FURNITURE PRIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . by Carol Giusti

Joinery Primer

Second in a series of educational primers for retailers and retail sales associates. Take a coffee break and get up to speed.


Wood joinery is a furniture construction and finishing technique used to craft strong, functional and even decorative joints. Many examples of wood joinery abound on the sales floor and can be a key differentiating detail that helps close a sale. Demonstrating a working knowledge of wood joinery is an asset for the sales associate. This helps customers make the best choices when shopping for better wood furniture and will help convince any consumer that quality does matter at any given price point.

This primer defines the main types of wood joinery used in today’s bedroom and functional furniture. It also provides a few tips on how to use this information to help customers make informed buying decisions. Selling up isn’t just a way to make more money; it positions both you and the dealer as a source of good information and quality products.

Traditional wood joinery, and some modern variations, are integral components in the planning, design and production of machine-manufactured furniture. Demonstrating the craftsmanship of wood joinery can appeal to both male and female sensibilities and thereby raise the shopping comfort zone. Simply put, wood joinery adds an intriguing tactile dimension to the selling process.

Modern Techniques
Metal reinforcements and other non-wood mechanisms join modern technology with traditional wood joinery methods. Harvey Bigelow of Harvey Bigelow Designs, a furniture manufacturer in southeastern Massachusetts, reinforces joints with pocket joinery. A special jig bores a strategically positioned hole (or pocket) for a screw. The screw is then driven through the wood and into the adjoining member to make a solid butt joint. “This method adds excellent strength to drawer and general construction butt joints for many different applications,” Bigelow said.

Manufacturers are always looking for new efficiencies that add value and reduce cost. Today, dowels have all but replaced traditional mortise and tenon construction. “Nothing is more simple than drilling a hole to produce a mortise in both parts and joining them with a dowel,” said Pete Dodge, now working with August Lotz in Wisconsin. “Dowling parts together is widely used and, as long as boring and subsequent clamping is done carefully, the joint between the parts is usefully strong. The holes (mortises) need to be bored in the right locations and to the correct depths for a quality joint,” he said.

Other contemporary joinery includes RTA (ready to assemble) hardware. These cams and posts, self-seating conformat fasteners and other joinery options offer the consumer the opportunity to save money by building the furniture at home. Ikea has become famous worldwide for their all-RTA format.

There are many great resources both online and in print on this interesting topic. For further reading, try The Complete Book of Wood Joinery by R.J. DeCristoforo or The Complete Illustrated Guide to Joinery by Gary Rogowski.

Also, if you have the time, find a local woodworking shop or custom furniture manufacturer. Ask them to give you a tour of their shop so you can see and feel firsthand how wood joinery works. Together with this primer, you’ll be able to use that valuable knowledge as you communicate to consumers and close more sales.

Note: The names of all the joinery methods listed below are commonly used, but no definition herein is universally accepted. The subtle differences in joinery technique and jargon make for an interesting debate. We have tried to be plain in our explanations and simple in our differentiation to educate (and not confuse) the woodworking novice.

Butt Joint
For this common and simple joint, the end of one piece of wood is simply placed against the adjoining piece, forming a right angle. The two pieces can be fastened with screws, glued or dry dowels, or sometimes staples. RTA hardware consisting of a conformat (screw) and a barrel nut is another method of securing a butt joint. Also called a Lap Joint. (See illustration 1)

Cross Lapped Joint
In a cross-lapped joint, a rectangular channel is removed from both pieces of wood in the joint. The boards then interlock at right angles. The channels are cut to a depth that allows this joint to appear completely flush when properly constructed. The cross lapped joint is similar to the traditional rabbet joint and uses the same general technique. (See illustration 2)

Dado Joint
A dado is an adjustable blade used to create this simple joinery. Dado joints connect two pieces of wood by cutting a groove (with a dado blade) in one piece of wood which is equal to the height and width of the second piece. Dado joints are often used to insert a drawer bottom. The dado joint is similar to the traditional rabbet joint and uses the same general technique. It can also be used to join the end points of two parts or to join one to the other along the length. (See illustration 3)

Dovetail Joint
This form of locking joint looks similar to an outspread bird’s tail, hence the name. One board has a flared extension which fits into a matching flared cavity in the adjoining board. Use of a single dovetail is called a French Dovetail, and multiple joints in the same corner are called an English Dovetail. Better drawers often use a multi-dovetail because of its strong holding power. (See illustration 4)

Doweled Joint
Two or more small holes are bored into two pieces of wood. The boards are then joined by inserting small round pegs into the holes of one board. The dowels are then inserted into the other board and the joint is glued. You’ll often see sofa and chair frames with dowel joints (and a corner block glued and screwed in place as well). A doweled joint is also typically used in a butt joint and sometimes replaces the traditional mortise and tenon. (See illustration 5)

Miter Joint
Two pieces of wood are cut at a 45° angle and the two beveled edges are placed end to end. They are usually connected with glue, nails or screws. Depending on the size of the pieces being joined, they sometimes have an additional rabbeted joint as well.
(See illustration 6)

Mortise and Tenon
In this method of joinery, the mortised part has a recess cut into it. The tenoned part has a protrusion that matches the recess in the mortise. The pieces are sometimes glued together to strengthen the connection and sometimes a hole is drilled through both the mortise and tenon and a dowel inserted to further strengthen that joint. (See illustration 7)

Rabbeted Joint
For this joint, a groove is cut into one piece and a section of the other board fits into this groove. Similar to a lap butt joint;only one board is cut.

Splined Joint
Grooves are cut in the ends of each piece of wood so that they will line up when joined. A small strip of wood called a spline is inserted into each groove to join the two pieces of wood. Today the biscuit joint is used as a spline joint where biscuits (elliptical splines) are mass produced and biscuit jigs or tools make cuts that allow for accurate, strong and high volume applications.

Tongue and Groove
Two pieces are joined by cutting an edge or shape on one piece of wood which fits into a mirror groove cut in the other board. The tongue and groove must be cut in such a way that the boards fit together tightly without gaps, and the two surfaces remain flush. (See illustration 8) FLLS