Helical Crayford Focuser for Newtonian Telescope (Q54339)

The Crayford design allows for fine, smooth adjustment in focus, and doesn't require the focuser tube to have a rack machined into it, so it's ideal for ATM's. The helical Crayford looks like it would be a bit easier to print, so designed this one first. Spinning the focuser tube moves the eyepiece in and out, like a telephoto camera lens. Nov 4 '11- Changed the design significantly. i'll probably put this up as a V2 eventually, but think of it as V1.5 for now. the bearings are attached to 'petals' similar to a camera iris, which are held closed with a large hose clamp. I still need to add a focus tube lock screw, but check out the new design!