Quote:
Originally Posted by Stefan Buda
Werner,
In fact you can grind a good flat using only two discs but you need three later on when doing the figuring.
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Hi Stefan, What do you mean by figuring? To get a flat, I would proceed with 600 grit, 800 grit and finally cerium oxide to polish it.
Still using the three disks, I will only polish one. I planned to make a pitch lap for the cerium oxide.
Today I ground the three disks with 400 grit and nearly finished. One disk has still an area that shows as not being ground, very small. Once I have this disk showing all ground, I go back to the 600 and 800 grits. Should I go to a finer than the 800 before polishing with cerium oxide?
I am very careful not to chip the disks when changing over in the sequence, still getting chips on the rims. Is it just the glass I am using? It's float glass. Maybe there is better quality float glass. I will use the best disk for the flat for the auto-collimation test rig and cut the remaining disk down to 300mm.