Box joint is among the seven popular types of woodworking joints, such as dowel joint, bridle joint, lap joint, butt joint, and mortise & tenon joints. This type of joint is a product of cutting interlocking and complementary profiles using two wood pieces. Woodworkers apply a thick layer of glue to the surface area to keep the bond strong enough to hold the joint. From there, the wood pieces are glued to join them at the right angles. Box joint works similarly to dovetails, but it is less complex and is always available in the market due to mass production.
What are the Uses of Box Joints?
Box joints are a popular woodworking method of constructing box corners through their interlocking properties. It is excellent for joining solid wood panels, boards, and slats, significantly wider ones. Thanks to their tooth-like ends that aid in interlocking the joints. Box joints create a sturdy connection for the wood pieces through meshing teeth. They are helpful for daily woodworking projects like building trays, drawers, carcasses, boxes, chests, and tool totes, as they can stand heavy pressure. Here are the common uses of box joints:
- The right angles joints of box joints are perfect for creating odd shape boxes, such as hexagonal, octagonal, or oval. You can use the joints for all carcasses, boxes, and sides of lids, drawers, and chests to connect thin panels to the main structure.
- Drawers/Chests-You can never go wrong if you use box joints in making all types of drawers for cupboards, dressers, desks, tables, and closets. The joints offer a stable foundation for these items to maintain their shapes during everyday use.
- Carcasses-Don’t confuse yourself when you hear the word carcass in woodworking. It refers to the basic framing of large woodworking projects, such as bookcases, shelves, cabinets, closets, cupboards, pantries, and chests of drawers. A carcass is a skeleton of your wooden box projects. It is where you install the doors, drawers, and shelving. Using a box joint ensures that its interlocking properties guarantee that the carcass’ sides are secure and robust in place.
- Box Frames-Like carcasses, box frames can withstand the frequent use of wooden box projects over time. Using box joints helps create wooden box frames for small boxes for storing jewelry pieces, trinkets, cigars, and ample storage organizers, such as crates, tool boxes, toy chests, and clothes chests. The design of box joints is simple and user-friendly, making them ideal for all shapes and designs of box-like projects.
Advantages of Box Joints
Using box joints in woodworking is advantageous compared to other types of joints. It is simple to use if we compare it to open dovetail joints. Box joints do not need extra skills to cut into various shapes. They may look less appealing, yet they can last for years due to their durability.
Their versatility makes them a preferred joint to dovetails since you can use them for various box-like wood projects. They also have a large surface area for joining strong joints for some small projects that carry heavy loads.
Box joints are ideal for connecting two carcasses or frames to create a box corner. They also produce a special connection through their uniform notches and pins that lay along the sides of the joint’s corner. After gluing the joints together, it guarantees that it can stand against heavy loads and pressure due to its expansive surface area.
What is the Best Way to Cut a Box Joint?
Cutting a box joint can be done in two ways: by hand or machine. If you want it easy and efficient, cut it using a machine. Using a machine results in identical and even halves. The first and last fingers of the joint half may look different.
These fingers entangle each other through the calibration. To prevent errors during cutting, you have to write a line across the finger’s base to make it perfect. It is up to you to sand or leave the scribe line as is.
Newbies in woodworking can make some modifications to their crosscut sled. Lon Schleining, a woodworker, has a technique for cutting a box joint using commercial fixtures and jigs that he attached to a table saw crosscut sled to achieve the correct precision. He cuts the first box joint and then focuses on the adjacent joints.
Setting Up a Box Joint
Box joints are not as challenging as other woodworking joints as they are simple and less complicated. You can manually create a box joint with the same profile or use custom machinery.
The first thing that you will do is to place the blade on the table saw or dado stack to cut about one-fourth wide fingers. You can cut the fingers’ width according to your woodworking project.
If not using a dado set, use a standard one-eighth inches blade to form fingers of the same width. Install the miter gauge in the table saw slot. Get a piece of scrap wood as your backer and then hold it against the miter to create a cut using the blade. This method ensures that the cut’s height is more significant than the board’s width.
Methods of Cutting Box Joints
Cutting by Hand
Cutting box joints by hand are almost the same as manually cutting dovetail joints. You need some materials before cutting the box joints, such as a hammer, chisel, dovetail saw, marking knife, marking gauge, and square. First, lay out the pins’ depth on the wood using a marking gauge. Scribe several perpendicular lines to get the pins’ width using a marking knife and square. Use a chisel to score the scribed perpendicular lines and cut them using a dovetail saw. Knock out the waste using a hammer.
Cutting with a Table Saw
Tools you need when cutting box joints with a table saw are dado blades and jigs, which are available in-store or online, or make a DIY jig. Making your customized box joint jigs is advantageous as you can save money.
You need an indexing pin or key to make it in your workshop, ensuring that it has the exact width of the fingers. Position the indexing pin on the workpiece, and then space the finger’s width. Cut the first finger and then place the gap left after cutting on top of the indexing pin to make the next cut, repeating the steps to cut all fingers.
Using a Dado Set/Dado Stack
This tool is a saw blade to cut slots, grooves, and dadoes into the workpieces. It is an ideal tool for making joinery for door panels or drawer bottoms. It is excellent for cutting box joints’ fingers.
Cutting Box Joints with a Router
Woodworking joint routers can be table or handheld routers. If using a handheld router, you need a joint box jig or make a customize DIY router jig to save extra dollars.
A store-bought jig is easy to manipulate to cut three-fourth-inch or one-half-inch pins. There is an adjustable bushing to the router’s base with teeth resembling a comb, which accurately cuts the sockets and pins. You can adjust the bushing according to your requirements.
A sliding jig is essential when cutting box joints with a router table. The sliding jig is similar to a regular jig or a table saw jig. If using a store-bought jig, always read the manufacturer’s manual to understand how to set it up and use it.
A router table box joint jig refers to a jig for cutting box joints using router tables. It works almost the same as a table saw jig; it cuts the finger with a straight bit instead of using a blade.
The indexing key accurately positions your workpiece for the subsequent cuts after cutting the first fingers and repeats the steps to finish cutting all fingers.
Using a Multi-Joint Spacing System
This system cuts the fingers in various widths, such as 1/4 inches, 1/2 inches, and 3/8 inches. MJSS comprises a fence to clamp the top of your router table. It also has a right-angle block to straddle the guide rail around the wall and offers support to the workpieces while traversing over the straight bit.
Additional Tips on Making Stronger Box Joints
- The pins should be half or lesser than the thickness of your workpiece. Ensure that there are three pins on a workpiece and two pins on the other piece if using narrow wood pieces.
- Cutting the profiles can be quick if you install dado blades on the table saw.
- A spiral bit is ideal if cutting the joints on your router table to minimize the tearing out of workpieces.
- Always press the workpiece tightly by clamping it to the fence if working on large workpieces. Clamp the workpiece well to get accurate cuts and protects it from damage.
- Use a chisel and dovetail saw if cutting the box joint by hand to develop your woodworking skills.
- Lay the end of your workpiece flat against the jig or table during cutting to get the correct length.
- Double-check the matching set of workpieces to ensure that the jig does not change position.
- A DIY box joint jig is essential for mass production.
- Avoid clamping the box joints too tight or too loose. It becomes unsafe if it is to lose. There needs to be more space for gluing if it is too close.
- Apply both sides with glue on the joint.
Differences Between Finger Joint & Box Joint
Both finger and box joints have similar definitions. According to Wikipedia, both woodworking joints are a product of cutting a group of interlocking and complementary profiles of two wood pieces.
Their difference is that a box joint is joined at the right angles. It is composed of uniform pins and notches along the corner of the box length. It forms ordinary but pleasant-looking exposed connections.
A finger joint has a cross-section that looks like the interlocking fingers of two hands, where the name originates. There is a strong bond on the sides of a finger joint due to its large surface area for applying glue. It is more robust compared to a butt joint but less attractive.
These characteristics are also present in a box joint, which makes them more confusing. Looking closely at their appearance, you can tell their stark differences.
Finger points are delicate looking due to their thinner cut. They are composed of pins that resemble fingers with corresponding notches that interlock to connect two parts. They are best for working on long pieces of wood, such as boats, canoes, and molding, that pass through a den or kitchen.
Differences Between Dovetail Joint & Box Joint
Dovetail joints are noticeable by the trapezoidal shape of their tails and pins. These profile cuts slide in one direction, while the rectangular shape of the box joint’s pins slides in any direction.
Dovetail joints are famous for making log buildings, timber framing, cabinetry, and furniture. It is excellent for large woodworking projects because it does not need mechanical fasteners once you have finished gluing.
It has a formidable tensile strength making it an ideal joint to connect the drawer’s sides to the front. This woodworking joint comprises pins specially cut to cover one board and interlock using its tails cut towards another board end.
Dovetail joints are more aesthetically appealing than box joints but are challenging to cut. If properly glued, both woodworking joints offer stability to your wood projects.
Is Gluing a Box Joint Necessary?
Yes, it is. Gluing a box joint makes the box serve its purpose over years of use. The interlocking fingers produce a wide surface for gluing. You can apply some glue on some surfaces to create a sturdy joint. Woodworkers recommend an acid flux brush when using glue on the finger.