Valve mod - pcp pistol

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   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 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 10 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1415	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 09 Sep 2024 at 10:06pm
	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.

RangerPete Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 18 Apr 2023 Location: Cambridge. Status: Offline Posts: 884	Post Options Post Reply Quote RangerPete Report Post Thanks(0) Quote Reply Posted: 09 Sep 2024 at 11:08pm
	Good luck with that 😂
	Walk quietly, but carry a big stick.

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 10 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1415	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 18 Sep 2024 at 9:50pm
	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.

RangerPete Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 18 Apr 2023 Location: Cambridge. Status: Offline Posts: 884	Post Options Post Reply Quote RangerPete Report Post Thanks(0) Quote Reply Posted: 19 Sep 2024 at 10:19pm
	So how long are you planning on making the barrel?
	Walk quietly, but carry a big stick.

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 10 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1415	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 19 Sep 2024 at 11:19pm
	Barrel is around 300 mm, so not a small pistol.

J-S Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Senior Member Joined: 19 Oct 2014 Location: Auckland Status: Offline Posts: 425	Post Options Post Reply Quote J-S Report Post Thanks(0) Quote Reply Posted: 20 Sep 2024 at 11:39am
	very cool
	J S Airguns Air Arms TX200('s) Theoben Sirocco HW77 FWB 300s Webley Patriot One or two others... Current projects: Too many..

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 10 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1415	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 21 Sep 2024 at 11:46pm
	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.

nunga Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Forum Moderator Joined: 08 Mar 2013 Location: Pukekohe Status: Online Posts: 1012	Post Options Post Reply Quote nunga Report Post Thanks(0) Quote Reply Posted: 22 Sep 2024 at 8:34am
	Silly question, You are going to lap the seat in right? That brass looks nice but is it just the picture or are there a lot of machine marks still on the face of that? hope it seals. Nice work! I will get the other brass sent out again for you anyway and you can use it on another project if you dont need it for this now.
	2nd place HP springer - WFTF World Championships 2014

KiwiTR6 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 03 Nov 2022 Location: Stratford Status: Offline Posts: 282	Post Options Post Reply Quote KiwiTR6 Report Post Thanks(0) Quote Reply Posted: 22 Sep 2024 at 8:36am
	Paul, I've found Solvol Autosol to be excellent for final polishing. I'm not sure if it would be coarse enough to finalise the metal to metal seal though. I have heard of people using moistened cigarette ash on fuel needle jets, but that's probably finer again.
	FX Wildcat MK111 BT Sniper .25 FX Dreamline Classic .22 Diana Outlaw .22 Cometa Fenix 400 .177 Weihrauch HW50 .177 Crosman 2240 PCP Custom .22 Crosman 2250 PCP Custom .22 Brocock Grand Prix .22

Pauly5 Members Profile Send Private Message Find Members Posts Add to Buddy List Forum Moderator Joined: 10 Mar 2013 Location: Titahi Bay Status: Offline Posts: 1415	Post Options Post Reply Quote Pauly5 Report Post Thanks(0) Quote Reply Posted: 22 Sep 2024 at 8:49am
	Thanks guys, yes I was going to use something to bed the two together. I have Autosol, valve grinding compound and even toothpaste. Nunga, this is kind of a test run. I don't know how well this will work and so the good thing is that I can take the whole valve system out and replace it, so I will use your piece of brass because it was made for it. It means something to me to use the piece cast especially for it. I can make the mistakes on this first one. The other thing I was going to do was make the seat out of delrin.