Hi grinders,
Really having some trouble making progress with this 25" f4.7 (19mm thick) float glass mirror. Its polished up really nicely, but just no joy with the figuring
. What I think is happening is that because of its extreme thinness, its flexing too much as I work the laps (TOT). I may have pushed beyond the "thinness limit"
on this one. Was ok with 22"x 19mm with one usable mirror so far, and will get a second 22" to an acceptable stage before too long. What I am intending with the 25" is to make it a "sandwich" by marrying a second 19mm float disc to it
. In between will be approximately 100 25mmx25mmx7mm glass tiles centers around 2 1/2" arranged in concentric pattern. The overall thickness of the composite will go up from 19mm(3/4") to about 45mm(1.77"). As stiffness increases with the cube of thickness the substate (in
theory) will have an increase in stiffness of 13.285. This should enable me to finish figuring without a flexture problem.
