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RE: ??How Thick Should I Go??

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Posted by Stephen Campbell on May 6, 2000 11:01:34 UTC

Tony the TN!,Check this out,blanks in the somewhat medium sizes 10-14",for the cost VS.diameter and thickness the best size to go with would be the 13.1" from newport glass works, i bought one about 1.5 years ago for $172.50 it was listed as 1.5" thick but turned out to be 1.79"
thick,a 12" and 12.5" are only a few bucks less
so i went with the 13.1, a 14" the cost jumps another $100 bucks,the cost of the 13.1 undoubtedly has gone up, but still probably less than other suppliers,as far astigmatism with thin
blanks:here is how to avoid this:when fining with
a.o.30 or 25 clean blank and using a magic marker
mark an "X" across the blank and grinding tool
using circular strokes with light pressure and 1/4
diameter overhang (and of coarse the microgrit)grind in this way until the black lines
disappear completely,when this happens you`ll have
perfect contact and no astigmatism,ive never had
astigmatism using this method!,repeat this proceedure several times during the coarse of fining.oh and let the markings dry first(15-min)

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