Washing machine knob

Update: The fit on the shaft is just slightly loose. I figure this is better than too tight, because you can always shim the shaft with a bit of tape or a dot of silicone to make the knob fit snug. Since there's bound to be some very small variation in the shafts on different machines, I'll think about a way to make a friction fit work a little better and maybe post a newer version with some changes, but for now this works pretty well.

Designed to fit what appears to be a 1/4" (.250") D-shaped shaft. My washing machine happens to be a "Magic Chef" brand, but this knob should fit pretty much anything with a recessed shaft of these dimensions. The washing machine uses the same knob for the load size ('water saver') settings and for the hot/warm/cold water temp settings. It was missing one of the knobs, so luckily I was able to model up a perfect copy of the remaining one in SolidWorks.

Replacement knobs for appliances can be purchased for between $15 and $30, which seems ridi