See http://BrainRight.com/Projects/FourthAxis for more details. In this video I weld and machine the steel enclosure of a 4th axis assembly for my CNC machines, install the harmonic drive system, and try it out.
Here's the full playlist for this project: https://www.youtube.com/playlist?list=PL87zHuZbC0ec7DQ-YQjLNBppGahbjjEx2
