Thread Questions

[iansilbe]

I have a .625-24 UNEF-2A shaft that will go into an internal part.  I wanted to make this internal part (hollow cylinder) have an ID=.575".  While I can create the UNC and UNF threads for the .625 nominal size, I cannot create the UNEF.  I have to make the ID=.625" for the UNEF to be created on the female part.  I want to make sure I know why this is the case for the future, so how can I develop my intuition for this?  Is .625 the pitch diameter?

Relatedly, on the male part, is there any reason to have the diameter that the threads go on as 0.575", or should I just make it .625? (see below) Thanks!

[imajar]

For Starters, I would suggest using the hole feature, which automatically does all of that for you, and the 5/8-24 thread is available.

But for your question, I was able to put a 5/8-24 internal thread in a .575" hole, but inventor did complain about mismatched diameters and I had to accept the error.  But I think your approach is correct, you should model the hole at .575" for that thread.  Not sure why Inventor is throwing the error.