Having obtained eyeballometric measurements from the case, the next step was to doodle some shapes on graph paper and pencil in the dimensions. My motivation for not using CAD is simple: it’s easier (for me, at least) to doodle using a pencil.
The outside of the case had pretty much the same features.
The inside, of course, bore no resemblance to the battery pack; the shoulder and whatnot will support the circuit board.
The original battle plan was to build the case in at least two layers, simply because it had to be so deep the Sherline couldn’t reach to the bottom with any rational end mill. It would probably make more sense to glue up four sides on a machined bottom, but that requires actual skill.
This became the Front layer, with Front and Rear faces. The Rear layer attaches to the back of this one. In this picture, the Front layer is on the bottom, taped to the radio.
The two layers peeled apart, with the Front layer to the right. You can barely see the internal shoulder and external tabs.