Circular saws are one of the most important and versatile tools for any contractor or DIYer. They are very transportable and require little to no set up. With this though comes difficulty in cutting straight lines. Unlike miter and table saws there is no assistance from the saw (they do not have built in fences). It is all free hand. So when using a circular saw it can be very difficult to cut perfect straight lines.

Do not fear, I am hear to help. Below we will discuss multiple ways that you can cut a straight line with a circular saw.

How to cut straight with a circular saw

Cutting straight with a circular saw is hard. You can freehand cut with a lot of prep and concentration. There’s also a number of tools that can assist you in cutting straight; kreg rip cut, speed square, straight edge or kreg accu cut. You can also make a DIY guide.

Circular saw safety

When using your circular saw it is important to make sure you practice safe handling and cutting. Since they are so versatile and portable this makes them very dangerous if not handles properly. When cutting with your circular saw some things to keep in mind:

• Wear eye prottection
• Avoid loose or baggy clothing
• Check cutting surface for nails or screws
• Wait for blade to stop moving before setting saw down
• Start the blade without any contact from your cutting material
• Assess the sharpness of your blade before use and replace when dull

These are some of the most important safety guidelines to follow when using a circular saw. If you would like a more in depth guide, you can find that here.

Circular saw cuts

A circular saw gives you the freedom to make a number of different cuts.

1. Cross cut: when the blade of the saw cuts against the grain of the wood
2. Rip cut: when the blade cuts with the grain of the wood, these are typically longer cuts (think cutting the length of a piece of plywood).
3. Miter cut: cuts made at an angle across the width or face of a board. The angle of the blade does not change but the angle of the material does. An example of this would be a picture frame.
4. Bevel cut: this cut occurs with the blade of the saw positioned to a specific angle.

Now that you have a grasp on the cuts a circular saw can make, lets jump into the 6 ways to make straight cuts.

DIY guide

For this technique you will need to have a piece of wood or other material that you know is straight. By attaching this straight material to the wood you are cutting, you will create a guide for the saw to follow.

There are two ways you can go about this technique both of which will work great. The way I prefer to do this is by leaving math out of this and lining the saw up with you marks then attaching the guide board.

So first thing you have to do is make 2 marks on either end of the board you are cutting. Use a tape measure to do this so you ensure both marks are exact. By having marks on both ends of the board you can ensure the guide board is lined up.

Next you want to line the circular saw cutting notch (indicated with the blue arrow below) up with the line that you made on the board (indicated with red box below). You can see the notch of the saw is directly in line with the mark I made on the wood. Then using your other hand attach a spring clamp to connect the guide board to the board you are cutting.

Now that you have one end lined up it is time to make sure the other end of the guide board is the same. Measure the distance between the guide board on the mark you made. Make sure the far end of the board is the same distance away from the mark. Once you have this perfect you can attach another spring clamp.

With your guide board seccure on both ends, you can now start your cut.

Another option for this technique involves some math but will save you time in the long run. Instead of lining the saw up with the mark and then attaching the board, you can just factor the distance from the blade into the cutting measurement.

You will need to determine the distance the saw base is from the blade. So first determine which side of the blade base will be up against the guide board.

Once you determine the side you will be cutting from, now measure the width of that base. From the end of the base to the blade. Once you have that measurement you can add that to your cutting total.

So if you want to make a 10 inch cut and the distance between blade and guard is 1.5 inches then you will make your marks at 11.5 inches.

Now that you have your math done, you can make your marks on both ends of the boards. Then attach your guide board using spring clamps or quick grip clamps. With your board secure you are ready to cut.

Personally for me I prefer the first way because I am terrible at math especially if fractions are involved. Either way will work though.

If you are making lots of these cuts there are some real creative and great ways to make more permenant devices to assist you.

Kreg rip cut or track guide

The kreg rip cut circular saw guide is a great tool that is compatabible with most if not all circular saws. It allows you to make straight and perfect cuts without measuring or marking. This device helps control the saw while making precise cuts. It will allow for any rip cut to be made up to 24 inches.

The kreg rip cut is comprised of 3 main pieces. First is the sled which holds and attaches to your circular saw. Next is an aluminum guide rail that has a built in measuring scale to determine the width or length of cut you will make. And lastly an oversized edge guide that runs along the edge of the plywood to ensure maximum control.

This really is a great tool to add onto your circular saw if you will be making lots of straight cuts (24 inches wide or less). It will cost you about $45. So compared to the DIY technique above, this is much more expensive.

Speed square

This is one of the easiest and most consistent ways to make straight cuts with your circular saw. It is also one of the cheapest tools on this list. One thing to note is these cuts can only be made on shorter pieces of wood. A max cutting length of 6 inches is allowed when using a speed square. This is a great tool to use when cuttig 2×4’s.

First you must mark the wood where you want to cut it using the speed square and a pencil. Once the mark is in place set the circular saw up so the blade is in line with the mark you just made.

While holding the saw in one hand take your speed square in the other hand and but the straight edge up against the saws metal edge. Make sure the blade did not move during the set up. Hold the speed square nice and tight limiting any movement and start to cut.

Since the speed square has a straight and angled edge this technique can be used for cross or miter cuts. If using for a miter cut you can only make 45 degree cuts. Again this can only be used for cuts at or under 6 inches.

Metal straight edge

The metal straight edge is a great tool to use because they are often very long. So if you are making longer plywood rip cuts this may be the technique for you.

Overall this technique is similar to the DIY method above where we used a 2×4.

You will make two identical marks at either end of the material you are cutting. Once you have made your marks you can attach your straight edge to the material using your clamps. It is important to factor in the distance between the saw base and blade to your measurement. Or you can measure exact and attach the straight edge with the saw in line with your marks (see above in DIY method for full details).

Once you have your straight edge lined up and securely fastened, you can start cutting.

If you do not have a metal straight edge don’t worry! You can really use anything in your garage that has a straight solid edge. For me I often use my level since it is so long. Look around your garage and I guarentee you can find something that will work for you.

One thing to keep in mind with this technique is to ensure your clamps are facing away from where the saw will be traveling. This way the saw will not make contact with the clamps.

Kreg accu cut

The kreg accu cut is the gold standard for straight accurate cuts when using a circular saw. It basically turns your circular saw into a track saw. With that being said it will cost you about $90 dollars. So you need to be making a lot of these straight cuts in order to make this piece of equipment worth it.

If you do decide to purchase this piece of equpiment you will not be dissapointed. It really is very easy to use and makes your job so much easier. It can work for making cross cuts, rip cuts and miter cuts.

All you have to do is make 2 measurements at either end of the board at your desired cut length. Then lie the track down over these two marks and begin cutting. You do not need any clamps because it comes with anti slip strips that hold the track in place.

Similar to the Kreg rip cut, your saw attaches to the sled which allows the saw to effortlessly cut down the track. The nice thing about the sled is it will work on both the accu cut and the rip cut.

There are 2 versions of the accu cut. The first is the basic one that allows for 50 inch cuts. There is also the Kreg accu cut XL that costs $179 and will allow for 100 inch cuts.

Personally I do not own one of these becasue I do not make enough long straight cuts to make it worth it. With that being said I have used my friends once and I cannot believe how easy and great it was. Having a track for the blade to be in really makes cuts so effortless. It is perfect for limiting those dreaded circular saw kickback.

Cut without any assistance

Good luck! I have tried this method a couple of times with minimal-no success. I find this to be a very time consuming and difficult way to make straight cuts. The few times I attempted, the cuts were anything but straight.

With that being said there are people out there who are very good at this technique and prefer it. In my research I have found that the most important part of this technique is to make sure the material you are cutting is properly secured. You do not want any moevment of the material while you are cutting.

Conclusion

I hope this article helped you make perfectly straight cuts with your circular saw. Again it is a very difficult task. But now you have all the knowledge you need to confidently make any straight cut you need.

• Circular saw safety
• Circular saw cuts
• DIY guide
• Kreg rip cut or track guide
• Speed square
• Metal straight edge
• Kreg accu cut
• Cut without any assistance

If you found this to be useful, please let me know in the comments!