FRAME-AND-PANEL CONSTRUCTION

Подпись: This clamping setup focuses pressure on the corner joints to lock together the components of a frame-and-panel assembly. While glue bonds the corners, no adhesive is applied in the grooves that hold the panel, allowing it to move as the wood expands and contracts.

Frame-and-panel joinery was invented about 500 years ago, probably by a frustrated medieval craftsman determined to find a bet­ter way to build cabinets than simply fixing boards together. A major drawback of wood as a building material is its tendency to warp and split. Frame-and-panel offers a solu­tion to these problems.

Ever-changing moisture levels in the air cause wood to move, espe­cially across the grain. As relative humidity rises, wood swells; as the moisture content falls, wood shrinks. The central heating found in most modern homes compounds the problem. In a heated home in winter, the relative humidity can drop as low as 10 percent; in summer it can soar to 85 percent. The difference between the two levels can significantly change the cross-grain dimensions of a piece of wood.

Frame-and-panel construction is designed to accommodate the movement of swelling and shrinking wood, resulting in fur­niture that is both strong and stable. In the typical piece shown on the two pages that follow, individual frame-and-panel assemblies are joined together to form a four-sided cabinet. Each assembly comprises two vertical members—stiles—and two or more horizontal rails, all locked together by any one of a variety of joints. These can include dowel, plate, miter-and – spline and lap joints. This chapter will show you how to use the haunched mortise-and-tenon (page 48) and the decorative cope-and-stick joint (page 51).

The opening in the frame is filled by a “floating” panel, which sits in grooves cut in the rails and stiles. The panel is said to float because it is not glued in place. Rather, it merely fits in its grooves with room for movement. If the panel were glued in place, the assembly might eventually split.

Panels are set into their sur­rounding frames without glue to minimize warping. But in addition to their structural function, panels also serve an esthetic role. They are often “raised”—that is, they have bevels cut around their edges. This not only makes them easier to fit into grooves, but also gives them decorative interest.

With one frame-and-panel assembled, you need only repeat the process and vary it slightly to build a cabinet (page 59). Usually, two assemblies are joined together with side rails and panels, with the front assembly left open for a door.

As you will see in the pages that follow, frame-and-panel construction is a versatile furniture-building system. You can add a bottom panel to a cabinet (page 60), then a top (page 64) and either fixed or adjustable shelving (page 61). Installing molding (page 69) hides the connection between the frame and the top; it also adds a decorative flourish.

Although this method of construction is more difficult to master than building a simple carcase, the result is a sturdy, functional and attractive piece of furniture, which makes all the time and effort worthwhile.

Mounted upside-down in a table, a router fitted with a coping bit cuts a tongue at the end of a rail. Another bit will cut a matching groove into the stiles, making a solid and attractive cope-and-stick joint, one of the hallmarks of frame-and-panel construction.