Abstract: A ball nut and screw assembly has a ball screw mounting a nut assembly comprising a pair of ball nuts with the respective grooves of the screw and nut defining a pair of ball train accommodating axially spaced helical raceways. At least one preloading member is mounted between the nuts for imposing a preload on the raceways. External ball return tubes for each of the nuts communicate with opposite ends of each of the raceways for recirculating balls from one end of each raceway to the other. A unitary ball return tube clamp plate extends across the preloading member to clamp each of said ball return tubes to their respective nuts and fasteners extend between each of the nuts and the ends of the clamp plate for securing the return tubes in position while permitting the clamp plate to retain the nuts in preloaded condition.

Abstract: By using an existing ball nut and ball nut screw of a ball nut screw assembly as master models, imprint molds can be molded from a silicone rubber material which positively profiles the threading of the ball nut and ball nut screw with the crossover channel in the master model of the ball nut. A thermoset resin is added to the imprint molds and cured to form unitized all plastic ball nuts and ball nut screws with the helical grooving for accommodating the train of balls including the crossover channel in the ball nut molded therein to thereby provide an easily reproducable ball nut and screw assembly.