How to Sharpen a Chainsaw, Tips from Professionals

If your chainsaw blade is buckling and burning its way through the wood, it’s time for it to be sharpened. Dull chainsaws are not only slow, but they can be dangerous. Therefore, I recommend to sharpen them as soon as possible. In this blog post, I guide you about how to sharpen your chainsaw so you can get the work done quickly and safely.

How to sharpen a chainsaw:

• Step 1: Get a round and flat file, a file guide, and a depth gauge guide.
• Step 2: Prepare the chain.
• Step 3: File at the correct angles and stroke away from your body, maintaining the angle. Give 5 to 6 strokes to each cutter until its face becomes shiny silver.
• Step 4: Advance the chain and continue sharpening the cutters.
• Step 5: Sharpen the other side.
• Step 6: Use the file guide to check the depth gauge heights as they sharpen. Any protrusion above the file guide should be filed flush.

How do I know if it is time to sharpen my chainsaw?

“When should I sharpen my chainsaw?” is a common question I get from new chainsaw owners and beginners. The best and easiest way to judge is by checking the sawing waste. A lot of dust in the waste indicates the need to sharpen. On the other hand, wood chips indicate that the cutters are sharp.

You can perform a visual inspection of the cutters too. Sharp cutters have a shinier look, whereas dull cutters are identified by their dingier edges. Other ways to judge dull chainsaws are:

• The chainsaw needs a lot of pressure when cutting
• The chainsaw produces smoke even when properly oiled
• The chainsaw produces uneven cuts

When to Sharpen the Chainsaw Cutters?

How often you sharpen the cutters on your chainsaw depends on the usage frequency and operating conditions. I recommend checking the sawing waste for dust after every job. Sharpen if you see a lot of dust. Chainsaw cutters can be sharpened 10 times or even more before the chain needs to be replaced. This too depends mostly on the working conditions.

Keep in mind that sharpening a chainsaw is easy if the cutters have dulled from regular use. But if the cutters are nicked badly from accidental contact with rocks, dirt, or other hard objects embedded in trees. Then, you may need to have your chain professionally sharpened or buy a new one.

With these common yet important questions answered, let’s move on to the step-by-step sharpening procedure in detail:

Step 1: Gather the Tools you need for sharpening

You’ll need four basic tools to sharpen your chainsaw. They are inexpensive and can be found easily at hardware stores. Also, these tools are quite easy to use:

• A round file: The most important is a round file that matches the cutter diameter. The more popular diameters for medium-duty chainsaws are 7/32, 3/16, and 5/32 inches. Before buying a round file, please check the owner’s manual for the correct diameter, or use the chain identification number that is usually stamped on the drive link. Hardware stores usually have charts to match this number with the right file diameter for your saw.
• A file guide: You’ll need a file guide to hold the round file at a uniform depth as you sharpen each cutter.
• A flat file
• A depth-gauge guide: You’ll need it to reset the depth gauges.

Please do not use a standard rattail file to sharpen your chainsaw because its tapered diameter and coarse teeth can ruin the chain’s cutters.

Step 2: Get the Chainsaw Ready

Follow these steps to make your chainsaw ready for sharpening:

• Clamp the bar: Lightly clamp the bar in a vice after engaging the chain brake to keep the entire assembly locked in place as you sharpen.
• Place the guide: Place the guide between the chain rivets. The arrows on the guide should be pointing toward the front of the bar.
• Follow the angle: Follow the angle of the cutter top plate. The guide rollers help keep you from going too deep into the cutter’s side plate.

Step 3: Start Filing

• Rest the saw bar: Cut a 2-inch deep notch in a log and rest the saw bar in it to keep it locked in place while sharpening.
• Mount the file and file guide: Now, place the file and file guide into a cutter on the top of the bar, near the end. Mark the top of this cutter with a marker to indicate where you began using the chainsaw sharpener.
• Ensure the correct file angle: Line up your file with the factory-ground angle on the cutter, usually 30 or 35 degrees. Most file guides have 30, and 35-degree angles etched on their upper side to help you maintain the angle as you keep filing.
• Make the filing strokes: The filing strokes should be made to maintain the proper angle on the cutter. The filing strokes should be parallel to the ground and away from your body. On a dull cutter, the first few strokes will vibrate your hand a bit. But the strokes will become smoother as you continue.
• Finish up: Using steady, uniform strokes with the file, give each cutter 5-6 strokes until its face becomes shiny silver. Usually, when you feel a burr along the cutter’s outer edge, it means that the cutter is sharp. I recommend counting the number of strokes so that you can use the same number on each cutter. This gives a nice uniform sharpening.

Step 4: Advance with the rest of the chain

When you have sharpened several cutters, release the chain brake. Now the chain can freely rotate and expose more cutters to be sharpened. Remember to wear gloves as you advance the chain.

Reset the brake and sharpen this new section of cutters that you have just exposed. Keep repeating this step until one side of the chain has been completely sharpened.

Step 5: Sharpen the Other Side

Continue sharpening cutters by releasing the chain brake and rotating the chain until you’ve reached the cutter you marked at the very beginning.

Now sharpen the opposite-angled cutters at the other side of the saw bar. Keep using a similar amount of strokes per cutter. Release and rotate the chain after sharpening every couple of cutters.

Step 6: Keep Checking the Depth Gauge Heights

The cutters on a chainsaw have semicircular cutting edges with specific diameters. There is a shark-fin-shaped piece of metal in front of each cutter. This piece of metal is called a “depth gauge”. The depth gauge’s tip is just a bit shorter than the cutter’s tip, and it controls the depth of the cutter’s bite. The cutters can become level with the depth gauges after many sharpenings, preventing the saw from cutting. Therefore, the depth gauges must be lowered to the right height with a file guide and a flat file.

Therefore, as you continue to file, keep checking the height of the depth gauges with the filing guide. When their tips protrude above the guide, file them flush with the flat file.

Some Important Chainsaw Sharpening Tips:

• Sharpening frequency: Chainsaw cutters can be sharpened up to 10 times or more before the chain needs to be replaced. If your gutters become worn unevenly after a few sharpenings, seek professional help to regrind them to a uniform shape.
• The number of strokes and pressure: If your notice that the chainsaw pulls to one side when cutting, cutters on that side are sharper than on the other side. To have your saw cutting in a straight line, file each cutter with a similar number of strokes. Also, try to use for each stroke an equal pressure.
• Switching between chains: If you keep sharpening the same chain for a few years, then get rid of it and buy a new one. The new one won’t mesh smoothly with the bar and sprocket. This will result in rougher cutting and faster wear. Bob Tacke, a chainsaw expert, advises: “Buy two extra chains and switch off among the three occasions. This way, the bar, sprockets, and chain will fit together. And extend the life of your saw.”
• File guides: File guides that clamp to the bar ensure that you file at the same angle on each cutter. Sharpening with file guides takes a bit longer, but they restore the cutting edge to the exact factory-ground angle. This reduces the chance of you having to get your chain reground by a professional sharpener.
• Don’t work in doubt: It feels great to perform jobs yourself, but take your chain to a pro if in doubt. They will use a power chainsaw sharpener that resembles a mini-compound miter saw. They can precisely grind each cutter to a uniform depth and cutting angle.

Why does a Chainsaw Get Dull?

Over time, a chainsaw will get dull for the following reasons:

• Contact with the ground: A chainsaw can become very dull even with a single contact with the ground while running. This is because the ground contains sand and dust, which is abrasive and contains tiny rocks that are quite hard. Therefore, you should try to avoid cutting wood placed on the ground.
• Dirty trees: Over the years, tree bark accumulates a lot of dirt and soil carried by the wind. This dirt and soil can cause your chainsaw to become dull after even a short time of contact with dirty bark. One way to avoid this is to remove the bark from a tree before cutting.
• Contact with strong objects/metals stuck in wood: Strong, hard objects like nails are often nailed into trees to put up signposts while building a birdhouse or a treehouse for kids, etc. Contact with these hard objects can instantly make your chainsaw very dull. To avoid this, please take a thorough look at the wood or tree you are about to cut, and pull out any hard objects using pliers before you use your chainsaw.