Planetary Geared Clamping Knob

Clamping knob (or thumbscrew) design with internal planetary gears. The idea is that gear reduction allows for more torque (thus clamping force) and/or fine adjustment.

No specific scale to the .blend file, so it's something you'll have to figure out on your own. Resize/adjust as needed.

By the way this is a prototype design, so it likely needs some improvements like retaining clips, better gear ratio, etc. At least you can get some idea of how it's supposed to work.