Lead Screw

A screw mechanism that converts rotary motion to linear motion, widely used in linear actuators and Cartesian robot axes. Lead screw efficiency depends on pitch angle: low pitch is self-locking (cannot be back-driven) but less efficient; high pitch is back-drivable but may not hold position without brakes. Ball screws use ball bearings for higher efficiency (90%+ vs. 40% for sliding screws).