If you want any kind of accuracy and lack of backlash, I would replace the Acme with ball screw, if you go with rolled BS, it is cheaper but I would pay extra for the pre-loaded ball nut, especially for rolled BS.
If it is similar to the Bridgport, Nook Industries used to supply a BS conversion in different lengths , complete with cross over DogBone.
If you do not have three phase for the spindle motor, get a VFD, 1ph in-3ph out.
This can be controlled under CNC spindle command.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.