Re: ATM Polishing help

[Anthony Stillman <atmer@flash.net>]

>...11 hours...polish to the edge
>...see a ridge at about 1/2 inch in from the edge with the outer
>portion flatter.


Don,

A ridge?

I think you are describing a turned edge.  Assuming that you have strain
free glass glass, are in fact polished out as you state and are using a
full sized lap, then I would:

1) Trim my lap so that is was a tenth of an inch smaller in radius.

2) Work MOT center over center with a shorter than 1/3 radius stroke.

3) Lighten my stroke (lower the pin weight so to speak)

If this didn't work, (a mirror I'm working now also has a turned edge and
it hasn't responded to the above) I would (will) star the edge of the lap.
Just a little bit.

My last recourse is to re-fine-grind 1/3 C/C.  I hate doing that, but it
does work.

Anthony