I had an i3 mk2-ish clone that I wanted to upgrade to a Full Bear MK2 / MK3. Of course the MK2 nor MK3 does not use endstops on the Z axis, at least not the usual way, so I needed something that would allow me to use the bear and prusa parts without having to modify those parts directly. The endstop mount might look 'a bit overkill' but I got tired of getting the previous ones I used all loosened up because of the minimalist way they were designed.
I've included two versions, one for the X Motor from the MK2 version and one for the X Motor Bear Upgrade version (this one still untested).
Each comes with their corresponding endstop mount for the Z Motor mounts, they are different as the distance between the Smooth Rods and the X Motor screws are different and so they need to match for the screw to click the endstop correctly.
You'll need 2 small M3 screws (M3x6 to M3x8) with M3 nuts to attach the endstop (although zipties can work, though not as rigidly)
All models should 'print-as-is' when imported, as I designed them to print without supports and with a specific orientation for extra strength.
20% infill should be enough.
Print with at least 2 perimeters.