Quote:
Originally Posted by legswilly
As you say, if the measurements are the same for all the disks, which they are more or less, I was splitting .0005" graduations to arrive at 0.0003 and 0.00025, then the disks are flat.
Thank you Stefan
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I got it, thanks to you. I just wanted to find out why the discrepancy between the optical flat and the disks I ground.
Since you are using aluminium oxide, I will ask him to supply me with it instead of the quoted silicon carbide.
The disks I got were square float glass 19mm thick. So they are not precision optical flats, although they should be reasonably flat according to the measurements made. I want to make an auto-collimation test rig, as is on the Stellafane web site. The best one I want to use as the flat mirror with the hole in the centre.