A pretty and practical solution for keeping panels flat
Breadboard end construction is an ingenious time-honored technique for preventing panels from cupping, while allowing for solid wood’s natural seasonal movement across the grain. “Breadboard ends” are essentially grooved rails with oversized mortises that accept tenons on the end of a panel.
The joint is often used on furniture with a hinged lid, such as a blanket chest, tool chest, or specialty piece such as the “Top Secret Table” on page 34. It may also be found on the dangling ends of a drop leaf table or the long, cantilevered ends of a trestle table. Because I also like the joint simply for its looks, it is my favorite treatment for most tabletops, whether they need them or not. It can be made to look elegant and refined, or bold and rugged. It provides interesting detail without excessive ornamentation, and exudes fine craftsmanship if done well.
In addition to the tongue-and-groove and mortise-and-tenon aspects that are essential to the joint, I often like to add a few aesthetic flourishes. For example, I incorporate a tiny V-shaped groove at the intersection of the panel and breadboard end to highlight the joint. And, because breadboard ends will not remain flush to the panel edges during seasonal movement, I extend them past the panel about 1/4" so that the offset will always look relatively the same. Finally, I like to wedge my dowel pins with a contrasting wood, which just looks cool.
Order of Work
- Groove and mortise breadboard ends
- Saw tongue and tenons
- Fit ends and drill for pins
- Make pins and wedges
- Assemble panel and breadboards
Making the breadboards
Mill the material for the panel and breadboards together, as it’s critical that all pieces are identical in thickness. Process extra material for machine setups. Rip the breadboard ends to width, but leave them about 4" over their finished length for now. Saw a centered groove in one edge of each breadboard end, using a setup piece to sneak up on the exact width. Then lay out and cut the mortises; I use a hollow chisel mortiser for the job, as shown.
Two passes for a perfectly centered groove. Assemble your stack dado to cut less than the width of the finished groove. Then adjust the cut height to match the groove depth. Set your rip fence so that the blade is roughly centered on the setup workpiece. Plow the groove in two passes, rotating the board end-for-end, and then check the width with a hollow chisel. Adjust the fence until the chisel fits perfectly. Now saw your breadboard ends.
Cut the mortises. After laying out the length of each mortise on the edge of the breadboard end, set the mortiser fence to perfectly center the chisel within the groove. Check by pressing each face of the stock against the fence in turn, making sure that the chisel doesn’t cut into the groove wall either way. Set the machine depth stop to cut slightly deeper than your planned tenon length, then make the cuts as shown.
Cut the tenons
To set up to saw your tenon cheeks, rest a breadboard end on your table saw, and raise the blade to a hair below the lower edge of the groove. Then saw the tenon cheeks as shown. Lay out the tongues and individual tenons, and remove the waste at the bandsaw.
Tap the breadboard ends onto the panel to check the fit. If the joint won’t seat fully, check the tongue length, shortening it with a file if necessary. Note that the breadboard ends’ excessive overhang allows tapping them free harmlessly with a mallet for fitting.
Saw the tenon cheeks. Using a wide dado head configuration and a sacrificial fence, saw the tenon cheeks in multiple passes, initially making them just a bit too thick for their mortises. Set the fence, and take a maximum-width cut from both faces at the far ends of the panel. Then reset the fence to saw the tenons to final length as shown here. Use push blocks to apply consistent downward pressure on the panel.
Tenon layout. After transferring the mortise extents across the edge of each breadboard end, tuck the tenon section into the groove, centering it on the breadboard end. Then lay out the individual tenon widths, as well as the tongue. Incorporate a 1⁄8" gap on each edge of the outer tenons to allow for wood movement.
Plane to fit. Use a shoulder plane or a rabbet block plane (shown here) to cut equal amounts off both tenon cheeks as you trim them to fit. The tenons should slide into their mortises snugly without using excessive force.
Drill, sand, and shape
Extend each tenon centerline onto its breadboard end, and use an awl to mark a dowel pin hole center on the line 3/8" in from the edge of the breadboard end. Dry-clamp the whole assembly together, and drill the dowel pin holes as shown. Remove the breadboard ends and elongate the outermost holes at the drill press to create slots. Dry-assemble the parts again and sand them, starting with 80 grit to flush them up and remove machine marks. Then move through progressively finer grits up through 220 to smooth everything. Cut the breadboards to final length, and finesse their ends as shown. Finally, use 220-grit paper and a hardwood backer to sand mating 45° chamfers on the edges where a breadboard end meets the panel. Aim for creating a V-groove that’s about 1/16" wide and deep.
Drill for pins. Dry-clamp the assembly and use a 3⁄8" brad point bit to drill through a breadboard end and panel tenon at the same time to create the dowel pin holes.
Use a backer board to prevent exit tearout. Also mark a cutline on the end of each breadboard end 1⁄4" past the panel edges.
Elongate the outermost holes. Chuck a 3⁄8" Forstner bit in your drill press, lower it into the previously drilled hole in one outermost tenon, and then clamp your fence against the end of the tenon. Drill an overlapping hole to each side of the original hole to create a 3⁄4"-long slot. Then repeat for the remaining outermost holes.
Finesse the breadboard ends. Use a mill file to soften the sharp edges at both ends of each breadboard end groove
Assemble and glue-up
To prepare for glue-up, start by making the 3/8"-diameter dowel pins, cutting them about 1/4" longer than your top is thick. Chamfer one end of each pin by chucking it in a drill and spinning it against fine sandpaper at a 45° angle. The chamfer makes for easier insertion, prevents exit blowout, and—when left to project from the table’s underside—provides a nice surprise for exploring fingertips. I also like to wedge the dowels, primarily for added visual interest, so I slot them at this point too.
To make the wedges, mill a piece of contrasting species to 3/8" thick, then use the table saw to rip 1/16"-thick strips from the outer edge of the board. Afterward, crosscut and pare the individual wedges to shape as shown.
To glue up the assembly, clamp the breadboard ends to the panel after applying glue to only the center mortise-and-tenon joints. Then install the pins and wedges, trimming them flush afterward.
Slot the pins for the wedges. Using a back saw and a simple shop-made guide, saw a kerf perpendicular to the dowel’s end grain and a little more than halfway down the length of the pin.
Point the wedges. To shape a wedge, I place it against the fence on my bench hook, and pare forward and downward with a sharp chisel.
Pin and wedge. Install each pin and wedge in turn, beginning with the center pin, which is the only one to receive glue. Tap the pin in first, orienting its slot perpendicular to the grain on the breadboard end. If a pin starts to rotate during tapping, wrap a paper towel around it and grip it with pliers to correct the slot orientation. When the pin projects 1⁄8" from the underside, apply a little glue to the wedge, tap it home, and move on to the next hole.
Saw the pins flush. When the glue dries, use a flush-cut saw to trim the pins flush to the surface. I encircle the pin with a punched scrap of file folder as insurance against saw marks, then pare and sand away what little remains.
