The head will only come down slowly when the machine is switched off, so just place a block of wood on the vise/table before you turn it off for the day. I do that anyway as a general precaution.
I guess you are aware that the head may fall rapidly if you electrically disconnect the steppr motor.
Phil
Originally Posted by ProtoTrains  Thanks for the datapoint, Phil. My head has never been "loose" but it would slide down under its own weight, at least part of the Z travel. Each time I've adjusted the gib, it has taken less than 1/4 turn of the top screw to firm up the head. I check it by placing an old bathroom scale upside down on the top of the head door and pulling down on it. I've been adjusting to the low side of the 40-80lb that the manual recommends.
I'm very happy with the machining and resultant surface finish, so maybe I'll just leave the gib alone for a while and see what happens. As long as the head doesn't slide down far enough to land on the vise, things can't be all too bad... 
Randy |