Quote Originally Posted by cropwell View Post

When I was at school, the favourite trick was to put some steel on the surface grinder, with the chuck turned off, bring the wheel down and see if you could get the metal embedded in the far wall.
I did similar when grinding accross my Sine bar.
Except mine bit a sizable chunk out of the wheel and got the machine running frighteningly out of balance .
I hit the E stop but it had to run down through a resonance band , Got much worse before it got better.