On 2013-03-22, Martin Eastburn wrote:
Nice - to bad you can't use a hob ? I think that what thread cutters
are or Cob... They have cutters a foot long and 6" in diameter -
coated and all - here in Lufkin - the foundry at Lufkin Industries has
to do it all. Massive gears and massive bolts and nuts.

Yes, to do it properly, I would need to orient the rotary table at
angle to axis X. Too difficult for me to do it. I will mess with
making threads to see how geometry affects fit and how I can
compensate by fudging the diameter.

i

The traditional donkey that pumps out oil is twice as long as those made
by Lufkin. Their custom way saves space and when in buildings (hiding
the pump) it becomes important.

Martin

On 3/21/2013 7:45 PM, Ignoramus3931 wrote:
My guy asked me to cut a 1mm pitch thread on a custom shaft.

I could not do it on my lathe, so I finally bit the bullet and wrote a
subroutine to do threading with my 4th axis rotary table. I use a 60
degree chamfering end mill.

Now I can cut any thread, any pitch, right or left handed, and if the
thread is very coarse, the subroutine does it in several passes.

http://www.youtube.com/watch?v=JMENnIJrl9Y

I am afraid that it does not create a 100% correct thread geometry,
but I hope that I can do enough things with it to be useful with some
adjustments to diameter.

i