We needed a easier way to tuner the Z endstop on our Prusa Mendel i3, as reworked by eMotionTech (http://www.thingiverse.com/thing:119616). The original Endstop, while being very solid was not easy to tune precisely. So we took the idea of using a screw to tuner the relative position to the endstop and ... Voila ! ;) Works like a charm and make our life much easier ! ;)-Print all 3 Parts -Then glue together part1 and part2 (we used acetone to merge these two parts (ABS printed)) -unscrew/remove the original zendstop holder (and endstop) -install the endstop to the part1+2 group -using longer screws, fix part1+2 to the bottom left 2 motor -same thing here fix part3 on the X axis motor -screw a bolt (with a tuning nut) on part3 -then use the bolt to adjust Z endstop relative position -enjoy !