[ATM] next mirror .. hand grind or build a grinding machine??

["Robert OToole" <polaris@gsinet.net>]

I'm working on a 6" f/8 mirror for my son right now, all by hand.  I've
done a few mirrors, all modest in size.    After this I have my sights on
some aperture and I want to grind a mirror in the 14" - 18" range.   I
don't expect to do more mirrors after that.

  Anyway, I've heard that a grinding machine is the way to go on bigger
mirrors.  However, somehow I question putting the time, money, and
energy into building a grinding machine   for just one mirror! It would
become yet another project to complete.

  Instead, I'm thinking of forging ahead and just spending the effort on
the mirror itself.  I've ground a 16" mirror before, all the way to the
polishing stage. However, it's the polishing stage which will be a
"bear" methinks.

  Another half-way idea I had was the following:
  build a simplified machine ...  just a motor-driven turntable with a
pivoting overhead armature.   This would be for TOT work.  The turntable
would be for  just slowly spinning the mirror while I would manually
move the tool back-and-forth using the armature.  I would also be able
to stack weights on the arm to apply necessary pressure.

  This idea isn't too bad since it takes most of the grunt work off my
shoulders.  It would be a lot simpler to build than a full grinding
machine.



  Anyway, I want to solicit opinions and thoughts on this before moving
forward.

  Thanks,
Rob

-Robert OToole

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