Video by Mat Builds

If you have ever tried building furniture from construction lumber, pallet wood, or rough hardwood, you have probably discovered one frustrating truth: wood that looks straight is rarely perfectly flat or square.

That is where a jointer becomes useful. A jointer creates the flat reference surfaces you need before moving on to a planer or table saw. In this guide, we will walk through why and when to use a jointer, how to square rough lumber, and even how to clean up tapered furniture legs using the WOODSTARTER 6" Benchtop Jointer.

The workflow is based on the techniques demonstrated in the Why, When and How I Use a Jointer video, where rough hardwood, pallet lumber, and standard 2x4s are turned into straight, square stock ready for woodworking projects.

What Does a Jointer Do?

A jointer is primarily used to create two reference surfaces:

• One flat face
• One straight edge that is square, usually 90 degrees, to that face

This is an important distinction because a jointer does not normally make all four sides of a board parallel and square by itself.

Instead, the jointer creates the accurate reference surfaces that your planer and table saw can use to finish the remaining sides.

Think of it as the starting point for turning rough or warped lumber into usable woodworking stock.

Why Do You Need a Jointer?

Even lumber sold with straight-looking edges may not remain perfectly square. Changes in humidity, storage, transportation, and natural wood movement can cause boards to cup, bow, twist, or develop edges that are no longer 90 degrees to the face.

This is especially noticeable when working with:

• Construction-grade 2x4s
• Pallet wood
• Rough-sawn hardwood
• Hardwood offcuts
• Boards that have been stored for a long time

If you try to build directly from distorted lumber, small inaccuracies quickly accumulate. Panels may develop gaps, table legs may not sit correctly, and assembled parts may refuse to line up.

Jointing the lumber first gives you predictable reference surfaces for the rest of the milling process.

Jointer vs. Planer: What Is the Difference?

One of the most common woodworking questions is whether you need a jointer if you already own a thickness planer.

The two machines perform different jobs.

A planer references the surface resting on its bed. If the bottom of a board is twisted or bowed, simply running it through a planer does not necessarily create a truly flat reference face.

That is why a common lumber-milling sequence starts with the jointer.

How to Turn Rough Lumber into 4S Lumber

Woodworkers often use the term 4S or S4S to describe lumber that has been surfaced on all four sides.

The basic workflow shown in the video is:

1. Flatten the first face with the jointer.
2. Joint one edge square to the flattened face.
3. Plane the opposite face parallel to the first face.
4. Cut the final edge parallel using a table saw or another appropriate tool.

Once all four surfaces are flat, square, and parallel where required, you have stock that is much easier to measure, cut, join, and assemble accurately.

Step 1: Flatten the First Face

Start with the board's widest face resting on the jointer table.

During this first operation, the fence is not the main reference. Your goal is simply to remove the high spots until the face becomes flat.

With a very crooked piece of wood, the cutter may touch only certain areas during the first few passes. Continue taking light passes until the cutter has produced a consistent fresh surface across the face.

The process may require several passes, especially with heavily warped pallet wood or rough hardwood.

Do Not Force a Warped Board Flat

A common mistake is pushing aggressively downward on the middle of a bowed or twisted board.

If you force the board flat while it passes over the cutter, the wood may spring back into its original shape after the pressure is released.

Instead, let the jointer remove the high spots gradually while maintaining controlled pressure and stable contact with the table.

Step 2: Joint an Edge Square to the Face

Once the first face is flat, that surface becomes your reference.

Place the flattened face firmly against the jointer fence and joint one adjacent edge.

The fence controls the relationship between the face and edge, which is why keeping the board consistently against it is important.

After several passes, you should have:

• One flat face
• One straight edge
• A 90-degree relationship between the two

These two surfaces become the foundation for every operation that follows.

Step 3: Plane the Opposite Face

Next, move to the thickness planer.

Place the jointed face down against the planer bed. Because the planer references this newly flattened surface, it can cut the opposite face parallel to it.

Continue taking passes until the board reaches your desired thickness and the opposite face is fully cleaned up.

Step 4: Make the Final Edge Parallel

The last unfinished edge can be cut using a table saw with the already-jointed edge riding against the fence.

This produces an edge parallel to the jointed one and completes the four-sided milling process.

You now have square stock that is much easier to use for furniture, cabinetry, jigs, frames, and other precision woodworking projects.

Using the WOODSTARTER 6" Benchtop Jointer

The jointer used throughout the demonstrated workflow is the WOODSTARTER 6" Benchtop Jointer.

It provides a 6-inch cutting capacity and runs at 12,000 RPM, making it suitable for common workshop stock such as construction lumber, hardwood offcuts, pallet boards, and smaller furniture components.

The adjustable fence allows the face of the board to be referenced while jointing an edge, while adjustable cutting depth lets you control how much material is removed during each pass.

The machine also includes a standard 2-inch dust collection port, which can be connected to a compatible shop vacuum or dust collection setup.

For a small workshop, garage, or benchtop woodworking setup, a compact jointer can provide the reference surfaces needed for accurate milling without requiring the footprint of a large floor-standing machine.

How Many Passes Should You Take on a Jointer?

There is no fixed number of passes for every board.

A relatively straight board may clean up quickly, while a heavily twisted or bowed piece of pallet wood may require several passes before the entire face is flat.

In general, light and controlled passes are preferable to trying to remove too much material at once.

Stop periodically and inspect the surface. Once the entire reference face has been freshly cut and is sitting flat on the table, you can move on to jointing the edge.

Can You Use a Jointer on 2x4 Lumber?

Yes. In fact, construction-grade 2x4s are a good example of why a jointer can be useful.

Although 2x4s are inexpensive and widely available, they are often not perfectly flat or square. Jointing one face and one edge before planing and ripping the remaining surfaces can turn ordinary construction lumber into much more accurate project stock.

This is especially helpful when building furniture where several pieces need to stack, align, or join cleanly.

A Useful Jointer Trick: Making Tapered Table Legs

A jointer is not limited to squaring rough lumber.

The video also demonstrates a useful way to clean up tapered table or chair legs without building a dedicated tapering jig.

First, prepare a square piece of stock using the normal jointing process.

Then:

1. Draw the desired taper on the leg.
2. Cut slightly outside the line with a bandsaw or jigsaw.
3. Place the flat reference face against the jointer fence.
4. Take controlled passes across the rough tapered surface.
5. Continue until the saw marks disappear and the taper becomes straight.

A bandsaw or jigsaw can quickly remove most of the material, but the resulting cut is rarely perfectly straight.

The jointer provides a flat reference table and cutter path that can straighten the rough-cut taper, producing a clean furniture leg without requiring a table-saw tapering jig.

Why a Flat Reference Surface Matters

Most woodworking machines depend on reference surfaces.

A table saw fence assumes the edge riding against it is straight. A planer assumes the face riding on its bed is already reasonably flat. Joinery depends on faces and edges meeting at predictable angles.

If the original reference surface is inaccurate, every later operation can inherit that error.

This is why jointing happens early in the milling workflow rather than near the end.

Common Jointer Mistakes to Avoid

Trying to Make Both Faces Parallel on the Jointer

A jointer is excellent at creating a flat surface, but it is not the ideal machine for making the opposite face parallel.

After flattening one face, use a thickness planer to establish parallel thickness.

Pressing a Bowed Board Flat

Aggressive downward pressure can temporarily flatten the board while it is being cut, causing it to spring back afterward.

Let the cutter gradually remove the high points instead.

Ignoring the Fence When Jointing an Edge

Once you start creating the square edge, maintain consistent contact between the jointed face and the fence. That reference is what establishes the intended angle.

Removing Too Much Material at Once

Multiple light passes generally provide better control than one aggressive pass, particularly when dealing with hardwood or irregular stock.

Expecting the Jointer to Replace Every Milling Tool

The jointer, planer, and table saw work particularly well as a system. Each machine establishes a different relationship between the surfaces of the board.

When Should You Use a Jointer?

A jointer is particularly useful when:

• A board rocks when placed on a flat surface
• The face is bowed, cupped, or twisted
• An edge is not straight enough to reference against a table saw fence
• The face and edge are not square to each other
• You are preparing rough hardwood for furniture
• You want construction lumber to fit together more accurately
• You need to straighten a rough bandsawn taper

If you routinely buy perfectly surfaced lumber, you may not need to joint every board. But for woodworkers who use rough lumber, reclaimed material, pallet wood, or inexpensive construction stock, a jointer can dramatically expand the material that can be turned into usable project wood.

Is a 6-Inch Benchtop Jointer Enough?

For many home workshops, a 6-inch jointer covers a large percentage of everyday furniture and DIY stock.

It works well for common boards, 2x4 lumber, narrow hardwood pieces, rails, legs, frames, and other components that fit within the machine's cutting capacity.

A benchtop format also makes sense for workshops where floor space is limited or where the machine needs to be stored between projects.

If most of your woodworking involves relatively narrow stock rather than very wide slabs, a machine such as the WOODSTARTER 6" Benchtop Jointer can provide a practical entry point into proper lumber milling.

Jointer Workflow at a Glance

Frequently Asked Questions About Jointers

What is the main purpose of a jointer?

A jointer creates a flat reference face and a straight edge that is square to that face. These surfaces can then be used by a planer, table saw, or other woodworking tools to finish milling the board accurately.

Do I need both a jointer and a planer?

If you regularly mill rough lumber, the two machines complement each other. The jointer creates a flat reference face, while the planer makes the opposite face parallel and brings the board to a consistent thickness.

Can a jointer make all four sides square?

Not efficiently on its own. A typical workflow uses the jointer for the first face and edge, a planer for the opposite face, and a table saw or similar tool for the final edge.

Can you joint pallet wood?

Yes, provided the wood is safe to machine and completely free of nails, screws, staples, and other metal. A jointer can turn irregular pallet boards into straighter and more usable stock.

Can a jointer straighten a tapered table leg?

Yes. After rough-cutting the taper slightly outside the layout line with a bandsaw or jigsaw, the rough edge can be carefully jointed straight while referencing an already-flat face against the fence.

What size jointer is good for a small woodworking shop?

A 6-inch benchtop jointer is a practical size for many home workshops because it can handle common furniture stock and construction lumber while requiring substantially less space than a large floor-standing jointer.

Final Thoughts: Why a Jointer Is So Useful

A jointer may not be the first woodworking machine beginners think about, but it solves one of the most fundamental problems in woodworking: creating reliable reference surfaces.

Once you can turn rough, warped, or inexpensive lumber into flat and square stock, everything that follows becomes easier. Measurements become more predictable, joints fit better, panels align more cleanly, and furniture components stack the way they should.

The workflow is simple: flatten one face, joint one edge square, use the planer to create the parallel face, and finish the remaining edge.

And as the tapered-leg technique demonstrates, the jointer can also be useful beyond basic stock preparation.

If you work with rough hardwood, pallet wood, construction-grade 2x4s, or furniture stock and want to add proper lumber milling to a compact workshop, explore the WOODSTARTER 6" Benchtop Jointer and see how it can fit into your woodworking workflow.

Explore the WOODSTARTER 6" Benchtop Jointer →