Kitchen Aid Lock/Speed Knob

When the mixer gets dropped and a knob is broken. Then you look at it and say, "Hell, that's only a scaled sphere, three cylinders, and two cubes in OpenSCAD"
The hole is slightly undersized. This is intentional. It is intended that you heat the metal stem from the mixer with a lighter/small torch just hot enough to allow you to "press fit" the knob to the stem allowing for maximum grab.
The picture of the green one is just a stock picture from the web to illustrate the original knob. The white one is the repair