From: "mlbrown{at}everstrive.com" 
To: atm{at}shore.net
Reply-To: "mlbrown{at}everstrive.com" 



What happens when you don't vary the stroke length on a 1/4 stroke:
http://host67.everstrive.com/~mlbrown/ASTRONOMY/Foucault03Jan03.jpg
You polish the lap pattern into the glass.

I found I couldn't naturally vary the length randomly -- I kept getting
into a habitual length.  Instead I started a using the shortest stroke I
wanted to use (say, 1/8 dia) and gradually increased the stroke length
until I hit the maximum length (say, 3/8 dia), thus using every stroke
length in a range.  Marks on the back of the mirror and tool helped.

=Matt


Original Message:
-----------------
From: scottythefiddler scottythefiddler{at}cogeco.ca
Date: Mon, 7 Apr 2003 07:03:25 -0400
To: bader{at}hydroblendinc.com, atm-digest{at}shore.net
Subject: Re: ATM Polishing



What size is your mirror, and what size is the lap?

1) The air bubbles likely are not a problem.  If you run into dog
biscuit/bumpy surface, then you might want to deal with them.  Gently heat
them with a propane torch or a candle, and press immediately.

2)  1/4 W stroke TOT, always varying stroke length so that average stroke
length is 1/4 D.   The key to avoiding high and low zones is to vary stroke
length.   For many ATMs, including myself, polishing with MOT results in a
severely turned edge.   Others swear by it.

3) A perfect starting point...

Best of luck,
Scott Donaldson

----- Original Message -----
From: "Byron Ader" 
To: 
Sent: Monday, April 07, 2003 5:25 AM Subject: ATM Polishing


>
> I will be polishing here in a few hours and a have a couple of questions.
>
> My pitch lap has a few small air bubbles in it, does that matter?
>
> If I maintain a 1" over-edge normal stroke and rotate MOT and TOT for each
> wet, should that do the trick?
>
> The pitch lap is about an 8th of an inch thick, with groves channeled all
> the way down to the glass tool, is that sufficient?
>
> Thanks for your help,
> Byron
>
>





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