Advice on what the maximum high pressure of 2mm(1/16) steel is.

[Qyuubi786]

My 1377 bullpup uses a co2 hose from rap4 as the air reservoir. Consequently this gives it one high power shot and three low powered shots when charged to 850 psi.

I've used 15mm (9/16) OD steel tube as the air reservoir it has a 2mm (1/16) thick wall, I have tapped it to M13 (13mm). What's the maximum pressure that I should fill it to?

[Gippeto]

Without at least knowing the material, there's no way to know. You need the material strength (yield strength preferably), the od and the wall thickness to run the calculation.

Al

[rsterne]

The tube wall thickness remaining above the threads will only be 1mm, with a 13mm thread in a 15mm tube.... Where is the O-ring, inboard of the threads, or outboard.... makes a huge difference in the strength.... The strength of the threads in the plug will depend on material and thread engagement, as well.... The tube wall may not be the weakest point.... Details on the materials are crucial to the answer you seek....

Bob

[Qyuubi786]

Hmm not sure how I can tell if it's outboard or inboard.
I bought the steel tube from fleebay. It says "cold drawn precision seamless steel DIN2391/C high pressure hydraulic grade" (not sure if that's going to be much help).

[rsterne]

If the O-ring is inboard of the threads, where the tube is the full 2mm wall thickness, the threaded area is not under pressure, but is still under tension from the threaded plug trying to pull the end off the tube.... If the O-ring is outboard of the threads (ie on the end of the tube, or nearly), then the threaded area is under pressure, so the wall thickness of the tube is only 1mm instead of 2mm.... Obviously, this makes it much weaker, and able to safely stand less than half the pressure.... If the threads are tapered pipe threads, self-sealing with no O-ring, then you must treat them as under pressure....

Bob

[Big Bore Bart]

  A quick Google of the  DIN spec came up with this manufacturers chart.   The working pressure for the spec seems to be 251 BAR.

[Qyuubi786]

Ok it is outboard. The maximum pressure I'll charge it to its 1000psi since I have my 1377 with a 13ci tank for tons a high  shots per fill.