Re: [ATM] 20" FS Polishing machine, shafts, etc....

["Jerry" <wa4guu@verizon.net>]

Hello Bill..

That W stroke idea might work out so well. 

When working by hand and doing a W stroke one usually stands at a position
while doing the W and then takes a step and does some more W. To replicate
that on a machine you would need to have the turntable start and stop
frequently.

If the table continues to rotate the W will cause successive strokes to be
at different distances from the center of the mirror and at different
position angles over the glass. You would have to be very careful that the
rotation and stoke rates did not cause asymmetric wear on the glass. By that
I mean you could have W frequency to table rotation that would result in
more centered stokes at some mirror positions and more near edge strokes at
other mirror positions.

Probably best to just put the variation in to the work by stopping work
occasionally to jog the stoke position. You should stop to rotate the mirror
position on it's support anyway so you can jog the position of the stroke a
little at the same time.

James Mulherin has a file (Machine figuring Strokes.doc) explaining machine
figuring techniques posted on the Yahoo Torusmirrorgroup. It is located in
the files section. It is worth reading.

-----Original Message-----
From: William Marriott
 

In the ideal world, I would like to have a stroke that
swings to the left and right as per a normal
Strasbaugh type machine, but with an additonal
eccentric to add back and forth, so as the tool swings
from left to right, the second eccentric produces a W
stroke by pulling the tool forward and backwardd. I
guess this is sort of like a Draper style machine with
added left to right swing.



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