This is a follow-up to the Curtis Mitertite article by Dave Parker, and an attempt to answer the question about the feasibility of making this joint in the field. I previously posted some comments to Dave’s article and uploaded some photos of a prototype jig that I made with the resulting joint. This is a more detailed account of what I think a setup should be, taking into account the problems encountered with the prototype, and also addressing the need for different size casings.
As drawn, the jig should handle casing from 2 1/2 in. to 5 1/2 in.
The setup, as I envision it, would use two templates, and a template base, for each part of the joint, the leg and the head. These parts should be precision-cut, either on a mill, or with a CNC router. The rest of the jig would be shop-made from available materials.
The templates could be made of 1/4-in. melamine, plastic, or possibly 1/8-in. aluminum. The template bases could be made of 1/2-in. melamine or plastic, or 1/4-in. aluminum.
Let me say here that the drawings are done from theory, and may require minor adjustments to provide a tight joint after the first set has been cut and tested. The templates are based on using a bit and bushing setup, and require a 1/16-in. margin in the template. I used a 1/2-in. bit with a 5/8-in. bushing.
Now for the shop-made parts, and the setup of the jig.
We’ll start with the leg jig, which is the easiest. As my drawings show, the base can be made of plywood, MDF, or another flat material. The guide is 1/4-in. thick, and is shown as one piece in the drawing, but it would probably be better as three pieces with the head stop separate. These pieces would be sacrificial, and could be screwed to the base once they have been aligned in the jig. The part that I call “the receiver fence” should be cut to accommodate the height of the casing under the template base.
The template base is screwed to the receiver fence, and the templates fit into the base recess. The recess would be milled to allow the template to sit just proud of the base so there will be nothing to bump the router. You will notice the corner radius is different on the top and the bottom, so the templates will only fit in one direction.
The casing legs are cut square and milled face up in the jig. The left leg is placed against the left guide, and the right leg against the right guide. The templates are flipped over to make the opposite hand-cuts. The first cut template will cut the dado on the miter and the rabbeted area. The second cut template will adjust the height of the pin that fits in the dado cut in the head piece. Of course, the second cut will require adjusting the plunge depth of the router. Keep in mind that the template is not in contact with the workpiece, so any wobble will affect the cut.
The head jig is a little more complicated, but only for the initial setup of each casing. The head piece should first be cut to size with the appropriate miters. It will be milled face down and centered in the jig. The head jig is made like the jig for the legs, with the following differences: The left and right guides should be adjustable, and the head stop cut with a 90 degree angle. The head stop should be placed with the point at the exact center of the jig. Once it is properly adjusted, the head stop should not have to be moved.
To cut the head piece, the molding is centered face down in the jig. A custom shim will have to be used for each casing profile in order to support the thinner side. The back side of the casing must be absolutely level with the jig.
Since the rabbeted area on the head piece will change when using moldings of different width, you will have to place the casing in the correct position for the first cut. The short point of the miter should be aligned with the template (1/16-in. from the template edge), so the shoulder of the rabbet is cut to this point. Measure the perpendicular distance from the head stop to the miter, and make a right-angle or chevron shaped spacer block to that dimension.
The spacer block is only used for the first cut. It is removed, and the work piece pushed against the head stop for the second cut, which will be the dado cut in the head piece. Again, the templates will flip to make the opposite hand cuts.
Different casing depth and width would dictate the four cutting depths on the router; however, once set on a plunge base this should not be a problem. If I were doing a lot of this work, I would probably make a setup block with those depths for future reference (or use multiple routers). The use of a plunge base would also allow you to step the first cut, which could be pretty deep, especially on the leg piece.
This is just my concept. I don’t believe that this joint would appear in a tract house, but possibly in a custom house with a lot of trim. I think the initial setup could be made in the shop, and the jigs would be compact enough to go to the job site. Of course, the operator would have to be sharp enough to select the right cutting depth, and to stop the head piece dado cut before it hit the face of the casing.
I’m sure you will all let me know what you think, and your comments will direct where it goes from here. Since I’m mostly retired, I don’t have a need for one of these, but I do enjoy making jigs and trying to solve the problems!
(Illustrations by Wm. Todd Murdock)
Svend immigrated from Denmark to California in June of 1958. During the latter part of a three-plus year stint in the army, he worked part-time for a general contractor in northern California. The job turned full-time after he completed his time in the service.
After moving to the Palm Springs area, he worked in several different trades, starting a Masonry and Concrete business with a partner in 1975. He obtained his general contractor’s license in 1979, and in 1980 changed the business model to pre-cast concrete, commercial, and industrial general contracting. When the partnership dissolved in 1995, Svend had an opportunity to build a high-end custom home for a friend. That job led to building more custom homes in the same country club, which lasted for twelve years, until his recent retirement.
Svend enjoys woodworking, metalworking, and all projects that involve creating something with his hands. He also enjoys a tennis game once or twice a week.