IIP Thumbwheel cover and gauge

This slips on over the bed leveling thumb wheel on a Monoprice Maker Select Plus (IIIP) (aka, Wanho Duplicator i3 Plus) printer. The thumb-wheel has a 20mm diameter and screws onto a M3-.5 x 28 mm screw. One full rotation of the nut results in a 0.5 mm up/down movement. This has 10 position markings at 0.05 mm (aka, 5 μm) increments (0,5, 10, 15, 20, 25, 30, 35, 40, 45 μm). I didn't want to replace the nice metal thumbwheels with a plastic one just to get markings. So that is why I made this c