This creates a turning knob (volume knob) that can be customized.

a six sided hub is fitted on the turning axle, the knob is fitted over the hub.

this allows for a nice knob without screws showing.

This model is created using OpenSCAD.

in the file is a section where you can pick your favourite option. See the pictures for the different options.

The hub is connected with square flat nuts and an alan bolt.
I will add a picture of this later