Can I purchase a replacement for just the ball screw nut?
Nuts for rolled ball screws can be purchased individually. A pipe will be inserted into the nut as a temporary shaft. The ball screw shaft must be inserted into the nut carefully, as the balls will fall out if the temporary shaft is removed from the nut. Before inserting the ball screw shaft into the nut, make sure it is fitted tightly to the temporary shaft pipe.
However, precision ball screws must be purchased as a set of nut and shaft.