I read your first post and it begs the question....What size drill bit did
you use? Some of the 1/4-20 bolts here from Homedepot measure as low as
..236" and while they do fit sloppier than those in the .245" region they can
still hold without any inclination of stripping and that's in aluminum and
cast iron(albeit in tapped holes 1/2" deep or more). Assuming you're thread
cutting and not forming then your drill bit should either be #7 or 13/64",
that's .2010 and .2031 respectively. You shouldn't have a problem with the
bolt and tap diameters you mentioned provided the correct drill bit was
used. Heck, one of the 1/4-20 tap/drill bit combos from Homedepot should
work just fine if you live in the US. I've used them without complaints.

wrote in message
oups.com...
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.