Specific pitches and sales opportunities of the worm do not permit the worm equipment to travel the worm. This is beneficial when the software demands to lock the output if the software is managing in the opposite course. When the helix angle is considerably less than 5°, the worm is self-locking. When the helix angle is increased than 10°, the worm can be driven back again. Worm and worm gear assemblies need to be mounted on vertical, non-intersecting shafts.