7.1: Basic Woodworking Joints
- Page ID
- 67196
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\( \newcommand{\dsum}{\displaystyle\sum\limits} \)
\( \newcommand{\dint}{\displaystyle\int\limits} \)
\( \newcommand{\dlim}{\displaystyle\lim\limits} \)
\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)
( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\id}{\mathrm{id}}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\kernel}{\mathrm{null}\,}\)
\( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\)
\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\)
\( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)
\( \newcommand{\vectorA}[1]{\vec{#1}} % arrow\)
\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow\)
\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vectorC}[1]{\textbf{#1}} \)
\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)
\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)
\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\(\newcommand{\longvect}{\overrightarrow}\)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\(\newcommand{\ket}[1]{\left| #1 \right>}\)
\(\newcommand{\bra}[1]{\left< #1 \right|}\)
\(\newcommand{\braket}[2]{\left< #1 \vphantom{#2} \right| \left. #2 \vphantom{#1} \right>}\)
\(\newcommand{\braopket}[3]{\left< #1 \vphantom{#2}\vphantom{#3} \right| #2 \vphantom{#1}\vphantom{#3} \left| #3 \vphantom{#1}\vphantom{#2} \right>}\)
\(\newcommand{\qmvec}[1]{\mathbf{\vec{#1}}}\)
\(\newcommand{\op}[1]{\hat{\mathbf{#1}}}\)
\(\newcommand{\expect}[1]{\langle #1 \rangle}\)
\(\newcommand{\dfn}[1]{\emph{\textbf{#1}}}\)
7.1 Basic Woodworking Joints
Woodworking joints connect two or more pieces of material.
Some joints are simple. Others are complex. Some are designed mainly for strength, while others also provide alignment, appearance, or resistance to movement.
There is no single “best” woodworking joint. The appropriate joint depends on the material, the forces acting on the project, the tools available, and the appearance you want.
Learning Outcomes
After completing this section, you should be able to:
- Identify several common woodworking joints.
- Explain the basic purpose of each joint.
- Recognize the difference between a butt joint and a joint with interlocking geometry.
- Explain why different projects require different types of joints.
Butt Joints
A butt joint is the simplest type of woodworking joint.
Two prepared surfaces are placed directly against each other and joined with adhesive, fasteners, or both.
Common butt-joint arrangements include:
- edge to edge;
- face to face;
- end to edge;
- end to face; and
- edge to face.
An edge-to-edge joint is commonly used to create a wider panel from narrower boards.
A face-to-face joint is used when laminating pieces to create a thicker part.
End-grain butt joints generally have less useful glue surface than long-grain joints and often require another joint form or mechanical reinforcement.
Half-Lap Joint
In a half-lap joint, approximately half the thickness is removed from each of two overlapping pieces.
When assembled, the joint returns to approximately the original stock thickness.
Half-lap joints provide:
- a large glue surface;
- good alignment;
- mechanical support; and
- relatively simple construction.
You used half-lap joints in the picture-frame project.
Dado Joint
A dado is a groove cut across or through the surface of a piece of material.
Another piece fits into the groove.
Dados are commonly used for:
- shelves;
- partitions;
- cabinet construction; and
- box structures.
The dado provides mechanical location as well as additional glue surface.
Rabbet Joint
A rabbet is an L-shaped recess cut along the edge or end of a board.
Rabbets are commonly used in:
- boxes;
- drawers;
- cabinet backs;
- frames; and
- case construction.
A rabbet can help locate one part against another while providing more glue area than a simple butt joint.
You also used a rabbet to hold the glazing and backing in the picture-frame project.
Miter Joint
A miter joint joins two angled surfaces.
A common example is two pieces cut at 45 degrees and joined to create a 90-degree corner.
Miter joints can hide end grain and create a clean appearance.
However, a simple glued miter does not provide much mechanical interlocking, so miters are often reinforced in more advanced work.
Mortise-and-Tenon Joint
The mortise-and-tenon joint is one of the most important traditional furniture joints.
The mortise is a recess or opening cut into one piece.
The tenon is a projecting portion on the mating piece.
The tenon fits into the mortise.
Mortise-and-tenon joints provide:
- substantial long-grain glue area;
- mechanical alignment; and
- resistance to forces that might pull or rack the joint.
They are commonly used in table, chair, frame, and furniture construction.
Box or Finger Joint
A box joint, sometimes called a finger joint, uses a series of alternating rectangular fingers.
The fingers from the two pieces interlock.
This creates:
- substantial glue surface;
- mechanical alignment; and
- a distinctive visible pattern.
Box joints are commonly used for boxes, drawers, and casework.
Dovetail Joint
A dovetail joint uses interlocking pins and tails.
The angled geometry prevents the pieces from pulling apart in one direction even before glue is added.
Dovetails are commonly associated with drawer construction and fine furniture.
They are strong, visually distinctive, and require careful layout and fitting.
Dowels
A dowel is a cylindrical piece of wood used to help connect or align parts.
Dowels can:
- reinforce some joints;
- help locate mating parts;
- assist with alignment during glue-up; or
- act as visible or hidden mechanical pins.
In some edge-to-edge glue-ups, dowels are used more for alignment than for additional strength.
Choosing a Joint
When choosing a joint, ask:
- What forces will act on the joint?
- What grain directions are being connected?
- How much glue surface will the joint provide?
- Does the joint help align the parts?
- Will the joint be visible?
- Can the joint be made accurately with the available tools?
- Is the additional complexity actually necessary?
The most complicated joint is not automatically the best joint.
A well-made simple joint is usually better than a poorly fitted complicated one.
Check Yourself
- What is a butt joint?
- What material is removed to create a half-lap joint?
- What is the difference between a dado and a rabbet?
- What are the two parts of a mortise-and-tenon joint?
- Why are box joints strong?
- What mechanical feature distinguishes a dovetail joint?
- Why might dowels be used in an edge-to-edge glue-up?