Re: ATM Grooving on Pitch Laps

["Mel Bartels" <mbartels@efn.org>]

>>>
The grooves help the pitch lap's figure to conform to the
figure of the mirror, which is really required for f/4.
...
If your lap is a full size one, according to Texereau you
would have hard time to figure the mirror entirely with this lap.
<<<

I use oversized laps with no channels, only many shallow grooves cut by
running XActo knife across the surface at various angles.  I've used this on
mirrors up to 20 inches with great success.  My pitch is medium soft.

Mel Bartels