I have seen a few people do these, here is my version.
Materials
200mm × 200mm x 5mm perspex $4
3 x small stainless bolts $1
A printed picture of a 365 protractor (see below for an image)
1. Measure the focus knob, measure the clearances between the visual back and focus knob.
2. I used a jam lid as a template, trace the lid onto the perspex and cut out TWO of them with a jigsaw.
3. Cut out the printed 365 protractor
4. Drill the holes, then sandwich the paper between the 2 Perspex circles and bolt it all together.
Mark the center of the perspex circles and drill a hole that fits the telescopes focus knob (make sure its a very snug fit).
Now fit it to the telescope and hey presto $5 for a fine adjustment wheel!
