First grinding with 80 silicon carbide grit. Edge to edge sweep with the tool over the mirror. I'll grind only half or less of the depth required for the intended focal length with the 80 grit. Then move on to finer grits, progressively approaching the required depth. Deeping the mirror in steps as the grit gets finer will alleviate the need to keep restoring the bevel to the edged of the mirror.
Go to http://www.flickr.com/photos/sequoiastan/sets/72157621808663610/ to see photos of the mirror test set-up
great video. i am in the process of grinding a 10 inch f5 with a mirror o matic. i continually seem to be having problems with my spherometer. What did you use to check the sag on your mirror?
each time i "zero" mine out, it wont hold the zero point. I will place the spherometer back onto the surface plate, and it will read something very different from zero...........
any tips?
rocketeer090 1 year ago