I am also using a laser to align the lathe. Basically I need three references. 1) The lathe centre in relation to my front tool post - so that I can reference all my tooling to it.2) Positions for two drilling posts, mounted on the cross slide - to take the place of the tailstock, so that I can centre drill, and drill holes in the work peice from within a G-Code program.
I am using a laser mounted on the cross slide, shining parallel to the lathe bed to three Osram detectors mounted near the headstock. The idea is the cross slide will move across until the laser shines on one of the detectors, and stops - in exactly the right position.
I see no problem in incorporating the "homing" program in this. It is already written and set up. I have tried it, albeit with microswitches and it works well. Even using cheap micro-switches it was accurate to less that a thou. My idea is to write a macro - using absolute addresses, to bring the cross slide near to where I know it should stop, and then use the homing program to complete the movement the theory being the movement will be all in the same direction and since it uses the same program, will al be to the same accuracy.
The laser came today - watch this space.
Just as a by-word. I gave up with the micro switches, because if I over ran them, I bent all the switches and had to reset them. At least with the laser, physical damage should be avoided.