barkis

I love to see people taking on this challenge, and you have embarked on a very big one here. You certainly have the right attitude, which is a big plus in itself It's difficult to gauge the thickness of the blank, about 40mm perhaps? Also, does it have a pre generated curve, which would be a big help in reducing the amount of coarse grit grinding? How fast are you making it? f3.5 - f4.5 perhaps,? I'm only guessing. My largest mirror was a 14" f5, but I did the grinding with a full size blank. I only used sub diameter laps during figuring stages. I wish you well, you will have a mighty big photon collector, and I will follow your progress with extreme interest. Best Wishes . Ron.

:D:D. Very amusing. I enjoyed reading that, although I believe you are more capable than you imply. Anyone who can relate a tale like that, is no duffer.I too dabbled in stepper motors years ago, but in the end I resorted to RS Components for a work of art they sold. I made a camera platform with it as the drive, for the 1999 Solar Eclipse, and I and a couple of friends motored all the way to Devon. Unfortunately, cloud dominated the event. Anyway, it was an adventure we all enjoyed. I actually dug it out of the dark cupboard it was locked in, just a couple of weeks ago. Connected it to my Power Tank, and it still works. Cheers . Ron:)