How do I animate gears?
 

So Im making a robotic hand for class, and I have 2 gears that I need to work with eachother to make the finger move left and right at the knuckle. How would I go about doing this? Thanks!

look into set driven key to have channels driving other channels, the help docs go through it nicely. Connection editor is easier if you just want a direct relation ship e.g. cube.tx = sphere.ty