The Offcial Machinist Thread: Revised 01/04/2014

[jackssmirkingrevenge]

JSR will suggest you to make a pengun.

It's a good place to start LeMaudit relaly made an excellent tutorial.

http://www.spudfiles.com/forums/machine ... 22856.html

[wyz2285]

How can you make such small threads
Tap and die?

[jackssmirkingrevenge]

Yup, it's all in the tutorial

[jmez1996]

Cheers that looks like a great project

@Wyz2285
No don't have the mill attachment. I've seen its possible to do some milling by mounting a vice with vertical travel to the cross slide then putting the milling cutters into the lathe chuck?

anyone got advice on that?

[Gippeto]

Milling vice attachements for lathes do work...they do have limitations as well. Mostly related to travel and rigidity.

A decent compromise to meet budget and space constraints while adding capability.

If you follow airgun forums at all, you may know rsterne? Bob has built some pretty amazing stuff with a small lathe and milling attachement.

[wyz2285]

Finished trigger and filling plug also functional

[Goats spudz]

Do the sizes I have chosen for this part look about right for propelling a .22 +800 FPS, also do you guys think this will be able to withstand 3000 PSI?

[jackssmirkingrevenge]

Finished trigger and filling plug also functional

ou est le video huh?

Do the sizes I have chosen for this part look about right for propelling a .22 +800 FPS, also do you guys think this will be able to withstand 3000 PSI?

The Gunpower Stealth - AirForce Talon uses a very similar design, I'm guessing that's what you based it on ( http://www.stealthresource.org/home.htm ) so you should be good for that pressure and performance, assuming it's built from the right materials.

[Goats spudz]

Yeh I Based it on the Air force condor, It will be made from 316 Stainless, I just wanted to know if it would perform as well because I Don't have the measurements of the stock valve so I had to guess.

[Gippeto]

Old style valve and no return spring? Vaguely reminiscent of a "Blod" valve.

Know a guy with a home built condor who runs without a return spring in the valve, but have no idea how he tunes it to avoid tank dumps.

Porting is plenty big enough. Transfer port in my homebuilt "Disco" is .100"...15.9grain pellets peak @ 920fps on 2700psi fill.

These might help a little.

[wyz2285]

Another question: a year ago I made some plans for a PCP rifle. I did the strength simulation of the chamber. The program only has stainless steel, without any number to define what type. Back then I remember 1.5mm wall thickness would give a safety factor of 3 approximately at 200bar. However the simulation was done with seamless stainless steel tubeR recently I bought a stainless steel tube and it has 1.5mm wall thickness but from the inside I cab see the welding mark, the welding is very good though and can not be seen on the outside. Any advise if I could use it as chamber for a pcp?

[Gippeto]

I would recommend seamless tubing only.

Not overly fond of using a program to "run numbers" if you can't enter factual data into it.

Garbage in = Garbage out. When your safety is at risk, this is NOT acceptable.

[wyz2285]

Hydro-testings can be done using water as compressing fluid?
Then I'm thinking about build a manual hydraulic pump, something like 3mm piston diameter, 5mm wall thickness pump body and a long lever to push the piston. Will a paintball pressure gauge work with water though? I have a 6000 psi one and don't have any use for it.
Fill the testing chamber and pump with water then push the lever to raise the pressure.

[Goats spudz]

Old style valve and no return spring?

There is A return spring it just isn't on the drawing, I thought my porting was way too small looking at that drawing Im satisfied

[Gippeto]

Too large porting can dramatically lower efficiency and shot count for little gain in velocity.

wyz....hydro = water....yes you can use water for hydro testing. Would suggest filling with water or oil and using a grease gun to pressurize...a nice off the shelf solution.