While I still have the older style dovetail Z-axis, I figured this simple mod could help anyone with a taig using the original leadscrews:
It's a pretty straight forward solution, brass nut with a pin on it's OD to prevent rotation while still allowing translation in the Z-axis's main body. The body was bored with two steps, one to locate and seat the compression spring and the other to create a slip fit between the brass nut and main body. I quickly threw the completed assembly back on the machine and tested it with a DTI w/ .0005" graduations with zero visible backlash on the indicator.
While some may use just the weight of the motor to attain a similar effect, I have counterweighted my spindle's motor to remove the moment created on the main body. This allows the gibs to be tightened quite a bit more than before and helps to keep the spindle true to the workpiece. I've been doing alot of 3D surfing on the parts I work on, so removing the backlash and optimizing the rapid speeds of the Z-axis has proven to be critical in reducing run times. I hope this helps anyone else running into the same issues
Nice post, wouldn't mind getting this done on my newer (few years old) Taig.