Particular pitches and qualified prospects of the worm do not allow the worm equipment to generate the worm. This is valuable when the application needs to lock the output if the software is working in the opposite route. When the helix angle is significantly less than 5°, the worm is self-locking. When the helix angle is greater than 10°, the worm can be pushed back. Worm and worm equipment assemblies should be mounted on vertical, non-intersecting shafts.