Knob for 2.5mm D-Shaft Funky Switch

A replacement knob for the Alpine 7-way “Funky Switch” used on many sim racing wheels. It'll fit that switch, or any other rotary encoder with a 2.5mm D-shaft. I'm using it on a Cube Controls F-Core wheel, and it was designed to match the original knob from that wheel.

You'll want to print this with a 0.25mm nozzle and 0.1mm layer height. Larger nozzles can't print the hole for the D-shaft accurately enough, and it ends up undersized and won't fit on the switch shaft. 

I designed it to print with the D-shaped hole down, but it's such a small surface area you'll need some sort of bed adhesion promoter. A bit of hairspray on an old PEI sheet worked for me, but you might be able to get away with a brim