Creating Super Wood Joints
Build it strong with tried and true methods to join wood.
A variety of wood joints are used in furniture and cabinetry construction. They can vary in strength, depending on the joint and the design of the piece. Some traditional methods have been used in the past to create super strong wood joints. Today newer products and techniques have also developed. Following are some basic super-strong wood joints, both traditional and modern, and instructions on how to make them.
A glued butt joint is the weakest, a half-lap joint is stronger and adding screws creates an even stronger joint. But traditionally, the strongest wood joint has been a mortise-and-tenon, including both a blind tenon and a “through” tenon. These joints may be used to create frames for frame-and-panel doors, for dust webs, or drawer supports, and even in basic furniture framing, such as legs and rails for tables and chairs. These joints may be created in several ways. Tenons can be cut using a table saw, band saw or by hand. A tenoning jig makes the chore easier and more precise. Mortises can be cut using a mortising machine, a mortising accessory in a drill press, or by drilling a series of holes with a drill press and cleaning up the cuts with a chisel. Adding a peg to the mortise and tenon joint creates an even stronger joint—one that is used to join timbers in timber-frame construction.
Above and Below: Mortise and tenon
A dado joint is stronger than nailing and gluing cross members together, such as for shelving in a bookcase or cabinet. A sliding dovetail joint is stronger than a dado joint. A dado joint can be cut with a dado head in a table or radial arm saw. Sliding dovetail joints are cut using a router and a straight edge guide board.
The ends, fronts and backs of boxes, as used with cabinetry construction, are joined in a variety of ways. Glued miters are sometimes used; a splined miter joint is stronger. The miters are cut, and then a dado head is used to cut slots in the joints. Splines are cut to match and hold the pieces together.
Another common joint for boxes and some cabinetry, including drawers, is a finger joint. This consists of fingers of wood interjoining and creates a fairly sturdy joint, much better than nailing and gluing. Finger joints can be cut using a jig and table saw, or with a router and finger-joint jig.
A stronger joint for these applications, and also a very traditional joint is the dovetail. These can be hand-cut, or cut with a dovetail jig and router with dovetail bit. Dovetails may also be “through,” which means you can see both ends of the stock, or stopped. The latter is often used on drawers where a more economical wood is used on the sides with a finer wood for the front.
Another traditional joint is the dowel joint. This may be used to join boards edge-to-edge to create wider stock, or in framing as well. A doweling jig, drill and bits are used to bore precisely located holes to align the stock. Glue is used with the dowels to add strength.
Edge-joined boards can also be joined using tongue-and-groove. This is often a method used to create backs for cupboards, not gluing the boards together, but holding them in a frame. This allows for the natural expansion and contraction of the wood.
A more modern approach to edge-gluing is the use of small wooden biscuits and a biscuit cutter. The technique, however, is not limited to edge gluing. Inset panels between legs such as on nightstands, desks and others can be joined with this tactic. And, biscuits can be used as splines for 45-degree miter joints as well.
One of the newest joints is the pocket-hole joint. This utilizes screws fitted into angled holes in the stock to create extremely sturdy joints. Glue may or may not be used, depending on the joint and design of the project. Pocket-hole joints can be used for almost any woodworking application. The Kreg Jig K3 Master System is the ultimate kit for pocket-hole joinery. It features an interchangeable drill guide block with 1/8-inch adjustments for 1/2- to 1-1/2-inch thick material. Front side clamping speeds the drilling process, and a dust collector keeps things tidy. The K3 Master System makes it quick and easy to create a super-strong wood joint.