[ATM] artificial convex curve for pitch lap

[jeff newsom <triolian@earthlink.net>]

Howdy folks-
   This one's probably over the top but......... 
So,I've got a 14.5" piece of glass ,with an f/5 curve(hypothetically,soon to be a reality). This is approx as I'm not allowing for the bevel . I'm making the pitch lap base ahead of time out of layers of baltic birch(the good stuff! shite!) and the diameter is 10.5" . I'm using layers of poster board to simulate the convex curve. I've figured the sag roughly to be .181 and with a micrometer figured the number of pieces of poster board I'd need to  be about ten.I've cut smaller and smaller paper discs all roughly 1/4 smaller than the previous one. But this is obviously building up the central region too much.Now I'm guessing it probably won't matter that much after I poured pitch over it and pressed it, but how could I determine more accurately the different disc diameters??????  Thanks---JN
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