2×12 guitar amplifier cabinet made by Marcus
Shape and size is based on a guitar cab Marcus used some years ago, the Marshall 2×12 1936.
Basic shape with speaker cutouts, in 12mm plywood
The cutouts were made freehand with a jigsaw – just drew a circle with a radius made from a screw in one end of a stick of wood (for the fulcrum) and a hole in the other end (for a pencil) – set the radius by setting the distance from the screw to the hole. Then drilled a hole inside the radius in order to get the jigsaw through. Jigsaw the hole out. Then rounded over the edges with a ½" router bit. Used an old hessian sack (stiffened with spray lacquer) as speaker grille cloth.