The objective is to design a flush knob system that is 3D printable, as per Ibanez's famous Tonelock system for guitar pedals. It would allow installation on standard 16mm ALPHA potentiometers for DIY pedals.

The knob is flush, with the outer ring pointing where the tip is.

A push-release mechanism would raise, and lower the knob tip for manipulation, allowing to bring it back to flush after parameter edit.

I imagine an outer ring fitted to the potentiometer shaft, and in the void here a push-release mechanism to raise and lower the inner knob part.