*This message was transferred with a trial version of CommuniGate(tm) Pro*
Course
The course thread (BSW) is very similar to NC / UNC, except that the
angle
of the thread is 60o not 55o (this is from memory - don't quote me) so a
BSW nut will go on to a UNC thread, but not the other way round.
Your memory is very good, except that you have the angles reversed. UNC
and UNF threads have a 60 degree included
angle, while Whitworth threads have a 55 degree angle. Also, they tend
to fall in between UNC and UNF threads as far as
pitch is concerned. For example, in between 1/4-20 UNC and 1/4-28 UNF
is (I think) 1/4-26 BSW. This is from my
memory - my "Machinery's Handbook" is at work. I highly recommend that
book for anyone interested in the technical side of
threads, gears, materials, welding etc., all issues that frequently come
up working on military vehicles (had to throw in MV
reference to make the list).
Matt Tait
Fullerton, CA
This archive was generated by hypermail 2b29 : Mon Feb 21 2000 - 18:15:06 PST