RepRap Mendel auto bed leveling

Starting from this idea http://www.thingiverse.com/thing:273805 I have created this version for my RepRap Mendel. It works in the same way and you must follow the instructions from http://www.thingiverse.com/thing:273805. I have used POM 8X10X12 from SKF for linear bearing, M5 nut fixed with M2.5 screw and M2.5 nut. The limit switch is the Z limit switch from Mendel, and it must be inverted (changed) from Normal Closed to Normal Open. The construction is useful not only for auto bed leveling but