Re: [ATM] My 12.5 inch project

["Jerry" <wa4guu@verizon.net>]

No turned edge at all???  I can't explain it but I've noticed that I rarely
have a turned edge... no turn at all until the mirror is fully polished.

Pits near the edge, and none more than an inch from the edge? Those are
probably left from some stage of grinding not fully removing pits from an
earlier grade of carbo grit that roll and fracture the glass. Depending on
how deep they are they may or may not polish out in 7 more hours.  I have
polished through a bubble... all the way through. It was much larger than a
pit. It took a while but it can be done. It didn't take near as long as I
thought it would. Learned a lot on that mirror, Heee heeee!

I would suggest putting all of that 7 hours in with the tool on top. You
want as much of the work as possible to go on the edge. Mirror on top won't
do much there.

Jerry

-----Original Message-----
From: Francis J. O'Reilly
 
no TDE at all, but to my dismay, It was not perfectly spherical, as I
thought it should be, but rather was on it's way to being a parabola. I
attribute this to the half hour extra time of mirror on top at the time of
the test, but what do I know?

Back to the main issue,  At what point do I call it good and start figuring
this piece of glass? I am pretty much committed to going another seven hours
of polishing for a total of twenty hours, That should take care of most of
my pits, actually there are very few left at this time. Probable less than
one per square inch at the edge. I doubt that it will make much of a
difference at that level, none in the center or for that matter none more
than an inch from the edge.

I'd like to hear your input on the topic.

Best regards to all,

Francis J. O'Reilly
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