Valve mod - pcp pistol

I remade a new fill valve with protection for the gauge. The fill valve is a simple but effective system. I milled off some threads from the screw to let air past and the O ring stops it getting out.

Breech has been drilled and holes tapped to secure it to the tank/body.

Cap screws sized and retaining holes drilled, tapped and counter bored for them to hold in the fill and main valve body.

Basically I took off the knurling so there was an exact fit.

Unfortunately the wood bit isn't an exact shape with a flat spot making the resulting cut a bit like a flattened dome, so I cut a chanel out with the end mill so there's good contact. I will use a bit of fine sandpaper on a tube to take the sharp edges off the cut later.

So you can see what look like corrugations in the cut face. This is probably from my small mill picking up vibrations, but for this purpose it's fine and the light makes it look worse than what it is.

So I got the barrel fitted then milled out the loading breech. then drilled and tapped two retaining grub screws for the barrel. Next I chamfered the corners on the top. I'm not totally sure what I am going to do here, but have been toying with keeping it with clean lines and mount a small red dot. I could also fasten a weaver rail to it The result emerged from the aluminium mess.`

Now that the barrel is fitted I was able to start on the bolt. This turned out really well and confirmed that the barrel and bolt are nicely lined up.Alu had an 8.5mm bore and I reduced the stainless bolt to 8.3 mm at the back and 6.03 mm for the probe part and it slide into place beautifully, so I am very pleased with that.

I had also made a preliminary mockup for a fill valve to include a gauge. This is not the final piece, but I know what I want to do. Gauge is mounted into a boss that I plan to have a barrel support fitted to. Fill probe fits nicely underneath it. I just need to get a 10mm x 1.0mm thread tap for the gauge.

Also see the finished firing valve body, poppet and seat. They came up really well and I am excitied to see how well it works. Looks good for now anyway. Note the custom Nunga forged brass wrapped in my hori custom made spring.

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.

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.