How to Sharpen a Circular Saw Blade: Definitive Guide

If you are wondering how to sharpen a circular saw blade, you’ve probably cut a huge batch of lumber and noticed a decrease in cutting speed and quality.

Am I right? If so, you should keep reading attentively to learn all the important facts about circular saw blade sharpening methods. I can’t say that it’s extremely difficult, but you have to know which tools, angles, and techniques are appropriate for particular blades.

Otherwise, you can easily make it cut even worse or even damage the item. Ready? Then unplug your tool and remove the blade in the same way you do it when you need to change it.

How to Sharpen a Circular Saw Blade?
To sharpen a circular saw blade, you’ll need a file and a set of torx wrenches. First, remove the blade from the saw. Next, use the file to remove any burrs or nicks from the blade. Finally, use the torx wrenches to tighten the blade onto the saw.

Do Saw Blades Need Sharpening & When?

Sharpening Machine for Circular Saw Blades.jpg

Well-teared modern blades are tough enough to live long and make accurate chip-free cuts. However, all the blades get dull one day. The traction between the workpiece and the blade teeth causes the last to erase on the sharp edges, worsening the cutting quality.

Fortunately, you can easily identify the signs that your blade needs immediate sharpening. Here they are:

  • The blade cuts notably slower than before. It can even get stuck and stop cutting completely;
  • The blade creates more chips and tears than before;
  • You notice burn marks on the workpieces or even notice or smell smoke while cutting;
  • The saw’s motor sounds louder than usual when you cut;
  • You feel more resistance while cutting familiar materials;
  • It becomes difficult to follow the cut lines – this means that the blade can’t deal with the workpiece resistance and cuts the softest place instead of going straight.

These signs apply to both carbide-tipped and steel-tipped blades. For example, if you have a diamond-edged blade, the signs will include:

  • Blade glazing over – this would mean that the layer which holds the diamonds has started melting over.
  • The cutting surface of the blade looks smooth, indicating that the diamonds have been erased.

How to Sharpen Your Circular Saw Blade

circular saw blade sharpening

Suppose all the signs are that your tool’s blade needs sharpening. In that case, you should learn which circular saw sharpening tools are appropriate and use them according to my recommendations and manufacturer instructions (for automated sharpening machines).

Before you start, I must remind you to unplug your circular saw and remove the blade using the wrench provided by the manufacturer or any compatible wrench.

Now that the blade is in your hands, you have to make sure it’s clean. Follow my blade cleaning instruction in the “Tips for Keeping the Blade Sharp” section to make things right.

1. With a Dremel

Dremel is a famous portable grinding machine. This multi-function tool can be equipped with any attachment, which makes it suitable for blade sharpening.

Of course, it’s very difficult to maintain the right angle of the tool all the time, so you have to invest some time or cash to build or purchase a clamping device that can hold the Dremel steadily with the grinding attachment at the right angle.

If this isn’t a problem anymore, you must build a sliding pad with a spindle to install and secure the blade. Finally, you should be able to slide the blade in and out and rotate it. If everything is ready, follow these steps:

  1. Install the blade onto the sliding pad and secure it with a nut. Don’t tighten it too much, as you need to rotate the blade manually every 4-5 seconds.
  2. Without turning on the Dremel, move the blade in to check how deep you should go while sharpening. Use a pencil to mark the margin and hammer a small nail to block the pad from moving deeper by accident. This tip will speed up the process significantly.
  3. Adjust the Dremel angle or install the sliding pad at an angle to the sharpening attachment. It doesn’t matter which option you choose.
  4. Mark the teeth tilted to one of the sides and sharpened them first. You have to slide the blade in, hold it for around 4-5 seconds, and slide it back.
  5. Stop the tool, flip the blade over and sharpen the rest of the teeth in the same way.

2. With Automatic Sharpener

An automatic circular saw blade sharpener is a pretty expensive tool, which is of no use at a DIYer garage as it has quite a lot of space on the workbench and can cost up to 3-5 grand.

However, if you are a professional woodworker with a spacious workshop and a stable workflow, an automatic blade sharpener will save you many hours every month. All due to the automation and high speed of work. Here’s how to use the tool properly:

  1. Install the blade onto the spindle blade holder of the sharpener and tighten the nut to secure it. The tool must be turned off when you do it.
  2. Now adjust the spindle angle to achieve the right angle between the vertically installed sharpening disk of the tool and the tips of the blade. For most circular saw blades, it’s between 15° and 20°. You can check the right angle on the manufacturer’s website or the blade box if you haven’t thrown it away yet.
  3. Adjust indexing – all modern blade sharpening machines let you adjust the mechanism to skip one tooth, which is highly useful as most circular saw blades have tilted teeth. Some machines can alternate angles automatically (alternate chamfering beveling feature), which is also highly useful.
  4. Adjust the sharpening depth – depending on your blade’s teeth length, and you have to restrict the sharpening disk depth to avoid blade damage.
  5. Launch the tool – launch the process only after adjusting all the parameters correctly and ensuring that the blade is secured properly. When the job is done, the tool will stop automatically. You have to turn the power off and remove the blade carefully as it will be much sharper than before.

3. With Diamond Wheel Sharpener

Sharpening wheels with a diamond abrasive surface are used for sharpening blades with carbide teeth. Carbide is extremely tough, so it’s impossible to sharpen with a file or an average sharpening attachment. Here’s the step by step process:

  1. Install the blade on the sliding pad or the arm of the non-automated sharpening tool;
  2. Adjust the right sharpening angle – 5°-15° is the standard for carbide-tipped blades, but you can also use 18°-22° for ripping those softer materials;
  3. Mark the alternating teeth with a pencil or a highlighter;
  4. Launch the sharpening wheel and slide the blade in and out. You have to be careful, though, and avoid sliding the blade straight. Instead, you have to slide it in without touching the wheel and then press a tooth to the rotating wheel for 3-4 seconds.
  5. Finish one side, flip the bade or change its angle, and complete the rest of the teeth.

4. With a Mini Tapered File or a Diamond Sharpening Stick

The sharpening process for a tapered file and diamond sharpening stick is pretty much the same, but you have to lubricate the second tool with a few drops of an industrial lubricant. Ready? Here are the steps:

  1. Mount the blade on the workbench using clamps. You can mount it under any angle that feels comfortable, but vertical placement is recommended so that you can easier maintain the right angle.
  2. Place the file or diamond stick on the sharp edge of the tooth you need to sharpen and slowly move the tool back and forth. Three-four strokes are usually more than enough, but you can add a couple more if you see that the material is tough.
  3. Clean the blade when the job is done and put it back on the tool.

By the way, you can sharpen the blade manually without removing it from the tool. Unplug the saw or remove the battery, put the tool on the table or mount it with clamps, and do the job. Be careful with the sharpeners, though, as you can easily hurt yourself. I recommend wearing protective gloves.

Tips for Keeping the Blade Sharp

Many DIY woodworkers often forget that blades need proper maintenance to remain sharp longer. Below are the tips that I regularly apply to all my circular saw blades to prolong their lifespan as much as possible:

  1. Regular cleaning – regardless of the material you cut, deposits will stick to the surface of the blade. The most notable buildup remains after cutting resinous softwoods. Liquid tree resin mixes with the dust and hardens on the surface if you don’t remove it while it’s fresh and malleable. If you neglect the blade, the blade will meet higher friction, and the cutting edge will become more prone to overheating. You have to wash each side of the blade in 100 ml of dilution with a wire brush. Wash each side for 5 minutes. You can also use an oven spray (use outside only) and a fine brush. The blade must shine like new every time you put it in storage. Take a look at this great instruction on how to clean the blade for more details. It’s the same for all types of circular saw blades.
  2. Oil after cleaning – this is an essential step that will protect your clean blades from rusting. I recommend using camellia oil or any universal oil.

Also read:


Sherwood Circular Saw Blade Sharpener

Need more info? I knew it and prepared several brief answers for some of the most common questions my readers ask about circular saw blade sharpening.

Is it worth sharpening circular saw blades?

Yes, indeed. There are exclusions, too, though. Steel-toothed blades that cost 50 bucks or more are worth sharpening. There’s no reason for wasting your money on a new expensive blade just to have it sharp.

High-quality cutters can serve for years until they lose some of the teeth or they get erased too much. Cheaper blades have to be replaced right away.

How do you sharpen a circular saw blade at home?

For manual sharpening, you need:

  • a ring spanner – for removing the blade;
  • two screw clamps – for mounting the blade securely on the workbench;
  • a flat-file – for filing all the teeth to the same height;
  • a set of pliers – to ensure that all the teeth are mutually bent;
  • a triangular file – for actual sharpening.

You can also purchase a tapered file, a diamond wheel sharpener for carbide, an automatic sharpener, or a crank sharpener.

Can you sharpen circular saw blades by hand?

Sharpening circular saw blades by hand is possible but takes more time than sharpening with special tools, such as an automatic or crank sharpener. In addition, the manual method works only with the blades that weren’t specially hardened.

What are circular saw blade sharpening angles?

The right sharpening angle for the saw blade edge is usually 15°-20°. So you have to sharpen all the teeth under the same angle, but don’t forget that all the teeth are tilted left and right and alternate.

How do you sharpen a carbide circular saw blade?

The best way to sharpen carbide saw blades is to bring them to the local blade sharpening shop, where they have a diamond wheel sharpener. If you want to save time, get a diamond grinding disk, install it on a compatible power tool (a grinding tool will be the best), set the blade 90° to your table, and make sure that the face of the grinding blade is parallel to the hook angle of the blade teeth. Move the teeth in and out gently and hold them on the sharpening disk for around 5-10 seconds each.

Time For Sharpening?

Sharpen a Circular Saw Blade

Having all the right circular saw blade sharpening tools and knowledge from my guide, you can perform most blade sharpening jobs on time and with your own hands! If you regularly sharpen your job, you will always have the best cutting quality and keep your productivity on the highest level possible.

Using the saw, don’t forget to follow the circular saw safety guidelines, especially while detaching and installing the blades. Did my guide solve all your blade sharpening problems? If you still have questions after reading, you’re welcome to contact me via the comments below. I will reply ASAP.

Sean Chapman
Sean Chapman

“A good tool stays with you for many years and choosing carefully ensures the job is done right, your work is neat, and the tool is always a pleasure to use”

1 Comment
  1. Thank you for explaining how to sharpen with a diamond wheel sharpener. My brother needs to sharpen some of his tools. I’m not sure if he should use this himself, but I’ll be sure to pass this information on to him if he decides to try it out.

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