Thanks guys for all your help. I still have some more questions.
First of all to answer Pete's question, the fit of the bolt is really
loose, especially the first 3 or 4 threads. If put to the test
they usually will strip out.
Question: Does the class of fit (1 thru 4) refer to the tap or the
bolt?
In all of my catalogs and all my internet searches I have never seen
a class 4 bolt. Usually they are referring to the hardness of the
bolt.
In any event, does anyone know of a source for class 4 bolts? Also
a source for quality taps?
Finally, what do you guys think of a spiral pointed tap for open-ended
holes?
Thanks so much.