Some cars have electric locks on doors. An actuator - is a device used to move parts of such locks when electric signal comes. An ordinary car lock's actuator consists of an electric motor and a gear wheel which moves a gear lath.
This motor and a gear wheel can be used to move robots or other devices. But the final rotation speed is pretty high for directly rotation of wheels. A worm gear noticeably decreases this speed. The following instruction shows how to create such gear without any special milling equipment.
Required parts and materials: copper wires, steel stripe, a wheel for furniture, a car lock's actuator and some bolts and nuts.
Gear ring may be attached to a wheel by thermal glue - it is a plastic glue that melts when heat is applied and gets solid at room temperature.