I'm using Mach3 and I tuning the motors. As is they all seem to jog nicely, smooth and quiet. However when I make moves using gcode they bind and don't move or jerk violently when they do move. What s

Your g-code probably has the feed rate too high. You set the velocity and acceleration in your motor tuning, but g-code may be able to override these values. Try lowering the feed rate in either your CAM program or in the g-code manually. The feedrate code has an “F” then a number after representing the velocity.