Re: [ATM] Going price for a fine annealed 24" pyrex blank

["Jeff Anderson-Lee" <jonah@cs.berkeley.edu>]

I believe that 2.625 inches is a stock pyrex thickness (which should be 
cheaper).  Assuming you grind off 0.125 inches while shaping the mirror, 
that still leaves 2.5 inches edge thickness for the optic.  At that 
thickness, you can still support a 30 to 32 inch f/4 mirror 18 points or 
an f/3 mirror on 27 points.  Of course if you want something faster than 
that you may want more thickness in the blank.

Old cell designs required thicker blanks, but modern cell design that 
are optimized to the parameters of the individual optic are much more 
capable.

Jeff Anderson-Lee

Mark Cowan wrote:

>Jerry & Chuck:
>
>For custom blanks I buy from Newport there's a
>considerable cost savings off the standard thickness
>as they basically charge by the lb.  I'm guessing here
>but going from a 4.35" to 3" thickness on a 24" should
>drop the basic price down to around $1700.  It's not
>like they have stacks of 24x4.35" pyrex sitting
>around... 
>
>Cheers,
>Mark Cowan
>Salem, OR
>
>
>
>--- "Jerry B. Hillman" <JBHillman@ev1.net> wrote:
>  
>
>>Hi Chuck,
>>Newport Glass lists their 24" standard Pyrex blank
>>at $2450. It is 4.35"
>>thick and weighs 187 pounds (part number SPX2400). 
>>To get a 24" blank
>>thinner than this requires custom ordering.
>>You can order their catalog from their website.
>>Clear skies, Jerry
>>
>>_______________________________________________
>>ATM mailing list http://www.atmlist.net/
>>    
>>
>
>
> 
>
>
>
>	
>		
>__________________________________
>Do you Yahoo!?
>Yahoo! Photos: High-quality 4x6 digital prints for 25¢
>http://photos.yahoo.com/ph/print_splash
>_______________________________________________
>ATM mailing list http://www.atmlist.net/
>  
>

_______________________________________________
ATM mailing list http://www.atmlist.net/