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Valve mod - pcp pistol
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Pauly5 View Drop Down
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Posts: 1561 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2024 at 6:46pm
So i found a piece of brass to use. I have made the poppet valve and loctited it to the stem.

After it was fastened I finished off the seat and polished it so the it was concentric with the shaft. I am quite pleased with how it turned out, but of course being pretty doesn't mean it works.

I also polished the valve seat. I have some of the 3M polishing cloths, 800 up to 15000 grit. It is satisfying working through them and seeing the finish improve.
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Posts: 453 		Post Options Post Options   Thanks (0) Thanks(0)   Quote J-S Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2024 at 6:39am
very cool
J S Airguns
Air Arms TX200('s)
Theoben Sirocco
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FWB 300s
Webley Patriot
One or two others...

Current projects:
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Pauly5 View Drop Down
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Posts: 1561 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 20 Sep 2024 at 6:19pm
Barrel is around 300 mm, so not a small pistol.
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RangerPete View Drop Down
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So how long are you planning on making the barrel?
Walk quietly, but carry a big stick.
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Pauly5 View Drop Down
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Slowly doing stuff.

NZ Post has botched up Nunga's foundry delivery, so valve on hold. I bought a piece of 3.9 mm piano wire today. Pretty hard, and hopefully harden up, but I might try that for the valve stem.

I also decided to use the .25 cal FX barrel I had. It was off a Bobcat. I cut it down and reduced the breech end to fit into what will be the breech block for this build. Fits nice and snug with no movement.

FX only rifled the last 2 or 3 inches of these barrels and you can see that they make the muzzle smaller diameter to do this, then thread on a piece to match. You can see the marks on the outside where they "squeeze" the rifling in giving it a "smooth" twist.
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Posts: 977 		Post Options Post Options   Thanks (0) Thanks(0)   Quote RangerPete Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep 2024 at 6:08pm
Good luck with that 😂
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Pauly5 View Drop Down
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Posts: 1561 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep 2024 at 5:06pm
Well I tried cutting one of my donor screw drivers and it was hard. The hacksaw had trouble biting into it. It made a small nick, so I just put it in the vice and it snapped on the nick.

Doing pest control I was always up in ceilings and sparkies often forget stuff and they do like to have expensive screwdrivers which are decenyly hardened. So I have a couple I can wreck. So this will be my valve stem.
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Pauly5 View Drop Down
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Posts: 1561 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 08 Sep 2024 at 3:26pm
So should I remake that valve seat in brass and the harder material for the moving part of the valve. Poppet valve?
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Originally posted by nunga nunga wrote:

Thats because 385 brass as a lot of lead (around 3%) compared with other types of brass which makes it very good for machining it is also know as free machining brass. But it is a lot softer as well so i dont know how it would handle been used on HPA valve seat.

If you have had good results using it BC_Clark then i would be happy to mix up a batch for you paul, like i said i have everything here and i will be smelting other stuff this weekend anyway.


Some of my most powerful and highly stressed valves have been with 385 brass seats
so I can say that normal HPA usage is no challenge.
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Posts: 1050 		Post Options Post Options   Thanks (1) Thanks(1)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 2024 at 12:49pm
Thats because 385 brass as a lot of lead (around 3%) compared with other types of brass which makes it very good for machining it is also know as free machining brass. But it is a lot softer as well so i dont know how it would handle been used on HPA valve seat.

If you have had good results using it BC_Clark then i would be happy to mix up a batch for you paul, like i said i have everything here and i will be smelting other stuff this weekend anyway.
2nd place HP springer - WFTF World Championships 2014
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