Abstract: A screw-nut feed mechanism for effecting axial displacement of a movable member on a stationary member in accordance with rotation of a feed screw shaft mounted on the stationary member. The feed mechanism includes a first nut element threadedly mounted on the screw shaft and being connected to the movable member for axial movement therewith, the first nut element having internal threads in engagement with external threads of the screw shaft, a second nut element threadedly mounted on the screw shaft, the second nut element having internal threads in engagement with the external thread of the screw shaft and being fastened to the first nut element in such a manner that the screw shaft is applied with a pre-load in an axial direction to eliminate all of the clearance space between the threads of the screw shaft and the first nut element, and a support element coupled with the second nut element and being fastened to the first nut element to retain the connection of the first and second nut elements.