Another hazard is exceeding the rated speed for a particular disc. I've got a couple of air powered die grinders that can spin at 20K RPM or faster, depending on air pressure and volume. I have a 1/4" diameter mandrel that's made for attaching a cutoff wheel, and I can see where even a slight fracture at that speed would turn it into shrapnel. I ONLY use 3" discs rated for very high speed with that setup.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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