On Wed, 23 Feb 2005 02:27:14 -0800, "Terry G"
wrote:

I have been attempting to turn down the diameter of some small ceramic
magnets. I have been using my regular carbide inserts and have not been
having much luck.

You will use a diamond post grinder. Single point diamond turning will
be too slow for that diameter reduction and will still chip the
material.
But the good new is that a foredom handpiece will fit many Phase II
boring bar holders, and sintered bronze or even plated type diamond
shank-mounted wheels are cheap and available a lot of places.
You will not be able to observe the surface while you are machining
(wet) because the magnet itself will hold the particles, so will be
coated with black gunk.
(I once worked at an optics company. We routinely edged exotic
materials to round blanks: Sapphire, various ceramics and
glass/ceramics, etc.)