mirror size: 406 mm tool size: 330 mm simulation with Tool on top, moving along x direction, changing chordal stroke parameters: Effect of varying stroke, y offset kept same (center of Tool above edge of Mirror) 1a) y offset of 185mm, stroke 102 mm 1b) y offset of 185mm, stroke 135 mm ( I use this to grind down the untouched mirror edge) xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Effect of varying y offset, keeping same stroke. for rough and fine grinding, Mel Bartels suggests to use 1/3 W to 1/2 W, ( ie varies y offset from 1/3 D to 1/2 D travel) continuously, with stroke ( x direction) kept at 1/3D. D is diameter of mirror(NB this W stroke is different from w stroke used in polishing and parabolizing, eg in stellafane ) : In rough grinding: When you reach 2/3 of the desired depth( by hogging with a metal tool), flip the mirror face up. You will see that the edge of the mirror has hardly been touched. Put the tool on...