Telescope Fine Focus Assembly - Bresser Messier 254 Dobsonian

Fine focus arrangement (6:1) for Bresser Messier 10" Dobsonian Telescope. May fit others.

This is a DIY alternative to the fine focus knob commercially available for ~£93. Once fitted, you will have one knob which moves the focuser at the normal rate, and one which moves it at 1/6th the rate. The modification is fully reversible.

The assembly of this arrangement is straight forward, but I've provided (probably) overly detailed instructions. For those who aren't mechanically minded: All the screws are small, none of them need to be very tight, don't force anything.

Other parts required:

2 x M2.5 x 6mm Cap Head Screws
2 x M3 x 12mm Cap Head Screws
1 x Jackson Brothers 4511DA 6mm Ball drive dual anchor (I bought mine from eBay for around £12)

Original file location:
https://cad.onshape.com/documents/1dbb00339e42cf85fb3b3296/w/751956d19cdf779257ad3ff6/e/0e43900906e9a600decb83c7