To: Robert Fifarek 
Cc: atm{at}shore.net, owner-atm{at}shore.net
From: Hugues.Laroche{at}ses-astra.com
Reply-To: Hugues.Laroche{at}ses-astra.com



Hello Rob,

>I am wondering whether the need to have wide and deep grooves in the
>pitch polishing tool is really necessary? I am polishing out an f4, 16"
>plate glass mirror.

The grooves help the pitch lap's figure to conform to the figure of the
mirror, which is really required for f/4.

This way the polishing should be well uniform, and if your technique is
good will not generate nasty zones (I talk, I talk but every mirror I have
polished out so far had a certain degree of TDE - so I must something wrong
at some point)

If your lap is a full size one, according to Texereau you would have hard
time to figure the mirror entirely with this lap. The departure from the
sphere, for a 16" f/4 paraboloid is such that at a certain point the
lap will likely resist to your figuring efforts. Subdiam laps help there.

Happy polishing!

Hugues
Luxembourg, 6 deg E, 49 deg N




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