Originally Posted by JB3

I can see maintaining discipline as a real problem for a shop teacher. The next thing you know some stupid kid has removed his fingers messing around.

You should do what my old shop teacher did, made a hell of an impression on us.

He had this solid piece of harder foam rubber that was about 2 inches thick. It was about the same consistency of human skin, like a hand. He passed it around and made sure we all had a feel, then he turned on a standing belt sander and pushed it against the sanding surface. Instantly, the entire block was shredded and jammed through the 1/4 inch gap between work surface and sanding surface and fired down to the floor.

After that he looked around and said, "imaging if the rest of your arm was attached to your hand and that happened. All it takes is a micro second of inattention."