Quote Originally Posted by Clive S View Post
I think you are misunderstanding the difference between machine zero and work zero. You are correct to have the Z home to the top ten all z gcode will be negative. its nice to home the machine so that X & Y movements to the work position are +ve.

The work zero G54 is generally where you set it in CAD. So after you have homed you then move the machine to the Zero in CAD then touch off at that point. Work zero G54 can be anywhere on the table and in a different place every time if you want. The Home position is always in the same place.
Yeah I may be getting confused, I understand that I need to tell the machine a reference datum ie zero for a part once it is jugged into place, but at the end of the program the machine to stop in a position away from where I am undoing the fixings etc if that makes sense.