rog8811,

There certainly are a lot of similarities between our mill modifications. I hadn't thought much about how gas struts worked. Thanks for the education. The best I can figure, the original take-up spring in the Z axis feed is only to raise the quill. It certainly does not address backlash. As we both showed, you have to put a force on the quill to address backlash. Then the force acts through all gears to eliminate it. The trick is to apply enough force to overcome the downward pull of a large end mill. Apparently you have done that.

Thanks,

Rick