[ATM] Nearly polished...but...

[Bob May]

My choice for rechanneling is to just go and put the lap in some
hot water until it gets soft and then take a metal stick and
press it rapidly into the pitch, rocking as needed to get all of
the surface grooved. Press the mirror onto that lap and go for
it.  When polishing, a crude lap will do fine and produce a nice
surface.
You may also want to get some fine mesh (on the order of that
wedding veil stuff_ and do microfaceting of the surface.  The
only trimming thatt I'd do is to keep the lap the size of the
mirror or smaller.  excess chipping of the pitch only makes a big
mess and wastes the pitch that you have chipped off.
The TOT is a good idea and you can actually get a good surface
faster at this point than trying to bring the edges down with
MOT as you have to dig the center deeper by that method while the
TOT just makes a different ROC and the worst of that is that ou
wil see a hole in the middle until it is finished.
Also remember that light  has a 4 percent reflection on a
perfectly polished surface of glass.
Bob May
Due to the large volume of SPAM thaat I'm getting, add an open
square bracket to the subject line or my spam filter will reject
your post~
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.