Hi Ray: Looks to me you could do a carving on the inside and use it as a jewelry box lid. That would be different. The old fashion way to do this would be to use a core box plane to shape the inside and a lathe to turn the outside. Think "Pattern Making". Don't know if any Pattern Makers are still around what with 3d printers and cnc machines. Norm
When doing the 6" lid I had to slow my speed way down. The V Bit would try to over power the holding torque of my 4 axis instead of just cutting.
I started another box with an 8" lid this time and instead of V-Carving I went with a 3D model to lesson the strain on the 4 axis. The cut was 0.150 deep with a 0.0625 ball nose at 10% step over. The ballnose wanted to follow the grain of the wood which made for some problems. I finally got the model cut at a creep speed and still a couple of mistakes. Needless to say I have redesigned my 4 axis with a new motor & gearbox that has 5 times the holding torque and less backlash.
When cutting at 4" out from the center line it takes a lot to hold it in line.