Scuba Tank Valve Common Parts?

[Manatee Diver]

I was looking to add a valve stem and related parts to my save a dive kit, but I have three common valves in my fleet. I was looking at the schematics and I don't see specs for the washers.

So I was wondering how compatible are the parts between valves. In particular I have DGX, Thermo, and Blue Steel valves. I don't imagine that the stems are compatible, but what about the hand wheel washers and the packing?

 

[Tanks A Lot]

I'm not 100% sure on the DGX valves, as I don't get many into my hands, but I believe they are pretty much the same as the Thermos. I will treat them the same below. The BlueSteel valves are manufactured by San-O-Sub (SoS).

Starting from the outside.

• Handwheel Nut - Different between SoS and Thermo, but can be used interchangeably.
• Handwheel Spring - Different between SoS and Thermo, but can be used interchangeably.
• Handwheel - Different between SoS and Thermo, but can be used interchangeably.
• Handwheel Anti-friction washer - Different between SoS and Thermo, but can be used interchangeably.
• Packing Nut - SoS uses a 17mm nut, Thermo roughly 18mm (Stupid imperial system...). They are not interchangeable.
• Thrust washer - Both use a 2.0mm thick thrust washer.
• Stem O-Ring - Both can use a BS010 (6.07 x 1.78 | 90 shore) O-ring.
• Stem - Different between SoS and Thermo, but can be used interchangeably.
• Seat - SoS uses a 11.95mm seat, while Thermo uses 1/2" UNF seat. They are not interchangeable.
• Copper gasket - SoS uses a 11.5 * 14.5 * 0.8, while Thermo uses a 12.4 * 15.8 * 1.0 copper gasket. They are not interchangeable.
• The dip tubes are not interchangeable, as they have different thread dimension.

In short, except the copper gasket, seat, packing nut and dip tube, things can be swapped around.

You may find the attached schematics useful. One page shows a SoS valve, but BlueSteels SCUBA valves use the exact same inner parts. Please note that SoS manufacturers tons of different valves, so the above does not apply to all SoS valves, just the BlueSteel branded ones.

 

[Manatee Diver]

In short, except the copper gasket, seat, packing nut and dip tube, things can be swapped around.

Thanks, that means I only need to have a SoS and Thermo packing.

The other parts aren't field repairs as they would require the tank to be emptied.