Re: [ATM] turntable for grinding mirror

[Jim Burrows <burrjaw@earthlink.net>]

At 2004-10-06 17:13 -0400, Rob wrote:

>   Anyway, to avoid doing the "barrel waltz" I was thinking of making a motor-
>driven turntable to grind on.  The table would slowly rotate as I ground the
>mirror.  Of course, I'd still have to periodically give mirror a turn, as
>always.

Should work - that's how the professionals do it, except they have a motor 
driven arm to reduce the work even more.

The first test on my RC cass secondary gave 10,000 nm RMS <scary!>; I asked 
Bob Goff (great guy - too bad we've lost him) the usual amateur question, 
"Can I polish this out?"  He said yes - take 4+ hours, also it was a good 
idea to make or buy a spindle and polish on that.

It turns out that the computation of a starlap's shape for figuring is much 
easier for spindle polishing than for the usual stroke polishing.

         -- Jim Burrows
         -- mailto://burrjaw@earthlink.net
         -- http://home.earthlink.net/~burrjaw
         -- Seattle N47.4723 W122.3662 (WGS84)  

_______________________________________________
ATM mailing list http://www.atmlist.net/