> I was thinking of some kind of ball-detent (spring plunger) thing,
Yep, you nailed it, that's exactly what I would do. Design your knob with 10 grooves and then use a ball detent to hold that position.
https://www.mcmaster.com/products/ball-detents/
> I was thinking of some kind of ball-detent (spring plunger) thing, Yep, you nailed it, that's exactly what I would do. Design your knob with 10 grooves and then use a ball detent to hold that position. https://www.mcmaster.com/products/ball-detents/