Sculpted Joinery
Take advantage of the sculptural properties of wood with this skillfully and tastefully crafted joint.
Wood is a sculptural material and the longer I work with it, the more it coaxes me to sculpt it. On my Windsor chairs and stools, the way the compound angled leg joint always leaves a large portion of itself exposed underneath with only a small contact patch for the tenon shoulder has always bothered me. I have long tried to design a method that allows that awkward transition to ‘flow’ and play more to the sculptural tendencies of wood.
With the design of a crib for my daughter, I came up with a method that solves this design problem and increases the strength of the joint. It requires more work, but the end result is well worth it.
Safe Cutting
Otter made an L-shaped plywood jig to assist him while cutting the four blocks on his mitre saw. He also used clamps to secure the small blocks while cutting them to the correct size and angle.
Easy Angles
Rather than flip the workpiece upside down, and have to drill a compound angled hole, Otter positioned the flat underside of the block flat on the drill press table and secured the workpiece with clamps while drilling the 1" diameter through holes.
Saw and Shape
Once the circular outline of the leg was drawn on the underside of the blocks the majority of the waste was removed at the bandsaw. The joint was then shaped with chisels, rasps, files and sandpaper (below).
Added Insurance
Otter drove a 1/4" dowel into the joint to keep the leg from rotating at all.
A Flowing Joint
The finished joint almost looks fluid. It takes considerable hand-tool skills to finish with an even, smooth transition like this.
Cut the angled blocks
The method involves adding material to the underside of the crib that will allow me to carve a smooth transition to the leg. I begin with blocks of wood 4″ long, 4″ wide and 3″ thick. I choose wood with a close grain and color match to the rest of the piece. All planes need to be square to each other to ensure accuracy. I cut the blocks on the compound mitre saw to match the splay of the legs; in this case 12° toward the end and 6° to the side. A fence I made from 3/4″ birch plywood gives needed support while making the angled cuts. Clamps to hold the small blocks safely in position are also necessary.
Attach the blocks
Next, I position the blocks and glue them with the compound angled surface facing outwards. After the glue has cured, the flat surface on the underside of the block is placed face-down on the drill press table. This solves the problem of drilling the leg mortise at a compound angle. Making sure that each block is clamped squarely and correctly, I drill from the top all the way through with a 1″ bit.
Once the holes are drilled, I can place the turned legs in their respective mortises and check for a tight fit with the tenon shoulder. The compound mitre saw leaves small tooth marks, but a sharp block plane can remove these quickly without altering the angles. I also like to undercut the tenon shoulder 1/64″ when turning them on the lathe to ensure a tight fit. With the leg still in place, I trace around the shoulder with a pencil. This tells me how much material I must leave behind.
Shape the joint
I then bandsaw the waste away and begin the sculpting process. I use a gouge to start with and finishing up with rasps, files and sandpaper. I test the overall look frequently by inserting the leg into the joint and making sure the joint flows. The last little ridges can be removed with fine sandpaper after the leg is glued in place.
To glue the legs, I put a generous spread of glue in the mortises as well as around the base of the tenon and its shoulder. Then I clamp the legs tightly in place.
The joint is finish-sanded after the glue has cured. Working with 320-grit by hand, the last imperfections are removed and the point where the joint meets cannot be felt; it pours smoothly from one into the other. To prevent loosening, I drill a 1/4″ hole and drive a hardwood dowel through the joint, then cut it flush and sand it smooth. After several coats of my oil and beeswax finish, the joint begins to shine with the various contours catching the light and delighting the eye.
