"John B." wrote in message
...
On Sun, 14 Jul 2013 11:11:46 -0500, "Terry Coombs"

wrote:
"Paul K. Dickman" wrote in message
...


There is something wrong with your logic. Ignoring the question of
what fits what I believe you will find that all taps cut a larger
diameter then the nominal size of the fastener. If, for example you
were to thread a 10 mm rod in the lathe and than drilled and tapped
a
10 mm hole the male rod, being 10 mm must be threaded into a larger
hole, otherwise it would be an interference fit and damned hard to
screw in :-)
John B.

This one is easy to check. I measured a few 1/4" and 3/8" Greenfield
taps at 0.0015 - 0.002" under the nominal diameter.
jsw