Everything You Need to Know about Box Joints

If you’re making boxes for a woodworking project, the classic box joint is a great choice for crafting corners that are as strong and tight as they are aesthetically pleasing.

The simple interlocking design of box joints makes them relatively easy to create. They also provide a lot of surface area between both pieces of wood, giving you a strong and stable connection when the joint is glued together.

What is a Box Joint?

A box joint is a basic woodworking corner joint made by cutting offset profiles in two pieces of wood and interlocking the resulting rectangles or “pins” together. Since these profiles are cut straight, you can slide them directly into one another, then glue the joint.

Box joints are sometimes called “finger joints,” but only when the pins are really thin.

Types of Box Joints

Box joints can sometimes differ from the standard version described above. They still feature the same basic concept, but can appear in various box types.

Angled box joint

Although box joints typically create right angles, they can also form shallower or tighter angles — good for creating decorative jewelry boxes or octagonal trays. Angled box joints are more challenging to cut, requiring a custom jig.

Half-blind box joint

These allow the front side of the joint to stay hidden, good for connecting drawer fronts to the sides. The pins on one side are cut so they’re housed inside the edge of the other, and their end grain isn’t visible.

Common Uses of Box Joints

Box joints are one of the most common joints out there, suitable for lots of items:

Drawers

The most common application. Whether you’re making drawers for desks or cupboards, box joints provide the stability needed to keep their shape during frequent use over the years. I’ve often relied on box joints when putting together drawers for custom closets.

Carcasses

This is the basic box framing of larger pieces like cabinets, bookcases or chests of drawers. It’s essentially the skeleton before adding the shelving or doors. The strength of the box joint keeps the sides of a carcass securely in place.

Box frames

Wooden box projects like jewelry boxes, crates, open-topped tool boxes and toy chests commonly use box joints as well. Their basic design and simple construction make them well suited for a range of sizes.

Box Joints vs. Dovetail Joints: Is There a Difference?

Yes, although both are interlocking woodworking joints with alternating profiles. Dovetail joints feature trapezoidal profile cuts, like the tail of a dove, that only slide together in one direction. This design allows them to lock together like a puzzle piece.

The rectangular pins of box joints, on the other hand, can slide together in any direction. Their angular design gives dovetail joints more of a high-end craftsmanship look, but also makes them more challenging to cut.

There are different schools of thought regarding which joint is stronger. But once they’re glued up, both are extremely strong and stable.

Tips for Cutting Box Joints

Box joints are relatively simple to cut. If you’re just starting out, here are some tips:

• Keep the pins half the thickness of the material or less. If you’re working with narrower wood pieces, make sure you have at least three pins on one piece and two on the other.
• If you’re hand-cutting your box joint — a great project to improve your craftsmanship skills — go with a dovetail saw and chisel.
• Use stacked dado blades on your table saw to quickly cut your profiles.
• If you’re cutting box joints on a router table, choose a spiral bit. This reduces frustrating tear-out.
• Want to save time and ensure consistent cuts? Make a box joint jig. These are essential for any kind of mass production project.
• Box joints should slip together by hand. A little friction is good. But if it’s too tight, there won’t be room for the glue. And it it’s too loose, the joint won’t be secure.
• When gluing up the joint, be sure to apply glue to both sides.