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RE: [ATM] re: Working with thin mirrors
> When working large thin mirrors is it best to have a full size lap and
> MOT
> or sub diameter laps with TOT?
Just to jump in, I personally like full sized tools with mirror on top, even
up to 30 inch in size. Techniques are a little different though. I've also
had great luck with subdir tools of 50% size. A 16 inch tool on a 30 inch can
produce a really smooth surface with lots of control during figuring. That's
a problem with full sized figuring of large thin optics - lots of parabolizing
needs to be forced into the optic, you need to control the figure over many
zones, and, the flexing of the thin blank is quite noticable and will zone
easily if you repeat the stroke pattern too much.
For more, see http://www.bbastrodesigns.com/tm/largthin.html
Mel Bartels
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