What Does a Jointer Do?

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If you are just getting into woodworking, a jointer can seem confusing at first. A lot of people see one and assume it is just another machine for making boards thinner, but that is not really its job.

A jointer is used to create a flat face and a straight, square edge on a board. That makes it one of the most important tools for preparing rough lumber before moving on to the next step.

If you have ever tried to build something with a twisted, bowed, or uneven board, you already know how frustrating it can be. Boards that are not flat or straight make every step harder. Cuts are less accurate, joints do not line up as cleanly, and your finished project can end up looking sloppy. That is where a jointer comes in.

What a jointer actually does

A jointer is designed to do four main things:

1. It flattens one face of a board

This is the first job of a jointer. Rough lumber often comes with cup, bow, or twist. A jointer helps create one flat reference face so the rest of your work starts from a true surface.

2. It straightens one edge

Once you have one flat face, you can run the board against the fence to straighten one edge. That gives you a clean edge for glue-ups, ripping, and accurate layout.

3. It squares the edge to the face

A jointer fence helps you create an edge that is 90 degrees to the flattened face. That matters if you want tight joints, square assemblies, and better overall accuracy.

4. It helps remove cup, bow, and twist

A jointer does not magically fix every board in one pass, but it is one of the best tools for correcting common warping in rough lumber.

What a jointer does not do

A jointer is not the same as a planer.

This is where a lot of beginners get mixed up.

A jointer creates:

• One flat face

• One straight, square edge

A planer creates:

• A second face that is parallel to the first

• Final board thickness

So the normal workflow is:

Jointer first → Planer second

That is why woodworkers often say the jointer gives you a true reference surface, and the planer finishes the job.

When you should use a jointer

A jointer is most useful when working with:

• Rough sawn lumber

• Boards with cup, bow, or twist

• Stock that needs a clean glue edge

• Lumber that needs to be squared before planing or cutting

It is especially helpful if you want cleaner panel glue-ups, straighter boards, and fewer headaches during assembly.

When you should not use a jointer

A jointer is generally not meant for plywood or sheet goods. Plywood already comes flat enough for most uses, and running it over a jointer is usually unnecessary.

A jointer is also not a replacement for safe technique, proper lumber selection, or a planer. It is one part of the process.

Why a jointer matters in a small shop

Even for hobby woodworkers, a jointer can make a huge difference. It helps you stop fighting your material.

Instead of trying to force warped boards into square projects, you start with stock that is actually ready to work with. That means:

• Better-fitting joints

• More consistent cuts

• Easier assembly

• Cleaner finished projects

If you work mostly with construction lumber or rough hardwoods, a jointer can become one of the most useful machines in your shop.

A solid entry-level jointer to consider

If you are looking for a good beginner-friendly option, the WEN JT630H 10-Amp 6-Inch Spiral Benchtop Jointer is a strong entry-level choice.

It is a compact benchtop model that makes sense for smaller shops, and the 6-inch capacity is a practical size for a lot of common woodworking projects. It is a good fit for beginners who want to start flattening faces and straightening edges without jumping straight into a large floor-standing machine.

Final thoughts

So, what does a jointer do?

It gives you the foundation for accurate woodworking by creating:

• One flat face

• One straight edge

• One square reference corner

That may not sound flashy, but it is one of the biggest steps toward cleaner, straighter, more professional-looking results.

If your boards are fighting you every step of the way, a jointer is often the tool that solves the problem.

Check out our recommended entry-level jointer

If you are ready to add one to your shop, check out the WEN JT630H 10-Amp 6-Inch Spiral Benchtop Jointer on Amazon. It is a solid entry-level option for woodworkers who want to start milling lumber the right way.