Totally hypathetical (im not going to do this)

[in_cavediver]

Originally Posted by WD8CDH

The aluminum D and E medical tanks are .750-16 UNF o-ring seal. I have never seen a SCUBA valve that came with those threads. I have rethreadsd 3/4-14 NPS Scuba valves to fit but it's more expensive than buying a new SCUBA tank.

You're absolutely right. I was confused with another AL O2 tank that was old avaiation tanks.

[Luis H]

The old O2 tanks used the same 1/2” NPT tapered pipe thread as old Scuba tanks. Some of the first pony bottles were just converted O2 bottles.

I have seen pictures of wreck divers in NJ back in the mid 60’s with double steel 72, double hose regulator, and a pony bottle nested on the back of the double. The pony bottle was a converted O2 tank.

[waytooslow]

no jab dave, but

hypothetical definition |Dictionary.com

good read though