I have been using my newly built CNC router for a few weeks now and am very happy with everything other than my z-axis. I have a 425 oz-in stepper motor moving my z-axis via a ballscrew and linear ways. The problem is that after I mount my router to my axis, it is rather heavy and my stepper actually stahls out and looses steps intermitantly. There is no binding at all. I applied an upward force (with my hand) on the z-axis while it was moving and that eliminated any stahling. So as far as I know my two options are to either insert a spring in there somehow or rig up a counter weight. Does anyone have a preference as to which one to go with or another method altogether? I would appreciate the help. Thanks.