Take your watch off. They can get caught on things making it hard to get your arm back out. I also had one short out on a possitive terminal for about a 1/2 of a second. That was all it took to heat up the watch enough to give me a real bad burn!

If you drop your high speed grinder toss the backing plate in the trash. I did not know my brother dropped the grinder when it was turning max rpm's when I was using it, it blew apart. One piece hit me in the chest so hard I hit the ground and held my chest. It was one of those things that I was afraid to look at because in my mind with how hard it hit me it felt like it went into my chest. I was ok just a HUGE bruise and took me about a helf hour to feel like I could breath ok again.

Always cut away from your boddy parts with a knife...

If you mind tells you this is a bad idea it is and stop. I can think how many times I was like this is a bad idea, two seconds later I am on the way to get stitches.

always wear safety glasses when using anything that moves faster then you doi . had a 4-1/2 inch side cutter, blade snagged and came apart, bounced off something and hit me just above eye. felt like it cut thru, thank god for hard head.

Never walk backwards while power washing the ceiling or your boat dock.

When polishing small stainless parts, secure them to a block of wood... I had a cleat bezel snag the polishing wheel and it disappeared, never heard it hit the ground, the wall, NOTHING, just silence.
It took a few minutes to realize that it had went up thru the skylight (there was a beam of light from the hole) and out into the parking lot. It didn't hit any cars, but the impact on the concrete destroyed it!!!
I always wear safety glass but if it would have hit me I would have had a wicked headache!