A Guide To Dowel Joints & How To Make Them
Jan 13, 2022
The dowel joint is one of the most simple (at least in appearance and theory) joints a woodworker or carpenter can make. By drilling a few holes and inserting a few pegs, dowel joints can form strong joints without mechanical fasteners like nails and screws. But this method is somewhat old-school and not as popular today, so you might be asking, “what is a dowel joint?” Keep reading to find out.
What is a Dowel Joint?
A dowel joint, or doweling, is a type of joint used to connect two pieces of wood by drilling dowel holes in each piece and using a wooden peg (the dowel) to attach them. The dowels act somewhat like a mechanical fastener, as they bridge between the two boards and hold things together. They also swell when covered with wood glue, locking the joint in place. They’re invisible once assembled.
Dowel joints are strong, and the dowels themselves increase the glue surface by quite a bit. They also make use of each board’s long grain rather than simply the end grain at the end of a butt joint.
In most cases, the dowels are made from wood, whether hand-carved or store-bought, and they come in specific thicknesses. Fluted dowels have spiral indentations, and they swell by quite a bit when they come in contact with glue. There are plastic and metal dowels, but they’re generally for adjustable shelving construction.
The projects where you’ll most likely see dowel joints are woodworking and cabinetmaking. The dowels are excellent at securing butt joints for cabinet doors or aligning two boards for a flat edge joint, such as a tabletop. They’re also useful for drawers, picture frames, and other projects where glue alone might not be enough, but visible mechanical fasteners would derail the aesthetic.
Dowel pins are common in mortise and tenon joinery, but that’s a different method altogether.
The Tools to Make Dowel Joints
Dowel joints sound simple, but when a woodworker, carpenter, or DIYer is making a wood joint, their work needs to be precise. There isn’t any slack in doweling, so the craftsperson needs to lay out the locations of the matching holes on each board exactly where they need to be. If they’re off by as much as 1/16th of an inch, the joint might not work. Luckily, there are specialized tools to make the job easier.
One method of making dowel joints is to use marking tools known as dowel centers. A dowel center is a round, button-like plug with one cylindrical side and one side with a pin. The cylinder fits inside a drilled hole while the pin marks the location of another. With careful alignment, the user can push this pin into the surface of the mating board, leaving a mark for a corresponding hole. The user can then drill the other hole and form the joint. Other than a combination square, sharp brad-point drill bits, and a drill (though a drill press is better), dowel centers are all that’s required.
Another method of making a dowel joint is to use a doweling jig. This dowel jig will fit over a workpiece, clamp into place, and guide the drill bit into the wood. The user can then transfer the jig onto another workpiece and drill the corresponding holes. Because these jigs guide the drill bit, a drill press isn’t necessary. A sharp brad point bit, a combination square, and a power drill will do the trick.
It’s possible to create a dowel joint without dowel centers or a doweling jig, but it takes painfully exact layout and a very steady, straight drilling hand.
How To Make a Dowel Joint
The easiest method for making accurate dowel joints is to use a doweling jig. These jigs will have removable sleeves, several holes for choosing the appropriate dowel size, or fixed hole sizes. In general, you want to choose a dowel that’s around ⅓ of the board’s overall thickness, so choose the appropriate hole size accordingly. So, for a 1×4, which is ¾ inches thick, a ⅜-inch dowel is best, so chose the ⅜-inch hole.