Summary One of the early modifications I made to my printer (Hesine M505 Prusa i3) was to add an adjustable Z endstop (http://www.thingiverse.com/thing:1253186 and http://www.thingiverse.com/thing:149882). The endstop worked well until I upgraded my X axis (http://www.thingiverse.com/thing:1103976). With the new X motor mount, the Z plunger no longer lined up with the endstop switch. I create a design based roughly on the original endstop mount that would align with the new X motor mount. I then decided to redesign the offset adjustment plunger mount to add a better switch contact (previously it was just the end of the adjustment screw) and screw tensioning. This thing is the result. The Z endstop and offset mounts are fairly simple, just install per the attached images. The plunger may require a bit of explanation as some components are internal and not visible in the images. I believe that the adjustment screw and associated nuts are #6. I sourced them according to the original design, and don't recall specifically. The screw I used is around 3 inches long. To assemble the offset mount, screw a nut onto the adjustment screw so that about 5mm of thread extends past the nut. Put another nut into the bottom of the mount. Place a small section (about 8mm) of 3/8" compression spring over the end of the screw so that it rests on the nut. Insert this assembly into the top of the mount, compress the spring and screw into the nut on the bottom of the mount. For the plunger (the part that contacts the switch), install a nut into the recessed area and then glue the bottom piece in place. This traps the nut inside the assembly. Then screw another nut onto the end of the adjustment screw with about 4mm of thread extending past the nut. Screw the plunger assembly onto the end of the screw and use the nut to tighten in place. You will need to screw the adjustment screw in as far as it will go in order to access the mount holes to attach the offset assembly to the X axis motor mount.