I just finished my first real project using the new 4th axis that I built for my CNC router and posted at http://www.hobby-machinist.com/threads/4th-axis-harmonic-drive-build.57318/. I used it to engrave a micrometer dial that will be part of adjustable carriage stop for my lathe. I did the first video as a start-to-finish tutorial on using Fusion 360 to generate the toolpaths: The second part shows the actual machining: My 4th axis unit worked great, although as shown in the video I did run into some other problems related to the CNC controller that required some minor modifications. In the end I think the part turned out pretty good. I posted some more info on my web site at http://www.brainright.com/Projects/CNC/MicrometerDial/.