in ball screws having fixed internal return means and that is the necessity of supplying new internal return means to compensate for wear since the relative height between the return race 39 and the relevant portion of the ball race 22 is fixed once the return race 39 becomes worn in many rebuilding applications there is nothing to be done except to discard the internal return means 34 this results in a great deal of waste and expense and may improved construction provides not only for external loading of the ball bearings and a rocking motion of the internal return insert 36 but also for a height adjustment of the internal return insert 36 thus solving many longstanding problems in the art referring now to fig3 6 my improved construction can be seen as before a conventional ball screw 21 having a helical ball race 22 with a helical thread 23 is used i make no changes in the standard ball screw in my improved invention however the ball nut 25 having flange portion 29 and body portion 30 has the external area of the body portion 30 modified proximate the return openings 38 as can best be seen by fig4 and 5 a dove tail slot 40 is milled into the outer diameter of the body portion 30 of the ball nut 25 thus the overall height of the return opening 38 is reduced from its previous height of w representing the wall thickness by a distance a representing the depth of the dove tail slot to a total height of b likewise the height of the internal return insert 36 is reduced to a height of b or less as will be hereinafter explained.