Linear stepper motors are devices that convert rotational motion into linear motion. Linear stepper motors usually use a screw and a nut to mesh to achieve linear motion. There are two main ways to achieve this: the first is to build a rotor with internal threads into the motor, and the internal threads of the rotor mesh with the screw; the second is to use the screw as the motor output shaft and mesh with the screw through an external drive nut.