"Tim Williams" wrote in message
...
"Ed Huntress" wrote in message
...
Whoops, I should point out something else: The powder that will get in
the
air from either grinding or turning (amount unknown) could turn out to be
VERY nasty, even highly toxic, stuff.

It's my experience that magnets really like to stick together. I haven't
ground any so can't say if the average grinder would throw the dust hard
enough though.

Tim

from http://www.wondermagnet.com/magfaq.html

Can I cut, drill or machine magnets to my own sizes and shapes?

Yes and no. AlNiCo magnets are very easy to machine in any way you wish.
NdFeB magnets are by nature very hard and brittle. Although they can be cut,
drilled and machined, it should ONLY be done by folks who are experienced
with ceramics. If the magnets get over about 300 deg F, they will lose their
magnetism permanently. They are flammable, and it is not difficult while
grinding or machining to get them (or the chips and dusts from cutting) so
hot hot they ignite. If they do ignite, the fumes are toxic and the material
burns very fast and hot, like Magnesium! In our experience any machining of
these magnets should be done with diamond tools under lots of coolant with
good ventilation and the risk of fire in mind.

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