On Tue, 13 Dec 2011 13:46:42 -0600, Jon Elson wrote:

On 12/13/2011 11:35 AM, Lloyd E. Sponenburgh wrote:
fired this volley in
:

I use my fingers on the OUTSIDE of the part. Not on the bar. That's
why the use of a piece of leather. And then oil on the part. Putting
some sort of vibration dampening at the point of vibration generation
seems to work best.
Eric

The part isn't what's springing. I did my test cuts on a thin ring of
material solidly clamped in the chuck. I can assure you, it did not
contribute to the chatter I got.

"Fingering" the boring bar _did_ reduce the chatter to an almost-
acceptable level, but remember -- I've got a full 15" overhang on the
compound. That's _way_ beyond what's going to work on any lathe smaller
than (perhaps) a 36" swing.

You can put a bag of shot in a hollow boring bar, or wrap it with a
resilient material and then a heavy material like lead sheet. There are
commercial boring bars with Tungsten bars inserted in the tool end.

Jon

There are a number of boring bars MADE out of tungsten as well as
carbide


One could not be a successful Leftwinger without realizing that,
in contrast to the popular conception supported by newspapers
and mothers of Leftwingers, a goodly number of Leftwingers are
not only narrow-minded and dull, but also just stupid.
Gunner Asch