Z Axis cal Jig for I3 Mega

I could not fine a good way to measure accurately, and repeatable, the Z axis to set up both micro switches. I made this, I took the average distance between the X and Y 8 mm bars as my printer came, for me it was 64 mm when "home all" was done.
To use first clean up the print, then snap the wide end on the Y rail and rotate onto the X rail (with motor's turned off) adjust the Z screws by hand so the X rail just rests in the cup, with out bending or warping anything. Then adjust the long Philips screw that actuates the switch until it just makes, do the same for the other side, and repeat. Note: you may have to back off the adjustment screw to "unmake" the switch first.

Hope this helps, and I'm sure the concept will work with other printers too.