We occasionally get injuries from the power tools, usually from the older users (our instructor is fairly klutzy. Fortunately, twenty years of construction work have given him the reflexes required to not shred his hands). They were usually relatively minor (drilling of thumbs and burns most often). However, we did destroy two drill bits in 15 minutes last year.
What we were told was angle iron turned out to have some interesting thermal properties. When it got hot, it got
hard. One drill bit shattered, and the teacher came over to "show how it should be done." He said the secret was constant, large force while drilling. He attempted it, and the oil smoked, the angle iron turned funny colors, and the drill bit developed a healthy glow. Mr. J. stopped when it was cherry red, and starting to deform. As for the angle iron, it was barely nicked!
Crazy stuff . . .