The best way to sharpen a circular blade is with a calibrated machine. However, most of these machines are quite expensive and out of reach for most people.
An old saw will make your work difficult and will give you a dull finish. Your saw engine will have to work extra harder and this will lead to it to depreciate faster. In the end, you will incur more costs while replacing your saw or the blade.
Modern saws are tipped with carbide or diamond and make it hard for some people to learn the skill of sharpening the blade.
Carbide edged blade needs a professional to sharpen because of the following reasons.
- Carbide is a tough metal and requires to be sharpened using a diamond wheel. Sharpening becomes quite complex and the blade can easily be ruined.
- Carbide blades cut with the edges of the teeth and margins and if not cautious one can easily destroy the tips.
The circular saw blade comes in two different of teeth.
- The Rip teeth
These are chisel-shaped and are sharpened by filing four-sided through the blade.
- Crosscut teeth
These are knives shaped and are formed by filing at an angle to the blade.
Automatic sharpeners are not recommended as they might overheat or lose the correct angle of the teeth they are sharpening. Manual sharpening always will give you the best result.
You need the following tools to sharpen your circular saw.
- Hand file ( A three-piece is highly recommended)
- Crank sharpener
- Automatic sharpener
- A Marker or chalk or grease pencil
- A thin shred of wood
- Painter brush
- Bench vice
- Wire brush ( Look for one with a comfortable holder)
- Gloves ( Though optional)
- A rag for cleaning the surface
- Petroleum jelly
- G clamps
Below are the steps to follow while sharpening your circular saw
- Disconnect from the power source
Before starting to sharpen the blade at home, disconnect the saw from the main electricity connection or remove the battery if it’s a battery power-driven circular saw.
- Detach the blade from the saw
Modern circular saws have a locking device. This makes it easier to disengage the blade from the saw. You don’t have to jerk so as to loosen the screws that hold the blade. It is more like a switch system easy to operate.
Also, clamp the thin strip of wood to the saw bed and against the tooth. This protects the saw from spinning while you loosen the bolt that holds it in place.
- Secure the blade
Apply the petroleum jelly to the blade and allow it to set for 20 to 30 minutes. This helps to break the latex in the teeth.
Clamp the blade into a vice clutch. Use the wire brush to make it clean. Brush inside out up to the teeth. As you proceed, the rags will saturate the fine dust and residue.
Allow the blade to face upwards while the teeth face you. The vice should not be tightened as might damage the metal that grips the teeth.
- Do the Markings
Using a chalk or a marker, mark the first tooth. The mark should be a visible enough. This makes it easy to locate the end of the blade. It also saves you sharpening a tooth more than once.
Make sure every 2 blade points has a bevel on the side that is facing you. Hold your file about 20 – degree angle with respect to the slant.
Make around 4 consistent strokes up and down along the bevel of the first tip. If not successful apply more strokes or get a new file.
- Pay Attention to the Bevels
Slopes appear on every second blade. It’s important to skip one in between. Repeat this process until you get around the whole blade. Apply an equal number of strokes as you did in the first blade.
- Repeat on another side
Turn the blade over once this is done. Repeat the process applying the same techniques as in step 3. Make a mark just like step 4.
File the tips of each tooth. No need to apply multiple horizontal strokes here. Run the file to a back and forth manner across the front edge of the top of the blade point. This ensures you don’t wear the blade down more than you should.
The best procedure to master would be, sharpen one tooth, and skip one tooth. Sharpen, skip, sharpen skip. More like a pattern.
Saw teeth normally incline in different ways. One will incline to the right while the other will incline to the left. This means that each tooth will incline in the opposite direction.
The teeth are normally aligned this way so that the cut is wider than the width of the blade.
File around the blade adjusting in the vice as necessary as it may be until you come to the tooth that was initially marked.
- Remove the blade for the second time
Turn the blade in 180 degrees point and clamp it back into the vice. Repeat again the sharpening for the teeth that were skipped.
Place the file on the marked tooth. File back and forth at least four times. No need to skip a tooth.
Repeat this process for all the teeth. You should stop sharpening until the blade is bright steel.
It is important to note that a file can easily become blunt if you stroke back and forth. Should you hear a screeching sound, then that should tell you that you are not using the file properly.
- Install the blade
Unravel the blade from the vice grip, and install back onto the saw.
Use a soft brush and a rag to remove any residue that has remained
In conclusion, you don’t have to take your circular saw to a professional you can actually do it at home using a file. You will never have a dull moment with a dull blade.