A Slanted View of Mortises and Tenons

In the Stickley side table from the November 2006 issue, there are enough variations of mortise and tenon joints to give your hands and your head a real workout. One of the things I enjoy most about woodworking is puzzing out how to do things.This is the top of one of the back legs. The tenons in the back rail are standard-right angles all the way around, but the side rail tenons are at an angle to match the splay of the legs.The two mortises intersect, so the ends of the tenons are beveled back to keep them from interfering with each other. The idea is to keep as much length as possible in the tenons, not to have a pretty miter joint inside the leg where no one will ever see it.I fit each tenon individually; then I take my block plane to the ends. The tenon on the back rail is straight; so I could cut the shoulders on the table saw. I was tempted to use the same method for the angle tenon on the side rail, but I didn’t want to mess around with changing the angle on the fence of our sliding table back and forth between square and the angles I needed. To make the shoulder cuts on both faces of the rail, the setup would need to be reversed. That isn’t impossible, but it’s one of those cases where using a machine isn’t the easiest, most accurate method.

Instead, I made an angled guide block to use with my Japanese-style saw. I’m using the fingers of my left hand to keep the saw tight to the block. Once the kerf is established, I don’t need it there and move it out of the way. The kerf then registers the next cuts and the placement of the guide block.

After making the four shoulder cuts, I used a tenoning jig that slides on the table saw fence to cut the cheeks. I used an agled block to support the rail against the vertical fence on the jig. At the start of construction, I cut a piece of scrap to the angle of the legs from horizontal. I used it for the tenons and also under the legs when cutting the mortises for the angled tenons. My bench always looks pretty trashy because I hang on to things like this, but you never know when something might come in handy.

Here’s one of the completed tenons. I aim to get a fit that can be put together by hand without beating on it that will stay together if you pick up the piece with the tenon. I usually use a shoulder plane for trimming and tuning the fit, but sometimes I use a rasp on the faces of the cheeks. A couple days after I finished fitting everything, we received some cool planemakers floats that I will use next time I do something like this.

I want the shoulders to come down tight, and the cheeks to be snug, but I leave a little room at the bottom and ends of the mortise. I tend to put things together and take them back apart as I go, and the space at the ends of the mortise lets me wiggle the joint to get it apart.

Down at the bottom of the table, there are keyed through tenons where the front to back stretcher joins the arched lower rails. Once again, I could have cut these with the table saw, but I thought it faster and more accurate to do it by hand. I used another guide block for the saw, this one was beveled to make the top and bottom shoulder cuts. Everything looks a little rough at this point, I like to fit the joints before making the parts smooth enough to finish. Pieces can get beat up during fitting, and if I make a mistake on the joint I don’t have a lot of labor invested.

 

Most of the mortises were made with a hollow-chisel mortiser or a plunge router. I really don’t have a preference between the two. I started this project intended to use the mortiser for everything but it broke down after a few mortises and I had to switch to plan B and used the router for the leg mortises. The rails were too short to clamp down and get the router in position, so I switched to plan C, wasted most of it with a forstner bit in the drill press and finished up with chisels at the corners and the rasp for the long edges.

A couple of readers have asked how the web frame is attached inside the rails below the drawer. It’s simply glued in place, it can go in either during or just after assembling the base.

– Robert Lang