Thickness Planers Explained – Beginner’s Guide

When you are working with raw materials like wood, you need the correct tools to give your material the desired finish. Since wood often comes in all shapes and sizes, a tool to make the surface smooth and even is a must; that’s where your thickness planer comes in.

What Is A Thickness Planer?

A thickness planer is a woodworking tool that is designed to create a uniform finish on both sides of a board. Depending on where you live, you may refer to this tool as a thicknesser or simply a planer, which is a common term in the United States.

What is a thickness planer used for?

You can use a thickness planer to adjust the surface of a piece of board. If you are working with reclaimed wood and want to give the material a much more even finish, this would be your go-to tool. Furthermore, a thickness planer is ideal for cleaning up sawn edges as well as cutting your wood to a custom thickness.

How Does A Thickness Planer Work?

A thickness planer features a set of blades, sometimes called knives as well as a set of rollers. These rollers move the wood through the tool as the blades take off the desired amount of wood. There is also a cutting table onto which the wood is placed and this can be adjusted to alter the cutting thickness.

There are two types of thickness planer; the portable and the fixed. The portable thickness planer typically has its table connected to the rest of the device. There are also industrial grade thickness planers, which were the original type of tool and these are much larger and have far more powerful motors. The domestic versions tend to be lightweight but are typically noisier and have less power.

Dewalt thickness planer on a moveable trolley
Portable Thickness Planer
Fixed thickness Planer

What Is The Difference Between A Thickness Planer And A Jointer?

While thickness planers and jointers are designed to do similar jobs, in that the work to smooth a wooden surface, there is a key difference. The thickness planer is used to make parallel sides of a board even whereas a jointer is used to even off a single side or edge. If you want to ensure that a board has the same thickness throughout, then you would opt for a thickness planer.

Moreover, the design of the two tools differs with jointers having their cutting knives located on the table, cutting from underneath. Conversely, a thickness planer cuts from above.

Thickness Planer vs Drum Sander

One of the reasons that a lot of people opt for a thickness planer instead of a drum sander is that the former is able to remove stock far more quickly than a drum sander. When using a drum sander, you would need to use very coarse grit but this would not give you the smooth finish you are looking for, so you would also need to make several grit changes over the course of the work.

Drum sander
Drum sander

How To Use A Thickness Planer

If you are going to need to cut large amounts of stock then a thickness planer is by far one of the best tools you could choose. It will remove uneven surfaces giving you excellent results, but it is important to make sure that you get to grips with using it first to save getting it wrong and ending up ruining your material.

Where you choose to set up your equipment is one of the most important first considerations. There must be enough space at either side of the table to feed the wood through. Even though most modern thickness planers are compact enough to fit into a small workshop, this space is imperative. You might also consider the type of wood you will use. While you can use any type, it is important to make sure that it is at least 14 inches in length and around three-quarters of an inch in width.

You’ll begin by adjusting the depth using the crank on the machine. Once you are happy with this, you can begin to feed the wood through on the first side. It is also important to make sure that the machine is turned on before you begin feeding the wood through; never place the wood in first. Be aware that, in order to get the uniform surface you are looking for, you must feed the wood through on both sides. When feeding, be sure to insert the wood from the front of the tool and gently guide it through. You should never try to pull the wood out of the back of the machine.

Of course, there are also many safety considerations such as keeping your hands clear of the cutting area and ensuring that you wear suitable PPE such as goggles and ear defenders.

Thickness Planer Tips And Tricks

Understanding how to use your thickness planer is one thing but really getting to know it and how you can really use it to your advantage may take some time. But don’t worry, with our handy thickness planer tips and tricks, you’ll soon be on your way to becoming quite the expert.

Remove Nails Or Metal Protrusions From Workpiece Before Work

It will come as no surprise to you that a thickness planer is not designed to cut through dense materials like metal. If there are any nails, screws or other metal protrusions in the wood, these should always be removed prior to planing.

Adjust The Planer In Small Increments

If you know the exact thickness you want to achieve then it’s pretty easy to set this without too much thought. However, if you’re unsure of what you want then it is a very smart idea to adjust the thickness planer little by little. There’s no rush to get the job done and it is far better to have to pass the board through more than once as opposed to setting the depth too far and taking off more than you intended.

Never Overload The Planer

The capacity of the machine should never be exceeded. Doing this will put far too much pressure on the blades and will ultimately destroy them. That said, it is also perfectly possible to overload the blades by making more light passes but then, this won’t cause anywhere near as much damage as overloading your tool.

Adjust For Planer Snipe

When you put your wood through the planer, there is a chance that you will end up with snipe. This is where the planer cuts more deeply into one end of the wood or the other as it feeds in and out of the device. This ruins your even surface and completely contradicts the point of the tool. However, there are ways to avoid this.

You see, snipe happens because when the first and final parts of the stock are moving through, they are not held by all of the rollers, only one. This means that the cut will not be consistent. You can counteract this by lifting the board slightly as it goes in and out but there are preferable methods.

One of the best ways to avoid this is to feed a piece of scrap wood directly before and after the piece you are cutting so that it is this that suffers the snipe. You can also attach two longer pieces of wood to act as support rails at either side of your material; these will bear the brunt of the snipe leaving you with a perfect finish.

Create A Planer Sled For Warped Or Uneven Boards

If you have uneven or warped boards, then your planer won’t work well with them. In this case, you may benefit from using a planer sled. This is simple to create and involves taking a longer piece of wood that measures just shy of the width of your planer. For example, if the planer is 12 ½ inches in width, you would make the board 12 ¼ inches. In any case, the sled needs to be longer than the stock you are cutting.

At the bottom of this board, you will screw in a strip of wood to prevent the warped piece from slipping off. It is important to ensure that you drive the screws deeply into the wood so that they aren’t protruding in the event that the knives run over the area

When you place your piece of warped wood onto the sled, you’ll notice that there are gaps where it lifts. To make the piece more stable, you may simply glue wedges of wood under the lifted areas which will instantly improve the stability as you feed it through, preventing the material from moving around as it is cut.

A great video demonstrating how to make and use a planer sled for use with your thickness planer.

How To Change Thickness Planer Blades / Knives

Thickness planer blades don’t come cheap, so we would always recommend taking good care of your blades to avoid having to replace them too often. However, as with anything, there will come a time when they need replacing and doing this is relatively simple.

  • You’ll need to begin by ensuring that the power is turned off; it’s best to completely unplug the thickness planer.
  • Each planer will differ but in any case, you will need to remove various panels to access the blades. The best way to understand how to do this is to refer to your user manual.
  • The blades are held in place with bolts, you will need to loosen these. Before you remove them, take a look at which way they fit in so that you can be sure to insert the new ones correctly. It is also worth pointing out that, if the blades have merely dulled, it is possible to sharpen them rather than buying new blades.
  • Clean out the slot where the blades sat before inserting the new ones. You will need to use a blade setting jig so you can make sure that the blades sit in the cutter head at the right depth.
  • Tighten the bolts a little at a time until everything is secure.
  • It is important to check the blade before moving on to the next one. Do this by rocking the ends of the jig, if these move at all, you will need to reset the blade.

Video showing how to change your planer knives / blades

Thickness Planer For Sale – Where To Buy

There are several places you can purchase a thickness planer. Of course, one of the best options is online or at a DIY store. Looking for reputable brands such as Dewalt or Makita is a good idea. You may also search online marketplaces such as Amazon, where there are several good deals.

Many people put tools for sale in classified ads and while you may be able to pick up a bargain, it is important to check the tool first and see it in action.

Thickness Planer Hire

If you don’t want to invest in a thickness planer for fear that you won’t get maximum use out of it, it is also possible to hire one for a single project. Typing thickness planer hire into Google will yield many results in your local area. But if you are looking for national hire then companies such as HSS Toolshop are some of the most reputable and reliable options.


A thickness planer is a very specific tool that will help to make uneven pieces of stock smooth, uniform and parallel. It is important to get to grips with the tool and understand how it works in order to get the most out of it.

Thickness Planers Explained – Beginner’s Guide

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