I was considering a laser cross-hair for my mill and found this video of some great setup hacks that [Greolt] put on his mill. The video is pretty short, but I’ll fill you in just in case you don’t want to play/load it. A laser cross-hair is mounted at a known offset to align the X and Y axis. A PC board is wired to a sensor to zero in the Z axis. When the bit makes contact, the machine knows that it’s at 0 + the PCB thickness. A shuttle pro controller adds jog controls and a macro takes care of moving the bit to the zero that was measured with the laser cross-hair. You can find more details on his zero touch setup here.