Subjects
 
Optical Shop
Polishing Bowl
Edging Machine
Null Tester
Tube Fittings
Worm Drives
Optical Workshop Equipment
Spindle Nose & Adaptors
Slip Ring Seting Circle
Mirror Cell
Diagonals
Odds and Ends
 













 

FOCUSSING UNITS.

Crayford Focussers.

I gave some thought to this type of unit and decided it could be made almost as squat as a helical unit. So I made one up. I decided there was too much work in it and the cost of the four small bearings was out of proportion to the rest of it. After some thought I decided to use teflon buttons instead of bearings. I made one up, annodising the tube. But I found that the friction on the buttons was greater than the friction of the roller on the spindle and it would not move. So I cut fine serrations in the tube for the roller to engage. It worked beautifully, very easy and smooth adiustment. Drawings of the 2' and 1 " models are below, with dimensions of the latter.