Technical Thread pitch/size on metal valve stems?

I have several, but my pitch gauge is not fine enough to measure it.
I’ve a need to pressurize a tank, and would like to drill and tap it.
Thanks.

 

This type?

 

That would work as well. Thanks. I have several leftover from my dads owner/operator days, but don’t mind buying another.

PS, the ones I have aren’t NPT, but use a nut and a rubber washer. But that will work out better!

 

That’s why I asked about type. Stems for wheels use a nut since they pass thru a hole only. That threw me off as to how you’d thread it on then get it tite.

 

All good, I had a plan. But much easier with 1/8th NPT.
Thanks again!