Originally Posted by
DSL PWR
Well on my table (homebuilt but I have the same controls as you) I had the same issue.
1. Move the motors away from the rack and run a program. Unless you have some neat gear you need to tune your motors using your hearing and touch. Some dithering at a standstill is normal, but when running the program the motors should run smoothly. At first my y axis was herky jerky in the slower parts of the arc.
2. The spring on my x axis wasn't strong enough and the pinion would walk out of the rack on accel and decel, causing more roughness. Also make sure the pinion is parrellel to the rack.