I remember when I was trying to run 1.56 or even 1.60 Index lenses years ago. I was trying this cutting them with a 113 generator and an owner that believed in generator diamonds lasting forever. The curves were never accurate and never mind the elliptical error induced when cutting steep cross curves. But we did the best we could and when we finnally got one out, it would come right back to the lab with backside lensometer scratches.
Back then only the large laboratories had the backside coaters and small labs were unable to afford them. But with all of todays modernized LOH equiopment like 3 axis generators and computerized cylinder machines which allows a PC to control pressures, fining and polishing times by material and back side coaters becomming more affordable those problems are of the past. I have very little hair left due to those problems.
:bbg:
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