Wood joints are an aspect of woodworking that involves attaching two different pieces of wood together to create a larger more complex structure. While some joints rely on more than just precise cuts to create a joint and use materials such as brackets or adhesives, other advanced forms of jointery create cuts that are so well crafted and sized that two pieces of wood will come together and lock at their joint due to nothing more than friction.
These are some of the more popular wood joints. The distinguishing factors between any of these varieties come down to strength, flexibility, toughness, appearance, and application.
This is a broad category of joints, so while there are many examples of corner joints out there, the definition is a joint that connects two pieces at their ends, thus forming a corner.
Specific examples include the end lap joint, the mortise joint, and the incredibly common butt joint.
1. Butt Joint
Constructing a butt joint is quite an easy process. All one must do is use screws to attach two pieces of wood at their respective ends. Although this method is preferred for its simplicity, it does leave the screws uncovered. To avoid having the screws come loose, thus causing the joint to fail, either countersink them or apply putty.
2. Dowel Joint
Creating a dowel joint is nearly identical to the general process for butt joints. The only difference is that you will apply dowels rather than screws. Line the wood up and drill a hole from one through the other. Drive dowels through the holes and glue them in place.
You can hide the dowels by drilling only the interior of the boards and inserting the dowels in the hidden holes. Keep in mind that hidden dowels are less secure than full dowels.
3. End Lap Joint
If you need to build an end lap joint, begin by sawing the end of each piece of wood half-way so that when you lay one piece flat, one end looks like a step pyramid. Turn the step pyramid on one of the pieces upside down, and place it on the other piece’s cut end so that they fill in the missing end half for one another. Align the boards and secure them with screws. Then countersink the screws or cover them in putty.
4. Mortise Joint
Both mortise joints and tension joints are made by carving thin notches into the edge of the wood that many would consider the side that determines its “thickness.” The end of another piece is then whittled away on either side of the end, so a thin extension emerges. The thin extension is then slotted into the notch on the opposing piece.
The notched and slots can be made using a power saw and a dado head. You then either screw or glue the pieces together.
5. Open Mortise and Tension Joint
If you have a higher technical skill, you can use a mortising chisel on a drill press to make an open mortise and tension joint. These joints are harder to make, but they are stronger.
Joining a Top Plank to a Side Plank
Similar to the way a corner joint joins two ends of wood, the following cuts attach the top plank to the side plank.
6. Lock Miter Joint
This is similar to the end lap joint in that you carve a nook out of each piece and they rest against one another. The difference in this case is that the nook is carved out of the top plank and side plank respectively as opposed to the ends of the timber.
However, unlike the end lap joint, this instance of jointery requires a bit more carpentry skill. In fact, when executed properly adhesive is not necessary as the two pieces can for a strong yet unnoticeable bond.
7. Rabbet Joint
Rabbet joint is similar to the open mortise and tension joint, but can be made with simple hand tools. If you have access to power tools that can shape the planks, the mitered rabbet is also a popular option. While it does require an adhesive like glue for the joint to actually hold together, the positioning of the planks completely hides the grain, which some people find unique and attractive.
8. Finger Joint
The finger joint is a type of milled joint. As seen here, multiple grooves are cut from the plank leaving multiple protruding peaks and valleys, or fingers, which interlock.
When executed with enough precision, this is another joint that can hold to together simply due to friction. This joint is especially popular for joining the pieces that make up the frame on a set of drawers or a dresser.
Attaching a Plank to the Center of Another Plank
These final two woodworking techniques can be used to join two planks at their centers.
9. Butt Joint Variation
The center oriented version of a butt joint is similar to a regular one. An obvious structural difference is that while a regular butt joint attaching at the corners will form a 90 degree angle and an L shape, this variety also forms a 90 degree meeting between the two planks, but due to the center positioning ends up creating more of a T shape.
10. Stopped Dado Joint
The dado is a common bit of woodworking and is also sometimes the same name used to describe the woodworking tool you may use to make one of these cuts.
A stopped dado joint resembles the previous joint, but the center plank of one of the timbers is cut into so it resembles the open mouth of a wrench, with the groove not spanning the entire width of the plank, and then the other timber is placed into that opening.
This is just a sampling of some of the jointery that is possible with a few tools and a little skill. If any of these descriptions are lacking, there are multiple examples of each of these available online along with woodworking tutorials.