XS60C PCP Repeater project

[rsterne]

Got my .300 cal. Barrel, Carbon Fibre sleeve, Loctite 638 to glue them together, tapered valve spring, assorted hammer springs, taps and O-rings today.... so I think I have all the parts now to complete my build.... Hopefully back in the shop tomorrow....

Bob

[stalwart]

Got my .300 cal. Barrel, Carbon Fibre sleeve, Loctite 638 to glue them together, tapered valve spring, assorted hammer springs, taps and O-rings today.... so I think I have all the parts now to complete my build.... Hopefully back in the shop tomorrow....

Bob

Woo Hoo!

Finished the tube's slots and holes tonight. Reamed it from the block back, to fit stock parts... cut the least labor intensive slot at the bottom. It will allow loading the valve from the back, if desired, while presenting the o-rings with the least amount of challenges.

This one is set to index the trigger housing to the back, you can see the little ears protruding back into the mounting slot. This will be SOP, unless a customer wants a safety.

The pin's slot is a bit narrower than stock, and it now rides on steel only.

[RHytonen]

Got my .300 cal. Barrel, Carbon Fibre sleeve, Loctite 638 to glue them together, tapered valve spring, assorted hammer springs, taps and O-rings today.... so I think I have all the parts now to complete my build.... Hopefully back in the shop tomorrow....

Bob

Woo Hoo!

Finished the tube's slots and holes tonight. Reamed it from the block back, to fit stock parts... cut the least labor intensive slot at the bottom. It will allow loading the valve from the back, if desired, while presenting the o-rings with the least amount of challenges.

This one is set to index the trigger housing to the back, you can see the little ears protruding back into the mounting slot. This will be SOP, unless a customer wants a safety.

The pin's slot is a bit narrower than stock, and it now rides on steel only.

This looks much stronger than cutting away the bottoms of the receivers.

Rod

[stalwart]

I'm sure it is, but the force required to demonstrate that would have to be both very specific and in an absurd quantity.

With that steel backbone, I could lighten the receiver into lace, and unless it was used as a splitting maul, you would never miss that metal. Considering that many rifles are held together with 2 small screws, in the same place these still have solid metal... I firmly believe that a bayonet could be effectively used with these, if not an entrenching tool.

[RMM]

Got my .300 cal. Barrel, Carbon Fibre sleeve, Loctite 638 to glue them together, tapered valve spring, assorted hammer springs, taps and O-rings today.... so I think I have all the parts now to complete my build.... Hopefully back in the shop tomorrow....

Bob

Woo Hoo!

Finished the tube's slots and holes tonight. Reamed it from the block back, to fit stock parts... cut the least labor intensive slot at the bottom. It will allow loading the valve from the back, if desired, while presenting the o-rings with the least amount of challenges.

This one is set to index the trigger housing to the back, you can see the little ears protruding back into the mounting slot. This will be SOP, unless a customer wants a safety.

The pin's slot is a bit narrower than stock, and it now rides on steel only.

Stalwart, I'm honored to have this build in my stable, thanks. 

If it wasn't for you and Bob, and there are more, whom have helped me with your willingness to share I wouldn't have challenged myself to do some of things I've been doing, but I still have a lot to learn so please keep sharing, teach this man to fish. 

[StevenG]

I'm sure it is, but the force required to demonstrate that would have to be both very specific and in an absurd quantity.

With that steel backbone, I could lighten the receiver into lace, and unless it was used as a splitting maul, you would never miss that metal. Considering that many rifles are held together with 2 small screws, in the same place these still have solid metal... I firmly believe that a bayonet could be effectively used with these, if not an entrenching tool.

Will you be putting prices for bayonet mounts on your website or should we email you?

[stalwart]

 

Are you sure you wouldn't rather have a battle axe? Grappling hook?

Seriously? I have been pondering a stone cold survival rifle for a very long time.

[RHytonen]

I'm sure it is, but the force required to demonstrate that would have to be both very specific and in an absurd quantity.

With that steel backbone, I could lighten the receiver into lace, and unless it was used as a splitting maul, you would never miss that metal. Considering that many rifles are held together with 2 small screws, in the same place these still have solid metal... I firmly believe that a bayonet could be effectively used with these, if not an entrenching tool.

That's great news - for the ~45" long 1"steel octagon-handled 20 pound splitting maul I'm building
You never know what might come through the door out here, and when the air runs out... LOL

But serially folks, I have to admit I'm just an overdesign/overbuild kind of guy.
There's going to be a lot of stuff hanging off that tube-
& a barrel already trying desperately to droop from extreme weight and length.

I was up all night thinking tooling scenarios for shaving it down to clear the tube. Everything from feeding it under a fixed grinder, to a sort of router and fences with a side mill cutter, to handheld whatever....using a worn (7/8") cutting wheel... Dremel stone??
HF portaband, mounted with a table and fence?
I'll just have to see what cuts it with the least tool bearing load.. Good thing I also got a shorter barrel to practice on.

Monster Barrel Liner is ordered as of yesterday - and I can't wait!
Need the actual dimension to know how much to grind away.
....Even though it's still 10 degrees outside, and nowhere near metalworking (even gluing) season, here in darndest WV  - YET
 
(4' of 4130 arrives today. Shoulda ordered more, the shipping is what hurts.
It's always as much as the steel  -But Shapiro guarantees no Chinese steel.)

3/4" Brass heavy wall tube also coming to experiment with sealing a stock tube better
(rsterne's oring support bushing.)
Call it machining practice now I guess. Or maybe I can try building a valve some day.

Rod

[stalwart]

"Stalwart, I'm honored to have this build in my stable, thanks. 

If it wasn't for you and Bob, and there are more, whom have helped me with your willingness to share I wouldn't have challenged myself to do some of things I've been doing, but I still have a lot to learn so please keep sharing, teach this man to fish."

Mike, thank you for the support you've given... takes guts to order a gun that has never been built before.

[StevenG]

Are you sure you wouldn't rather have a battle axe? Grappling hook?

Seriously? I have been pondering a stone cold survival rifle for a very long time.

I was mostly kidding, but that survival rifle idea has some merit for sure. Not really my style though. Now a straight pull, like a K31, would sure get my attention.
I have always wondered why that is not more popular in pellet guns. We don't need a strong caming force, which it lacks and that makes the design limited in the powder burner world. Probably just adds expense and not that much upside for the average joe.

[rsterne]

After a couple of days of running around, I got back in the shop today and drilled and tapped the three mounting holes in each Tank Block, plus the upper air passage....



These things are really taking shape now.... This step took 1.5 hrs., total now 14.25 hrs. (4.75 hrs. per block).... hopefully more progress after lunch....

Bob

[rsterne]

I got the bottom air passage drilled, tapped for the plug, and the safety bleed hole drilled....



This was another hour, for a total of 15.25 hours to this point, so let's call it 5 hours per block.... The only thing left is to make a short 1/8" pin to activate the pin valve in the regulator (or, that can be removed).... On my own blocks I am going to machine a mount for a barrel band on the top front corner, and dress them up a little bit with a groove around the middle, just for appearance.... However, stalwart's is ready to go.... I hope you all have enjoyed seeing what goes into making a reversed tank block.... It's not too surprising that JDS Airman charges $70.00 - $85.00 for his conventional tank blocks without a Picatinny Rail.... Here is a photo of the first assembly to the tank and block to the Grizzly....



I'm really pleased with the results so far....

Bob

[RMM]

I got the bottom air passage drilled, tapped for the plug, and the safety bleed hole drilled....



This was another hour, for a total of 15.25 hours to this point, so let's call it 5 hours per block.... The only thing left is to make a short 1/8" pin to activate the pin valve in the regulator (or, that can be removed).... On my own blocks I am going to machine a mount for a barrel band on the top front corner, and dress them up a little bit with a groove around the middle, just for appearance.... However, stalwart's is ready to go.... I hope you all have enjoyed seeing what goes into making a reversed tank block.... It's not too surprising that JDS Airman charges $70.00 - $85.00 for his conventional tank blocks without a Picatinny Rail.... Here is a photo of the first assembly to the tank and block to the Grizzly....



I'm really pleased with the results so far....

Bob

I for one have enjoyed your build and I hope to be able to machine a reverse block some day, but I have a lot to learn before that happens.   Thanks

[rsterne]

I finished off my own blocks this afternoon, made the barrel band mounts and made a cutout between the tube and regulator just to get rid of the "blocky" appearance....



The total time for blocks to this stage works out to 6 hours each.... That could be reduced by larger runs.... a more competent machinist.... or a CNC, of course....

Bob

[stalwart]

As the front trigger mount nut is more of a "Y" than a "T", I ran a dovetail cutter in the receiver's slot, and got plenty of clearance for the hammer. The screw needs to be shortened slightly, or a washer placed under it, to clear, but there is plenty of room now.

Does anyone know the hammer weight and stroke of the Discovery and the Crosman 22xx guns?

Bob, how much space is between the tank and the tube?

[rsterne]

Stock Disco hammer is 58 grams (22XX is 60 gr.) and the stroke is 0.58".... Very easy to increase the stroke to 0.65" by shortening the valve stem (no change to lift as stock the valve spring goes coil bound).... Increasing the stroke further requires lengthening the breech and tube slots, shortening the back of the valve and drilling the front of the hammer, shortening the back of the bolt and/or moving the hammer pin back, in other words similar problems to the XS-60c.... If you do everything you can get about 1.15" total travel, including the valve lift, so with 0.200" lift that is 0.95" stroke.... Maximum hammer weight, including a 7/32" guide, is about 80 grams, unless you add a weighted cocking knob.... You can get more hammer weight and stroke in the XS-60c....

About 0.010" max.... basically they touch.... Remember I asked you if you wanted enough for a 9 oz. CO2 and you declined.... I like it up snug, it can't stress anything if you drop/fall on the gun....

Bob

[RMM]

Bob, in your reverse tank block design is your pin valve an on/off??  If not do you fell there's a need for an on/off?

[rsterne]

Nope, no On-Off feature.... If your gun doesn't leak, there is no need for one.... You have to remove the gauge and fill fitting to rotate the regulator anyway, so really no way to keep air in the tank if you have to remove it.... It would be quite easy to modify the tank block to have a screw operated pin to depress the valve in the regulator in this design, in fact I did one a couple years ago that was like that.... You have to seal the pin with an O-ring, of course, and make it so that removing the screw doesn't launch any parts under pressure.... The only advantage is that if you want to get into the gun you can turn off the regulator, drain the reservoir on the gun and remove the tank block from the front of the tube, without draining the tank....

Bob

[rsterne]

I got my new tapered valve springs the other day, and today I installed one in the valve.... It turns out that to get the same preload on the spring the valve has to be shortened 1/2", which means tapping the 16 mm x 1.5 mm threads deeper.... I also opened up the slide slots in the valve and streamlined the end of then for better flow.... There is a TON of room to get air to the poppet now.... You can see that the original raised seat for the poppet is gone, and the back of the valve is now 1/2" ID.... I saw no reason to shorten the male threads, as the entire tube is part of the valve with the front being opened up so much.... Note that the front of the valve is also drilled out to 3/8" ID....



The piece above the valve is a test piece for finding out how the Loctite 638 cures when gluing Carbon Fiber to Steel.... It consists of a 3" long piece of 1/2" OD steel rod, and two 1.5" long pieces of 1/2" ID CF tubing I had.... I wrapped 1" wide masking tape around the middle of the rod so that the two pieces of tubing would have a 1" long overlap.... On one piece I used Loctite 638 (green) Slip Fit Retaining Compound, cured at 100*F for 3 hours and then post-cured at 175*F for 3 more hours.... After that, I then glued on the other end (same Loctite), but just a 24 hour cure at room temperature.... I had been told that some plastics/composites don't cure properly without baking them, so I thought I would find out.... The plan is to put the piece in a vice and compress the ends of the tubes inwards until something fails.... The tubing is a thinner wall than my barrel sleeve, and I expect the tube to break long before the glue, but this afternoon I'll find out and report back....



Bob

[rsterne]

Here are the test results for the Loctite 638.... First, the method.... Pressure applied until failure of both sides....



Now the parts after testing.... You can see where the parts were overlapped before they were clamped in the vice.... 1" overlap on each end.... The vice is just snug, there is enough pressure that the parts didn't fall out of the vice and I could take the first photo....



The left side failed without a lot of pressure, I turned the handle on the vice about 1/8th turn from snug.... There was increasing resistance and then you could feel the joint yield on the side that had been cured for 24 hours at room temperature.... I wound the vice in until the steel rod contacted the vice on that end, and then started applying more pressure until the oven-baked side failed.... It took many times the force, and failed with a BANG!.... I then took the test piece out of the vice, split the tubes and slid them off the end....

The 24 hr. room temperature cured side (left) was mostly cured, but the glue line sheared.... The Loctite felt slightly soft, and there was a trace of liquid at the outer end, you can see the shiny line of it at the very left end inside the tube, and there is no corresponding cured residue on the steel on the outermost 1/4" of the overlap.... I assume that more time would have cured that material....

The side that was cured at 100*F, and then post-cured for 3 hours at 175*F was completely cured.... The residue on the steel, and inside the tube, was uniform and completely hard.... I have no doubt that with the amount of force required to break the joint that using this method to glue a carbon fibre sleeve to a barrel would work perfectly.... It is quite possible that a room temperature cure would eventually reach the same strength, but it might well take a week or more.... However, I think that even with a room temperature cure, that the Loctite 638 would work just fine for this purpose....

Bob