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Re: [ATM] After a layoff of 3 yrs or so.............

John
 Your pictures from the Foucault test look a bit like the one I did 
after leaving my mirror stationary on to of the rotating lap,  which 
caused a series of bands where the intersections of the channels meet on 
the lap.  see http://www.jamescrombie.com/pics/firsttest.jpg
 I went back to occillating  the mirror and in an hour or so it was back 
to a nice spherical shape.
http://www.jamescrombie.com/pics/ronchi1.jpg
 I was using 40 rpm, 6 strokes per minute and about 15lbs of weights 
with about 2" of overlap per side.

James Crombie
http://www.jamescrombie.com



John and Bernadine Murray wrote:

> Evening all,
>     After a year of three of lurking and not much else, the bug has
> bitten again. I dug the old machine out and dusted the majority of 
> dust off
> it. We decided to throw a mates 8" piece of glass that had 2 hours of 
> hand
> polish onto the machine. After 7 hours or so the result was the same 
> as it
> had always been. The edge from 80% on out was out of control. I then 
> thought
> about varying the sweep, overhang and stroke length every 10 minutes 
> or so.
> The results are the best we've seen using the machine. Manuel wants to
> figure it by hand using a full size lap. Any suggestions as to how to
> approach this and what strokes? All suggestions considered. We have both
> decided it would be nice to finish this mirror before we take another 
> long
> beer break.......!!
>
> Picures are at
> http://users.cyberone.com.au/onslow/
>
>
> Cheers
>
> John Murray
> Whyalla
> South Australia.
>
> Ps I know word is a crap html editor but it's the best I could figure out
> after a few beers to celebrate the machine starting up again. And yes, 
> I had
> to discover again why an overarm stop is required.......again....!!!!!!!
>
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>
>
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