A few days ago, I bought the first sanding disc for my high rpm Makita 4" grinder that I had bought in ten years. Just don't do that much fine finish work.
I have done hundreds of hours of using a grinder. I know the kick spots. But I had it grinding in the 9 o/clock position of the wheel and KICK! Went flying, and sliced the top of my left hand. Nice 2.5 inch incision, half deep, half just along the fat line, and not down into the meat. Nice little white things in there looking like cotton line, but didn't cut any. Lots of flowing blood, as I am on coumadin.
Wrapped a compressed bandage on it from my huge first aid kit, and went and got nine stitches.
Came home and continued working.
Same damn thing happens again, only this time, I have hold of the grinder near the back end, and not choked up, as the first time. I had thought of this during the time I was getting all poked with Novocain and sutures. Grinder went flying through the air, missing everything except the workpiece, table, and floor. Contacted no organic material that time. Still caused by the 9 o'clock point of contact. Think I learned something, even if it is to use air to finish sand instead of 14k rpm grinders.
Crap, that would have been a difficult thing to explain to SWMBO.
Anyway, watch the kick points on your grinding and sanding blades.
Damn, those things happen in a hurry.
Doctor said that if he had to draw a line on the back of my hand for surgery, it would be right along where I had opened it up. Missed everything but skin, fat, and a little meat. Probably feel better when it quits hurting, too. Stitches for ten days, that's the aggravating part.
It's always something.
Steve