A small modification of ScribbleJ's excellent Z Rod Constraint which adds a flat surface to mount a mechanical switch endstop.I didn't have enough room for both a Z Rod Constraint and an endstop holder on the bottom of my left Z-Rod, so I combined them.Update: I printed it out and it didn't quite fit, so I extended the endstop holder. Also, I added the sketchup files as requested.Your mechanical switch endstop will need to be glued onto the flat face of the modified part.A 608 bearing will need to be placed into the middle of the part and bolted onto the bottom/top of the z-rod with an M4 bolt, nut, and washer.