These are kinda Beta right now, I have several versions but rev3 is the latest, I also uploaded some longer arms for the y switch and I am using one of those . So these are extremely close clearance switch mounts (at least on the Y axis) - I didn't want to lose any work envelope. . They utilize existing holes and I think I used M3 and M5 hardware. I haven't wired them up yet but I had good repeatability testing with the multi-meter. (within .1) . I also had to modify the belt clips so the wheels could get this close to the end. .http://www.temcoindustrialpower.com/products/Limit_Switches/CN0097.html . Credit Where Credit is Due, http://www.thingiverse.com/thing:486796 - I was originally planning on using this but didn't have the right hardware (and I couldn't get the switch to fit the pins) So I made my own using openscad . I cleaned up some stuff in the Rev 2 Scad file, and have a Z Axis switch in there that doesn't workThe SCAD file has some stuff at the top to configure it. FLIP_SWITCH (Flips the switch over) Y_TAB (Makes the Y tab appear or disappear) TAB_OFFSET (moves the Y tab a little farther along - mine are really too close) I used Sli3r with pretty much the stock settings, printed in PLA 40% FILL and avoid crossing perimeters to help with the holes. I also bent some contacts in on the Y axis to make sure it didn't make contact with the alu