Re: NEW member Suitable conversions?

In a message dated 02/17/2000 11:20:22 AM Hawaiian Standard Time,
dfs@... writes:

<< As a second question, how good is the accuracy of threading on
systems with encoders on the spindle or chuck?

Clearly it must work, but I still have doubts considering the
rotational speeds of the work, and the inertia of it, and the tools
themselves.

I'm talking single point on CNC lathes in particular.

Is it really possible with any accuracy, and can it be
done in multiple passes and pick up at the correct location?

Marc >>

Marc,
We have a Hardinge DVM-59 fitted with a Fagor / Upgrade Tech CNC slide
unit. I have threaded thousands of parts with it and it can do small threads
like 1/2-20 at several thousand RPMs. It is a blurr when doing the cuts. I
have gaged the threads and they are better than most threads I have ever cut
with manual machines. It is so gentle with the carbide points I use that I
can often thread hundreds and hundreds of stainless parts with one insert
edge.
On 1/2-20, I think I cut it in about 10 to 15 passes. The last pass is
to remove any "spring". It can cut tapered threads, threads that taper then
become cylindrical, inside, outside and multilead.
In industry, I think very few threads are cut with manual single point
machines any more. Most are either CNC turned or milled. Of course smaller
internal threads are still tapped.

People prove it's possible everyday.

Peter
THRD, Inc.