I needed to operate a 16 way Hexidecimal switch as part of a midi player project.
The switch was pcb mounted 18mm inside an enclosure and had a small rectangular knob attached.
A larger external knob with a shaft fitment of 1/4in (6.25mm) was to be used to operate the switch.
The solution was a shaft extender. This was drawn up and the file format converted to the required STL file format for the 3D printer.
A 25min print time and.... perfect solution.
See photos and files attached