Re: ATM 21" f/6 report: status and questions

["Jeff Arnold" <scoper10@hotmail.com>]

Bill:

>Thanks for the tips on fine-micron grinding.  5 hours to fully polish a 22"
>with a 14.5" lap is very impressive!

Well, really almost all day :^)......5 hours on the glass ! The lap would 
last about 2 1/2 hours them I'd re-channel. With a weight of 30 lbs on the 
spindle and some high speed (45 rpm), yes, 5 hours on the glass.


>I suppose it all boils down to tradeoffs.  Polishing time versus superfine
>grinding, number of grit step versus number of cleanups, etc.  One's skill
>level, experience, tools, and overall resources need to be considered when
>choosing a technical path to a completed mirror.

Yes, certainly time really wasn't saved over polishing from a 9 micron 
surface considering the extra steps and clean-up. Kind of an experiment but 
a 1 micron surface IS something to see and feel!

>Can't resist: here's my personal best polishing setup, a 20" mirror on top
>of a 23" lap.  Starting with a 9 micron surface, after a non-stop 3hrs30 it
>reached "flashlight test" quality on the whole surface, and "laser test"
>quality by 4hrs30.   >
>http://www.kupercontrols.com/misc/20top23.jpg


((http://www.kupercontrols.com/misc/20top23.jpg))

NOW THAT'S IMPRESSIVE !!!
Nice set-up !


Jeff

_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Share information about yourself, create your own public profile at 
http://profiles.msn.com.