On Fri, 6 Jul 2012 05:01:31 +0000 (UTC), mark
wrote:

After investigating a scraping noise, I found about 10% of one of the 2
halves of the magnet broken off. Removed and cleaned it up and it runs ok
except there seems to be a little vibration. I assume the field is not
balanced? What kind of glue/epoxy would work to reattach the magnet?

http://www.kjmagnetics.com/blog.asp?p=sticky-business-how-to-glue-neodymum-magnets
I had a similar failure on a PM motor. The problem was that I could
not tolerate much of a gap on the glue line. So, I cleaned both sides
of the break with a brass wire brush and alcohol to be sure there was
no loose debris. I used high strength epoxy and clamped both halves
under as much pressure as possible using two pieces of wood and some
glue clamps. Despite all this, I still had to sandpaper the PM motor
ends to recover my clearances. 4 years later, it's still running.

Good luck.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558