How to Sharpen Circular Saw Blades by Hand?

Stuart Wellbert
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Circular saw blades need to be maintained as part of a regular maintenance schedule on all rotating equipment. Circular saw blades have different number of teeth per inch. The fewer the teeth per inch, the finer the material that can be cut effectively. The distance between the two flutes determines the thickness to which material can be cut. The most commonly used width is 4–. diameter.

Useful Key Points

When sharpening a circular saw blade it is best to use a flat file, and to begin and end each stroke at the edge of the saw blade, thus utilizing the full length of the file. Hold the file square to the saw plate-the file should be 90 degrees to your saw plate. Use a file card to clean the file of metal and wood build-up. Grasp the file in a vise with the teeth of the file projecting into the vise.

It has been found best to remove the blade, clean off all the pitch with an 8 in. or longer flat file or smooth, hard metal file, and then proceed as below:

The image above is a 10" high-speed, two-wheel saw blades. This is a hybrid blade designed for both crosscutting and ripping. This steel blade is 3/4" thick and has a diameter of 8".

For the blade mounted in the saw, use a new, fine-cut flat file to thoroughly clean all the pitch from the teeth. File firmly, but not too hard as to burnish the teeth.

Locate the best measuring point for the base of the tooth by visual inspection. Place a feeler gauge between the tooth and the saw blade and measure the blade to the base of the tooth. Use a new, fine-cut flat file to file all the teeth to the same measurement on both sides of the saw plate.

How to Sharpen Your Blade

Step 1: Determine the amount of blade you will be sharpening. From the center of the blade measure the circumference and multiply by Pi (3.1416) Example: 13.5" x 3.1416 = 41.508"

Step 2: Cut a piece of plywood to that length with a small enough width to fit in your vise. Make sure the "Good" side is up (smooth side). The extra edge will hold your blade parallel to the bench.

Step 3: Place the blade in the plywood with the bevel down. Pinch like you are sharpening a chisel. Try to keep the bevel in line with the plywood supporting it.

Step 4: Hold the back of the blade at the center mark and pinch at 12 and 6 o'clock. You should now have the blade supported by two edges with the center free and able to pivot.

Step 5: Hold the blade horizontally in your vise. Pinch the blade like a chisel at 1/3, 2/3 and ¼ from the tip. At each point, check the depth and smoothness of the stone. Try each of the three stones in the vise.

Other Important Specs

Blade diameter vs Blade diameter: For every 1/8" increase in diameter there is a 1/8" increase in cutting depth per tooth. For example a 9-¾" diameter blade will have 1/8" more cutting depth that a 9.25" diameter blade due to it's increased diameter. The maximum diameter a blade can be is 10" (250mm) and the minimum is 6" (150mm).


There are several other equipment used to power the circular saw. The sharpening of the blade is very important to make sure that the blade is very sharp and there are several benefits of sharpening the circular saw blade.

The equipment for sharpening the saw blade is very expensive and sometimes people at home are not sure of how to use the equipment to sharpen the saw blade manually.

This manual tells how to sharpen the saw blade manually at home.

In this manual, you will find information on how to sharpen the saw blade in different ways, what equipment to use and the steps for sharpening the saw blade by hand.