Re: ATMer's: I need figuring lap sizes

[lindberg <lindberg@olywa.net>]

Ryan Hess wrote:
> 
> I'm going to be figuring a 4.5" mirror soon, and
> I need to know what size sub-dia. laps I will
> need, and what areas they will polish. 

Ryan: 
        Unless your mirror is very fast, in the under f/4 range, I recommend
figuring it on a full-sized lap. Very small polishers can be hard to
control and have harsh, unpleasant effects. I recently reviewed my
mirror log books and saw that I had once used a polisher poured on a
baby food jar lid. I had used it to reduce a central hill, but then
needed to blend the resulting rough surface with a larger polisher.
        I first started using small polishers while working on a 6" f/6. I
figured it TOT with a 4.25" lap. This worked very well and was easy to
control. If you want to use small laps, this might be a good size ratio
to experiment with. 
        Steve.