I wanted to change my DIY-Kit Stratocaster from regular white/chrome hardware to black hardware. But unfortunately i couldn't find a fitting black knob for the pickup selector.

So I quickly made this model. 

Print was made with a 0.2mm Nozzle in 0.10mm layer height - but i believe that with a 0.4 Nozzle it will also work. 

The Support Structure for the inside cavity was no problem to remove afterwards.

The size of the rectangular blade of the pickup selector switch in my case is 1mm thickness and around 3.8mm in width.

The Knob press-fits onto the switch end nicely but is also not hard to remove if needed.