Precision Ball Screws – The ball screw drive is an assembly that converts rotary motion to linear motion (or vice versa). It consists of a ball screw and a ball nut packaged as an assembly with recirculating balls. The interface between the ball screw and the nut is made by balls which roll in matching ball forms. With rolling elements, the ball screw drive has a low friction coefficient (typically up to 98%). The forces transmitted are distributed over a large number of balls, giving a low relative load per ball comparatively.