How to Cut a 45-Degree Angle With a Circular Saw (Step-by-Step)

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Square joints are often made with 45-degree angle cuts that not every tool can execute. It’s a widely-used technique for different trimming projects, but can you do it using circular saws?

Rather than doing a trial and error by yourself, you should learn how to cut a 45-degree angle with a circular saw properly, which our woodworkers will show in this guide.

Bevel vs. Miter 45-Degree Cuts

Most circular saws are capable of executing bevel and miter cuts. However, before you start cutting, it’s important to note their differences. 

If you need to do a miter cut, you’ll need to deal with the square side of the wood board. The entire cut must be done from the wood’s top to face down. 

bevel cut

On the other hand, cutting a 45-degree bevel cut on the face of the wood. If you want accurate cuts, you must only begin cutting when both wood pieces are in a 90-degree cut line. 

Tools and Materials You’ll Need

Method #1: Making a 45-Degree Bevel With a Circular Saw (Length and Width)

Step #1: Draw the Cutting Line

You can only achieve a clean bevel angle cut if your circular saw blade is in perfect alignment. We suggest using a speed square so that you can measure and mark the cut line on the work surface. 

It’s a pretty straightforward process, so you must carefully line the wood board for a cleaner cut. 

Step #2: Clamp the Square

After you measure and mark the cut line with a speed square, it’s time to place your circular saw on the wood piece. You must align the line you drew earlier with the kerf indicator near the saw’s shoe.

If you look closer, you’ll see that you can choose between two lines: the 0 or the 45-degree option. We’re choosing the latter if you want an accurate angle. 

cutting 45 degree angle with circular saw

Next, put the speed square next to the shoe and clamp them together. It will serve as an angle guide to get the perfect cut. 

Step #3: Set Your Circular Saw’s Bevel and Depth

To cut 45-degree angles, you must adjust the bevel angle and cutting depth through the adjustment knob. Depending on what kind of circular saw, you can set the blade angle could be set in detents like 45-degree or 22.5-degree. 

After you adjust the circular saw to a 45-degree angle, find the depth adjusting knob. We advise doing this to let the saw blade stick out a bit underneath the wood surface. However, it’s not something you need to do if you’re aiming for a rough cut. 

Step #4: Cut Away

To avoid inaccuracies, re-check if the shoe is lined up firmly against the straight edge of the speed square. 

Carefully guide the circular saw as you cut the wood to prevent twisting tendencies that might cause your tool to stir away from the intended 45-degree angle.

cutting 45 degree angle

Step #5: Sand the Edges

After you’ve successfully cut 45-degree angle cuts on the wood board, remember to run a piece of sandpaper over the material’s edge to prevent splinters[1].  

Method #2: Making a 45-Degree Miter With a Circular Saw

Step #1: Draw the Trimming Line

As you did with the above method, you must mark the cut line using a speed square and pencil to get perfect cuts. Double check the square’s edge and ensure that you’re marking it at exactly 45 degrees.

Step #2: Clamp the Square

Unlike the beveling method, you should place the circular saw over the wood surface with the indicator set at 0 degrees. 

Once that’s done, ensure that the square’s bottom is against the shoe’s edge before clamping them. It’ll act as an angle guide as you perform the miter cut later. 

cutting 45 deg angle

Step #3: Set Your Circular Saw’s Blade Depth

Just like how you use a miter saw, there’s no need to adjust for bevel angles as the blade will be slicing the wood perpendicularly. It would be best if you slid the blade guard back before pushing it against the wood. 

The blade depth must also extend around ¼-inch over the material’s bottom or overall thickness.

Step #4: Cut Away

Again, don’t forget to check the speed square’s straight edge alignment before slicing away. You can retract the blade guard from the circular saw to prevent any resistance during the cut.

Step #5: Polish the Cut

Once the material is cut, finish the task by sanding the sliced edge. You can use a typical sandpaper or wood file for this. 

polishing the angle

Method #3: Making a 45-Degree Compound Miter With a Circular Saw

Step #1: Draw the Trimming Line

It doesn’t matter if you’re making pieces for a window trim or cupboard—the reality is you need speed squares and pencils to mark the area you’ll be cutting with the blade. 

Step #2: Position the Square

Your tool’s shoe must be aligned at 45-degree angles, which you can verify through the indicator line. The square’s edge must be against the shoe to guide the blade in making compound miter cuts. 

Step #3: Set Your Saw’s Bevel Angle and Depth

In the front part of the circular saw, you should be able to set the bevel knobs to 45 degrees. Our team also advises changing the blade depth configurations so that it can reach below the wood’s surface.  

Step #4: Cut Away

You must slowly point the blade’s edge to the line you marked earlier. Keep your focus on the saw base plate, and see to it that it doesn’t wobble until the compound miter cut is achieved. 

Besides that, wear protective gear during this process. Given that a circular saw runs with a sharp blade and produces dust, adding an extra layer of protection is necessary.

45 degree angle

Step #5: Sand

Lastly, grab a sanding paper or wood pile to smoothen the wood board’s edges. To avoid accidental blade contact, you must unplug and set aside the saw before doing this step. 

Other Ways to Make a 45-Degree Cut Using Your Circular Saw

T-Bar

You can opt to attach a T-bar to the power saw and adjust the tool’s position so that both components can align. The most important part of this method is setting the right angle, or the output won’t be precise.   

Miter Box

If you have a 2×4-inch miter box, that could aid you in cutting 45-degree cuts with a circular saw. It lessens the chances of errors when cutting wooden boards and plywood sheets. 

Straight Edge Guide

Admit it or not, you can’t cut 45° angles perfectly without an angle guide. 

straight edge

You can clamp the straight edges to the material to keep it firm and in place.  

Tips for Precise and Clean Cuts

Conclusion

At some point, a good woodworker needs to learn how to cut a 45-degree angle with a circular saw, especially if you have limited tools in the workshop. 

However, our woodworkers still urge you to do a trial run with scrap materials, as this could be a tricky cutting technique to execute with this saw blade. 

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson

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