We needed some replacement knobs at work for some VGA A/B switches in conference rooms. The knobs the switches came with were junk and broke long ago. I decided to design a knob that would NOT break. This is that. There's a bunch of comments around the parameters at the top of the SCAD. You should be able to make this fit any situation you need. Setscrew is selectable on/off. Set "testprint" to 1 to generate a small circle with the shaft hole in it to print and see if it will fit your shaft before you bother printing the whole thing.