GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: Kirk B on January 19, 2011, 08:15:57 PM
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I am about to collect the materials to build a spring compressor and I had one question. Is it ok to have the muzzle in contact with a stop block as you apply pressure to the rear of the action or is it better to secure the action at the pivot? I've seen lots of pics of compressors but not many with a gun in them so I don't have much to go by. I don't want to damage the crown or put undo pressure on the pivot so any help will be greatly appreciated.
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You need to brace the receiver at the pivot point and NOT the end of the barrel for a couple of reasons. Yes, you could possibly damage the crown but mainly, you would be more likely to bend the barrel by putting a load all the way at the end of the barrel. And the other reason is, especially with a break barrel, is you may break the barrel. LOL
Or cause a cocking action. That would put everything out of control.
I'll try to find some photos of an action in the compressor but Google spring compressor or search here and you will probably find some.
Happy Shooting!!!!
Dave
8)
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Maybe this will help:
(http://i185.photobucket.com/albums/x226/daved20319/Tuning/Tuning-001.jpg)
(http://i185.photobucket.com/albums/x226/daved20319/Tuning/Tuning-002.jpg)
In addition to avoiding the possibility of barrel or tuner damage, this setup also makes for a much shorter compressor. Later.
Dave
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Outstanding, thank you gentlemen. I didn't think it would be a good idea to put the stop at the muzzle for exactly the reasons mentioned.
BTW, I dig the dowel and emery cloth hone too. I'd read about that trick here but hadn't seen it done yet.
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Yeah, the "hone" works quite well. Note the stiff plastic backer, it's just an ordinary plastic "For Sale" sign that I cut up as needed. WD-40 for cutting fluid, then clean with brake cleaner and compressed air and she's good to go. Later.
Dave
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Thanks Dave, I never thought about the backer.
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I think that Dave's design is about the best I've seen, very simple, straightforward, and elegant. I've got all the parts to make one, now all I need is a springer!
pv
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I'm building a version of Dave's this weekend. The only real difference is that I'm going to add another block to the middle to help secure the action.
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THAT'S the comment I was about to make. I like the design too. But didn't see any retention of the trigger end of the works. Without that it could slip and send pieces flying. And one other possible suggestion. On the breach end retainer, cut the inside "V" block the same width as the outside block and add a hinge on one end and latch or just a pin to lock the two piece together? But the design is quite doable and neat!!!!
Happy Shooting!!!!
Dave
8)
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Daved-Appreciate the pics of Your novel and simple spring compressor. Simple is always better. You sure had your thinking cap on. Good going
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I think I'm going to leave the v block as is and custom fit the 2nd block to the breech end of the action like Dave did but maybe add holes to bolt thru both to secure the whole works. That way I can lay any gun with any barrel in the v block and if need be, just make retaining blocks to fit various guns. That way the compressor is secure yet pretty much universal with interchangeable retaining blocks.
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The do all spring compressor that's done about em all from the Magnums on down. Also some of the tool's and homemade attachments needed to remove some of the trigger housing's etc.. Ed
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OK dumb question.
What is preventing the wood from splitting along the grain.
Or is the wood plywood, and the crossgrain lamination takes care of that problem?
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I can't speak for the other designs but the base of mine has steel braces running the length of it. My compressor doesn't bow or flex under the presser of removing or installing magnum springs and that's what I was looking for when building it. I do tune after tune but I'm always fabbing another part for airgun spring removal. This compressor design was taken from Genes compressor design. :D Ed
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OK dumb question.
What is preventing the wood from splitting along the grain.
Or is the wood plywood, and the crossgrain lamination takes care of that problem?
The wood I used is called Ipe, it's very dense and heavy, around 68 lbs. per cubic foot, and incredibly tough. That's the same weight as water, and yes, it usually sinks, and almost twice as dense as black walnut. It gets used around here for high end decks, which is why I have scraps of it around :-).
When I built that compressor, I literally used what I had on hand. And yes, it could use all kinds of improvements. But in the meantime, it just keeps doing what I need it to do. It's probably not as flexible or as safe as Ed's, but I've taken a lot of guns apart with it, including some magnums. One of these days I'll get around to overhauling it, but in the meantime, I've got guns to work on :-). Later.
Dave
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The only reason mine had to be adaptable is to accept all the different types of airguns that I tune but as always I'm making a new part for another shooter hehe. I put a lot of overkill into the base since I didn't want the base to buckle and a shooter spring under pressure bouncing around my shop and me tucking and rolling out the door to escape the damage that it would inflict on me and the shop lol. Ed
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The wood I used is called Ipe..
I'm not really familiar yet with how much pressure is required to take a springer apart. Do you think your design would work ok with softer wood? The only thing I have on hand is a hard pine board but I have access to oak or maple.
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I would think 3/4" pine would be fine as long as there are no large Knots which could be weak points, and I wouldn't worry about cracks along the grain, as long as there are none to begin with. Ply would be a lot stronger, 3/4". No need for $5-6/ft lumber, unless its something you have.
pv
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The wood I used is called Ipe..
I'm not really familiar yet with how much pressure is required to take a springer apart. Do you think your design would work ok with softer wood? The only thing I have on hand is a hard pine board but I have access to oak or maple.
Hi..
the pressure required is a lot less than yer mite think...
The average air gun spring has a rate of 35 to 45lbs
IE...35 to 45lbs per inch of compression.
so on the upper limit of 45lbs..
if theres 2" of pre load that gives a force of 90lbs.
( 45lbs for every inch of compression)
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Yup, what Pete and Paul said. Not nearly as much pressure as you might think, the 90 lbs. that Pete mentioned is probably on the high side, even for a magnum. And Paul is right, 3/4" ply would be as good or better, and a lot cheaper. Like I said, I had the Ipe on hand :-). Later.
Dave
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Sweet. I actually have some 3/4 ply that's left over from a floor repair in my last house.
Yes, I actually moved with it - I throw nothing away. :D
I'll use that for the end plates. I'll still use the pine for the middle piece to hold the action.
Thanks guys for helping me get this thing together.
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Don't forget pics of the finished product, I LOVE to steal other people's ideas :-)! Later.
Dave
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Don't trust that Daved guy.
He's stingy and unwilling to help as they come.
;)
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I just finished up my compressor and wanted to thank you guys again for the ideas and advice. I'll post up a pic tomorrow because it's late now and I need to warm up a little. It only took about 2 hrs but it's in the low 20's outside so I'm a little chilly. I can't wait to get heat out in my garage. My wife thinks I've lost my mind. ;D
Edit for photo:
Ok, here we go. I still have to drill the holes in the v plate to secure the retaining plate but I wanted to wait until I could lay the gun in there to be sure everything fits. I may epoxy the end plates to the clamp faces to help keep the plates from deflecting under load. I guess I should finish the wood with something to seal and protect it as well.
(http://img13.imageshack.us/img13/2152/img1389z.jpg)
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Look's like a great start and another safety item to have around when doing spring compression is safety glasses. I wear them when doing my work around the compressor. You want to keep the peeper's safe for shooting at your target's or critters when your done giving your shooter some TLC. Ed
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Good point, thanks Ed. I'm terrible about wearing safety glasses unless my young son is working with me. I try to set a good example for him but when no one's around, you know how it is...
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This is Da Thread!
How can I add a subscribe to this specific thread?
Kudos for the pics and tips, I am just terrified to open that springer and *(&^ break loose...
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Great job, Kirk, and you can be certain I'll be stealing some of your ideas :-)! The screws for the retainer plate are a nice idea, but I suspect they'll only be use once or twice :-). I do like the center block, I've never had a rifle slip, but I've always been extra careful, just because I know that Murphy lives in my back pocket and it was a real possibility with my very minimalist design. On your next iteration, you might consider a hinge and draw bolt (think tool box) latch, that way it's all one piece that stays together, and is easy in and out.
One other suggestion that you may have already planned for, lots of guns need to have the spring retaining block compressed into the comp tube, impossible with a flat bearing surface. I solved that by simply drilling a hole and slipping a bolt in it for the block to bear on. It's a little trickier with the Diana rifles, since the safety sticks out the back, but that fits in the hole when the bolt is removed, problem solved unless you're working on a 54.
My only other suggestion would be to try and find a C-clamp with the same thread, and swap out the screws. I had an old 6" clamp kicking around that was the right size, more than doubled my screw length. No more worries about spring length or preload :-).
Again, great job, now go take something apart :-). Later.
Dave
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Grizzly, just click the "Notify" button at either the top or bottom of the thread.
-Scott
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By default, if you post in a thread, you SHOULD automatically receive an email notice any time there is a post or moderation of the thread. If not, go to your Profile tab, click on Notifications & email and check the 4 boxes. I also set mine in the drop-down box to Replies & Moderation. That way you automatically receive notice when a thread is updated that you have posted to.
Happy Shooting!!!!
Dave
8)
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One other suggestion that you may have already planned for, lots of guns need to have the spring retaining block compressed into the comp tube, impossible with a flat bearing surface. I solved that by simply drilling a hole and slipping a bolt in it for the block to bear on. It's a little trickier with the Diana rifles, since the safety sticks out the back, but that fits in the hole when the bolt is removed, problem solved unless you're working on a 54.
Yeah, I figured there would be a few accessories or mods required along the way but it should be easy to do with that flat plate to attach stuff to.
My only other suggestion would be to try and find a C-clamp with the same thread, and swap out the screws. I had an old 6" clamp kicking around that was the right size, more than doubled my screw length. No more worries about spring length or preload.
Good idea. Have you ever run into one that needed more preload than the original bar clamp thread length could accommodate?
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Shadow, What are those cylindral wood pieces?
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Daved, what is the name of that tool you use?
I went to Harbor Freight and was difficult for them to understand...
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The Cylindrical pieces are wood dowels cut with different notch's in them to fit into different actions to remove trigger assemblies. I tune many different airguns and some tool's are made to fit particular airguns. Ed
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Daved, what is the name of that tool you use?
I went to Harbor Freight and was difficult for them to understand...
Do you mean the pipe clamp? If so this is the one I used:
http://www.harborfreight.com/2-piece-3-4-quarter-inch-heavy-duty-cast-iron-pipe-clamp-31255.html (http://www.harborfreight.com/2-piece-3-4-quarter-inch-heavy-duty-cast-iron-pipe-clamp-31255.html)
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Good idea. Have you ever run into one that needed more preload than the original bar clamp thread length could accommodate?
Oh, yeah. Diana 350 and Beeman R9 both had more preload than I had screw length. Even with the short screw it took off enough pressure that I was able to deal with the last little bit by hand. Still, it's nice to have the longer screw, especially on reassembly.
GrizzlyMan, like Spook said, it's called a pipe clamp, they're available at most any hardware or Big Box store. They're really not sold as a complete unit, the clamp is a two piece set, and then you buy a piece of black iron (gas) pipe however long you want or need. You can get them to fit either 1/2" or 3/4" pipe, I've always used the 3/4" ones. Pony used to be about the only brand you could get, but now there are other companies offering them, Home Depot sells the Irwin brand. If you go this route, make use you get black iron pipe, not galvanized. The galvanized pipe will let the clamp slip. Want to guess how I know :-)? Later.
Dave
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Oh, yeah. Diana 350 and Beeman R9 both had more preload than I had screw length.
Thanks Dave. I was just wondering though, how did you get the screw out of the c clamp? I never really looked, does the clamping pad have a snap ring or something holding it to the ball on the end of the screw?
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Main strength and awkwardness :-)! I just unscrewed it until the clamp pad popped off, then recut the ball end in my lathe to fit the bar clamp pad. If you don't have a lathe, a grinder and file would also work. On my bar clamp, the screw is held in place with a rivet that can be popped out with a screwdriver. If needed, I'd have tapped for a set screw,but the rivet still works fine. Later.
Dave
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Cool, thx again.
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Here's mine and I live by the same rule,secure at the pivot.Thanks
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Spook, I am trying to make another spring compressor using the pipe clamps 1/2", only thing I noticed is the length of the bolt.
If there could be a way to find a similar thread, but longer size bolt. In some rifles the spring when decompressed extends out the back around 2", then one adds the spring guide making the situation much worst. I compared two different pipe clamps, one from Home Depot and the other from Harbor Freight, and both have similar length in thread for adjustment.
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Nice compressor Bandit. I was going to build one that style but I thought the pipe clamp thing would be a little easier.
Griz, I used a 3/4" clamp so maybe that has a longer thread? Per Dave the screw might be replaced by one from a c clamp of the proper size but I haven't looked into that yet.
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+Just want to addd a bit of food for thought, my first compressor was my better than average drillpress. Lotsa run for precompression, heads turn with the capw/o friction can be readily adapted to almost any design, just make an adapter/plate to fit in chuck. First one was engine valve with leather glued on.
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It ok an 8" (C clamp or other) of free play on spring compressor for pre-charge spring?
It enough length to work on various types of AG or do I need more or less length?
JC
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8" is more than enough, 4" is probably adequate, I replaced the screw on my Pony bar clamp with the screw from a 6" c-clamp I had kicking around, it just happened to be the same pitch and diameter. Later.
Dave
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This is a great thread. I am in the process of building one so I can learn on my gamos I have. I will take pics and post up the process. I will be welding some and use some wood as well. As daved said I will "Steal" some ideas from all the compressors I have seen so far..I am a welder so I will use the metal where I can for strength and adjustablilty(not to mention I am not the greatest with wood). I will be using a 12" piece of 5/8" all thread with a 5/8" coupler instead of the cut down C-Clamp..I was going to ask but I think daved answered my question about the amount of travel I will need. I was going to try for at least 7" of travel??? Will this be too much,not enough or just right?? Thanks..I hope to have it built by tonight..This dadgum 20 degree weather for south texas is just not right..I guess I will just have to stay inside and build my compressor ::) ..Thanks again for the great thread.. This forum is really awesome..Adios' for now..Hank
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I finished my spring compressor this weekend. Based on a Harbor Freight 3/4" pipe clamp and plywood out of the scrap box. I opted to have a "floating" middle support that I can position at will. The receiver is held into the central support via a strong bungee. I've got a 1 1/8" aluminum tube in the compressor in the picture just to see how the bungee would fit.
Bad idea (the bungee) or should be okay? Anybody ever have significant movement during assembly/disassembly?
Thanks all - JMJ
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Anybody ever have significant movement during assembly/disassembly?
As long as the gun's lined up straight and there is do deflection of the 2 end plates, friction should hold it in place, as evidenced by Dave's experience using no receiver restraint. The biggest benefit I think you'll see from your design is that it'll act like a 3rd hand, making it easier to get the gun in straight and keep it straight while you start cranking.
Since I mentioned deflection, I have to say that was a slight problem for me the first time I used my compressor. The plate at the screw end was angled back enough that it wasn't pushing the internals straight back into the tube. I think the tube was in the compressor a little high (too far from the black pipe) and it had too much leverage for those 2 little screws holding the plate in place.
I'm going to epoxy the end plates to the clamp pieces and do a little cutting to try to the gun down closer to the black pipe to minimize that deflection. If that doesn't work, I'm going to have to come up with some kind of shim to keep that end plate perpendicular to the pipe.
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Thanks Spook.
Since the HF pipe clamp is a bit sloppy, I'll give it a try and if it doesn't work out well, I'll redesign. I bought 2 other long clamps to monkey with just in case, but they have less adjustment range.
JMJ
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Sorry, if this is a dumb question. I see how these work for compressing the spring, but in my case with a Diana Model 5, the end of the spring tube is a threaded metal cap. How do I unscrew this cap with a clap applying force to it?
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Is the end cap what's holding the spring in place? Sounds like that could make things more difficult.
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Yeah, I have unscrewed the end cap once, and the spring forces it off last couple threads. It took two people. The spring pressure wasn't too bad if controlled but I'd rather use a clamp of some sort. Don't want to risk getting shot in the face with the end cap.
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You could try mounting small lazy-susan or similar with a small section of plywood so you can compress and spin. Some folks use a drillpress as a compressor (or a large lathe if you have it).
JMJ
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Try placing a piece of rubber,leather or cork between the end cap and compressor to protect the end cap. Next place two lubed washers between the compressor and the end cap protector. This should allow you to loosen the compressor while turning the end cap.
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Rogn show some pics of the drill press compressor in action. Have a 15 speed floor drill press I was thinking of using.