How To Cut 4×4 Post In 8 Easy Ways

If you’re one of those folks who love cutting timber for fun, or god forbid for work, and want to know more about the process… Well, you’re in the right place. And today, we’re looking at the big stuff.

Cutting smaller pieces of dimensional lumber, like 2x4s and 2x6s, can certainly be done using a variety of different tools in the standard toolbox, but cutting wider boards or more frequently used thicker pieces of dimensional lumber, like a 4x4, is more difficult.

For that reason alone, we decided to look into the equipment you needed to cut a 4x4 post and offer alternatives for doing so, even if those pesky fence posts are already embedded in the ground.

What Is A 4x4 Post Used For?

As you probably know, a common component of outdoor woodworking is the 4x4 post. Because of its substantial diameter, it is structurally sound enough to act as the vertical support for fencing and decking.

These posts usually undergo pressure treatment to withstand various outside applications and to enable the post to be planted partially buried in the ground. Sidenote, the actual dimensions of a 4x4 post are actually 3 1/2 inches by 3 1/2 inches, not 4 1/2 inches by 4 1/2 inches, as is the case with other dimensional timber.

Ways To Cut A 4x4 Post

This is where it gets a bit more difficult. For the majority of DIY-ers, a 4x4 post is one of the more challenging pieces of dimensional timber to cut properly, whichever tool they want to use, simply because of its thickness.

While a chainsaw can readily split a 4x4 post in half, doing it with much accuracy is tricky, if not impossible. This is also true for a reciprocating saw.

A 10-inch miter saw cannot produce a complete cut without dangerous modifications to the tool's safety features, and most circular saws have a maximum cutting depth of 2-1/2 inches.

On the other hand, while using a traditional handsaw to cut a 4x4 might provide greater precision, it is a difficult operation that can slow down the project and strain your arm.

So yes, whichever angle we’re looking at, it’s not going to be easy, but let’s break it down a bit more in detail.

1. Table Saws

The maximum cutting depth of a 10-inch table saw is 3.5 inches, which is just big enough to cut through a 4x4 entirely. However, even with the aid of a fence, making a crosscut on a 4x4 post that is 8 feet long on a table saw, is difficult.

Beware, even with an additional set of hands to help guide the timber, it can be challenging to uniformly feed a lengthy 4x4 piece of wood through the table saw's blade. Due to this, it is challenging to maintain the post's end against the fence of the table saw in order to create a straight line.

2. Chainsaw

If you think of a small tree and compare it to a 4x4 post, they have a similar diameter and form. As you can imagine, cutting through a post is an easy task for a chainsaw.

Having said that, chainsaws are not made to make precise cuts, which limits their usefulness for cutting posts used for fencing, decks, or other purposes. If you’re looking for a precise cut, it’s best if you put down the chainsaw.

3. Hand Saw

Cutting a 4x4 post with a handsaw may not be the best option because it demands more arm strength than an electric motor or gas engine. But since using a handsaw takes longer, it may result in a more precise cut of a 4x4 post.

Start by marking a cut line on the top and front of the post when using a hand saw. To make a groove for the blade to slip through, start by making a back cut with the saw on the line. Once the groove is in place, start cutting back and forth with the saw.

Utilize as much of the blade's length as you can by making extended strokes. This will help the cut go more smoothly and maintain the blade parallel to the cut line. Periodically pause to check that the blade is parallel to the cut and adjust as necessary.

4. Circular Saw

One of the greatest tools for cutting a 4x4 post is a standard circular saw. This tool is getting more and more popular with DIY enthusiasts. 4x4s are simple to cut from the ground thanks to the saw’s mobility, and it can produce precise cuts. However, most circular saws have a maximum depth of just 2.5 inches, so you will need to make two cuts.

To use this technique, measure the 4x4 and draw the cut line on the post on two different sides. Cut through the post entirely on the second cut line after cutting the first side, following the cut line, and turning the board 180 degrees.

5. 12-Inch Miter Saw

If you’re a proud owner of a 12-inch miter saw, you’re onto a winner. The saw's two extra inches make cutting through 4x4s fairly simple.

A 12-inch miter saw, in comparison to a 10-inch tool, can cut up to 4 inches deep, which is just enough to allow the blade to pass cleanly through a 4x4 without requiring unsafe modifications to the saw's safety measures.

This approach is ideal because it provides precision. After mounting the 4x4 on the miter saw, just align the cut line with the blade and pull the material through. Supporting the length of the 4x4 to achieve a level cut is the most difficult part of cutting through the material. However, this issue can be resolved by utilizing a solid sawhorse.

The only drawback is the price, this power tool costs a great deal more than a typical circular saw, so it’s not widely used. But if you’re lucky you might have a DIY-friend who’s ready to lend a hand - with a 12-inch.

6. Smaller Miter Saw

Hey, if you don't have the luxury of owning a 12-inch miter saw, you can also whip out the 10-inch version to do the job. However, just so you know, it can't be done in one pass.

To do this, you must cut once, rotate the board, and then cut again in order to slice through the post with a 10-inch miter saw.

Unsurprisingly, the same set-up applies as it would with a 12-inch miter saw. Place the post on the miter saw while supporting the off-end with a sawhorse. Cut the guard with the initial cut, dropping the blade as far as it will go.

Turn the post 180 degrees after that cut is finished so that the initial cut is now facing downward on the miter saw. Aligning the two cuts can be challenging depending on how the post will be used, so this step requires some skill.

7. Radial Arm or Slide Saw

Most professional woodshops or specialty hardware stores use these big power tools. The slide saw is essentially a circular saw with a long arm that lets it travel perpendicularly over a board.

Because of its construction, the radial arm saw can cut wood that is at least a foot wide. It is similar to a typical miter saw in terms of depth, and the majority of radial arm saws feature 10-inch blades, allowing for a cutting depth of 3.5 inches.

However, a radial arm saw is different because of its sliding movement, which enables it to perform a complete cut and overcome the blade's curve to entirely cut through a 4x4.

8. Reciprocating Saws

A reciprocating saw can easily cut through a fence post thanks to its large blade. Since most reciprocating saw blades are between 3 and 12 inches in length, they have sufficient length to accommodate a 4x4 post's 3.5-inch thickness.

A reciprocating saw's disadvantage is that it is a tool intended for rough cuts and demolition. Precision cuts are not designed to be made with this tool.

Conclusion

As you can see, there are many ways to cut a 4x4 post, but not every method is ideal. Depending on what is available to you, you can make the best decision by using this guide as a reference before chopping into your favorite post.