Also known as single-start and self-locking lead screws and nuts, these have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won't unexpectedly move when the lead screw is at rest.

Also known as single-start ball screws and nuts, these have a single thread that runs the length of the screw. They operate with more torque than fast-travel ball screws and nuts.