Simulating a screw turning a gear My goal is to model the parts for a guitar in FreeCAD and Blender, and then use Blender to make sure they will work before I have them made. I've started with the tuners, which consist of a screw turning a gear (and a post attached to the gear, and a little handle and enclosure).

I've figured I need to constrain the position of both main parts, and limit their rotation. But I can't figure out the best way to rotate my parts. The game engine doesn't seem to use precise enough collision detection, and I have trouble making my screw spin with regular Blender physics. I've tried adding wind to spin the screw, adding a vortex force to the screw, tweaking the weights of the objects, and nothing really works.

Here's the blend file.
Animating gears is usually done using the Copy Rotation  constraint, in your case you want to copy the rotation from another axis therefore you might want to use the Transformation constraint to copy and scale the rotation from one axis to another:





Video Tutorial:
Gear rigging tutorial constraints

Note: This is only to do an animation, I'm not sure whether Blender is suitable for simulation of mechanical parts from an engineering point of view.