Re: [ATM] trepanning mirror

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

For grinding, there is no need for closing up the core as the
surface will be just fine with that big hole in there.  Your
problem starts when you try to do polishing of the mirror and
that is because the pitch will go up into the hole and you'll
have serious problems polishing.  For thqt, you will want to plug
the hole witha piece of glass so you will want to make a plug of
glass and wax it into the hole for grinding.\ as one choice for
the job.  Another alternative is to make the lap a ring lap by
removing the center part and polish that way.  This second way
may end up making some interesting shapes on the glass if you
don't randomize the stroke lengths a bit.
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
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