Re: ATM To thin for a first mirror?

["Bob May" <bobmay@nethere.com>]

About the only thing that you have to be wary of with that 12:1 ratio is
that you don't get astigmitism into your mirror.  After initial coarse
grinding, you will want to reduce the pressure on the glass and more let it
coast back and forth over the tool.  The other thing is to make sure that
you turn the tool and "walk the barrel" at a good pace.  Spending more than
2 or 3 strokes in the same general direction is not a good idea in the first
place and is even more important as you go thinner.  I try to get the
grinders to learn how to let thier wrist rotate and the other hand slide a
bit so that the mirror rotates about 10-20deg. per half stroke.  I do
suggest that you do get a 55gal drum (or make a box of about that height and
fill with sandbags) so that you will indeed be able to walk around the tool
and thus keep the astigmitism to 0.
F7 will be a good ratio and won't dig into the glass too much.
As some say, grind more and worry less.
Bob May
My new web space address is http://webu.wigloo.com/bobmay/ or
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and my new email address is bobmay@nethere.com
Bob May