Enhance the look and stability of solid-wood tabletops, lids, and doors.

Capping the ends of a solid-wood panel with rails hides end grain and prevents the panel from cupping, all while allowing for seasonal expansion and contraction.

The basics

In this article you'll become familiar with five types of breadboard ends, each with its own purpose and level of complexity. But all breadboard ends share certain traits: Each comprises a grooved rail, typically 2–3" wide, mated to a tongue on the end of a panel. The groove width equals one-third the panel thickness; its depth measures two-thirds the rail width. The rail attaches to the panel tongue with dowels, fixing its center and allowing for wood movement toward the edges.

Plan for wood movement

Learn more about flat-, rift-, and quartersawn boards. woodmagazine.com/logsawingWood expands and contracts most across its width but changes only slightly lengthwise. So, the breadboard rail should be long enough to prevent the panel edges from protruding beyond the rail ends at the most humid time of year. Flatsawn panels move about 14 " for every 12" of width; quartersawn, about 18 ". (This accommodates an annual change of 8 percent moisture content—plenty for most parts of the country.) So, for a 24"-wide flatsawn panel built in the dryness of winter (panel at maximum shrinkage), cut the rail 12 " longer, so the ends protrude 14 " beyond each panel edge. For the same panel built in summer humidity (panel at maximum expansion), make the rail ends flush with the panel edges.

Full-length tongue and groove: Simple as possible


Form a basic tongue-and-groove joint with open ends [Photos A–D]. Tap dowels into place, gluing the center dowel to the rail and panel tongue, and the outer dowels only to one groove cheek. With the glue dry, trim and sand the dowels flush.

Form a tongue on the panel, using a follower block to prevent chip-out. Use a dado set, start shallow, and make progressively deeper passes until the tongue fits snugly in the rail groove.
Drill 1⁄4" holes for dowels, either all the way through to expose the dowels, or from the bottom, stopping 1⁄8" from the top surface, to conceal them.
Elongate the outer holes in the tongue one-half of the total panel movement allowance in both directions with a plunge router and 1⁄4" upcut spiral bit.

Sliding dovetail: A classic look


Tip! Even a carefully constructed panel can cup when left to sit. To hold a cupped panel flat, clamp a jointed board to the panel [Photos F and G].

A decorative and structural sliding-dovetail joint requires pinning only at its center. Start by cutting a centered 316 "-wide groove in the rail, slightly shallower than the height of the dovetail bit [Photo A]. Complete the dovetail groove [Photo E]. Leave the dovetail bit at the same height, move the fence to expose only a portion of the bit, and form a mating dovetail tongue on the panel [Photo F]. Install the rail on the panel [Photo G]. Drill a hole centered on the rail length that intersects the dovetail tongue, and glue in a dowel. Trim and sand the dowel flush.

Note: Sawing a slot in the rail removes excess material, making it easier to rout the dovetail slot while also reducing burning.

Set a dovetail bit at maximum cutting height, center it in the sawn groove, and make two passes over the bit, one with each face of the rail against the fence.
Form a centered dovetail tongue on the panel, routing on both sides. Start shallow and move the fence back in small increments until the end rail slides on, snug but not tight.
Draw the rail onto the panel using a bar clamp. Do not apply glue.

Stopped tongue and groove: A clean look


To draw as little attention as possible to the joint, conceal it. First, groove the rail [Photo H]. Form the panel tongue [Photo B] and notch the tongue ends [Photo I]. Pare the notch flush with the tongue shoulder, using a chisel [Opening Photo]. Drill holes, form slots, and install dowels as shown previously.

Form a stopped groove with a series of progressively deeper cuts, using an upcut spiral bit. Position stopblocks to control the cut length and make passes with each face against the fence to center the groove.
Cut back the tongue ends to fit the rail groove plus an allowance for panel expansion. Position the blade slightly away from the tongue shoulder to avoid nicks.

Mortises and tenons: For wide or thin panels


Haunched tenons and mating mortises reinforce the groove cheeks of rails on wide panels (over 24") or when a thin panel (under 34 ") dictates thin groove cheeks. Start by forming a shallow stopped groove in the rail, using the method shown in Photo H. Without moving the fence, form the mortises [Photos J and K]. Next, form the panel tongue [Photo B]. Then, notch the tongue ends [Photo I, Opening Photo]. Cut the tongue to form haunched tenons [Photo L]. Drill holes, form slots, and install dowels as shown for a full-length tongue and groove.

Rout the center mortise, making progressively deeper cuts. Position stopblocks to control mortise length and make passes with each face against the fence to center the mortise.
Position the stopblocks to rout the end mortises and make the first passes at each end. Reposition the stopblocks and make the second pass at each end.
Bandsaw the panel tongue to form haunched tenons.

Laminated rail: A simpler route for the rail


Speed up making the rail for the previous two joints by planing three pieces of stock to one-third the thickness of the panel and slightly wider and longer than the finished rail. Then stack-laminate them [Photos M and N]. (We show laminating a tenoned rail; use the same process for a stopped tongue and groove.) Remove excess glue from the groove and mortises before the glue fully hardens. Joint the rail edges and trim the ends.

Bandsaw notches in the rail center lamination and trim material between them to form mortises and a shallow groove in the laminated rail.
Glue and clamp the three laminations, drawing them against a scrap block to keep the part edges aligned as you squeeze them together.