[ATM] Polishing/figuring not going anywhere.

["Bob May" <bobmay@nethere.com>]

Got a problem with some BK-7 glass that is getting me kind of
tee'd off.
The problem is that the glass isn't changing despite doing all
different kinds of things on it.   I'm trying to match one lens
to another and am sitting at about 35 rings and need to get down
under 5 rings before I'm happy.  The surface is a convex surface.
To date, I've used a small pitch tool on a MOM machine and let it
sit at the edge.  Nothing happened at all.  Next tried a larger
pitch tool and let that sit with a bit of overhang, not touching
the center of the glass.  Finally I'm using a ring of fresh pads
on a full sized tool and letting the pads work back and forth,
leaving the center alone.  Despite 3 hours of doing this, the
glass hasn't moved anywhere.
Anybody got some ideas?  I'm about fresh out of them.  I had
expected that the small lap would have shortly gotten me a worn
down edge into the 50% zone with a ridge there.  Things didn't
move at all!  Didn't matter whether the weight on the lap was
light or heavy other than the heavy load on the lap eroded pitch
off of the lap.  I'm still at the 35 ring diffeerence.
For testing, I'm using a green light source and getting good
rings promptly and am able to see a lot of rings without troubles
until the rings get so close together that I can't seperate them.
The pressing together of the centers of the two pieces of glass
decrease the number of rings with all of the rings running into
the center which indicates that the concave has a smaller radius
than the convex that I'm working on.  The concave has the right
radius for the application.
The interesting thing is that it is really easy to see the TDE on
the two pieces of glass.  The concave surface is going to have
the TDE part ground down a bit so that the sharp edge of the
glass doesn't hit the mounting point but that is something that
will be done later.
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.

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