Tap (Loaner) Needed 1/2” 12TPI (Not 13TPI)

[mtkreitz]

I know this is a longshot but I am hoping someone has a non-standard tap that I could borrow. I guess prior to World War II the standard threads per inch on a 1/2 inch threaded bolt was 12 not 13 like it’s common place today. I purchased several drill press clamps and need to create backing nuts to hold them to the drill table. If anyone has one that they are willing to loan me I will get it back to them in a few days. Thank you.

 

[-Spike-]

You probably thought of this but- are you sure it's not metric?

 

[splitshot]

Last time I needed an oddball die was on a vintage Ford tractor. Ended up buying off Amazon. Something like $40 for a tool I will never use again.

 

[Saddletramp]

I might have this in my grandfathers taps and dies.

1/2 in very coarse thread. Will look in the am

 

[mtkreitz]

Thanks Steve. I double-checked that it was not metric, that was the only thing I could think of until I learned about 1/2 12TPI. I counted the threads and boom there it was. Not 13 as I first counted but 12...

 

[Saddletramp]

Sorry to report no 12 by 1/2 NPT

I did have a 9/16 12 circled above in red.

Lots of 13 by 1/2 and other stuff

 

[mtkreitz]

Thanks for looking!!!