Have you tried the heavy duty fiber reinforced disks? Another thing you might be doing is putting some undue pressure on the disk causing it to bind up and shatter.

Ok, I returned my rotozip, and picked up a Dremel.<P>Took it out, and looked in the guide, put a bit in, and took it to the plastic part of my case.<P>zzoomm, right through, no problem.<P>Tried the ...