From: Michael Lindner 
To: atm{at}shore.net
Reply-To: Michael Lindner 


I'm embarking on my first "real" houghton-type project, and will
be needing to order glass for the correctors. I've never ordered glass
before, other than mirror blanks. Looking at the Newport site (I presume
other glass companies want the same information) I see they want some
things specified, that I have no idea how to specify.

I'd like to find out what are reasonable values to specify, and what some
of these terms mean. Looking back through the ATM archives, I find very
little reference to any of these:

* Material type required;
        OK, I'm looking at BK7 or crown
* Index (nd-vd) code- Homogeneity requirement;
        I know what nd and vd are, but what is a reaonsable homogeneity
requirement?
* Material Grade - Striae Grade;
        Grade A? Grade B? What's the difference? Is striae grade different from
material grade?
* Bubble quality;
        I presume this refers to the number and size of bubbles permitted, but
how is
this specified and what is reasonable in terms of performance and cost?
* Dimensional tolerances;
        OK.
* Certification required;
        I presume none.
* Annealing requirement - Stress birefringence
        For a lens...fine? precision? commercial?

Thanks in advance for your assistance.
--
Michael Lindner
ATM Site http://www.atmsite.org        TM Web Ring
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