How To Cut A 4×4 Post With A Circular Saw (Quickly & Easily!)

Ryan Womeldorf
by Ryan Womeldorf

When you get involved in DIY activities, you will be shocked at the versatility of some of the tools that you use. For instance, a circular saw is likely to come in handy on more than a few applications or projects in the future.

For thicker timbers, something like a 4×4 post, a circular saw makes for an effective tool. But it is a little more complex than measure and cut. Because the timber is thicker, there are a few more steps. Make sure that your cutline is accurate. You will also have to rotate the post toward you more than once to ensure a complete, accurate cut.

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What 4×4 Posts are Used For

When it comes to most DIY household projects, you likely are not working with a thicker material. That said, if you plan to take on something more comprehensive like building a fence or deck, then you would need more heavy-duty materials.

Generally speaking, 4×4 posts are great for providing structural support. They act as the foundation for your deck or fence, providing stability and structural port throughout. With proper positioning, a deck can be adequately supported by 4×4 posts for years to come.

The Cutting Depth of Circular Saws

As versatile as a circular saw can be, there are limitations. For most smaller household DIY projects, a circular saw can cut through them with little to no issue. But when the thicknesses start to grow – in the case of a 4×4, in particular – then the cutting depth is important to know.

Circular saws that have a standard 7 ¼-inch blade come with a maximum cutting depth of around 2 ½-inches. When it comes to your cordless saws that have slightly smaller blades, that number is more like 2 1/8-inch.

That 2 ½-inch cut is typically deep enough to make one-pass cuts. But when you are dealing with thicker stock, either a 4×4 or 6×6 post, then you will need a speed square and a few more passes.

How To Cut A 4×4 Post With A Circular Saw

Step 1: Mark the Cutline

Marking your cutline is one of the most crucial aspects of performing a cut. If the line is accurate, all you have to do is follow it for a pristine cut. And depending on the project at hand, being off even a little bit can create a lot of problems.

Use your speed square to guide your pencil as you make your cutline. Take the show of the saw and place it flat on the face that you are cutting. Make sure you line your blade up to the cutline as accurately as you can.

Step 2: Making the Initial Cut

Remember, when it comes to thicker materials like a 4×4 or 6×6 post, you won’t be able to make your cut in a single pass-through. So, in this step, we are focusing on making the initial cut. Hold the square tight while pulling the saw away slightly from the wood.

When you are comfortable with your positioning, pull the trigger on your circular saw. You will make the cut by using the edge of your speed square to guide the saw along that cutting line. Remember that this is an initial cut, so don’t worry about applying all that much force.

Step 3: Rotate the Post

After making your initial cut, rotate the post towards you. The initial cut that you just made is also known as a kerf. You will want to use the kerf that you just made to properly align your speed square once again.

Put the blade of your saw, now stopped, in the kerf and then place the square against the shoe of the saw. Hold onto the square tightly to keep it in position as you pull the blade out of the kerf. Pull the trigger on the circular saw, using the edge of the speed square to guide you in your next cut.

For 4×4 timber posts, you will need to make three separate cuts. So, you would need to repeat this step to get that third cut, helping you to effectively saw through the entirety of the post.

Step 4: If You Have a 6×6 Post

When you upgrade to a larger timber like 6×6, then you will have to make one final rotation. Follow the steps from above to do so. Use the kerf of the third cut to be your guide to making the fourth and final cut.

You will then want to take a handsaw and cut through the uncut wood located at the timber’s center. You can use the kerfs to guide you while you use the handsaw.

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Related Questions

Now that you understand how to cut a thicker timber like a 4×4 effectively, there may be other questions on your mind. Furthermore, not everyone has a circular saw at their disposal. If you have another tool you would like to use for the job, there are other questions to be asked.

Can You Use a Table Saw to Cut a 4×4?

Table saws are a regular item in garages and workshops across the globe. So, if you need to cut a 4×4 but don’t have a circular saw handy, you may be wondering whether or not you can make those cuts using your table saw.

A 10-inch table saw, the industry standard, cannot cut through a 4×4 in a single pass. The deepest possible cut that it can make is around 3 1/8-inches. If you have a high-end table saw that has a 12-inch blade, then you may be able to cut through a 4×4 with a maximum cut of somewhere around 4 inches.

Can You Cross Cut a 4×4 on a Table Saw?

You can, however, cut a 4×4 across the grain with the use of a miter gauge. You will have to make at least 2 passes on the 4×4 in order to cut through it if you have the standard 10-inch table saw.

  • Raise the blade. Move the blade up as high as it will go, which should be just over 3 inches. Go ahead and make your normal crosscut then flip the 4×4 over. You will want to lower the blade so that it cuts through the material leftover, just make sure that it is not up too high to avoid safety concerns.
  • Cut off the remaining wood. This part is optional but can help to ensure that the 4×4 will be cross-cut at the right length. You can cut off any of the remaining wood with just a little extra material leftover. That makes it just a little easier to use the wood while also slowly trimming off more material over the next few passes. The result is a perfect cut.
  • Only if you don’t need scrap. This process is fine if you aren’t planning on using the scrap portion of the 4×4. If you do need that scrap, then try to make sure your second cut is lined up as accurately as it can be. If there is a little material left over after that second cut, you can use a router to finish it off and provide the perfect cut.
What Other Saws Can You Use to Cut a 4×4?

The way that one cuts a 4×4 probably comes down to the tools available. A circular saw is one of the most common tools in workshops across the world. That doesn’t mean that they are in every workshop or garage, however. Here are a few other tools that you can use in their place.

  • Miter saw. Another common option. When you need to cut a 4×4, a 12-inch miter saw will work just fine and do so in one single pass. Just line up your cut and pull the trigger, pulling down on the saw until it cuts all the way through.
  • Jigsaw. Jigsaws are highly versatile as well. It is not recommended here since the blade won’t go through. It can get the job done but there are a lot better options.
  • Reciprocating saw. A reciprocating saw can cut through a 4×4 with no issue, but there may be accuracy issues. You are better off scrapping a 4×4 with a reciprocating saw rather than building something with it.
Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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