This knob fits a 6mm potentiometer with a slotted actuator.

Why yet another design?  This design uses grip fins and a rib to prevent slipping and has a nice press fit that is tolerant to variations in print quality.  I also include Step and Fusion 360 files so you can modify.

I wanted to just print an available model, but the tolerances for a press fit are tight and all the existing designs I looked at didn't solve this problem.  If they print small they are incredibly hard to press fit and then won't come off, and large will slip off.  Grip fins solve this problem.

Print settings (3MF file includes these) :

• face down
• align seam with the dot (back aligned .. rotate model so dot faces back)
• reduce speed of outer wall print to 20mm/s … so all layers print at same speed to reduce/eliminate banding.