"Tim Wescott" wrote in message
...
On Tue, 14 Aug 2007 00:12:17 -0600, SteveB wrote:
snip----

Certainly with pipe
threads the hole is straight and the pipe is tapered.

Sorry, but that's not true unless you're dealing with straight pipe threads.
The typical (tapered) pipe thread (NTP) is tapered, both male and female.
The hole may start out dead straight, but as the thread is generated by the
tap, the entire thread profile ends up tapered with what is virtually a 100%
thread. The tap is, indeed, tapered 3/4"/foot.

Harold