A very simple spring loaded endstop holder for aluminum frame builds such as the mendelmin. Moves slowly up and down via the knob at the bottom. Use this, not the overly complex one. This holder moves smoothly and can travel a greater distance. Lock down the bottom capscrew to the frame, keep the second t-nut free to slide. Requires: 2 M5x10 socket head capscrews 1 M5x20 pan head screw 2 T-nuts (preferably printed, plastic slides better inside the aluminum) 1 M5 hex nut (or 3 if you are printing the t-nuts) 1 Spring Part of the mendelmin printer. http://www.thingiverse.com/thing:185402