RE: ATM (Whack Test)Plate mirror warnings

[Doug Tanaka <dtanaka@seanet.com>]

>	If there were a brave soul in the group, they could try making say a 6
>inch plate glass mirror, polish it to a sphere, then give it a walloping
>good whack with a rubber mallet. Then test it again. That could be an
>interesting experiment.

What about hitting the plate glass before grinding begins?  It would seem to me that if there was a question as to the integrity of the glass, this would answer it before any labor was wasted.  If a bump was going to change the figure after figuring, perhaps it would do it before.

Doug Tanaka