On Sat, 26 Feb 2005 09:30:17 -0800, Greg
wrote:

Grady wrote:
Anybody got a link to a good thread cutting tutorial? Also, when machining
both the male and female items to be threaded, how much clearance do you
allow to start with between the two?

Not exactly an answer to you question, but if possible, as you approach
finished thread depth, stop and test fit (without taking the part out of
the chuck). Then just take light passes until the fit is what you want
it to be by feel. Make sure the thread are clean when you do this.

Of course, this does not work when one part already exists and is too
big to bring near the lathe. Also, I'm assuming this is hobby work and
the exact clearance is not critical.

-Greg

That's what I do, try it. Lately, I'm cutting an internal sort of
acme thread, 3/4" x 5tpi. "Sort of" because it is intended to fit mop
handles, and they are NOT precise, at least to thread form, depth,
etc. So I chopped off a $1.95 broom handle with a metal tip to test,
then removed and tested on another handle with a plastic tip. Oops,
have to break the edge and open up the i.d.

Picking up the thread again wasn't too bad. I just stuck the piece
back in the collet, engaged the tool in the thread with the crossfeed
with the boring bar loose and the threading dial at the right spot,
then clamped the boring bar. To set the threading dial, I disengaged
the drive and rotated the spindle (with the tool retracted out of the
threads, of course).

I followed a suggestion I believe I read here a while back, and
threaded in reverse on the back side. It worked very well, because
the carriage travel was left to right, or out of the bore. At 5 tpi,
it moves pretty quick, even in back gear.

Pete Keillor