Patio Chair

By Chris Spoerer March 18, 2024

Loose-tenon joinery is fast, strong and simple

What good is a table without a matching seat or two? I designed these bar-height chairs with comfort in mind. They are wide and deep, with contoured armrests and stretchers to rest your feet. As with the matching table, I relied on loose-tenon joinery. This technique ensures solid construction and streamlines the assembly process: cut the parts, make your mortises, and then piece the chairs together.

Construction Sequence

Make the legs and stretchers.
Cut mortises in legs and stretchers.
Fit the back slats,
then dry-fit the frame.
Make armrests and cut armrest mortises.
Assemble the chair and install the seat.

Make a rear leg template for tracing, routing, and mortise layout

Take your time making a rear leg template from 3⁄4" plywood; it’s a critical project ingredient. After making the template, mark the locations of all the slat and stretcher mortises on both faces of the template so you can transfer this layout to your legs. Screw a cleat to the bottom of the template as shown below, to create a stop for quickly aligning the template. Then put your template to work, first for tracing the rear leg pattern, then for template routing and mortise layout.

Line ’em up. A cleat screwed to the bottom of the template simplifies alignment as you trace the rear leg shape onto the workpiece.

Rough ’em out. To make life easier for your router, saw 1⁄8" outside the layout lines.

Now rout away the rest. Attaching handles to the template helps keep hands clear of the pattern-routing bit. To prevent the leg from shifting when routing, I screwed the template to the workpiece at the mortise locations.

Fitting 40+ loose tenons into matching mortises might seem daunting, but it’s not difficult if you follow my simple strategy. First, I cut the legs and stretchers to final dimension, identified the “show” faces, and marked the parts to make sure that they maintained their correct orientation through assembly. Next, I used my template to lay out the locations of the stretchers and back slat locations on the rear and front legs. (Remember that the legs are mirror images of each other, so make sure to mortise the correct faces.) After marking centerlines on the ends of the stretchers, I was ready to start mortising (see photos, below).

Mark your mortises. Register each leg’s end against the template’s cleat, and mark the mortise locations. Include centerlines for positioning your mortiser.

Stacked for strength. I cut the first mortise on all the pieces first, then shifted the Domino’s fence and cut the second ones.

Referencing the same face of the leg (rather than flipping the stock) prevents alignment problems.

onlineEXTRA

No Domino? No problem. You can still build this chair by plunge-routing mortises with a simple jig. Find out more in onlineEXTRAS below.

Cut wider mortises for the back slats

Simply put, the back slats are super-sized loose tenons. To make the 21⁄2"-wide slat mortises, I shifted my Domino and cut overlapping mortises. If you’re using a plunge router reposition your jig or use an edge guide.

Once slat mortises are cut, you can cut and rout the slats for a snug fit. A 1⁄4" round-over bit will create a close match for the Domino XL’s 12mm cutter. Tip: Mill an extra slat and use it to sneak up on a perfect fit.

Overlap the slots for the slats. The retractable stop pins on the Domino’s front edge register the machine against one side of the mortise so that the machine doesn’t shift.

Rout the round-overs. Rout the outer edges to fit. It’s better to err on the snug side and sand the ends to fit.

Dry-fit the frame, then make & install the armrests

It’s time for a test assembly to make sure your final glue-up will go smoothly. When the chair frame is together, you can mark up the armrests, cut them to fit, and curve them for comfort. It’s important to complete the armrest’s rear mortise before notching the back of the armrest to fit against the back leg. You’ll need to shorten the armrest’s rear tenons, but this joint will still be plenty strong. Once the armrest’s joinery work is complete, concentrate on curving the top and softening the edges.

Start at the back. Set the armrest flush with the back leg’s inside face, then mark for the rear mortises and the notch in the armrest. Mortise the rear end of the armrest before cutting the notch.

Now for the front. Fit the notched armrest against the back leg, then lay out the remaining mortises on the arms and legs.

Clamp-made curve. Any thin straight-grained strip can serve as a tracing template. Adjust the clamp’s pressure so that the strip matches the desired curve.

Ready to resaw. Maintain a steady feed rate for a smooth cut. You can use the offcut as a custom-shaped sanding block.

Assembly: Start with sides, finish with seat slats

The trick to managing so many loose tenon connections is breaking the process down into easily-managed subassemblies. In this case, I assembled the sides first, and then joined the two halves.

The only parts that require cutting and installation after this major glue-up are the seat slat cleats and the slats themselves. Screw the cleats to the chair’s front and back rails so that the slats sit flush with the tops of the rails. After cutting and smoothing the slats, fit them in place with equal spacing between, and install them by driving screws through cleats and into slats—just one screw into each slat end will do.

Side-by-side setup. Assembling the chairs in sections takes the pressure off you so that you can put more pressure on the joints that need it most. Have a few extra clamps and cauls at the ready in case you need to draw the armrests tight to the legs.

Gravity-assisted assembly. Fitting a multitude of tenons into their mating mortises is the trickiest part of the process. An extra pair of hands can help guide the top half into place.