I'm looking for a picture, I think I saw it in this forum, or atleast on arfcom, it was a diagram of the 1/2x28 thread pitch, with measurements and so forth. I'd like to find that diagram so I can take it to my gunsmith because he is going to make a thread adapter for my rifle.

Suppressors here are almost always in 1/2x20 UNF, but AR's are in 1/2x28 TPI and is something of an unknown here, I am not sure if the gunsmith only has the info for 1/2x28 UNF threads or if he has for 1/2x28 TPI too.

I'd like to find that diagram to make sure.

Also I don't know but maybe UNF and TPI are the same?

1/2"x28TPI means the threads are half an inch in diamter and there are 28 threads per inch.

Here is a .pdf file of the 1/2 x 28 thread pattern that YHM makes available in their installation instructions.

www.yhm.net/store/media/.223.pdf

You will need Adobe or some other .pdf reader to view.

Quoted: I'm looking for a picture, I think I saw it in this forum, or atleast on arfcom, it was a diagram of the 1/2x28 thread pitch, with measurements and so forth. I'd like to find that diagram so I can take it to my gunsmith because he is going to make a thread adapter for my rifle. Suppressors here are almost always in 1/2x20 UNF, but AR's are in 1/2x28 TPI and is something of an unknown here, I am not sure if the gunsmith only has the info for 1/2x28 UNF threads or if he has for 1/2x28 TPI too. I'd like to find that diagram to make sure. Also I don't know but maybe UNF and TPI are the same?

http://www.silencerresearch.com/Forum/viewtopic.php?t=367

There are three companies threading specs on my site.  AAC's, Gemtech, and YHM.

Silencer Research