Rough cuts
I did the initial roughing out by fitting an angle grinder and Arbortech into the jig. First, I fitted a dummy disc or stylus, slightly bigger than the real cutter. This was because I wanted to leave a generous 3mm, 1/8in above the final surface before carving in detail.

The advantage of an angle grinder rather than a router is speed. Depending on the type of disc selected, it can give up to 100,000 more cuts per minute than a router.

With the stylus set 6mm. 1/4in too far out, I completed the preliminary roughing out in minutes. The shape was achieved without any need for measurements or calculations. A second cut was then taken with the stylus set 3mm, 1/8in too far out. This left the finished carving, hidden by a 3mm, 1/8in skin of ebony.

Roughing out to this stage took about one hour, but the main disadvantage of carving with a 100mm, 4in diameter cutting disc is you cannot follow fine detail.