Step 2: Outer shape
Do not cut away the heel, as it will be needed to create the inside. You can make it more cylindrical with a small chisel.
The tool mount can be adjusted so the tool rests closely to the piece you are working on.
It should be at center height while cutting. The tool itself should be approx. 20° below the horizontal line.
The tip of the small chisel has to be pointed in the cutting direction.