"Bugs" wrote in message
ups.com...
Machinery's Handbook, or any other machinist's handbook will give you
exhaustive information on thread turning. In general, I use a couple of
thou. for clearance, but it makes a very tight fit. The class of the
thread, based on strength requirements and size determines the
clearance.
It's a good idea to stick with published standards for
interchangeability.
Bigs


What's an even better idea is to learn to properly apply thread wires so you
can stick to the standards. They are of no use for internal threads, but
perfect for outside measurements, and cheap to own. For those that don't
understand, wires are the proper way to measure threads, and are used for
calibrating thread gages. There is no better method.

Harold