[ATM] Problems With Central Hole Unchanged

[Bryan Stiles <bryan.stiles@gmail.com>]

Good Evening Everyone, I am hoping that someone out there can give me
a hand. I am working on a 8" f/6 mirror. When I attempted to figure
this mirror, I worked about 15-20 with a W stroke. Apparently my
stroke was too long and this produced a nice hole in the middle of the
mirror about 4.25" in diameter. I have worked to try to get this out
for about 4-5 hours now and don't seem to be getting anywhere.

Here's what I have tried:
1. MOT 1/3 COC. This didn't really do anything that I could see.
Quickly abandoned this method after about 30 minutes.
2. TOT 1/3 COC. This seemed to smooth the hole somewhat but not get rid of it.
3. Cut a paper disc the size of the hole and cold pressed for ~30 min.
More TOT 1/3 COC.

The dang hole is still there. I have warm pressed, cold pressed, with
mesh (microfacet), without mesh, more pressure, less pressure, thicker
CeO and thinner CeO. I feel that I'm getting pretty good contact but
I'm getting nowhere fast.

I am looking at my mirror on my Foucault Tester (Homebuilt Stellafane
Type) with the razor edge and Ronchi grating. The blade is coming in
from the left and I am assuming the light to come from the right (thus
a hole not a hill). When using the Ronchi grating (100 lpi) the lines
will hardly deflect when crossing the hole.

I am using soft burgundy and have rechanneled my lap 4 times now and
am closing in on the fifth.

I am seriously considering going back to 500 grit and trying it that
way. I have really enjoyed making this mirror and don't mind the extra
work but I am losing my patience with this problem. Any helpful advice
would be very much appreciated.

Thanks, Bryan
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