Roger wrote:
But as to safety, I've had a half inch drill bit pull a piece a 1/4
inch Aluminum out of the clamps and try to beat the column to death,
but I've never seen anything throw a piece like an innocent looking
surface grinder. I saw one smash a hole in concrete block wall.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

You got that right about the surface grinder! I worked in the
Wichita State University machine shop during engineering school,
and I once saw the surface grinder throw a BIG hunk of steel
across the room. Along with the shrapnel from the grinding
wheel, it was pretty impressive. The thing that made it even
more memorable was that the grinder was being operated by the shop
foreman at the time g

Don W.