On Fri, 17 Dec 2010 14:34:57 -0600, Ignoramus30138
wrote:

I am drilling this aluminum sheet:

http://picasaweb.google.com/lh/photo...eat=directlink

This is a holder for a (almost complete by 1/64) set od DA collets
that I have in a bag.

Unfortunately, when drilling, it flexes more than I would like. It is
under control but I now realize that I should have used some
sacrificial backing material, or a step drill.

The question is, what material is friendly to the mill. I thought that
wood (plywood) was somehow bad.

thanks

i

FWIW, I use AL plate. Used stuff taken off a scrap machine. One plate
will last for hundreds of parts.

Karl