Re: [ATM] Trying to reach sphere

["Francis J. O'Reilly" <foreilly@verizon.net>]

Paul,

No pressure whatsoever, alternate tool on top woth mirror on top, if the 
mirror and tool pass over each other without grabbing and releasing, you are 
probably OK, but spend some extra time with the 305 emery anyway, judst to 
remove pits. Two hours total time with 305 should be good. I would not worry 
too much about the figure until you are fully polished out (Probably after 
about ten hours of alternating tool and mirror on top for 30 minutes 
sessions, no more than an hour at a time.)

FRancis J. O'Reilly
----- Original Message ----- 
From: "Adam Krause" <krausea34@yahoo.com>
To: <atm@atmlist.net>
Sent: Sunday, November 25, 2007 10:08 AM
Subject: [ATM] Trying to reach sphere


> Hi everyone,
>
> I'm in the final stages of fine grinding and I want to be as close to 
> spherical as possible before entering polishing.  I'm using 305 Emery 
> (equivilant to 5 micron).  I've done the sharpie test and it is grinding 
> away the edge before the center.  This perplexes me because I had reached 
> a sphere a grit or two earlier, and I have been using tool on top 1/3 COC 
> ever since, which is supposed to be what you use to solve "hole in center" 
> contact problems.  Lately, my stroke has been getting shorter (about 1/4 
> COC TOT).  I have three questions:  What else can I do to reach a sphere? 
> What is the effect of stroke length on grinding TOT.  Does the stroke 
> length have the same effect whether it is TOT or MOT?
>
> Thanks for your input,
>
> Adam Krause
>
>
> 
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