The file 'Laser Cut Low-Cost Rotary For Laser Engraver' is (cdr,pdf) file type, size is 2.7MB.
This is a low-cost rotary adapter for my laser engraver, made from 4mm plywood and scrap parts from other projects that I had lying around.
https://www.youtube.com/watch?v=MU9nrsXyCf8
https://www.youtube.com/watch?v=nF63Rftva8A