Tank valve install issue

[MacLir]

Hello all

I am in the process of assembling a set of doubles and have met with a valve problem. The tanks are brand new xs scuba steel 100s. The valves are new Thermapros. I have lightly christolubed the threads on both valves and tanks. However, for both valves on both tanks, I find that when the valves are screwed in about 3/4 of the way into the tank, they stick and will go no further. In my experience with singles, valves usually hand tighten all the way down with no wrench needed (except for torque at the final tightening), so I have been reluctant to use a wrench to force anything here. Does anyone have any advice on what might be the problem or on next steps to solve it?

Thanks in advance!

 

[Dsix36]

Is it possible that you have the wrong threads on either the tanks or the valves? Not everything is compatible.

It is also possible that the threading process was not complete or proper. Difficult to tell from the internet though. Do you have other valves and tanks to check the fit with?

 

[redacted]

I think I would be opening up one of my Al XX and do a little trouble-shooting.

 

[MacLir]

Thanks. It is beginning to look like a misthread problem with the valves. Being assessed by the vendor via emailed photo. We shall see.

 

[OkByMe]

Look on the stamp markings on the shoulder or near the cylinder neck. I hope you DON"T find M25x2, that means metric threads. If you can spin the valve into any other cylinder and bottom by hand, but not these, you need to get your money back. If the threads are metric and they are DOT, then what else have they screwed up? If they are not DOT, you will not find anyone to hydro test, if the threads are metric, you can't get a valve with a burst disk. The hydro and burst disk is requirement in the good ole USA.

 

[spectrum]

Yea that should all be spin on as you describe. If bought locally have them run a stock valve in there to see if the valves are messed up and then run the valves into an open cylinder. Somewhere there is a clinker. If it's blatant enough to isolate in a photo then there you go!

Pete