How to Sharpen a Circular Saw Blade: 5 Easy-to-Follow Steps

Last Updated on January 10, 2023

A circular saw is a fantastic power tool to have for woodworking projects and in your arsenal of tools. These versatile power tools offer excellent cutting power and precision for wood and other materials. Just like a hammer drill, you can use them for many different DIY jobs!

But a drawback of these tools is that the circular saw blade will eventually become dull and need replacing or sharpening. Did you know that it is possible to sharpen a circular saw blade yourself? You can save money and avoid the hassle of having to buy replacement blades. If this sounds like something you want to tackle, we look at how to sharpen a circular saw blade in the below guide.

Should I Sharpen My Circular Saw Blades or Replace Them?

First, we must look at the reasoning – why should you sharpen your blades and not replace them or send them to a professional for sharpening?

To start, continually replacing blades is expensive. Using a professional sharpener can also be costly. You can sharpen most saw blades that have a carbide tip several times. Therefore, sharpening the blade yourself is a tremendous cost-saving exercise.

However, if you are not confident in your skills, replacing blades or sending them for sharpening may be the better choice. It depends on your circumstance and what you are comfortable with doing!

How to Know When Your Circular Carbide Blades Are Dull?

So, you want to try sharpening the blades yourself. But how can you tell if your blade needs filing? There are several strong indicators of the quality of your carbide blade and its state. You can uncover these by regular visual inspections, but also when using your circular saw:

• More inferior quality of cuts.
• Your circular saw motor is overworked.
• An excess of material chipping.
• Excessive burn marks.

Firstly, you will notice a deterioration in the quality of the cuts. Wood is an easy material to cut. If it becomes difficult to keep a straight cut in the wood, it’s time for sharpening! A dull blade requires more force to cut a piece of wood – this force will make inaccurate cuts.

Next, whilst using your circular saw, how does it sound? As you use the circular saw, you should become accustomed to the sound of the motor. If it appears that the engine is overworked or that you notice a change in the sound of the circular saw, this could point towards dull blades. Dull blades mean the circular saw has to work harder to cut the material. When doing cutting work, you should feel little to no resistance, and the motor should not sound strained.

Finally, you may notice other features like burn marks and material chipping. As mentioned above, a dull blade requires more force to cut a piece of material. That extra force on your tool will create friction which will lead to burn marks. If your blade has several of these marks, it’s time to sharpen it or replace it!

Perform Regular Simple Inspections

Whenever you use your circular saw, you should perform a simple visual check of the blade. The most obvious signs to look for are broken and rounded teeth. Chipped or broken teeth may mean that the blade is unusable, and sharpening may not work – this depends on the chips’ size and how many teeth are damaged. Alternatively, rounded teeth are a clear indicator that the blade is dull.

How to Sharpen a Circular Saw Blade – a Step-by-Step Guide

Now that you understand the pros and cons of self-sharpening or simply replacing them, we can look at how to sharpen a circular saw blade manually. This job requires a decent knowledge of tools and should not be attempted by those who have limited DIY skills.

Step 1: Detach the Blade from the Circular Saw

It should be obvious, but you cannot sharpen a circular saw blade whilst it is still attached to the tool! Hopefully, you should have read the instruction manual fully and be competent in changing and removing the blades. A blade release switch usually allows you to remove the saw blade without too much effort quickly.

In which case, detach the blade and place the circular saw in a secure storage area. You want your working area to be free from clutter and distractions. Also, you don’t want to potentially get tangled in the power cord or knock the saw off and cause injury!

Step 2: Secure the Circular Saw Blade Ready for Sharpening

Once you have the blade detached, you must secure it to work on it without it moving. The best way to secure one blade is to use a vice grip. If you have a hold, the blade should be secured between the vice, with the teeth pointing towards you.

Pro-Tip – Be careful not to tighten the vice too much as you could end up warping the blade and rendering it unusable.

If you do not have one vice, you could secure the blade in between two heavy objects. Ensure that the objects won’t move as you don’t want the blade to slip while using your hand file or blade sharpener.

Step 3: Place Markings on the Blade for Reference

People make a common mistake to sharpen a blade tooth or even an entire side of the blade several times. Consider this – circular saw blades are symmetrical and have several teeth. How will you know, therefore, which teeth you have sharpened? Moreover, how will you know which side of the cutting edge you have sharpened?

To ensure there is no confusion and that you don’t do the sharpening process on the same teeth twice, mark the first tooth you intend to sharpen. You can mark it with a pen, pencil, or a marker – something that will easily rub off once you have finished sharpening.

By marking the first tooth, you know exactly where you have started and where you need to finish!

Step 4: Use Sharpeners to File the Blade Teeth

Before sharpening the blade, you need the correct tools. You can find many different sharpening tools, including a diamond wheel sharpener, a diamond file, or a simple blade sharpener. It is essentially the only tool you will need – some device capable of completing the sharpening process.

It is also essential to check if the blade can be sharpened! Some blades with specially hardened tips and teeth cannot be sharpened!

Once you have your tools, the first stage is to ensure the teeth are the same size. Over time, blade tips are worn down, and this can result in uneven teeth – this can affect the cutting quality and accuracy. Using your sharpener, file the tips of the teeth so that they are all even.

Now it is time to sharpen the teeth. It is essential here to understand angles, and you should generally sharpen at a 20-degree angle. On the underside of each tooth, run the sharpening tool back and forth in a smooth motion – you should do this around three to four times. You need to apply a decent amount of pressure, but the key is to use the same amount of pressure for each of the teeth.

Pro-Tip – If you find it difficult to file, consider using some lubrication to make the file move easier over the circular saw blade.

You must then repeat this simple filing process for each tooth. Always use the same angle and the same pressure if you want to keep the blade in a usable condition.

Step 5: Re-Attach the Blade

Your saw teeth and blade should now be sharpened and ready to use again! You can now un-clamp the circular saw blades from whatever device you used to secure them. Once loose, you can re-attach the circular saw blade to the power tools. Before doing so, make sure that you have brushed away and filings and that the blade is clean.

Blade Sharpening Tips

To finish, we have listed a range of preventative tips that should minimize the need to sharpen your circular saw blade.

1. Invest in a Quality Set of Circular Saw Blades to Minimize Sharpening

The best way to minimize sharpening or buying frequent replacements is to invest in a quality blade first! The quality and life of blades can vary greatly. A cheaper circular saw blade might not hurt your wallet. However, it will have a shorter life and will become duller much quicker.

2. Practice on Broken Blades, So You Don’t Damage Usable Ones

Until you gain confidence in your performance, don’t attempt to sharpen usable blades! It is a sure-fire way to rack up expense and damage functional blades that will then need replacing.

Instead, practice on broken blades. For example, you may have one blade with burn marks, chipping, or even broken teeth. If you have one blade like this, use it as your test circular saw blade! Instead of throwing it away, you can use it to practice sharpening!

3. Use the Correct Blade for the Right Task

The quickest way to blunt your circular saw blades is by using them for the wrong job. For example, for woodworking jobs, you don’t need a super-strong blade. Alternatively, if you try and use a standard blade to cut through more challenging materials, the blade will run blunt much quicker. Check before any job that you are using the correct tool – this applies to DIY work in general.

4. Regularly Clean Your Saw Blades

Over time, saw blades naturally accumulate dirt and grime. It can negatively affect performance. Indeed, you could mistake a blade as dull when it just needs a thorough clean! You should avoid using harsh chemicals, as this could strip any protective coating from the blade.

However, you can clean a circular saw blade using a nylon brush and a cleaning agent like solvent. If you soak the cleaning agent’s blade for 20minutes, you can then give it a clean using the nylon brush. It should remove any grime and allow you to see correctly if the blade needs sharpening.

5. Store the Saw Blade in a Dry Area

Proper storage can improve the longevity of your saw blades. Exposing the saw blade to moisture is a quick way to cause corrosion and rust the metal. That is why you should always store your blades securely and in a dry area where moisture cannot build up.

Circular Saw Blade FAQs

Is It Worth Sharpening a Circular Saw Blade?

Yes! If you have the confidence to do this and the tools, you can save a great deal of expense. A saw blade like this is meant for sharpening – it is not meant to be thrown away once it is dull.

Providing that the teeth are still usable, it makes sense to sharpen a saw blade yourself. By sharpening your blades, you can effectively reduce the amount you have to spend by 2-3 times, depending on how many times you can sharpen one saw blade.

How Many Times Can You Sharpen Your Blade?

Typically, you will sharpen a durable blade between three to four times. However, the key to this is how worn and damage the teeth are. If the teeth are highly worn after just one sharpening, there may not be enough material to sharpen the blade again.

How Long Should This Type of Blade Last?

This depends on the type of blade, its performance, how often you use it, and the purpose. It is not uncommon for blades to last for up to 120 hours of usage. However, they can last for as little as 2 hours of usage. It all depends on the material you cut, how you use the blade, and how you maintain it.

It’s Always Better to Be Sharp

Circular saw blades are excellent power tools that you can use in almost any project, DIY or commercial. However, to make sure they are always performing optimally, you must know how to maintain them. One way is always to keep them sharp.

How to sharpen a circular saw blade? It mainly depends on your preference. You can go to a professional to have them sharpened, or you can do it on your own.

If you prefer to sharpen the blades yourself, this guide will surely come in handy. So, if you notice that your circular saw blades need sharpening, go back to this guide, and you are good to go!

Did you have fun reading this guide? Do you have other questions, or do you have suggestions you’d like to add to this guide? Let us know in the comment box below!