Specification for M25x2 neck thread

[TrimixToo]

Thanks Trimix. It was actually the details of the chamfer which retains the o-ring (similar to the SAE ports which are the standard for the LP and HP fittings). I will do a straight counterbore which is a relatively easy to design and to dimension - I use that lots for hydraulic designs. Our cylinders here are all metric and so are my spare valves.

Nothing wrong with a straight counterbore in my book (or in Parker's, come to that, with the right dimensions). It's certainly easier to measure the step than it is to measure tool travel (unless you have a DRO or dial indicator on that axis) or an angled bore. It hadn't quite dawned on me yet that there were tanks with metric threads, but of course there are. I actually used to know that, I think. Guess I should have had more coffee this morning. Or something. My money is still (well...again...) on 6H as the class of fit. It's closest to 2B, which is the CoF for 3/4” x 14 NPSM tank threads, IIRC. But Machinery's Handbook is downstairs in the shop and this conversation already reveals how good my memory is, so a quick lookup is probably in order before you make chips.

Happy fabricating and Merry Christmas!

 

[inka]

i confirm 6H ( see file attached post #2 : taraudage/ thread neck tank= 6H , valve/vis thread = 6g)

 

[inka]

deleted

 

[The Chairman]

If you're drilling tapping into the orifice, why do you want/need the specs for the o-ring?

 

[TrimixToo]

If you're drilling tapping into the orifice, why do you want/need the specs for the o-ring?

So the tank valve makes a seal. He wants to use a regular valve to attach regs to, and supply HP air to the valve.

 

[The Chairman]

Here's what I did...

Yoke fitting with bleed off is attached to a steel braided flex hose rated to 5,000 psi.

3/8" thick brass plate drilled to accept a tank valve. The four holes in the back bolt it to the table. The two in front are drilled and tapped for the 3/8" and 7/16" SPT port holes. I put a vise in one and can screw on the first stage to give me some stability.

I tapped a peice of PVC with a 3/4 SPT to act as a lock nut, then I simiply plumbed to the flex line with the yoke adapter. I'm teaching a reg rebuild class this weekend and will take pics of it in use.​

 

[The Chairman]

For clarity, I used a pro-valve to make this so I can test both DIN and yoke variants.

 

[TrimixToo]

Here's what I did...

View attachment 496003

Yoke fitting with bleed off is attached to a steel braided flex hose rated to 5,000 psi.

View attachment 496004

3/8" thick brass plate drilled to accept a tank valve. The four holes in the back bolt it to the table. The two in front are drilled and tapped for the 3/8" and 7/16" SPT port holes. I put a vise in one and can screw on the first stage to give me some stability.

View attachment 496005

I tapped a peice of PVC with a 3/4 SPT to act as a lock nut, then I simiply plumbed to the flex line with the yoke adapter. I'm teaching a reg rebuild class this weekend and will take pics of it in use.​

Pete, I just have to ask*: Is there a regulator out of sight somewhere? Or are all those lines and fittings rated for HP? Or maybe you don't use full tanks?

Disclaimer: I can spell "engineer," so I am not one. In particular, I am not a MechE. That said...for safety's sake, I'd want to make what the OP is proposing from a convenient chunk of steel with somewhat more wall thickness than that found on a steel tank and a 90* turn from the feed to the valve bore for the NPT fitting so the hose feeds out the side. (I actually own everything I'd need, including the steel, but I'm too lazy to make one so I just put a small pony bottle on the bench instead.) Then I'd feed HP to it direct from a tank.

* You're a big boy, but others might see your setup and try to duplicate it without thinking of any of this stuff.