Re: ATM Hogging Out

["B. Bainbridge" <brianb@u.washington.edu>]

I discovered this effect by accident. I was working a small mirror with
tool on top to reduce the sagitta (overshot). For some reason I started
inadvertantly applying extra pressure to the edge of the tool. I was
puzzeled that the sagitta continued to increase! The old books sometimes
reccomend attaching a handle to the center of the back of the mirror.
Maybe this was helpful in part because it applied all the force to the
center of the mirror.
Brian



Re:
 It occurred to a young friend and I, as we were hogging out an 8 inch
mirror tonight, and starting with two 8 inch blanks, that perhaps the
chordal stroke that everyone seems to use for hogging out is not the
fastest way to dig a hole in the center of the mirror.  So we put
the mirror on the bottom,