Re: [ATM] What the schmidt?

[Jarvis Krumbein <jkoptic@juno.com>]

George, are you putting the correction on both (1/2 & 1/2) sides of the
corrector?  If you are, do you have to adjust the sagitta depth to
account for the glass removed from the first side?  While I'm not working
on a Schmidt this is a question I've always been curious about.

Jarvis Krumbein

On Sat, 17 Feb 2007 04:29:16 +0000 (GMT) tillerman1@videotron.ca writes:
> The vacuum pan is complete and the rim was greased, boiled distilled
> water added to the pan and the 6.125" corrector blank gently 
> pressed
> in place so as to remove almost all bubbles.
> I sucked the pan down to the required sagitta and left it alone, 
> after
> 6 hours it had lost half the sagitta. Sucked it down again and left 
> it
> for another 8 hours, lost about 1/8 the sagitta. Sucked down again 
> and
> left it for 10 hours with no loss.
> Spent a little over an hour tonight with 400 grit cautiously 
> grinding
> the tool profile into the corrector blank. There is about a 1"
> diameter spot in the middle that isn't ground yet and the tool has
> changed to try to match the original deeper sagitta of the vacuum 
> pan.
> I'll regrind the tool tomorrow night after the kiddies are in bed 
> and
> then go back to grinding the corrector and do a few more passes (I 
> hope).
> I think this is the most time consuming part of the grinding, once 
> I
> get past this it should go pretty fast (comparitively) through the
> other grits and then comes the hours of polishing.
> Many thanks to Bob Pfaff and Dave Rowe for the documentation and
> knowlege they have put on line on various sites.
> 
> George Anderson
> Montreal Canada
> 
> Clear skies and good health
> 
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> 
> 
 
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