Servo Pull-Pull wheel will allow for a 1mm steel cable 'like a break cable from a bike, to transfer rotational or linear motion to a point of axis. Used widely in animatronic to allow small parts to be manipulated. to be used in conjunction with this. https://www.shapeways.com/model/605455/innerbreed-pullpull-24mm-casing-v1-3-15-06-2012.html