I was toying with the MZ command on my bot as a way to set Z height and got a response I didnt expect...
I turn on the control. I set a known .5" thick piece of wood block material on the material surface and manually Z zero to this block. I remove the block and type "MZ -.5" I expected the bit to lower the half inch to the cuttable material but instead it raised about 5/8-3/4" ?