[ATM] ? grinding mirror on top

[hermit]

horace r davis wrote:
> I have stop hogging with my 16 inch mirror polishing started with 80 grit
> 4 1/2 hr know 120 grit 1 hr center depth has went from .180 to .193 why
> dose this happen with mirror on top not a problem because I wanted .200
> but would like to under stand why.
>   
There have been discussions about this before.  Mirror on top (mot) will 
deepen the center.   Flip it and you will go the other way.   Why?  You 
could look in the archives.  Always assured to get some conflicting 
'facts'. ;)

Ken Lowther