Ball Screws

Ball screws consist of a hardened shaft with precision ground or rolled helical grooves commonly referred as the screw (inner raceway), a nut with an internal groove (outer raceway) and a circuit of precision steel balls that re-circulate in contact with both the inner and outer raceways. 

Ball screws are designed to convert torsion loads to thrust loads as either the screw or the nut is rotated driving the other component to transcend in a linear direction.