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.

Found in hand-powered clamps, vises, grates, doors, and work tables, lead screws and nuts have broad, square threads that are well suited for quick assembly, high clamping forces, and lifting and lowering heavy objects.