What is a Jointer

Powermatic wood planer in a woodshop.

Woodworking is an art that combines creativity and craftsmanship to transform raw lumber into exquisite pieces of furniture and functional structures. One of the essential tools in any woodworking shop is the jointer machine, a device that plays a pivotal role in achieving straight, smooth, and accurate surfaces on lumber. In this article, we enter the world of jointers, understanding what they are, how they work, their functions, and the pros and cons they bring to the woodworking table.

What is a Jointer Woodworking Machine?

A jointer, also known as a surface planer is a woodworking machine designed to create a flat, smooth surface on the face and edge of a piece of lumber. The Jointer is a critical tool in the arsenal of woodworkers, as it helps prepare wood for subsequent stages of construction, such as gluing, edge joining, or simply achieving a refined finish. A jointer should no be confused with a Planer, which is an entirely different machine.

Before the advent of the electric Jointer, woodworkers and craftsmen would use hand planers to straighten their wood pieces for projects The Jointer as we know it today has allowed for extreme savings in terms of the time it takes to produce pieces.

How Does a Jointer Work?

At its core, a jointer consists of a flat table and a rotating cutter head equipped with a series of sharp blades. The process begins by placing the rough lumber on the jointer’s infeed table, adjusting the cutting depth to the desired level. As the lumber is pushed forward, the rotating cutter head shaves off the high spots, leaving a flat and even surface. Simultaneously, the fence on the machine’s outfeed side ensures that the edge of the board is straight and square to the newly planed face.

The blades can come in varying configurations. They may either be straight blades that span the length of the jointing span, or many blades in a spiral or helical configuration. All types have different benefits and contractors, however, the main differences come in overall end product vs. cost. The more expensive configurations give you better results, while cheaper options leave something to be desired.

Functions of a Jointer in a Woodworking Shop:

Flattening Surfaces: One of the primary functions of a jointer is to flatten the faces of rough lumber, ensuring they are smooth and even. This is essential for creating stable and level surfaces for subsequent woodworking processes.

Edge Jointing: A jointer’s ability to create perfectly straight and square edges is crucial for creating strong and seamless joints when gluing boards together. This is particularly important for constructing panels, tabletops, and other pieces that require tight-fitting joints. This in particular is one of the main things we use our jointer for! See our shelves and tables

Dimensional Accuracy: By using a jointer, woodworkers can achieve precise dimensions and corners on the edges of their projects. 

Surface Preparation: The smooth surface produced by a jointer is an excellent starting point for achieving high-quality finishes through sanding and other finishing techniques. This is similar to a planer which is able to remove a consistent amount of material from the faces of a project which helps in preparing them for sanding as well. 

Pros and Cons of a Jointer::


Precision: Jointers are renowned for their ability to produce accurate and flat surfaces, which is essential for achieving professional-level results in woodworking. Using a warped board is a bad plan, and Jointers are integral in ensuring the warps are straightened out.

Time-Saver: Using a jointer can significantly reduce the time spent on hand planing or sanding rough lumber boards to achieve the same level of flatness and smoothness.

Edge Jointing: The machine’s capacity to create straight and square edges enhances the quality of joints and makes projects more durable.

Consistency: Jointers allow woodworkers to replicate precise dimensions across multiple pieces of lumber, ensuring uniformity in the final project.


Skill Required: Operating a jointer requires a certain level of skill and experience. Improper usage can result in tear-out, which can be frustrating and wasteful. Jointers are also dangerous when used improperly. 

Limited Width: Jointers come in various sizes, and the width of the boards they can handle is restricted. This limitation might pose challenges when working with wider lumber.

Noise and Dust: Jointers can be noisy and produce a significant amount of wood chips and dust. Due to this, you must utilize proper protective gear for your ears and eyes as well as dust collection systems.

Initial Investment: High-quality jointers can be expensive, especially those designed for professional woodworking shops. As with any woodshop tools, here are several smaller and less expensive versions available that can be useful for certain shops but they of course will come with their own drawbacks.

The jointer is an indispensable tool for any serious woodworker. Its precision, efficiency, and ability to create smooth, flat surfaces on boards make it an asset in achieving the highest level of craftsmanship. While it does require some skill to operate effectively and comes with certain limitations, the benefits it brings to the woodworking process are invaluable. As with any tool, proper usage, safety precautions, and a commitment to craftsmanship will yield exceptional results and make the jointer a cornerstone of woodworking excellence.

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