How to Use Dowel Joinery

Doweling has been used for centuries by woodworkers who needed to strengthen their joints or fix stripped screws. The principle behind doweling is simple: small round but evenly cut sticks of wood, called dowels, are inserted into perfectly matched holes in corresponding boards that, when glued in place, provide a strong, durable woodworking joint. Sounds easy, right? Not exactly.

A great number of today's woodworkers tend to eschew doweling for less problematic methods such as biscuit joinery or mechanical fasteners such as pocket joinery, but the simplicity and strength of doweling shouldn't be discounted. Doweling typically entails using a diameter of dowel that is no more than 1/2 of the width of the board. For instance, when joining 3/4-inch width boards, a 5/16-inch or 3/8-inch dowel would typically be utilized. Using a wider dowel would weaken the board, and a narrower dowel would not be strong enough to hold the joint.

The holes to accommodate the dowels should each be drilled about 1/16 of an inch deeper than 1/2 of the length of the dowel section being used. Dowels 1 1/2-inches long are commonly used, so in this case, you would drill each of your doweling holes to 13/16 of an inch in length.

Birch dowels are commonly used in doweling, although commercially created plastic dowel kits (including the drill bit, a drill stop, and metal doweling centers) are also readily available in home centers. Should you choose to cut your own dowels, a here are a couple of tips to make your doweling easier:
First, it is a good idea to chamfer the ends of the dowel to make insertion into the holes easier. Second, cut a small groove down the long axis of your dowel to provide a channel for the glue and air to escape. This can be done easily with your band saw and a pair of pliers to hold the dowel safely.

Doweling Jig

In addition to a drill bit, your dowels and glue, you'll find your doweling will go much easier if you use a doweling jig. These doweling jigs are typically metal and are designed to guide the drill bit into the stock square to the edge of the board. Your jig should include bushings to accommodate bits of varying diameters.

Drill Your First Holes

To begin doweling your joint, align the two boards to be mated into their final positions. You'll need to use at least two dowels for each joint, more if the joint is particularly wide. One rule of thumb is that if the board(s) are less than 6 inches wide, place one dowel 1/4 of the way across the joint, and a second dowel 1/4 of the width in from the opposite side. So, for a 6-inch wide board, the first dowel would be placed at 1 1/2 inches in from one edge, and the other dowel 1 1/2 inches in from the opposite side. If the gap between the dowels exceeds 4 inches, add an additional dowel.

Using a pencil, make a mark at the desired locations on both boards. Then, separate the boards and align the doweling jig with one of the marks on either board. Install the drill bit into your power drill or cordless drill and position the drill stop onto the bit at the desired depth.

Drill your first hole through the jig to the drill stop, then reposition the jig over the second hole and repeat. Continue until all holes on this board have been cut.

Align the Holes

With all of the holes in the first board drilled to the proper depth square to the board, do not move onto the second board just yet. Instead, position the doweling centers that came with your dowel kit into the holes (that is, if you are using packaged dowels - if not, you may want to pick up some doweling centers, as it will make your doweling much more precise).

With the doweling centers positioned in the holes, align the second board into place and press it against the doweling centers. Be certain to be precise, as the doweling centers will make a perfectly-positioned indentation on the second board, showing precisely where the next holes should be drilled. If you have no doweling centers, you can try to measure and get the proper location, but if your original holes were slightly out of place, the chances that your new hole will match are slim.
Separate the boards, and align the doweling jig with the newly marked points, and drill the holes.

Install the Dowels

When all of the holes have been drilled, remove the jig and the doweling centers from the first board. Place a small amount of glue into each hole in one board and insert your dowels into the glued holes. You don't need much glue, as too much glue will either squeeze out or make it difficult to insert the dowels. Immediately clean up any glue that does squeeze out with a slightly dampened cloth.

Next, insert some glue into the opposite holes and position the board onto the corresponding dowels. Push the board straight onto the dowels as far as you can by hand, being careful not to use a twisting motion.

When the joint is closed as best, you can by hand, use a woodworking clamp to tighten the joint the rest of the way until the joint is closed completely. Keep the clamp in place until the glue has dried fully, typically 24 hours.