Summary Optical Enstop Hold for Z-Axis Very easy and accurate adjustments are possible. Fits LMK10UU and LMK10LUU and 10mm rails SKP files included for Sketchupm so you can easily modify them for your needs All parts can be printed at once without any support with usual PLA; maximum .25mm layer height (more won't work, less is better). The flag parts needs to flipped by 180°C in the X-Axis for printing it without supoort, sorry for that, I will fix that later. You need a spring an a bunch of M3-Screws and nuts Instead of a spring you could use a second nut aswell, but I haven't tested that and might get more wobbly. And of course an usual very cheap optical endstop from Ebay, Aliexpress etc. like this one: http://www.ebay.de/itm/381672946365?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT For the adjustment screw and flag parts I've made version for M3, M5 and M6 screws I've also made a knob for M3 screws, as screws with knurled knobs are often hard to find in M3