Z Axis Endstop Adjuster for Rigidbot

This is a remix of mikedifilippo's excellent idea http://www.thingiverse.com/thing:362662.
I had trouble printing the original so I beefed it up with more plastic. There's still a very thin section of the wall that may not print well, but just trim it off and the part works fine.
Mount it to the bearing holder with a short m3 screw and use a long, fatter screw (M4, 6-32, etc) for the adjuster. Drill and/or tap the hole as needed for a slightly snug fit with the adjuster screw. If the screw