How to Sharpen a Circular Saw Blade [Step-by-Step Guide]

A dull blade not only slows down work but can also be dangerous as it may overheat, create rough finishes and even cause kickbacks.

Before you can use your circular saw, it's a good idea to sharpen it.

Circular Saw Blades are generally either masonry blades or carbide-tipped blades. 

Masonry blades cut only using the face of the blade. They are also cheap in comparison with carbide-tipped blades. 

They are chiefly used for cutting cinder blocks or concrete blocks and usually don't last that long.

Carbide blades cut with both the face and the sides of the blade and can saw almost anything. 

Sharpening with regular sandpaper is not as ideal as replacing your blade but it can be a temporary fix.

Things You'll Need

• Bench Vice. (or Clamps)
• Circular Saw Blade.
• Oil (Any wood lubricant or lapping fluid would do fine).
• Sharpening Stick (a File or Sandpaper is also acceptable).
• A small piece of wood.

Video Guide- Sharpening a Circular Saw Blade

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Step-by-Step Guide to Sharpening a Circular Saw Blade

Now, before you start sharpening, it's a good idea to clean the circular saw blade first.

Next, take a small piece of wood not more than 5 inches long and 3 inches wide.

Stick sandpaper on the piece of wood.

Glue sand paper on wood

Next, carefully remove the saw blade from the circular saw.

Take the dull saw blade and, using a clamp or a bench vice, fix it in place.

Mark the first tooth before sharpening beings, so you'll know when one full pass has been completed.

Marking tooth

Apply some oil or lubricant onto the sandpaper.

Oiling on sand paper

Place the sandpaper on the face of the tooth and begin filing back and forth on the face of the tooth.

You don't have to sand the top of the tooth.

Filing using sandpaper

After filing around 5 to 10 times, you can move on to the next tooth. 

Continue this process until all the teeth have been sharpened. 

With this step, you have successfully completed sharpening a circular saw blade.

Sharpened Circular Saw Blade

Tips for Sharpening Circular Saw Blades

• Since carbide blades cut with its teeth and its sides, you can end up rounding off these edges. So be careful while sharpening.
• One way to look out for the dullness of the blade is by examining the cuts themselves. When new cuts are made using a dull blade, they often tend to have rough finishes and take a longer time to complete. The sound of the motor can also be an indicator.
• Heat generated while cutting will be excessive in dull blades, and so burned marks may be observed on the cut.
• Using oil/ lapping fluid prolongs the life of the sandpaper/ sharpening stick.

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Frequently Asked Questions

Is it worth sharpening circular saw blades?

A circular saw blade is worth sharpening because you can sharpen it at a cost lower than replacing it. Depending on the kind of blade either a hand sharpening or a grinding shop may be used. For a regular masonry circular saw blade, hand sharpening will do just fine.

How many times can you sharpen a circular saw blade?

You can sharpen a circular saw blade 3-4 times if done on your own. Thereafter it can be sent to a grinding shop. A grinding shop can restore the blade back to its factory quality.

Can you sharpen a circular saw blade with a file?

If the circular saw blade is steel-toothed, you can sharpen the blade with a file. A hand file or a crank sharpener may also be used. For carbide-tipped circular saw blades, filing should not be used as files can dull the blade further.

How do you sharpen a saw blade by hand?

For sharpening a saw blade by hand, use either sandpaper or sharpening sticks. Hold it flush against the face of the tooth before sanding. Using a lubricant makes sandpaper last longer and results in a smoother finish.

How long does a circular saw blade last?

A regular masonry circular saw blade would last anywhere from 12 and 120 hours of continuous use. A diamond blade will last even longer as they are more durable. Proper maintenance can further increase the longevity of the circular saw blades.

Can a carbide saw blade be sharpened?

Carbide saw blade can be sharpened either by hand or at a grinding shop using specialized tools. Since the carbide tooth cuts with both the front and the sides, a grinding shop is highly recommended for sharpening carbide saw blades.

How to Sharpen a Circular Saw Blade

Yield:

Sharpens a saw blade

Prep Time:

5 minutes

Active Time:

15 minutes

Total Time:

20 minutes

Difficulty:

Easy

Learn how to sharpen a circular saw blade

Materials

• None

Tools

• Sanding Block
• Bench Vise

Instructions

1. Take out the dull saw blade from the circular saw
2. Take a 5 inch by 3 inch piece of wood and cover it with sandpaper to make a sanding block.
3. Fix the dull blade on the bench vise
4. Mark one tooth on the blade with a marker to know when one full pass is done
5. Start sanding each tooth of the blade back and forth with the sandpaper.
6. Keep shifting to the next tooth after 10 back and forth movements.
7. Go on until every tooth is sanded.
8. This completes the sharpening of the circular saw blade.

Notes

Some blades cannot be sharpened using this method.