Fly Cutter with R8 arbor for the mill..Plans available by Rossbotics.

[Toolmaker51]

Nice fly cutter there. I can see where having a set of these in various diameters would be nice. I have to believe that this is a better balanced solution than some fly cutter designs.

Partly that it's extremities aren't outside bearing diameters of the spindle. Retraction and locking quill also results with improved finish.