Don Foreman wrote:

On Tue, 30 Oct 2007 17:59:18 -0500, "Karl Townsend"
wrote:



This is driving me crazy. I've tried everything I can think of.

BTDT.

The solution is insert style cutoff tool. I made the change and all my
troubles went away. Just engage the power X feed and collect your part. I
use manchester separator system, there are other good choices, especially
iscar.

Karl


I respectfully disagree. I think the issue is rigidity of the machine.
I've had zero problems with cutoff or chatter using ordinary HSS
parting blades on my import (India, not China) 15x50 lathe.

Carbide tooling always requires a more rigid machine than well-ground
HSS tooling to work well.

Amen!

Insert tips, at a couple to ten bucks each, have a REALLY short
lifespan under contitions of extreme flex and movement.

Sometimes the answer is a thinner cutoff tool, sometimes the answer is
to go balls to the wall, and run the lathe at the verge of stalling the
motor.

I have seen, but not used, setups with a block of material under the
tool, supporting it against the forces of the cut.

Sometimes, supporting the end of the work with a steady or a center
rest is a help. Let off the pressure once the cut is nearing center, or
it eats your tool. :-)

If available, I use the power cross feed to part with. Cuts down on
opportunities to waffle, and it does not let up on the cut. More often
than not, I have found that the apprentices in out shop are unwilling to
make the tool work, and it skips and drags across the surface until it
won't ever cut.

Cheers
Trevor Jones