Cutting double-angle miters
Recently the general contractor I work for was low bidder on the finish phase of a large Victorian-style office building. The job called for crown moldings, 20 raised-panel doors surrounded by 4-in. casings and hundreds of feet of 7-in. high baseboard. Both the baseboard and the casing had a 5/8-in. Roman ogee milled on one edge. At each doorway, the base and casing were to be mitered. The miter where the ogees met at the top of the joint was 45°, but this angle changed on the flat face of the trim pieces, as shown. The question was how to cut a lot of these double-angle miters with speed and accuracy.
I solved the problem by drawing the joints full size (both right-hand and left-hand sides) on 3/8-in. plywood, and then cutting each one apart along the lines of intersection. I added stops along the ogee-edge side of each pattern, making it easy to align them with the stock. Clamping the stock and patterns together as shown in the drawing, I cut each joint with a small router using a 1/4-in. bearing-over-cutter bit (see FHB #10, p. 38). Armed with these guide jigs, the rest of the crew joined me in production-cutting the miters.
Bob Grace, San Jose, CA