This section features two time-tested methods for permanently joining legs to the rails of a piece of furniture: the mortise-and-tenon joint and the dowel joint. Two more contemporary ways are also featured; both involve using knock-down leg hardware—suitable for furniture that must be taken apart and reassembled periodically.
To some extent, the type of leg will dictate the way you join it to the rails. You would be unlikely, for example, to use a hanger bolt to fix a cabriole leg to a fine ffame-and-panel cabinet. A mor – tise-and-tenon joint would be a more appropriate choice.
There are several techniques for making the mortise-and-tenon. You can use a table saw to cut the tenons (page 104);
the mortises can be bored with a router (page 50) or a drill press (page 106). You may also choose to use hand tools. As shown below and on page 134, tenons cut with a handsaw and mortises chopped out with a chisel are traditional methods that many woodworkers consider particularly suitable for the cabriole leg. Whatever method you choose, the strength of the joint will be enhanced by its large gluing area.
As a rule of thumb, the length of the tenon should generally be about three – quarters the thickness of the leg. The tenon is typically about one-third as thick as the rail, but many woodworkers base the tenon’s thickness instead on the width of the chisel with which they will chop out the mortise.
Cutting the tenons
Outline the tenons on the rails, then secure one of the workpieces end-up in a vise. Cut along the lines on the end of the rail with a hacksaw; tilt the saw forward and cut to the shoulder line of the tenon (above, left). Then complete the cut with the saw level. To remove the waste from the tenon cheeks, clamp the rail face-up to a work surface, protecting the stock with a wood pad. Cut along the shoulder line on the face of the
rail; turn over the stock and repeat the operation on the other side (above, right). To cut away the waste on the edges of the tenon, secure the rail end-up again and saw along the edges of the tenon to the shoulder line. Finally, clamp the rail edge – up and cut through the shoulder lines on both edges of the rail. Repeat to cut the tenons at the other end of the rail and at both ends of the other rails.
Chiseling the mortises
For each of the mortises, clamp the leg to a work surface, protecting the stock with a wood pad. Then, starting at one end of an outline, hold a mortising chisel square to the face of the leg and strike it with a wooden mallet. Use a chisel the same width as the tenon and be sure that the beveled side of the blade is facing the waste. Make another cut Vs inch from the first. Continue until you reach the other end of the outline, levering out the waste to a depth that slightly exceeds the length of the tenon. Test-fit the tenon and widen or deepen the mortise as required.
Outlining the mortises
Mark mortise outlines on each leg in two steps, using one of the rail tenons as a guide. First, hold the cheek of the tenon flush against the leg, with the top of the rail aligned with the end of the leg. Draw a pencil along the edges of the tenon to outline the length of the mortise, then use a try square to continue the lines across the leg. To mark the width of the mortise, hold the edge of the tenon centered flush against the leg (left). Extend the marks along the leg until the two outlines intersect. Repeat to mark another mortise on the adjacent face of the leg for the adjoining rail.
4 Gluing up the leg and rail
Spread a little glue in the mortise and on the cheeks and shoulders of the tenon. Fit the two together, making sure that the tops of the rail and the leg are flush. Protecting the leg with a wood pad, hold the joint together with a bar clamp. Align the bar of the clamp with the rail, then tighten it until a bead of glue squeezes out of the joint. Once the adhesive has dried, remove any excess glue with a paint scraper. Repeat the procedure to fasten the adjoining rail to the adjacent face of the leg and to glue up the remaining legs with the other rails.
1 Locating and boring dowel holes in the rails
First, mark location points for the dowel holes. Holding one of the rails end-up, set a cutting gauge to one-half the thickness of the stock and scribe a line across the end of the board. With the gauge at a slightly wider setting, etch two marks on the end of the rail that intersect with the first line (right). To avoid splitting the stock, use grooved dowels no more than one-half the thickness of the rails. Fit a drill press or an electric drill with a bit the same diameter as the dowels, then bore a hole at each location point; the depth should be slightly more than one-half the length of the dowels. Use the same technique to bore the dowel holes at the opposite end of the rail and in the other rails.
2 Pinpointing mating dowel holes
Insert dowel centers in the holes. Then align the top of the rail with the top of the leg (right), and swing the rail up so that its outside face is flush with the edge of the leg. Tap the other end of the rail with a wooden mallet. The pointed ends of the dowel centers will punch impressions on the leg, providing starting points for boring the mating dowel holes. Repeat for the other rails and legs.
Boring the mating dowel holes and gluing up
Bore the holes in the leg to the same depth as those in the rail (page 135). If you are drilling into a tapered leg on a drill press, be sure to keep the square part of the leg flat on the machine’s table. Spread a little glue on the surfaces of the leg and rail that will come into contact with each other, then dab a small amount of adhesive in the bottom of the dowel holes with a pencil tip. Avoid spreading glue directly on the dowels; they absorb moisture quickly and will swell, making them difficult to fit into the holes. Insert the dowels into the legs, then tap them into position with a hammer. Remember not to pound on the dowels, which can cause the leg to split. Fit the rail onto the leg, then close up the joint with the same clamping setup used for the mortise – and-tenon joint (page 135). Glue up the other legs and rails the same way.
1 Preparing the rails
Install commercial hardware to attach rails to a leg following the manufacturer’s instructions. For the type shown in this section (page 138), test assemble the leg, the rails and the mounting plate, then mark the location of the plate flanges on the rails. To cut the slots for the flanges, align each mark with the blade, then butt the rip fence against the rail. Set the blade height to the length of the flanges, adding Vie inch for clearance. Feed the rail into the blade with the miter gauge (left). (Caution: Blade guard removed for clarity.) Repeat for the other rail. Slip the flanges into their slots and mark the screw holes on the stock. Bore pilot holes at each point and then screw the mounting plate to the rails.
2 Preparing the leg
First, cut a notch out of the leg for the mounting plate. Stand the leg up and hold the rail-and-plate assembly on top of it, aligning the ends of the rails with adjacent sides of the leg. Mark a diagonal line across the top of the leg along the mounting plate. Next, align the top of the plate with the top of the leg and mark a line along the bottom edge of the plate across the inside corner of the leg adding Vie inch for clearance. To cut the notch, set the leg on a band saw table and tilt the table to align the blade with the diagonal line. Butt a board against the leg and clamp it to the table as a rip fence. Feed the leg into the blade to make the cut, then clamp a stop block in place to help with repeat cuts (right). Complete the notch using a handsaw. Test-assemble the leg and rail-and-plate assembly again and mark the hole on the stock for the hanger bolt provided. Fit your drill press with a brad-point bit and bore a clearance hole for the bolt using a shop-made V-block jig (inset).
Fastening the leg to the rails
Insert the screw-thread end of the hanger bolt into the clearance hole in the leg. Unlike other fasteners, a hanger bolt has two types of threads: screw threads at one end and bolt threads at the other; it also has no head. Screw nuts onto the bolt-thread end and tighten them against each other with a wrench, forming a temporary head on the bolt. Tighten the bolt with one of the wrenches to drive the screw threads completely into the leg, then unscrew the nuts from the bolt. Slip the rail-and-plate assembly over the bolt and screw a nut on it, making sure that the flanges are in their slots. Keeping the top of the rails flush with the top of the leg, tighten the nut (left).
2 Boring pilot and clearance holes
Install a brad-point bit on your drill press and mark the center of the long edge of the block for a hanger bolt. Secure the workpiece in a handscrew and clamp it in place as shown, with the center aligned with the bit. Then bore the hole. Next, mark two holes on each side of the clearance hole and drill pilot holes (right), repositioning the block in the handscrew as necessary.
3 Fastening the leg to the rails
First, fasten the corner block to the rails: Spread some glue in the grooves in the block and the rails, then fit the splines into the grooves in the block. Press the block up against the rails to fit the splines into the rails. Then, keeping the rails snugly against the block, screw the block to the rails (left). Prepare the leg as you would for commercial hardware (page 137), cutting a notch out of the top for the corner block and boring a clearance hole for a hanger bolt. Fasten the leg to the rails with the bolt (page 138), slipping a washer between the nut and the corner block. Tighten the nut (below) until the leg and rails fit snugly together.
Set the frame and the glass on a work surface, then place the molding in position. Bore a pilot hole every 2 inches using an electric drill fitted with a small finishing nail with the head snipped off. Then drive the brads in place using either a hammer or a brad driver. With the hammer, hold the molding flush against the frame of the door; use a piece of cardboard to protect the glass (above, left). To use a brad driver, insert a brad into the pilot hole, then position the jaws and tighten the locking nut. Holding the frame steady, squeeze the jaws to set the nail (above, right).