Additional Photos of Interest
The casting was made wrong in the area where the Y axis nut mount attaches, leaving no metal in one area where the mount sets (black arrow). Those clever people at the factory installed a socket head screw (red arrow) to provide more bearing surface for the mount. It would have been nice if they machined off the head to be the same height as the casting.
The original X axis nut and screw. The slot in the nut and screw provide a method for reducing the backlash in the nut as it wears. Tightening the nut this way provides only a small area where the nut is tight, so I would expect it to wear faster after adjustment.
Since the original conversion to CNC, I replaced the home made pulleys with ones I purchased from MSC. This allowed for a shorter belt and eliminated some vibration.
To eliminate some slop in the Z axis, I originally installed some springs on the depth gauge and tightened up the coil spring. This helps some on cuts that do not generate a lot of pull on the quill. Currently I have removed the depth gauge and installed an air cylinder to replace the springs. This provides a constant amount of UP pull force. The air cylinder is supplied with 90 psi through a relieving regulator.