Although I built in the past few CNC machines I can’t remember what is a comfortable height to set the Z axis support plate. If I use a 3/8 bit which is about 3” total length there is some room for the spindle to go up/dn but if I use a 1/8” bit which is about 1.5” total length then the available room is really small and most likely will trigger the limit switch.

Any hints how to go about this setting?