One of my favorite stories from being an aircraft sheetmetal guy.
#10 screw with high tourque head (countersunk and weird) A tip cap screw for a helicopter.
They let their mechanics and sheetmetal guys get hold of it before me, I was tied up removing all the others they had stripped.
Anyway, #10 CS hard as a rock screw, 2, yes 2 broken cobalt bits wedged in on the edges of the broken off "easy out".
The production control NCO looks at me and holding a straight face says I need to get that out, and "don't screw it up"
I looked at him and said "too late"