Harold and Susan Vordos wrote:
"Tim Wescott" wrote in message
...

Harold and Susan Vordos wrote:

"Andrew VK3BFA" wrote in message
egroups.com...
snip----



Still dont know what an
ACME thread is. Have a small Unimat lathe


If your Unimat has a lead screw, chances are good it is an Acme thread.
The thread has an included angle of 29 degrees, and the root and crest

is

flat.

Harold

Merry Christmas! (Or should that be Happy Holidays?) g


In other words, an acme thread has a kinda-square profile, as opposed to
a triangular profile like "regular" threads.

--

Tim Wescott



Well, sorta. You have to be careful to not confuse an Acme with a square
thread, which resemble one another quite a bit. Difference? The 29
degree included angle that the Acme enjoys as opposed to the square
shoulders of a square thread.

Harold


Yes, sorta. I could have been more clear, but while I felt that your
description was perfect for telling the difference between acme and
square it wouldn't necessarily ring any bells in the head of a non
mechanical person.

Do you know what the functional differences are between acme and
60-degree "regular" threads? I assume it's because regular threads tend
to wedge in when they get tight which is a good thing in a fastener and
a bad thing in a lead screw -- but I don't know.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com