Q:

New Bullpup Valve done (Pictures) – Safety Concern..

1- What materials do you guys usually use? and how do you protect it from rust?
(Just got a lathe, absolutely new to this. I used stainless 316 cos I’m afraid of rust.)

2 – Will this valve hold up to 3000 PSI? please see images for my circled ‘danger areas’ and let me know what you think.

Thanks for advice in advance!



Mods/Machinists

All Replies

Viewing 7 replies - 1 through 7 (of 7 total)

It actually won’t be in a tube. just stick out at the back. The BSP hole at the back is for gas input from a large tank. designed so the tank isn’t inline with the gun.

this valve will be in a tube for air pressure i assume , so there is no place for it to expand/move . id be 100% sure at 3000psi it would not budge .

what is the back threaded hole for ? is there ,more to the valve.

looks nice , ive used regular 4140 steel for valves and had no trouble with rust some 10 years old .just oild it before putting it in .
or brass . but if you want stainless steel thats the best , i use it alot

@FairlyInconspicuous, I may take imgs again when i get a chance, got rid of them after uploading. I’m in another country, C6 is more common here than KFC! I don’t have a mill..


@Marc
, yea section A may render the valve safe only for CO2 eh. Other sections look fine for HPA?

What other material can I use besides stainless guys?

My gut feeling tells me section A would be a big concern! The math confirms that to!.

Stress in that thin part is 140MPa from the pulling force exerted by the pressure. Yield strength for 316 is somewhere around 550MPa. But be noted I did not include sharp corners and a safetyfactor of at least 2.5(you don’t want this to blow up in your face)! Machined corners look pretty sharp to me.
Taking those into account the safetyfactor and “notch” factor of about 1,7 you can calculate with a yield strength of about 550/2.5/1.7=130MPa. So that leads me to conclude it’s on the thin side, and I would redo the part where the valve rides in.

Take care and be safe!

AWWWWW YEAAAH.

PORNO.

You are my hero. Care to share the ‘big picture’ with us?

Also, where’d you get the SC6 from? Aaaaaand, do you have a mill?

I got a Seig C6. Took very small cuts and slow speed to do the machining.

Stainless 316 insanely hard to machine.. (for me at this stage).

what materials normally used? and how’s rust prevented?

I am not for sure on the thickness, but the machining looks nice. What type of lathe did you get?

Viewing 7 replies - 1 through 7 (of 7 total)

  • You must be logged in to reply to this topic.