On Sat, 31 Dec 2005 02:48:01 -0500, "Peter Kiproff"
wrote:

HI ALL

I need to make a dozen ball nut adapters, requiring a 15/16 - 16 tpi
internal thread

first thought was a single point, small diameter rotating tool. Graduated to
what was on hand

a 3/8 - 16 tpi tap, then I ground off all the other flutes except for one
untouched row.

mounted this in a mill, did a circle command & included Z - .0625

on each pass the entire hole was threaded @ once as Z moved down 1 pitch.

8 passes later the part mates great!

I always wanted to try this & now I'm enthusiastic.

My question is, What other tooling besides the correct tap & what seems
expensive Thread milling tool

or methods do you use, I could have done this on the lathe semi manually but
this would take more time as

I could not just let it run & walk away. ;-)

I also want to do 1/4 - 20's & 3/8 -16's but I guess that's really pushing
it.

Is there a recommended way?

Peter

Thread milling cutters are expensive, as you said. But you can buy
thread milling inserts pretty cheap. And make your own cutter body.
However, a 1/4-20 inside thread will need to be done with a cutter and
not an insert.
ERS