How to Sharpen a Circular Saw Blade

A man uses a circular saw.
  • 1-3 hours
  • Beginner
  • 10-20
What You'll Need

Sharpening a circular saw blade is something that should be done to maintain the life of your saw for many reasons. If you’ve ever had the experience of shaving with a dull razor, then you know how much more effort is involved with using dulled blades as opposed to sharp ones. The same logic applies to the blade of your circular saw that you may be using at home or on the job site. Most people opt to just buy new blades for their saw when it dulls, particularly with the challenges associated with sharpening modern blades that are tipped with carbide or diamond. However, with the purchase of a diamond file, it is possible to do it yourself following these easy steps.

Step 1 - Remove the Blade

Some saws have a blade release switch, which makes this task much easier. Older models, however, require that you use a wrench in order to loosen the bolts that hold the blade.

Step 2 - Secure the Blade Down

Secure the circular saw blade in a vice grip. You want to have the blade facing up with the teeth towards you. You need to also be aware not to tighten the vice grip too hard, or you will warp the metal that holds the teeth.

Step 3 - Make Your Marks

Make a mark at the top most point of the blade so that you’ll be aware of when you have gone all the way around the blade (and thus prevent double sharpening). You should see that every two blade points has a bevel on the side that is facing you. Simply take your file (again, diamond-file for best results), hold it at about a 20-degree angle with respect to the bevel, and give it 4 consistent strokes up and down along the bevel of the first tip. You should be able to notice if has been successful, and if not then simply apply more strokes (or get a new file).

Step 4 - Pay Attention to the Bevels

Since the bevels appear on every other blade, skip one blade and go to the next beveled edge. Repeat this process until you get around the entire blade, applying the same number of strokes that you did with the first blade.

Step 5 - Repeat on Other Side

Turn the blade over once you have done this, and repeat the process (apply the same technique that you did in step 3). Again, it is recommended that you make a mark so that you will know when you have reached the starting point of the blade.

Step 6 - File

File the tips of each booth. For this, instead of applying multiple strokes, just run your file back and forth once across the front edge of the top of the blade point (so that you do not wear it down more than you need to). Complete this process for all blade tips on the saw blade.

Step 7 - Install Blade in Saw

Unlock the blade from the vice grip, and install back onto the saw.

Following these steps can save you a lot of money and time in the long run. You can now begin enjoying a renewed life to your old dull saw blade.