With nothing more than wedged tenons and some good engineering, this is a phenomenally strong bench. The wedged tenons create a splayed dovetail effect that completely locks this bench together. I built this bench using only The Little Shop Mark II, a workshop on wheels that uses only $1,000 in tools. Begin construction by cutting out the four boards according to the Cutting List. The extra length on the stretcher and legs is to accommodate a little extra length on the tenons for trimming. After cutting and cleaning up the tenons, lay out and cut the through-mortises, which are angled to accommodate the wedged tenons.
Cut the mortises to fit right over the tenons. To lay out the arc on the stretcher, drive a nail into the top of the arc at the center of the board. Then drive a nail into the starting point of both ends of the arc, as close to the edge of the board as possible. Take a strip of wood approximately 1/8″ x 1/2″ x 36″ and bend it into an arc between the nails and trace a line on the stretcher. Remove the nails, cut out the arc and clean up the edge with a drawknife. Now make the cutouts in the end panels. Lay them out according to the diagram, then cut them out with a coping saw. Make some relief cuts into the waste side to make cutting it out a little easier.
Once you have all the joinery fit, it’s time to get ready to assemble the bench. This is a completely clamp-free glue up. The wedges driven into the tenons act as the “clamps” to hold the entire bench together. The wedges are cut at an angle wider than the 5° of the mortise because the wedge itself becomes compressed when driving into the tenon. This compression takes away some of the wedges’ ability to spread the tenon. That’s why you make wedges with a 7° taper. This yields a good spread on the tenon during assembly. Now is the time to test a set of wedges in a joint. Using no glue, assemble a joint. Tap in a couple of wedges and see if they completely spread a joint apart before bottoming out in the tenon slot. If they leave a little room, cut a little off of the wedge’s narrow end and taper it to fit the top of the slot accordingly. This gives a little more play to spread the tenon apart. Gently disassemble the dry-fit joint and proceed to glue up the bench and drive home the wedges with glue on them. It helps to wait a bit to clean up the squeezed-out glue. This lets it get a “skin” that keeps the mess to a minimum. Clean up with a chisel and a damp rag. After cutting the tenon a little proud, mask off the tenon for sanding by taping around the entire tenon with two widths of masking tape. The tape keeps you from sanding a depression in the top around the tenon. Chisel and plane an angle on all four sides of the tenons and round them over with a sander. Remove the tape and sand the rest of the bench to 150 grit. Apply three coats of clear finish and rub out your finish with some steel wool and wool wax, a lubricant you can find at many woodworking stores. PW