On 23 Feb 2005 14:09:50 -0800, "Terry" wrote:

Don, you mentioned using a diamond wheel. What would I use on my
lathe to turn down the diameter? From experience so far, a sharp point
turning insert does not work very well. Maybe I should try one of my
larger radius inserts.

Do they have any type of diamond impregnated abrasive material I can
use on a lathe? I am just throwing things out right now. I don't
really know what else to try.

I would think of it more as a grinding or abrasion operation than as
turning. I don't think I'd do it in a lathe because I wouldn't want
that abrasive mess near it. The little ferrite machining I've done
has been freehand with diamond burrs in a Dremel or diegrinder.

You might use a 1/4" shaft diamond "burr" or even a diamond wheel in
your mill. For wheels, see
http://www.cyberrockhound.com/grinding_wheels.htm
Set up a spin index or rotary table, mount the workpiece to that, and
advance the work toward the spinning burr by moving the mill table.
Rotate the work 360 by hand, advance another coupla thou and do it
again, and so on. If I had a lot of them to do, I might rig up a
slo-syn motor to the crank of the rotary table.