Summary

These mounts are used to add an adjustable Z-endstop switch onto a rebuilt CubeX (would also fit the Duo and Trio).

By using a screw from the CubeX and a standard microswitch, anyone setting up open-source firmware such as the Marlin can circumvent the built-in magnetic Z-endstop. This also allows for mechanical z-gap adjustment.

The instructions outline the assembly steps and components used.

Instructions

For the screw holder:

Print parts A and B and glue them together. The two pins fit into the holes of the metal bracket at the back-left corner of the build plate.
A screw from the inner floor of the CubeX is used to hit the endstop switch. These switches came with the Azteeg X3 controller I used to rebuild the CubeX.

For the switch holder:

Two short segments of 1.75mm filament fit right through the switch's holes and into those of the holder. Glue these pegs into place.
The switch can then be placed at the back-left corner of the printer and attached by replacing the plastic spacers and feeding the two screws there through the printed holder's holes. You may also want to tape it to the plastic bar holding the black cable chain (above the new screw holder). Lineup this placement so that the screw strikes the microswitch consistently every time the plate rises.

Both parts were printed on a Solidoodle 2 with no support and ~80% infill (Slic3r).

CubeX Z Endstop Adapter