
Ironically, this is coming from the guy who ("very carefully" :P) made pipe bombs as a kid and lived to tell the tale.
All's I got to say is don't go there ................. shoot another gun for awhile until the coast is clear.
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AFAIK the "explosion" tube has not been located...or at least reported. This one was purchased in February.
I offer it as backup for the warnings I have given. I do not need to add more details...or shouldn't need to.
Those that have been around here very long or know me personally can attest I have no agenda besides the safety of our family!!!
Well, you're asking us to refrain from speculation and assumptions, so some information with the pictures is helpful. We don't all know you. ;)
In the pictures i see some pretty bad metalwork. If this is the standard with these guns, i would just chuck 'm. It appears to me pretty irrespobsible and stupid to put this onder high pressure. The americans do not seem to do a better job here than the chinese. Of course i'm assuming the tube and action were not mal-treated and this is all pre-sale quality we're seeing. I don't know you of course. :D
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AFAIK the "explosion" tube has not been located...or at least reported. This one was purchased in February.
I offer it as backup for the warnings I have given. I do not need to add more details...or shouldn't need to.
Those that have been around here very long or know me personally can attest I have no agenda besides the safety of our family!!!
Well, you're asking us to refrain from speculation and assumptions, so some information with the pictures is helpful. We don't all know you. ;)
In the pictures i see some pretty bad metalwork. If this is the standard with these guns, i would just chuck 'm. It appears to me pretty irrespobsible and stupid to put this onder high pressure. The americans do not seem to do a better job here than the chinese. Of course i'm assuming the tube and action were not mal-treated and this is all pre-sale quality we're seeing. I don't know you of course. :D
It does look like the casing and or tube substaintained some damage. Dented metal, chipped patina. I would wonder if this was the first time this gun was disassembled.. was it done by someone who knows what they are doing and or how many times have they put it back together.
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That was one of the very first suggestions given directly to the participants.
Did they get people out there with metal detectors? If they did I apologize, I must have missed it.
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Id still buy one.
Matter of fact if someone doesnt want theres anymore?
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I would still buy one too. I just recommended one to my brother. I believe that Mike will be checking them to make sure he isn't sending out an unsafe product, now that he is aware of it.
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AFAIK the "explosion" tube has not been located...or at least reported. This one was purchased in February.
I offer it as backup for the warnings I have given. I do not need to add more details...or shouldn't need to.
Those that have been around here very long or know me personally can attest I have no agenda besides the safety of our family!!!
Thanks for the info Dave! I think you've done a great job in monitoring the situation for us. As much as I hated to do it, my three FDPCP are currently mothballed.
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As a machinist with 35+ years in the business I can tell by those pictures what happen in the process. The die head had at least one broken die most likely all 3 or 4 (depends on the die head style). To make the threads to be able to thread into the mating part the die was adjusted to cut smaller.
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Well, the first FD PCP I took apart (newer glossy-tubed version) had its threads well formed and within specified dimensions. And when the parts were mated but not tightened against the seal, there was just the slightest hint of perceptible play, certainly what I would characterize as a secure fit.
Last night I took apart a second one, an older matte-tubed version, and both the tube thread major diameter and receiver thread minor diameter measured within 0.001" of the first one. Visually the threads are sharp and distinct. And again, the parts mate securely. Andy, this rifle is the one you sent me. No mothballs here :)
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As a machinist with 35+ years in the business I can tell by those pictures what happen in the process. The die head had at least one broken die most likely all 3 or 4 (depends on the die head style). To make the threads to be able to thread into the mating part the die was adjusted to cut smaller.
Dez, do you have a measurement of the major diameter on that tube to confirm Ricky's suspicion?
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Thenks Jason. or which ever one you are lol =) Ill learn your name..
thats my point.. I wonder who ever took apart that barrel Dez posted.. whats the backstory to it. You know rifles. youve been around them. You posted details.. no assumptions to be made.
Pics by any chance?
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They say a picture is worth a 1000 words. In this case, these speak volumes. I hope you choose to listen.
Please remove your FD-PCP airguns from service until they can be properly inspected.
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0323_zpshyfuyg5o.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0324_zpsq5ertpcp.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0325_zpsghuxdxlv.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0326_zps1zntxcwo.jpg)
(http://i979.photobucket.com/albums/ae272/ezman604/IMG_0327_zpss7gad9dn.jpg)
Could we please have descriptions to go with these photos? I am not trying to be a smart @@@ here but having done failure analyses these images raise more questions than they answer.
We seem to be seeing two different tubes.
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They say a picture is worth a 1000 words.
We seem to be seeing two different tubes.
Daves top 2 pictures are the same end, but tube being rotated for 2nd ... 3rd picture is the other end of tube that contains a shorter threaded portion.
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To add some clarity, the parts in the photos did NOT fail in use, the gun was inspected and removed from service as a result of the incident in question.... This gun was disassembled and reassembled several times (they are, after all, sold as a "tinkerer's gun").... However, anyone can understand that the damage to those steel tube threads could not possibly have occurred from screwing them into (not crossthreading) the much softer aluminum receiver.... although the damage to the receiver threads could most certainly have occurred by installing and removing the tube, with those horrible threads on it.... If the tube was crossthreaded into the receiver, there would be evidence of that, and even that would not have damaged the tube threads closest to the shoulder on the tube, because you couldn't have screwed it in that far (if crossthreaded)....
To further clarify, this is NOT a tube from an XS-60c, made in China, but one from an FD-PCP, made in the USA.... They are longer, and a different ID and OD than the original tubes, but are supposed to be threaded 22mm x 1mm to match the original receiver.... In my personal opinion, I see no possibility other than the tube threads were manufactured like that, passed quality control during installation, and were supplied to the customer in that state.... If someone else has any other reasonable explanation, I am prepared to listen....
While I would hope that this is an extreme case, other FD-PCP tubes that have been checked since the event that started this thread have been found to be undersize.... by that I mean smaller than the tolerances listed on "Engineer's Edge" as I posted at the top of Page 10 of this thread.... It is because of the condition of the tube in these photos, and subsequent reports of undersized tubes, that the GTA Administration felt they had to act by recommending that all FD-PCPs be degassed, disassembled and inspected to insure safety before further use.... I wholeheartedly support that decision....
Bob
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Thanks Bob and Dez,
Take the air cylinder in question off your XS60c and inspect before continuing to use ;)
Pretty simple vs. the alternative ............. Kirk
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I have steered clear of this thread. But I have to admit I have kept up with each post and picture.
I have to come forth as the (FANG / WHITEFANG/LOBOWHITEFANG / Owner of JUNKYARD AIRGUN'S ) Say that I back EZMan on his stand on the parking of the said gun.
Much reported data has come forth and is recorded here on the GTA. BUT, as always some unknown to all lingers outside the box. Just the way this business works. But SAFETY for the community is of the MOST importance.
Not taking a side to anyone but EZman for his making a bold statement that is justified on the gun. Or any issue of such reguardless the brand after all the findings by members of any forum. Some may be questionable but for the most the GTA has many qualified engineers and craftsmen that know there occupation.
I have to admit in my work of QC the last pictures were not in anyway or form exceptible as a true craftsmanship. But
Thanks Ezman!! You have controlled the issue sir!!👍
FANG💀👻
JUNKYARD AIRGUN'S
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From what I have seen in these pictures, the problem appears to be poor manufacture of an aftermarket tube? Is there any evidence of receiver issues? I have not seen any pictures which would lead me to believe the receivers are faulty? Have people measured the receivers and are they consistently within tolerance?
Please keep cool heads lads. Nobody is pointing any fingers at anyone. Please don't make more work for the moderators, I cause them enough grief for all of us.
Has the group consensus distilled to poor QC on the part of the aftermarket tube? Is there more than one manufacturer of the aftermarket tube? Actually the thread has interested me in possibly getting one of these after the forum's engineers bless the fix.
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There are too many unknowns in this whole deal to narrow it down for certain. As you state, we are not here to point fingers or assign blame to anyone. THAT is not the point and will not be on this forum. The point is there is a possibility of an unsafe setup and we are STRONGLY advising folks to empty their FD-PCP and wait for the safety checklist to be posted.
These can and will be good airguns. And to back that up, I'll step out and say this. I have one that was donated by a member to use as a monthly GTA raffle item. We put that on hold after this thread began. After this airgun is checked and retrofit (if needed) it WILL go back up for raffle. That would not happen if we didn't feel sure of the product safety and the forthcoming inspection checklist.
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A few receivers may be marginal as to thread tolerance, but if the tube was on the large size of the tolerance range it would not be a problem.... I think the big problem is that some FD-PCP tubes are at, or below, the minimum tolerance diameter.... Mating that with a large ID receiver is even more of a recipe for disaster.... I suggested way back on Page 10 that people disassemble and measure their tubes and compare them to the tolerances given, but VERY FEW have either done that or reported their findings.... If you measured your tube and receiver, and you didn't publish your results, you aren't helping get to the bottom of the problem.... be your results good or bad.... JMO.... Hopefully, now that the GTA has issued a warning to do this, more will heed the request and share their results.... There will, as DEz mentioned, be a safety checklist coming to assist you....
Bob
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gen 2 gloss black tube , major diameter .8595 , receiver minor diameter .830
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Gen 1.5 glossy tube. Tube threads= .859 and receiver threads= .823. Threads are in pretty decent shape, nothing like the picture above. I've also noticed the fill end of the tube on mine is spaced further from the barrel than most other guns? The tube has quite a bit of wiggle until tightened, and I'm seeing the receiver is on the low side of spec measurement.
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I can only comment on whether the measurements of your tubes are within or outside the tolerances published on "Engineer's Edge", not on the safety of the combination.... Obviously a small receiver ID and a large tube OD will have less "wiggle" and greater strength.... If the receiver ID is on the large side and the tube OD on the small side, there is less overlap of the threads, so less strength, and the parts will "wiggle" more....
spike - tube and receiver within tolerance....
Sprungout - tube within tolerance, receiver 0.0005 undersize.... However if you state that the tube wiggles quite a bit that doesn't make a lot of sense.... I would double-check the receiver ID just to make sure....
Realistically, the only time an undersize receiver would be a problem (smaller ID than spec.) would be if the tube OD was on the large side and the tube was difficult to thread into the receiver.... The same would apply to an oversize tube (larger OD than spec.).... not an problem unless the receiver ID was on the small side.... Basically, the threads can't be too tight if they thread together by hand, IMO.... in fact that is what I would prefer....
Bob
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Well, I checked it again and got the receiver to read .8235. I spent many years working on Japanese motorbikes, so maybe my idea of a lot of wiggle could be skewed by the precision of those machines. At any rate, I think it's good to go and I'll see if Mike has a reseal kit while I'm already dug in. Should I wait until an official checklist/decision comes out before reassembly? This thing is just too accurate for $80, I don't want to trash it.
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I don't, as yet, know what tolerances will be "officially" recommended by the GTA.... but I don't think it will be much longer before we know that.... Your gun is "tighter" than the one I have for my son.... I'm not scrapping it, at least not yet.... I would be happy to have a receiver on the minimum (tight) side of the tolerance, especially with a tube approaching the minimum (loose) side....
Bob
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So the tube left in one piece (nothing remains in the breech) Finding the tube will reveal details, however you would expect the threads on the steel counterpart to have even less damage than the receiver (aluminum) being the weaker part.
I have seen separation of two parts where there was barely any damage to the threads on both parts (pressure was in the 1200psi realm). I was shocked to find no sheared threads, and could only conclude that the outside part expanded to the point of letting go of the inserted part.
I am wondering what the expansion rate differences (if any) between the two metals would do?
I imagine the softer metal breach may expand faster when heated by the sun than the harder metal tube causing a loosening fit of the threads for a period of time. I have read that aluminum expands at nearly 5 times the rate of carbon steel, I don't know that to be true. I do know that that would vary with specific alloys. The looser fit would minimize the damage as they parted.
Just a thought from someone who has had a gun in the sun heat considerably. Don't leave your guns in the sun at all, is my advice and general practice.
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The thermal expansion coefficient for aluminum is 12.3 x 10^-6 per degree F, and for steel is 6.7 x 10^-6.... In other words aluminum expands twice as fast as steel.... We are working with a 7/8" diameter, so if we calculate the expansion for a 50*F change in temperature (ie 70*F to 120*F) on that diameter, we get....
Aluminum 0.0000123 x 0.875 x 50 = 0.00054"
Steel 0.0000067 x 0.875 x 50 = 0.00029"
The difference is 0.00054 - 0.00029 = 0.00025" (a quarter of a thou).... I don't think that is the cause.... From freezing to boiling (180*F difference), the difference in expansion is still less than 0.001"....
Bob
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The thermal expansion coefficient for aluminum is 12.3 x 10^-6 per degree F, and for steel is 6.7 x 10^-6.... In other words aluminum expands twice as fast as steel.... We are working with a 7/8" diameter, so if we calculate the expansion for a 50*F change in temperature (ie 70*F to 120*F) on that diameter, we get....
Aluminum 0.0000123 x 0.875 x 50 = 0.00054"
Steel 0.0000067 x 0.875 x 50 = 0.00029"
The difference is 0.00054 - 0.00029 = 0.00025" (a quarter of a thou).... I don't think that is the cause.... From freezing to boiling (180*F difference), the difference in expansion is still less than 0.001"....
Bob
I did not think it could be "the cause" but that it could be a contributing factor to a already near to failed thread fit. Kinda "the straw that broke the camels back" so to speak. I have used heat to remove ceased bolts many times. That is what got me thinking it could contribute to a bad fit by loosening it just a little more.
Granted if it is that close it would fail soon anyway.
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If a quarter thou expansion made the difference (even a thou).... then IMO the tolerances were WAYYYYYYYYYY to close to the limit to start with.... PCPs should be dealing with a 3:1 safety margin....
Bob
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If a quarter thou expansion made the difference (even a thou).... then IMO the tolerances were WAYYYYYYYYYY to close to the limit to start with.... PCPs should be dealing with a 3:1 safety margin....
Bob
Very true, I was looking at it as more of away to explain the breech threads being more or less in-tacked.
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Again, if they were only overlapped by a quarter thou (or even a thou), they were going to fail anyway.... All the difference in expansion could do is mean that a quarter thou less material would be shaved off the aluminum by the departing tube, if it simply pulled out....
Bob
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Again, if they were only overlapped by a quarter thou (or even a thou), they were going to fail anyway.... All the difference in expansion could do is mean that a quarter thou less material would be shaved off the aluminum by the departing tube, if it simply pulled out....
Bob
Exactly, a little more thread left behind. I can only look at the pics and not measure them but the threads were not even close to stripped out like reason would say that the softer metal should be, if the fit was tight at all. The harder tube had to be under sized in relation to the breech and ready to let loose when bumped. I read this whole thread tonight, and am glad I did not buy one a while back, I almost did.
I also will reexamine all my converted Crosmans, to remain confident that I have every detail right and that there is no visible signs of fatigue or wear.
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drained the pressure all the way down this afternoon, by firing cheap daisy pellets through it. This gun is very efficient, took me almost 40 pellets to drain that 600 psi (daisy flat pellets were around 750 fps at 600 psi, by the way). Emptied the last little remaining air by pushing the striker with a screwdriver.
Took it apart and measured the tube OD and receiver ID:
*Tube thread OD, receiver end: at the beginning of thread (the edge that goes into the receiver and press against the flat seal) is 0.849; near the end of thread is 0.862"
*Tube thread OD, Foster-nipple-cap end: 0.861" all the way.
*receiver thread ID: 0.820"
not sure if it means anything........the difference between tube OD and receiver ID is 0.029~0.042" ( I suppose that indicates the amount of thread engagement? ); in the thread spec posted by Bob, class 6h/6g, the OD/ID difference is from 0.026" (min OD - max ID) to 0.042" (max OD - min ID).
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If I understand this correctly, with internal minor Dia. of .825 and external major Dia. of .847 measured with a good quality dial caliper, it needs parked? Just my luck if so, it has held air for a year and stacks pellets at 16 yards. Regards, Tom
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Again, if they were only overlapped by a quarter thou (or even a thou), they were going to fail anyway.... All the difference in expansion could do is mean that a quarter thou less material would be shaved off the aluminum by the departing tube, if it simply pulled out....
Bob
Exactly, a little more thread left behind. I can only look at the pics and not measure them but the threads were not even close to stripped out like reason would say that the softer metal should be, if the fit was tight at all. The harder tube had to be under sized in relation to the breech and ready to let loose when bumped. I read this whole thread tonight, and am glad I did not buy one a while back, I almost did.
I also will reexamine all my converted Crosmans, to remain confident that I have every detail right and that there is no visible signs of fatigue or wear.
Just to be clear... the latest set of pics that were posted by Dave are NOT of the gun involved in the incident. As bad as these threads are, this tube did not "launch". Even tho the potential is quite evident.
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I have a question... can the ID of the tubes safely be expanded to create a better/safer fit? I mean, we really aren't talking about a whole lot here are we? Would the threads be further compromised if stretched just enough?
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We appreciate the enthusiasm with draining, disassembly and measuring of the components. Post or save that data for now. But PLEASE wait a bit longer for the inspection procedure to be posted before asking questions about is mine safe or not.
Thanks!!!
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How could the issue be compounded by imperfect thread pitch engagement? This happened at Lufkin Industries after they started sourcing castings out of China. Tapped holes that would not properly accept made in USA bolts.
If something like this could be the case then everything would feel right during initial assembly of the parts. The damage to the threads we are seeing could very well have occured during initial insertion of a made and threaded in USA tube into made and threaded in China receiver. The new tubes would have to be threaded in and removed for visual inspection to know any damage had occured.
I cannot believe Flying Dragon would assemble parts with visibly damaged threads. Inconsistent OD of the aftermarket tubes would only aggravate the issue.
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I am somewhat surprised that guys are finding receiver threads that are under tolerance.... ie less than 0.8235" ID.... However, that is NOT a real problem as long as the tube threads in by hand....
The tube threads should have no significant taper to them.... other than 1 thread at the end, and maybe a couple of threads where the threads stop.... In between they should be round (within a thou or so) and consistent in diameter over the length of the threads....
DO NOT stretch the tube to increase the diameter.... Doing that means you have exceeded the yield strength of the steel, which could either lead to it cracking where it is thin (ie at the bottom of the threads), or breaking where a crack had already started.... REALLY BAD IDEA....
"Believe" what you like, but there should be NO tubes out there that measure less than 0.858" OD, IMO.... If you think that threading a steel tube into an aluminum receiver, by hand, would cause the damage shown in the pic, please enlighten me as to how....
The problem with trying to figure out the thread "overlap" is that we don't know the exact profile of the threads on either the tube or the receiver.... It is the pitch diameters, and how closely they line up, that governs the actual overlap.... Think of it this way.... In a perfect thread, the area in shear on each part is half the total area of the overlap at the contact point (the pitch diameter).... However, as the female thread gets larger, and/or the male thread gets smaller, the contact point moves towards the points of the threads on both parts.... This puts less area in shear, and this greatly increases the stress on the metal, and reduces the force required to make it shear off....
The other danger (IMO much more important) is that as the thread is cut deeper, there is less wall thickness left on the inside of the tube, below the valley of the thread.... In the FD-PCP (and the XS-60c), this area is subject to "hoop stress" because it is under pressure, in addition to "tension stress" in the tube trying to pull off the end of the receiver.... The weakest point is right where the tube emerges from the receiver.... Not only is the tension stress the greatest, but the tube wall has NO support from the receiver to prevent it from failing from the internal pressure.... As you cut the threads deeper, the wall gets thinner, and the stress goes up.... The easiest way we have to ESTIMATE how thick the wall is, is to measure the OD of the tube threads....
The nominal thickness of the 7/8" OD FD-PCP tube is 0.065".... If the 22mm threads were cut to the maximum specs (the threads being ~0.022" deep), the tubing wall left would be 0.039" (60% of its original strength).... If the threads are cut to the minimum OD, then the remaining tube wall is only 0.033".... That means that if the thread OD is barely within spec, HALF of the original strength of the tube is gone.... If the threads measured 0.850", the tube wall remaining would only be 0.029".... That is less than 1/32" of metal to contain the pressure AND take the stress trying to pull the tube out of the receiver.... Not near my face, thank you....
Bob
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How could the issue be compounded by imperfect thread pitch engagement? This happened at Lufkin Industries after they started sourcing castings out of China. Tapped holes that would not properly accept made in USA bolts.
If something like this could be the case then everything would feel right during initial assembly of the parts. The damage to the threads we are seeing could very well have occured during initial insertion of a made and threaded in USA tube into made and threaded in China receiver. The new tubes would have to be threaded in and removed for visual inspection to know any damage had occured.
I cannot believe Flying Dragon would assemble parts with visibly damaged threads. Inconsistent OD of the aftermarket tubes would only aggravate the issue.
You may be somewhat correct,
But from experience those pics of the bad threads on the tube were not damaged during installation, the aluminum threads on the receiver could possibly have been damaged by the Steel threads on the Tube! I have cut a lot of threads over the years on metal and aluminum and those threads on the tube was definitely damaged while being made and not after the fact. A set of worn dies, no lubrication or over sized/undersized material or dies will cause the damage as seen in the pics above on the tube shown here.
You can say what you want (and that goes for anyone) those AG's need to be nationally recalled, this is not about seeing who got lucky and managed to hit the lottery and got a safe gun that has no flaws in workmanship, I have already seen listed here that most of the PCP's mentioned are not within an agreed or set tolerance.
Just wait until one of them things goes off like a rocket again and hits someone. Flying Dragon as far as I am concerned should have pulled the plug and done a recall already.
I make no comment on what happened or how it happened, due to I don't know what caused the failure, but I see that their is something wrong somewhere on all/or most of these AG's!
Yes I would own one and buy one, but I would inspect it before using it to see if the tolerances were within spec's first, the problem is most average people don't have the ability to know if their gun is within a safe margin or not.
I have had all my high-end AG's tubes off for resealing and cleaning and believe me they all have perfect threads and fit as smooth as buttered glass with no wiggle or tight spots while going together. Thats the way all of them should be.
William
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OK…made me look. Didn’t really buff it clean the parts, just a quick swipe with a clean rag.
Generation 1 rifle (one of the last half dozen .22 Gen 1).
Receiver runs something about .827-.828”.
(http://i157.photobucket.com/albums/t50/ribbonstone/XS%2060C/813e4062-25ac-429c-a356-d67f11fe0415.jpg) (http://s157.photobucket.com/user/ribbonstone/media/XS%2060C/813e4062-25ac-429c-a356-d67f11fe0415.jpg.html)
Tube thread runs something between .855-.856”.
(http://i157.photobucket.com/albums/t50/ribbonstone/XS%2060C/5a969eec-6863-4e4d-9eb6-6f8ca16488be.jpg) (http://s157.photobucket.com/user/ribbonstone/media/XS%2060C/5a969eec-6863-4e4d-9eb6-6f8ca16488be.jpg.html)
Not the cleanest threads, but pretty well formed without flats/skips.
Think I'm keeping this one in (1500psi) service.
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Receiver size is nice, and the threads look OK.... The tube threads aren't the greatest, but no big chunks missing.... Being on the small side of the tolerance is a bit of a concern, but at least you know what you've got....
Bob
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But from experience those pics of the bad threads on the tube were not damaged during installation, the aluminum threads on the receiver could possibly have been damaged by the Steel threads on the Tube! I have cut a lot of threads over the years on metal and aluminum and those threads on the tube was definitely damaged while being made and not after the fact. A set of worn dies, no lubrication or over sized/undersized material or dies will cause the damage as seen in the pics above on the tube shown here.
You can say what you want (and that goes for anyone) those AG's need to be nationally recalled, this is not about seeing who got lucky and managed to hit the lottery and got a safe gun that has no flaws in workmanship, I have already seen listed here that most of the PCP's mentioned are not within an agreed or set tolerance.
Just wait until one of them things goes off like a rocket again and hits someone. Flying Dragon as far as I am concerned should have pulled the plug and done a recall already...
William
I have a little, reoccurring, waking nightmare. Goes like this:
You just had a gun fail in your hands... your first realization is that you just got away with scratches and splinters, and relief floods in. Then your second realization hits you: You just launched a 2# missile, with a Wad Cutter tip, into a neighbor's backyard 5th birthday party...
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How could the issue be compounded by imperfect thread pitch engagement? This happened at Lufkin Industries after they started sourcing castings out of China. Tapped holes that would not properly accept made in USA bolts.
If something like this could be the case then everything would feel right during initial assembly of the parts. The damage to the threads we are seeing could very well have occured during initial insertion of a made and threaded in USA tube into made and threaded in China receiver. The new tubes would have to be threaded in and removed for visual inspection to know any damage had occured.
I cannot believe Flying Dragon would assemble parts with visibly damaged threads. Inconsistent OD of the aftermarket tubes would only aggravate the issue.
You may be somewhat correct,
But from experience those pics of the bad threads on the tube were not damaged during installation, the aluminum threads on the receiver could possibly have been damaged by the Steel threads on the Tube! I have cut a lot of threads over the years on metal and aluminum and those threads on the tube was definitely damaged while being made and not after the fact. A set of worn dies, no lubrication or over sized/undersized material or dies will cause the damage as seen in the pics above on the tube shown here.
You can say what you want (and that goes for anyone) those AG's need to be nationally recalled, this is not about seeing who got lucky and managed to hit the lottery and got a safe gun that has no flaws in workmanship, I have already seen listed here that most of the PCP's mentioned are not within an agreed or set tolerance.
Just wait until one of them things goes off like a rocket again and hits someone. Flying Dragon as far as I am concerned should have pulled the plug and done a recall already.
I make no comment on what happened or how it happened, due to I don't know what caused the failure, but I see that their is something wrong somewhere on all/or most of these AG's!
Yes I would own one and buy one, but I would inspect it before using it to see if the tolerances were within spec's first, the problem is most average people don't have the ability to know if their gun is within a safe margin or not.
I have had all my high-end AG's tubes off for resealing and cleaning and believe me they all have perfect threads and fit as smooth as buttered glass with no wiggle or tight spots while going together. Thats the way all of them should be.
William
I did some talking to a fella who had bought one of the first FDPCP rifles when it first came out on the telephone. I no longer have his number and I don't think he visits this forum. I hope his rifle is okay to shoot.
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Are lots of ways for any PCP system to fail....I'd rather not have a mal-treated, unmaintained tank up to my face as a stock either.
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I have a question... can the ID of the tubes safely be expanded to create a better/safer fit? I mean, we really aren't talking about a whole lot here are we? Would the threads be further compromised if stretched just enough?
DO NOT stretch the tube to increase the diameter.... Doing that means you have exceeded the yield strength of the steel, which could either lead to it cracking where it is thin (ie at the bottom of the threads), or breaking where a crack had already started.... REALLY BAD IDEA....
Thank you.
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fill cap end of tube major diameter .059 , receiver end of tube major diameter .0595 ,just checked the fitment of the fill cap to the receiver end of the tube , as one would expect from the higher reading of the receiver end , the cap screwed on more snugly and with tighter fit than on the fill cap end
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I assume you mean 0.859", not 0.059".... I'm a bit surprised you can feel the 0.0005" difference (on tubes near the minimum size) by using the fill cap.... it must be a fairly snug cap....
Bob
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I'll offer to measure and inspect these parts for anyone that would like. Just need to get them to me. I travel North Alabama and Mississippi ad well as West Tennessee and Kentucky regularly.
Thanks to Rstern and DEzman for heading this effort for the community sake. Thanks to PakProtector for bring up this subject. As for those questioning Dave's integrity, Iv'e had the pleasure of meeting him and exchanging ideas on a couple of occasions. He is a stand up guy and if I had one of these rifles I would take him at his word for what needs to be done.
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I assume you mean 0.859", not 0.059".... I'm a bit surprised you can feel the 0.0005" difference (on tubes near the minimum size) by using the fill cap.... it must be a fairly snug cap....
Bob
yes , I meant .859 , yes the cap fits snug on the cap end and a bit more so on the receiver end , cant get the fill nipple out with out marring the brass valve to measure the minor diameter of the cap
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An update on this matter:
As previously stated the GTA Staff has been working on solution to the possible FDPCP problem that was brought to all our attention. I am 'bumping' this thread as the GTA Staff waits for some answers to so we can provide some sound solutions to the owners of these air guns.
At this time, we have a sticky in the GTA's Announcement Gate listing out fellow member rsterne's (Bob's) tolerance recommendations regarding the FDPCP found in this thread for easy convenience. Some members have chosen to pull their FDPCP's down and used calipers to take the measurements already to ascertain answers if their FDPCP's pose any possible safety issues to themselves and others.
We have appreciated all your patience. I know we all want answers and we are getting closer to some, but in the meantime the GTA Staff wanted to bring this matter back up as an update on where we stand and to let everyone know we haven't forgot about this as safety will always be a major concern and we take that very serious.
Here is the link in the Announcement Gate:
http://www.gatewaytoairguns.org/GTA/index.php?topic=99476.msg955714#new (http://www.gatewaytoairguns.org/GTA/index.php?topic=99476.msg955714#new)
Have a blessed Christmas.
BZ
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An addition was made and to add here two things (Yes, I will sound like a broken record).
1. DEGAS YOUR FDPCP COMPLETELY BEFORE DISASSEMBLY!
2. IF YOUR AIR TUBE IS OUT OF THE SAFETY SPECIFICATIONS RECOMMENDED AT THIS TIME, PLEASE CONTACT FLYING DRAGON AIR RIFLES FOR A REPLACEMENT.
All the information needed again is in the announcement thread.
BZ
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Not to throw some gas on a smoldering fire, but what if it is a thread pitch issue versus a thread diameter issue? That would explain how our tubes are still wiggly when almost tightened, even when measured up to spec. And if the pitch angles are different, I can't imagine good engagement now matter how deep the threads are. Thoughts?
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Good point. And why I would suggest these airguns be examined by someone with a lot of knowledge in this area. And we have some very qualified folks right here willing to help.
I want to toss out a few more comments and thoughts on this.
This IS a serious issue that needs to stay fresh in everyone's mind that has one of these airguns or have thoughts of purchasing one.
First point....the remains of the "exploding" airgun have undergone professionally unbiased forensic examination. Without the reservoir, no EXACT cause can be determined. But the available parts DID show evidence of strike damage. Whether this damage happened before, during or contributed TO the "explosion" cannot be determined with the info that is available.
There have been NO other reports of this type of incident.
There have been a few of these airguns examined and found to be questionable as far as safe tolerance.
So we sent our alert out to everyone out of concern for our community. On our part, there is NO other agenda or reason for this alert!!!
We felt that GTA is a leader in the airgun community and had to do something.
We certainly hope everyone with one of these airguns will take the time to inspect or have it inspected to insure it is safe. We cannot MAKE anyone do anything, we can just alert and suggest.
Those of us that give suggestions for safe tolerance and offer remedies if found out of tolerance assume no responsibility. We are merely trying to help our fellow airgunners. What you decide to do is up to you. And YOU assume full responsibility for that.
I hope this was an isolated incident but we cannot just turn away and do nothing, even if we are not responsible for this issue.
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Does anyone have images of the strike damage?
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I'm sure someone does.
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Good point. And why I would suggest these airguns be examined by someone with a lot of knowledge in this area. And we have some very qualified folks right here willing to help.
I want to toss out a few more comments and thoughts on this.
This IS a serious issue that needs to stay fresh in everyone's mind that has one of these airguns or have thoughts of purchasing one.
First point....the remains of the "exploding" airgun have undergone professionally unbiased forensic examination. Without the reservoir, no EXACT cause can be determined. But the available parts DID show evidence of strike damage. Whether this damage happened before, during or contributed TO the "explosion" cannot be determined with the info that is available.
Was a report written by the professional, unbiased examiner? If so, can it be published here?
Thanks,
Mike
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Is there any more interest in this topic?
I saw today that Dave posted (In the Announcement Gate) that there is now a defined set of inspect criteria that every FD-PCP owner should undertake.
Where can that be found?
Thanks
Mike
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Mike, the checklist will be posted in that Announcement Gate sticky. It should be there shortly. And will also break the rules (this time it's justified) in the PCP Gate.
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A few receivers may be marginal as to thread tolerance, but if the tube was on the large size of the tolerance range it would not be a problem.... I think the big problem is that some FD-PCP tubes are at, or below, the minimum tolerance diameter.... Mating that with a large ID receiver is even more of a recipe for disaster.... I suggested way back on Page 10 that people disassemble and measure their tubes and compare them to the tolerances given, but VERY FEW have either done that or reported their findings.... If you measured your tube and receiver, and you didn't publish your results, you aren't helping get to the bottom of the problem.... be your results good or bad.... JMO.... Hopefully, now that the GTA has issued a warning to do this, more will heed the request and share their results.... There will, as DEz mentioned, be a safety checklist coming to assist you....
Bob
It seems to me the inconsistency between the ID and OD surfaces of the REA$ONABLY PRICED caliper's jaws, on the digital calipers available to most people (certainly myself,)
renders our measurements all but useless, in the tolerances needed to determine this issue.
I'm just saying beware of trusting that difference, unless you (for instance) transfer the measured ID somehow to an OD so you can use the SAME caliper jaws(internal OR external) for both measurements.
I have long coveted a QUALITY (Starrett or Mitutoyo) analog or "Vernier Dial" caliper.
And a passive (no-dial) caliper for making the above transfer (at least for the interior thread's major diameter) is almost as costly...
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;) ;) ;) Please forgive my personal observation which is only marginally on topic in this thread... First, let me say I learn a lot in this forum ;D and I too am only human and have bias and prejudice beyond my own personal awareness. :-\
I have been following this thread and "This is what can happen" and find the tone and tolerance levels to be completely different. ::)
True people have reported Dave to be a "nice guy" ;) and Alex to be a "arrogant brute" >:( .
This thread has managed to stay on topic while the other degraded to a complaint about a part that was not used in or the cause of the incident. :o
While Alex was criticized for not establishing a recall... Flying Dragon is not. ???
A spirit of investigation and cooperation ;D exist on the Flying Dragon incident but not on "Can Happen"
While bashing and infighting was common in the "Can Happen" thread :-[ I am not seeing it here.
So I ask you all: Not, why do we dislike the brute :( ? That is obvious. But, how can we instill a feeling of cooperation and desire to improve the safety and well being of the entire airgun community on ALL airgun issues ;D.
Again apologies for my naivete and unrealistic desire for a peaceful and united community of users... there must be a way to get closer to that if even if only in my imagination. 8)
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Sorry, I just really do not get your point. The staff of the GTA continually strive to maintain an extremely family oriented forum. We are dedicated to "a peaceful and united community of users"(in your words), and we spend countless hours on the site to insure that goal to the best of our ability. The growth we have seen in the last few years has made it difficult(for myself and many of the staff) to just log on and just enjoy the gates we have the most interest in. Our time is spent carefully going over all of the posts to assure compliance with the rules all have agreed to but are frequently forgotten or ignored. Should you have any specific recommendations about how we may improve our performance, I'm sure they would be considered. Please feel free to PM any of the staff with your thoughts.
pv
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Poorman plinker is a troll. He spouts gibberish, deliberately attempting to make people angry.
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And I suppose your post here makes it better sir or are you feeding the fire, be careful with what flame you light. David
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I defer to your position. Have a good day.
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I found the tube. Will have pix and some measurements by the end of the day.
cheers,
Douglas
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Douglas,
Where did you find it?
Taso
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I found the tube. Will have pix and some measurements by the end of the day.
cheers,
Douglas
Yeah, now we can see what happened.....
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Oh, I get it, you found THAT tube! Cool. Was it sticking out from between the ribs of a human skeleton perchance? Or a deer skeleton? Jammed into a tree?
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Thats been quite a spell of time ... Rain and inclement weather during its absents surely to muddle evidence we're all looking to find out.
Do tell Douglas :o
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I 2nd that!!💀
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Post as you can...multi pcitures even if rust covered...some of us have managed to (intentionally or not) destroyed stuff in experiments enough times to figure out what likely went wrong.
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Douglas,
I was curious if it was where you thought or did it hit something and bounce off or did the mower find it?
If I remember correctly you thought is could have been in a pond or something?
But more importantly the analysis of the reason for separation?
Thanks,
Taso
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Curious to know where the tube was an in what kind of conditions it is after all this time.
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Will be good to see the photos and measurements. But here are a few reminders as we dredge this topic back up again.
1) It will be impossible to piece this incident together not having all of the facts about everything leading up to and after the event. On many points it will simply come down to one person's word against another's. And we will NOT play that game.
2) This entire incident created enough turmoil that it caused us to lose a long time respected vendor. I regret this in a way but also will not tolerate the lack of support from any vendor. The incident proved an eye opener in that regard. It set a precedence for handling issues with GTA approved vendors.
3) This forum and me personally took a lot of flak and mud slinging with accusations of a cover up. There could be nothing farther from the truth. This thread is a proof of that. I am not willing to go through another round of that MESS!!!! And it will serve no useful purpose but to possibly do more damage. Which was probably a motive of some in the first place.
4) We had asked that folks exercise extreme caution in the use of these airguns. We tried to create a safety checklist for the regular user to follow that might determine if your airgun is safe. We were never able to come up with a checklist we were comfortable publishing, for fear of putting some kind of liability in our laps. We (GTA and it's volunteer staff) have NO liability associated with the sale or use of these airguns!!!
So since this has come up again, I will make this statement. You use these airgnus at your own risk. We have given more than ample warnings of a possible unsafe condition. If you even THINK your airgun could have an improper fit airtube, REMOVE IT FROM USE IMMEDIATELY!!! Return it to Mike to see if he will do anything for you or simply destroy it and move on.
There will be NO MORE slander or slamming of anyone on GTA or this forum itself over this issue.
And you can take that to the bank!!!!
Douglas, please do post photos and thank you for the update. Folks, read and heed my words. There will be no more mud slinging over this on GTA Forums!!!
Show the photos so we can close this issue once and for all and move on. And be thankful no one has EVER been injured from the use of one of these.
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Pix next. Measurement of the major diameter: .8444 on mics. Fowler vernier, that are officially out of calibration by time, but have effectively been out of service and used very little since regular calibration.
From the Announcement Gate post on the threads:
External Threads (Class 6g):
Major Diam:
Max. 21.974 mm 0.8651"
Min. 21.794 mm 0.8580"
These are nearly .014" too small; the major diameter was turned too small.
cheers,
Douglas
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Pics are too big, and I don't want to shrink them.
Douglas
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Douglas,
I was curious if it was where you thought or did it hit something and bounce off or did the mower find it?
If I remember correctly you thought is could have been in a pond or something?
But more importantly the analysis of the reason for separation?
Thanks,
Taso
It wound up in the long grass by my parts Jetta. It did not make it far enough to land in the pond. I found it whilst cleaning up tools after taking a line trimmer to it so I could get some bits off it.
Douglas
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Pics are too big, and I don't want to shrink them.
Douglas
Huh? Change image size to 600x800, save as "x" and it's done, 5 seconds tops
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Pics are too big, and I don't want to shrink them.
Douglas
Most people would just make a copy of the original and put them in safe keeping and use the copies to resize or what ever they wished, the copy will be exact duplicate of the original.
Ok here goes,,, put original in a folder named original (???) then make new Folder and name it copy of (xxx). Then right click on original pics and select copy, then open the Copy OF folder and right click in the open space and select Paste.... then resize as needed and you will still always have the Oringinals,,,, see that wasn't hard at all,,,, now show us the pics!!!!!!!
William
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Here are the pics that Douglas emailed me.... If you click on them, they should enlarge....
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FDPCP%20Tube1_zpslat16br4.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/FDPCP%20Tube1_zpslat16br4.jpg.html)
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/FDPCPTube2_zpsynwcf9xg.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/FDPCPTube2_zpsynwcf9xg.jpg.html)
The tops of the threads appear truncated, which could, IMO, mean two things.... 1. they were not cut deep enough, or 2. the OD of the tube was too small, prior to threading.... Since the measured OD of the threads is 0.8444", and since you can see in the photos that the top of the threads is a long ways below the surface of the tube, I would say that the latter was the case....
Bob
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Well they say "A picture is worth a thousand words", these pictures tell me everything I need to know to figure out the root cause of the failure.
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Thanks Bob for assisting in getting the photos up. Photobucket.com loading requires no resizing.
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Thank you, Douglas.
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Yup, flat topped threads like those are unlikely to hold even half what full-depth threads can do. Not at all surprising it popped free under pressure. The only surprise I see is that it held beyond the first attempt at filling.
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Here is a drawing, to scale, showing the tolerances for the threads, and where the failed tube sits by comparison....
(http://i378.photobucket.com/albums/oo221/rsterne/Flying%20Dragon%20PCP/Failed%20Threads%20FDPCP_zpsqdvhuyhw.jpg) (http://s378.photobucket.com/user/rsterne/media/Flying%20Dragon%20PCP/Failed%20Threads%20FDPCP_zpsqdvhuyhw.jpg.html)
The red line is the threads in the receiver, at maximum diameter permitted by the tolerances.... The black line is the threads on the tube, at nominal diameter, and the blue line is the threads on the tube at minimum diameter permitted by the tolerances.... The green horizontal line is the OD of the failed tube, measured across the threads.... Note that there is only a 0.005" overlap between the top of the tube threads and the bottom of the receiver threads.... At the minimum allowable tolerances on the parts, that overlap would be a minimum of 0.012".... These only applies when the tubes are centered.... If the threads are additionally a loose fit, then the tube can move sideways in the receiver, reducing that overlap even further....
While I cannot state that tube threads at the minimum OD tolerance, and receiver threads at the maximum ID tolerance, will not fail.... stalwart did run a test to failure on such a setup, and it did not fail before the valve screws sheared at 6000 psi.... We now have one set of data where a failure did occur.... If you measure the OD of the threads on your tube, and the ID of the threads on the receiver, and they are not within tolerance, I personally wouldn't continue to use the gun.... The thread tolerances can be found here.... http://www.gatewaytoairguns.org/GTA/index.php?topic=99476.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=99476.0)
Bob
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Can I ask how far that part flew through the air before hitting down?
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Good follow up guys.
Thanks for the pics Douglas, and for the explanation and measurements Bob.
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Can I ask how far that part flew through the air before hitting down?
When I read this thread last year they could not find the tube , don't know if it has turned up since ? .
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See Post #336...
pv
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Can I ask how far that part flew through the air before hitting down?
About 50 yards. The angle at which it was discharged is unknown, and would of course have a great effect on potential distance.
Douglas
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I'm glad I finally saw this thread. I have two of the 1st gen rifles that have been out of service for a while. I was getting ready to start using them again but after reading this thread I immediately degased both of them...geuss I'll go from there.
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Finding the tube helped put to rest at the mechanics of how it happened. We've all had miss-matched screw threads either pull loose or strip under stress; seems like the same kind of event.
Would be better to know than to guess/hope. Take it down, measure the threads, then decide if you air it up again.
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That was the plan...degassed awaiting disassembly and inspection. I only have cheapo harbor freight calipers though.
Edit:
And I need a battery.
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Hey Douglas, I haven't been shooting much for a couple years but started into the AGs again. Do you still do fun shoots out at your place? If so maybe I'll make it out some time and sweet talk you into measuring the threads on my FDPCP. For now I'll degas it. It's been sitting for 2 years gassed! Yikes.
Andy aka LARSPAWN.
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From the looks of the photo, it would not take a caliper to see the threads were too shallow. The tube probably wiggled when it was tight on the Oring.
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I have a question. When turning threads on tubing is the O.D. of the thread measurement supposed to be smaller than the tubing's O.D.? It looks like it from the picture shown.
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The OD of the tube pretty much has to be less than the ID of the receiver. If they were the same, would need a rather long pipe wrench to screw them together. All things that screw together have to have a little slack (or it's a "crush" fit that isn't coming back apart without some heat or some damage). In this rife's case, you HAVE to unscrew the air tube in order to get the valve out, so there has to be something besides that "crush" fit in order to do basic repairs (can consider a "crush" fit as a one-time fit....it won't be that tight the 2nd time).
Which does bring up a wear factor. The more often you unscrew the tube and screw it back on, the sloppier the fit becomes. Can't really avoid that, it's just in the nature of things screwed together tightly.
Took 14 or 15 pages of posts before I got off my lazy-butt and took mine apart to do the measurements. I understand just how disagreeable it is to take apart a non-leaking, shooting just fine, air rifle can be and resisted it for a long time.
In this case, give in to the urge.
http://www.gatewaytoairguns.org/GTA/index.php?topic=96148.msg933666#msg933666 (http://www.gatewaytoairguns.org/GTA/index.php?topic=96148.msg933666#msg933666)
Didn't come out to "max", but did come out with enough "bite" to the threads that I kept it in service (strict 1500psi limit...the Chinese pump sold with the rifle is good about that, as 1500psi is just where the green section starts).
Had considered other reasons for failure, but the photos rule those out. At least 1 full thread hangs out, unsupported by the breech, so at that point the tube strength is only as strong as the depth of the metal from the bottom of the groove...which is an UNIMPRESSIVE thickness (something like .04-.045")...which pretty much explains the 1500psi rating. HAd thought that it might have radially cracked at that thread (esp. as it "went off" when removed from a pickup bed...and might have been dropped in its case).;
Photos prove that is NOT THE CASE...it wasn't a bending/impact stress...seems to have been a shallow thread tube.
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So are we saying these are not safe at all and should be destroyed? Sorry I'm late to the thread but getting very concerned that I should get rid of this. There's no solution?
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I have a question. When turning threads on tubing is the O.D. of the thread measurement supposed to be smaller than the tubing's O.D.? It looks like it from the picture shown.
Oops missed Bob reply 341. So the next question is. So what caused the O.D. of the threads to be reduced in diameter so much? Was it turned in a wrong or faulty die? Or some kind of wear on the thread?
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I have a question. When turning threads on tubing is the O.D. of the thread measurement supposed to be smaller than the tubing's O.D.? It looks like it from the picture shown.
Oops missed Bob reply 341. So the next question is. So what caused the O.D. of the threads to be reduced in diameter so much? Was it turned in a wrong or faulty die? Or some kind of wear on the thread?
The tube was probably turned undersized then threaded.
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What we are saying is that each of us must make our own decisions regarding these guns. On the last two pages of this thread there is all the info. you would need to make an informed decision. The recommended tolerances are posted. You must make careful measurements of your gun. If it is within the limits recommended, you would likely be fine ONLY filling to 1500psi. If you are in doubt, you can contact the dealer and see what recourse you may have with him.
pv
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Gentlemen,
Is it then the consensus that it was a badly machined, out of specification tube that was missed in quality control and that the system, as designed, is safe?
Thanks,
Taso
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Read post above yours. You are the only one who can make the final decision as to whether or not your rifle is suitable for use.
pv
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Paul,
Thank you.
Taso
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Eric (stalwart) did a pressure test to destruction on more than one gun.... The first item to fail was the valve screws, which sheared at 6000 psi.... Using the ASME industry standard for pressure vessels of 3.5:1 safety margin to UTS (failure) of the first component, that gives a maximum safe working pressure of 1700 psi.... so the original FD-PCP recommendation of 1500 psi seems reasonable, FOR TUBE AND RECEIVER THREADS WITHIN TOLERANCE.... If you are running a regulated setup, you should have a 1.8K burst disc downstream of the regulator, to insure the pressure never exceeds that even if the regulator fails....
I have one of these guns, and the tube threads are within tolerance, so I feel comfortable filling it to 1500 psi.... Now if I could just get it to stop leaking.... ::)
Bob
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Not sure I should say what I am about to say but I am going to anyway!
Okay, here is what the problem is period, everyone keeps talking about what it should be, what its not and what to do!!
It is a hurry up and make these so we can sell and make money!!!
No quality control what so ever, in other words a cheaply made piece of junk that could be or have been a very highly perfect reasonably priced Air gun!
This is what happens when you get cheap labor and people just do not care about how anything is made into a safe finished product!
It is obvious that no body checked any of the AG's before the final assembly, under and over-sized material and cheap tooling used.
Personally, I would buy one with no problem, but I would check the tolerances of the tube and receiver fit before using it, it is a wonderful little rifle that can be a lot of fun or to just mod it the way you want.
But my last words are fact and final...
They need a complete recall on these Air Guns before someone gets hurt or killed. This is due to not many users will have the ability to know what is safe/not safe to use or even know there is a problem unless someone tells them. Whats it going to take, the death of one poor unsuspecting person!!!
Now you know why it is so cheap!
You sure don't hear problems like this with the higher end Air guns and if you did there would be recall placed immediately.
William
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William,
You have a lot of valid points but there was one point you missed. I remember it was clearly stated that the $100 FD PCP's were tuner/project guns that needed work and not Discovery level quality, fit and finish. I don't have the exact wording or copy of the listing.
When I bought my 2 rifles I was aware of that and bought them as platforms to learn on. I agree the design was a little funky and I moved on to B51's because of that.
I cut my teeth on the FD PCP as it was my first pcp. I learned how to create a power curve by adjusting hammer springs and fill pressures.
This point does need to be taken into consideration. Whether it was right or wrong to offer these rifles as basic platform/tuner rifles is up to debate. From my dealings with Mike, his willingness to help and go above and beyond I don't feel there was reckless intent.
Thanks,
Taso
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This is strictly an opinion from the sidelines, as I've never even seen a Flying Dragon rifle in person, but my impression from having followed much of the discussion of these rifles echoes what Taso stated but perhaps more strongly. From the beginning it was clear that the ultra-cheap pricing was directly tied to the potential for many of these rifles being 'duds' which either needed massive machine work to make them functional or would ultimately be disgarded. $100 is a give-away price, a favour for those in the community with the skills and knowledge to make use of at least some of them.
For comparison, a couple of years ago I gave away 40 violins to a school music program, out of a collection of old instruments I'd purchased. These 40 were all potentially usable, but none of them could achieve a value on the market of more than $500, and considering the repairs needed and new parts there just wasn't any potential for me to make any profit at all on them. But throwing them away would have been a shame, as at least half of them could be recovered with modest skills, perhaps some cheap or even donated parts. So I found a school willing to take on the project. Had it involved packaging and shipping the violins I would have had to make a token charge... something like $50 to $100 per violin. But the school teachers came to me and collected them, so no charge.
I regard Mike's offering as being in some ways very similar to this exercise. He was passing along an opportunity, with rifles which otherwise might be junked.
Then more and more novices picked up the rifles, along with the more experienced PCP guys. Mike was of course not in a position to say no to people on the basis of their unknown skill levels, but he did make it abundantly clear that these were project rifles, not ready-made products suitable for use out of the box. Unfortunately people eager for a bargain tend often to blind themselves to such trivial details as he was giving, all they saw was a great bargain on a cheap PCP.
So now a recall? No. Unless you're talking about the manufacturer issuing a recall. And that seems highly unlikely. These rifles are like so much from China (or India, Pakistan, wherever there's cheap labour) where there is little in the way of quality control for the cheapest products. I've seen absolutely brilliant work out of Chinese shops in my own field - some of their violins and doublebasses surpass what is coming out of Eastern Europe yet at far lower pricing. But for the cheaper instruments one often finds products about 95% finished, but that last little bit is problematic. Seams which pop open because varnish has leaked between, making re-gluing difficult. Threads on tuners cut wrongly (like these pressure tubes) such that they fail under string tension. Neck joints which weren't really fitted properly so they fail with the slightest bump. But hey, if you want a cheap instrument, don't come crying when the workmanship is cheap! China can supply any level of quality. You get what you pay for. In this case, $100 gets you a problematic rifle which likely needs work, and may have to be disgarded.
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William,
You have a lot of valid points but there was one point you missed. I remember it was clearly stated that the $100 FD PCP's were tuner/project guns that needed work and not Discovery level quality, fit and finish. I don't have the exact wording or copy of the listing.
When I bought my 2 rifles I was aware of that and bought them as platforms to learn on. I agree the design was a little funky and I moved on to B51's because of that.
I cut my teeth on the FD PCP as it was my first pcp. I learned how to create a power curve by adjusting hammer springs and fill pressures.
This point does need to be taken into consideration. Whether it was right or wrong to offer these rifles as basic platform/tuner rifles is up to debate. From my dealings with Mike, his willingness to help and go above and beyond I don't feel there was reckless intent.
Thanks,
Taso
You may be right about a project or tuner. But that has absolutely nothing to with it being safe, it is also an out of the box user Air Gun, so that completely eliminates the project part.
By tuner or project definition I think that it means it is just a lower end shooter that may need a lot of tuning or trigger work, not something that has to be completely disassembled and have a machinist go over with a fine tooth comb. Like I said it is an out of the box ready to use AG! Nowhere does it say it is not safe to use, kind of defeating the purpose. You cannot sell something to customers that is unsafe to use when it is supposedly a ready to use product out of the box!
I am very surprised there has not been someone from some agency already looking at the possibility of doing something about the quality of this product! There has been a lot of publicity going around on the problem that's for sure!
Anyway, I think its a great little gun, it just needs more quality control put fourth to save it's continued productivity!
William
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I'm a little hesitant to post but feel I must to clarify a few points here. The comparison you made of the violins is not quite the same. These were not sold as "project" guns. These are Chinese made Co2 airguns that Mike chose to modify to HPA. His intent was NOT to make a wheel barrow full of money. If you know Mike, you know that. He gives more away to the members of our community than he takes in. How he continues to do this, I don't know. But the fact is he does.
Anyway, his intent and purpose was to offer an entry level PCP to those that don't have the means to sink money into an airgun and the support equipment. But he wanted to expand the number of folks enjoying the benefits of a PCP. His intent was very honorable and the idea was a good one. It was not executed properly. And the first few airguns he built and sold very possibly had misfitting reservoirs. After the first 50 were made, he changed the tube he was using as well as the threading process. The threading of the first 50, as you can see, was not of good quality. And in an HPA, this can be a very serious and possibly deadly mistake.
Now once again I will say. PLEASE remove your FD-PCP from service until it can be properly inspected for safety. Either yourself or someone qualified need to examine and measure it. A visual inspection of the threads will tell you a lot.
If you even THINK you have an unsafe airgun, take it out of service permanently or speak to Mike. He has stated to me that any tube found to be improperly threaded can be exchanged.
And once again I will state this. We will look at the photos, give the necessary warnings, then we are moving on. This subject will not be debated and opinions tossed around. We don't need it and it serves no useful purpose.
See post #330 and take it to heart. Much more and this thread will remain visible to all but will be locked for further comments. And I'd rather not do that.
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Ah, thanks for that clarification. I didn't realize he'd threaded the tubes himself, and that there were known problems with the first 50. In that case it does seem he ought to have contacted those first 50 buyers and offered replacement tubes or refunds, considering he knew there was a serious problem. Not taking a jab at Mike, as I know his reputation is great and he's well liked, especially for what seems to be charitable work. But if it's a problem limited to 50 rifles it seems something which could have been dealt with better before it ever got so far as this.
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...Much more and this thread will remain visible to all but will be locked for further comments...
That would be "better late than never." You've let this go on far too long. Please do it now.
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Thanks for finding the tube and getting the pictures posted. Really does clear up how it is most likely to have happened (OK...pretty much the only way).
Glad you didn't just give up.
But it's time to tuck this post in, sing a little lullaby and put it to sleep.
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Thread has run it's course. It's now locked but set as a sticky for all to find and see. We need the safety message to be available to ANY person that owns or buys one of these second hand.