I am using mach3 control, probotix monster mill kit and vectric vcarve pro 7.0. My x and y axis use 1/2-10 precision acme lead screw with 280 oz-in stepper motors. My z has 3/8-12 two start acme precision lead screw with 400 oz-in stepper motor. Only when using the vcarve/engraving toolpath the z will gain height and cut above the wood. I have no other problems when using other toolpaths. I have already checked coupling slip and that is not happening. It seems to be losing its postion and I do not know why. Just wondering if anyone has seen this before and what to do to correct the situation. I know the electronics and kit that I have are capable of cutting 2.5d and 3d toolpaths but something gets out of sorts when using the vcarve/engrave toolpath.