From: "CSC" 
To: "Atm" 
Reply-To: "CSC" 


When hand grinding (something of a rarity today), I have gained the habit
of making the mirror rotate in my hands while stroking.  It goes around
pretty regularly, and I barely miss a stroke when I shift to a new stroking
direction.  Now that I use a slow turning spindle, I stroke from the same
standing position and keep the mirror slowly turning while stroking. Only
during figuring spells where the mirror will turn less than about 5 times
do I make note of the relative position of the mirror and tool, and try to
make the rotations full.
For general grinding and polishing I do not worry.

Colin

-----Original Message-----
From: owner-atm{at}shore.net [mailto:owner-atm{at}shore.net]On Behalf Of J
Killea
Sent: Saturday, June 14, 2003 3:04 AM To: atm{at}shore.net
Subject: ATM Grinding, Randomness and Texereau




Random variation in grinding strokes ideally leads to a sphere; however,
Texereau advises turning
the mirror with each step around the barrel such that after one complete
circuit of the barrel the
mirror has completed an integral number of rotations in the opposite
direction (2 or 3, he
suggests).  Doesn't this integer requirement create a highly periodic,
therefore very non-random,
pattern?  What am I missing?  I would think it best not to start every
circuit with the mirror and
tool in the exact same relative positions.

Related point:  when rotating the mirror as one shifts to the next grinding
position, is it highly
important to lift the mirror off the tool (or vice versa)?  Or is it OK to
lightly and  smoothly,
turn the mirror as it sits on the tool?

JK

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