On Fri, 04 May 2012 18:04:38 -0500, Karl Townsend
wrote:

On Fri, 04 May 2012 10:59:33 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Jon Elson fired this volley in
om:

Thread milling is an awesome process, and great for things
you don't need a lot of.


It really is. In fact, I'd call it almost "fun".

I made my own tool from a single-point internal threading bar. It wasn't
perfect, but it did a satisfactory job. If I ever have need of the process
again, I'll buy the right tool.

LLoyd

This looks like my kind a deal, I'll start surfing fleabay for carbide
threading bars

Karl
Greetings Karl,
Right now I'm doing a repeat job that requires a 3/4-14 NPT hole. The
hole depth requires thread milling because there is not enough room
for the lead on a tap. The material is manganese bronze. I'm using a
full profile threading insert and bar made for lathe work. The program
is written to start at the bottom and come up out of the hole and it
makes two passes. Total cycle time for the threading operation is
about 30 secoonds and the threads are perfect. You could just buy the
insert and make your own holder but if you do much internal threading
on the lathe then having one of these threading bars would be great.
Eric