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Valve mod - pcp pistol
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kruzaroad View Drop Down
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Posts: 2692 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 2024 at 4:39pm
Just had nosey on web.
Starts at around 400° depending on stainless. Recomends a cutting fluid, breaks to let metal cool if drilling to long and this
Use a drill bit designed for stainless steel
Use a cobalt or titanium nitride (TiN) coated high speed steel (HSS) drill bit with a 135° point.
Begin drilling at a lower speed, around 30-60 surface feet per minute (SFM).

Edited by kruzaroad - 04 Dec 2024 at 4:42pm
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kruzaroad View Drop Down
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Posts: 2692 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 2024 at 4:31pm
Probly is to fast pauly.
Was watching video a week or so back and dude was having trouble with the drill hardening stainless around holes. Apparently stainless tempers at very low heats.
Might have to set up cutting fluid bottle with gravity feed and flow adjustment or something to keep temp down
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 2024 at 4:18pm
Work has been very busy the last couple of weeks, so progress has been slow. I have also had issues drilling and tapping this damn stainless probe. I thought I had it sorted, but I now think I had the drill speed too fast.
I also bought myself some decent metal cutting paste too.

Anyway, one thing I bought off FB marketplace was a Rotring  drawing board for $30. When I was at school I loved Technical drawing and used to have a similar board. I have a few of my parts hand drawn, so now I can draw them to scale. 

When making the part, I can now concentrate on the making rather than design and turning at the same time.

The probe is on it's 3 rd design change now and I am pretty sure this is going to work. I also made the hammer which you can see in the photo.
 It is made from steel, but has a delrin skirt that is just a touch bigger, so it runs on the delrin.  Aluminium is quite a sticky material and the delrin solves the friction between the steel and alu, especially when cocking. In my other pistols I have had to generously lube the tube to overcome this issue.

I also started on the grip, doing a trial run using some birch ply glued together. I plan on making the grip from some walnut I have. So I'll update that once I get into it properly.
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nunga View Drop Down
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Posts: 1083 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 26 Nov 2024 at 10:49am
yeah you need to be very careful with the threads. Pinning is the safer way to go for sure.

1 psi = 0.070306958 kilogram-force/sq. cm
1 kilogram-force/sq. cm = 14.2233433071 psi

Example: convert 15 psi to kilogram-force/sq. cm:
15 psi = 15 × 0.070306958 kilogram-force/sq. cm = 1.0546043695 kilogram-force/sq. cm


So 3000PSI equals 210.9KG of force.
2nd place HP springer - WFTF World Championships 2014
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 26 Nov 2024 at 9:42am
Thanks Ian,  I had actually watched that on Saturday.

I would be keep to give the threading a go as opposed to pinning the valves. I am cautious with all that pressure, so until I have seen the correct calculations from a competent person, I wouldn't try it.
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nunga View Drop Down
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Posts: 1083 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 26 Nov 2024 at 9:37am
I found this video on youtube, might be of some use.
2nd place HP springer - WFTF World Championships 2014
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RangerPete View Drop Down
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Posts: 1035 		Post Options Post Options   Thanks (0) Thanks(0)   Quote RangerPete Quote  Post ReplyReply Direct Link To This Post Posted: 20 Nov 2024 at 11:48am
Thats really good Pauly
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J-S View Drop Down
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Posts: 497 		Post Options Post Options   Thanks (0) Thanks(0)   Quote J-S Quote  Post ReplyReply Direct Link To This Post Posted: 20 Nov 2024 at 4:09am
Looks f@#king cool. wish i had the skills!
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 20 Nov 2024 at 2:58am
That's what is motivating me. I mull over something for a few days then go and make it.

I plan to feature a bit of nice wood on this too. I have some walnut for it. This is a mockup with a grip I had made ages ago, but I don't really like it. I will put some wood under the tank too. That should hide the industrialousness look of the tank. 

Excuse the mess. 
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jwabfrog View Drop Down
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Posts: 159 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jwabfrog Quote  Post ReplyReply Direct Link To This Post Posted: 20 Nov 2024 at 2:39am
Awesome Pauly, I am learning vicariously. It will be super satisfying to shoot knowing you've made the entire thing!
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 19 Nov 2024 at 4:59pm
Here you see the stainless probe being tapped. I learnt that with the harder material you need the correct drill bit size.

A std drill set has a 4mm drill bit, but it is most likely 3.9 mm, but a 4.2 mm drill bit is required for an M 5 tap. How many taps did I break learning this?

New tap set has 3 taps per size. Tapered, intermediate and bottoming. So you need to run all three through to get the final size hole. Fortunately I am enjoying all this learning.

The bolt handle will be a straight pull, being retained by a sprung clip. This way you can also close the bolt by the handle, or by pushing bolt with your thumb. Bolt just temporary for now.
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 19 Nov 2024 at 4:49pm
So having said that I have made some more progress on this build.

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.
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 19 Nov 2024 at 12:04pm
I got myself a proper drill and tap set. Amazing what a difference it makes having the correct drill size, especially when tapping stainless.
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Pauly5 View Drop Down
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Posts: 1676 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 29 Oct 2024 at 3:09am
Next I contoured the base of the breech to fit onto the 32mm tank. I used a combo of flat end mill and a 32mm wood bit.

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.
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RangerPete View Drop Down
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Posts: 1035 		Post Options Post Options   Thanks (0) Thanks(0)   Quote RangerPete Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2024 at 8:32am
Thats all looking really smart Pauly. Amazing stuff you'r doing there!
Im very keen to see how it is all going to come together   
Walk quietly, but carry a big stick.
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