I tried to drill out the back of a crankshaft to accept a 4 speed. It was a shallow undrilled 383 crank. I had a big drill bit and big 1/2 inch drill. I had to hold on with both hands.
So I got it cutting pretty good, i had my weight on it. I let go of one hand while it was running. It went a little off center when I let go of one hand and it caught a burr and whipped the drill around violently while I was still holding on with one hand.
I felt a big pop from my wrist and then it felt like my wrist was on fire. I let go and dropped the drill and I couldn't feel my hand.
Clean wrist break.