I have the same backlash on the cross slide of my U3.? I placed a thin,? small diameter brass washer between the knob and the lathe.? This reduced the diameter of the contact circle between the knob and the lathe and so reduced the change in backlash caused by the back of the knob not being exactly perpendicular to the lead screw axis.? There was still a bit of backlash, but still a definite improvement.
