I am just finding my way around the forum and see that there is a lot of neat info to explore here. I want to throw my 2 cents in about threads. I make a lot of air tubes and do a lot of single point internal threading, and finding "good" info about threads has been challenging. If I happen to have a tap of the correct size, I will usually single point the thread to within a few thou and then use the tap to barely clean up the last little bit and bring it into final size. But what is the maximum major diameter of the internal thread? I need that not only for information, but to do proper strength calculations.
I finally found a site that has a thread calculator that I really like. You have to read the glossary to really understand it, but gives the info for internal and external and all the classes. For example, the maximum major diameter of a 1.125-20 class 2B internal thread is actually 1.1382", not 1.125. That's important information if the tube wall isn't very thick and the single point threading bar has a sharp point.
Anyway, here is the link.
http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx
