plumbers/pipefitters- identifying thread size

[ZurBob]

@HoneyBadgerDC

A 5/16 tubing size compression fitting uses a thread size of 1/2" 24 threads per inch. You mostly see these used around light duty water applications like ice makers and coffee makers but air horns and a few other air fitting use them also. I am sure you have a 5/16 compression fitting.

I was in the process of replying that I too had considered this except for the fact that these fittings are cut with machine threads, not tapered pipe as the OP specified, when it occurred to me:

Tapered threads don’t have a major diameter. They can’t (they’re tapered).

As Lewis Black would say, “Something is ask-eeew here!” and perhaps the OP’s specifications are a little… off?

[HoneyBadgerDC]

@ZurBob

I was in the process of replying that I too had considered this except for the fact that these fittings are cut with machine threads, not tapered pipe as the OP specified, when it occurred to me:

Tapered threads don’t have a major diameter. They can’t (they’re tapered).

As Lewis Black would say, “Something is ask-eeew here!” and perhaps the OP’s specifications are a little… off?

 I have seen castings that are slightly tapered. I think it makes it a bit easier to machine. I believe this is just an example of a tapered casting.