When my CNC kit is built! I will use a slow moving 4th Axis. to handle the rotation. The 1, 2 & 3axis are normal CNC linear axis. Speed is not an issue. I guess the movement in degrees is proportional to the tool tip width. From the tool size you can work out backwards what angel you need to turn you part on this lathe. You do a full skin level removal using X, Y & Z then rotate a touch using 4th Axis. That's how i am going to build it. The hardest part is getting chuck to hold the wood/material both ends.