Re: ATM Need Figuring Help!

[Mel Bartels <mbartels@efn.org>]

Hi Bruce

Are the two zones discontinuous or do these meld smoothly at their boundary?

Several things to investigate:

1. strokes may be too regular, particularly with the side swing overhang, such
that the outer zone of the mirror never receives the same polish effort as the
center, causing it to lag behind, or look 'long' or 'turned down'

2. hand pressure may be excessive in center of mirror or tool

3. heat from hand may be influencing work - use gloves

4. pitch lap may be softer or harder in center because of uneven thickness from
center to edge (make lap 1/4 inch deep or more)

5. something on the work bench may be flexing the center or the edge of the
bottom piece, so that as you rotate the bottom piece, it is brought into the
figure in a regular manner

6. mirrors of longer focal ratio cool dramatically, giving all sorts of ugly
zonal views - with experience one can actually use this technique of watching a
mirror cool from torturous temps to purposefully exaggerate very slight
tendencies on the glass

try doing long slow strokes mirror on top with significant side swing and see if
that that brings down the center - watch carefully - rolled edge will result if
you carry this too far

--
Clear skies, Mel Bartels
http://www.efn.org/~mbartels