Posted By Preston Engebretson
We've just finished polishing to a sphere our 12.5" f3.8 by machine in about 3 hours with an 80% lap TOT using cerium oxide. Testing shows beautiful straight lines to the edge with 3 bands showing.
My question is, how would one parabolize at least to start on a machine...as at f3.8 there's a lot of material to be removed?
The machine is a Zeiss type, but we have only been using one stroke arm driving to simplify the motion.
Should we look at something like a star lap offset to one side of center?
Thanks in Advance