The Okuma LB15 is a two axis turning center/lathe which uses a ball nut mounted to the head (Z axis) that rides on a ball screw with end bearings on each end, the screw is typically driven by a belt which is housed in a cast box that also acts as the motor support. Over time the factory grease in the end bearings fails due to age, use, and contamination. This will cause delamination and pitting of the races and ball wear which translates into excessive backlash and play at the tool holder. End bearing replacement is a bit involved due to the rather complicated driven pulley for the screw which is used to trip a "shear sensor" for overload protection on top of removal of the belt housing/motor mounting and drive motor. Access of the Z screw and ball nut is done by removing the side covers opposite of the operator side, disconnecting the sliding covers secured to the tool head, and disconnecting the accordion style covers on the screw itself.