Potentiometer Dials:

What are the different types of potentiometer knob?

Apart from any dimensional considerations, potentiometers have three types of shaft: accordingly, it is important to choose a compatible knob.

The solid shaft potentiometer is the most common; it has no splines or splits. The best knob for this is one with a set screw.

Other potentiometers have a split shaft with splines. These are available with different tooth counts, so it is important to obtain a knob with the same tooth count to obtain a good, reliable fit without damaging the spline. These knobs simply push fit onto the shaft, and can be removed if sufficient force is applied.

The third and final type is a D shaft potentiometer. The shaft is a D shape, with a cut out flat spot. A set screw knob could be made to fit, but the results will not be satisfactory. It is better to obtain a compatible D shaft knob.