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Joining wood is part of virtually every woodworking project in your home. Framing a window or door, building a cabinet, table, or chair, or adding shelves in your bathroom, are all projects where wood is joined in one fashion or another.
There are different ways to join wood, and the use of biscuits is one of them. Not the biscuits and gravy kind of biscuits, though.
Biscuits used to join pieces of wood are oval-shaped, thin, dried, and compressed bits of wood or wood shavings, often made with beech wood. A tool known as a biscuit joiner cuts a slot into each of the two pieces of wood to be joined, adds glue to the slots, inserts the biscuit into one and then the other to join the pieces together.
Clamps are used to press and hold the two pieces of wood together to allow the glue to dry and the connection to set. The biscuit joiner aligns the slots precisely so that when the two pieces of wood are clamped together, the edges align perfectly, and the wood’s plane is maintained.
But what if you don’t have a biscuit joiner? Do you even need one? What are the other options for joining two pieces of wood together?
Are Biscuit Joints Necessary?
The short answer is probably not.
Biscuits used in edge-to-edge joinery keeps the faces of the wood joined aligned. This is so because of the precision cuts of biscuit joiners.
It’s especially helpful when joining solid wood to plywood, such as covering the plywood edge with solid wood. That alignment cuts down on sanding, and if the plywood is veneered, the risk of chipping or sanding through the veneer is reduced.
Otherwise, there are other options that, in some instances, would be preferable to the use of biscuits.
- Butt joints
- Mitered butt joints
- Half-lap joints
- Tenon joint
- Dovetail joints
A brief description of each follows.
Butt joints are inelegant and straightforward but can be quickly accomplished. It’s suitable for small projects on pieces that will not experience a lot of pressure or movement. They are also the weakest joints among all of these choices.
Mitered butt joints are butt joints of two pieces at a 45-degree angle. They require a miter cut to that 45-degree angle, and when glued together, form a right angle. You likely have them throughout your home, whether it be the trim around your windows or picture frames hanging on your walls. They are well suited for wood joinery that will remain stationary in place and not be subject to movement. As with butt joints, they are not a strong joinery choice.
Half lap joints are a good choice for bed frames, table frames, or a wooden deck outside your slider, as they provide strong and solid joinery. In half-lap joints, two pieces of wood with the same dimension each have a part of the timber removed, allowing the boards to fit together seamlessly.
Tenon joints, also called mortice and tenon joints, are another good choice where strength is needed at a 90-degree angle. The tenon, an extension at the end of one piece cut to the dimension of the mortice, is fit into the mortice – a slot in the other piece cut specifically to the size of the tenon. They are joined by both fit and by glue and provide solid joinery, adding excellent quality to the project being built.
Dovetail joints are traditionally used to build drawers, whether for your kitchen or a chest of drawers for your bedroom. They look like puzzle pieces fit perfectly together and are both decorative and functional, providing good strength and support with their interlocking nature.
Pocket Screw Joinery
Another joinery method that has become quite popular for professional carpenters and hobbyist woodworkers is pocket screw joinery. It has been made popular by many television handyman shows and YouTube videos and provides a method of joining two pieces of wood that is stronger than a tenon joint – if done correctly.
Special tools are required for this technique, and sets can be purchased at local hardware stores, large DIY stores, and online retailers. They include the jig that determines the gauge and angle of the hole to be drilled, the drills, and screws.
A hole is drilled guided by the jig into the face end of the piece to be joined. A pocket screw will extend through that piece of wood and into the piece it is being joined with and tightly pull the two pieces together. Two or three pocket screws will be used, and the joint created will be very strong.
The joint, and the bond between the two pieces of wood, is created immediately. This method can be used to join boards in almost any configuration, whether it be end to edge, end to face, or even mitered.
Here’s an excellent video on the basics of pocket screw joinery:
Can You Use Dowels Instead of Biscuits?
What about dowels, you ask? Let’s discuss.
Dowel joinery follows the same basic principle as biscuit joinery. Holes are drilled into each piece of wood to be joined; glue is applied to the holes; dowels are inserted into the holes on one piece, and then the exposed portion of the dowels are inserted into the holes of the other material.
The use of dowels is not as easy as using biscuits. The holes have to be drilled with great care and precision, both in location and in depth. Jigs may be purchased for this purpose, for the necessary accuracy.
The dowels must be of the same length precisely so that the joining is complete and without gaps. The dowel gauge should be about ⅓ of the thickness of the pieces being joined, but never more than ½ of that thickness.
Some tests suggest a dowel joint will provide stronger joinery than biscuits. Tests also indicate that dowel joints are not as strong as tenon joints or dovetail joints.
They do make solid and accurate joints, though. A dowel joint will be a better method than nails or screws and are much less susceptible to breakage. A dowel joint is certainly preferable to a simple glue joint, as well, far less likely to snap apart.
Which Joinery Method To Choose?
As you can see, there are many joinery choices, each with their advantages. The answer depends in great part on several factors:
- What are you joining? What is the project? Does the joinery require great strength? Does it need some aesthetic quality, a pleasing appearance, or will it be hidden?
- What tools and equipment do you have or need for each of the choices?
The avid woodworker who works on a variety of projects will likely be well-equipped with power tools, jigs, and talent. The beginner, perhaps not so much.
The nature of the project often determines the joinery need, too. Joining pieces of wood for a table top would be served well by either biscuits, dominos, or dowels and require the appropriate jigs for the slots or holes to accommodate either.
But, the well-equipped woodworker might choose, instead, pocket screw joinery for its additional strength and easy installation.
The old saying “The right tool for the right job” is apt when it comes to joinery as well: “The right method for the right job” certainly applies equally. Choose the best joinery option for your project, and make a joint that will hold well over time.