Whether you’re removing a pesky tree stump or cutting up firewood for a summer bonfire, a chainsaw is a useful tool to have in your shed. However, using a dull chainsaw is not only inefficient, but can be dangerous too. The good news? With this guide, the right tools, and some DIY skills, you can learn how to sharpen a chainsaw and keep your equipment running smoothly and efficiently.
Prepping to Sharpen a Chainsaw
First and foremost, it’s important to have a general idea of when it’s time to sharpen a chainsaw. It’s always best to have the chainsaw sharp and ready for use, rather than scrambling to sharpen it in a time of need. While there’s not a hard and fast rule, there will be a few key indicators that can help you determine if it’s time to sharpen the chain:
If the chainsaw is rarely used, sharpen it once a year in the spring for regular upkeep.
If you use the chainsaw more often, a general guideline is to sharpen the chain after every three hours of use.
If you notice dust is being emitted when cutting instead of wood chips, this indicates that the cutters are dull.
A noticeable change in quality when cutting or having to use more force when cutting than previously is another good indicator.
If the chainsaw pulls to one side or the other when cutting, it could be a sign of uneven cutting teeth or a dull chain.
If it has been stored in a moist or wet area, the chainsaw may not operate as effectively and need to be sharpened.
Keep in mind that if the blade is dull from normal wear-and-tear, this is likely a DIY project. However, if the blade has been damaged and nicked due to contact with rocks, dirt, or other foreign objects outside of wood, it’s best to have it evaluated by a professional or to purchase a replacement chain.
How to Sharpen a Chainsaw in 7 Steps
While there are different methods to complete this project, this step-by-step guide will walk you through how to sharpen a chainsaw using a file guide or round file with the blade still attached to the saw.
Select the Appropriate Tools
If you’re sharpening the chainsaw by hand, there are a few different files that you can use—a round file, file guide, flat file, and depth gauge guide. You can either purchase these tools separately, or look for a chainsaw sharpening kit to properly sharpen the blade. Before sharpening the chain, it’s helpful to understand the different uses for each tool.
Round file: A round file is used to sharpen the cutting edge of the saw blade. The round file’s diameter matches the diameter of the cutter. Some of the most common chainsaw diameters are 5/32, 3/16 and 7/32 inch, but you can find your specific measurement by checking the chainsaw’s owner’s manual or referring to the stamped chain identification number on the drive link.
File guide: The file guide can be used instead of a round file and is placed over each tooth of the chain with an angle guide to ensure the pitch is being filed evenly. Many prefer this option to the round file, as it takes the guesswork out of determining the proper angle. Most chainsaws follow the 30-degree marking, but check your owner’s manual to set it at the appropriate angle.
Flat file: The flat file is used to sharpen the depth of each tooth.
Depth gauge guide: The depth gauge is used in conjunction with the flat file and is set over each depth gauge (or raker) to check the height to guarantee they’re being filed down to the same depth measures each time.
Prepare the Chainsaw
Before sharpening the chainsaw, there are some preparations to make to ensure a safe and successful project. Remember to wear the appropriate safety gear, such as heavy duty work gloves and safety glasses, when you adjust the chainsaw blade and sharpen it.
Disconnect the power: If you’re sharpening an electric chainsaw, be sure to disconnect the unit from any power sources to avoid injury. If you’re sharpening a battery-powered chainsaw, disconnect the battery to prevent it from accidentally turning on. If it’s gas-powered, ensure the chainsaw isn’t running before you start working on it.
Clean the chainsaw: Remove any dust, debris, or oil from the chainsaw before beginning this project. Wipe down the housing and chain with an old rag and warm water, and use a wire brush to remove any sawdust from the teeth. If the tool is particularly soiled with oil or has built-up debris, you may need to use mineral spirits or compressed air to clean it properly.
Set the Chain Tension
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The chain must be set to a specific tension to get the best performance from the tool. A chain that’s too loose can kickback or fall off the guide bar when you’re cutting. Wearing work gloves, ensure the chain is tight before sharpening, and test it by pulling the chain up from the guide bar just enough to see the tips of the teeth and allowing it to snap back into place.
If it snaps back into place with no slack, it’s properly tensioned. If there’s slack when you let go of the chain, it will need to be adjusted.
To set the tension, adjust the screw on the front or the side of the chainsaw. Turn the screw clockwise to increase the tension and counterclockwise to loosen the tension. If your chainsaw has nuts on the side, loosen them first before adjusting the tension and tighten them again once you have the proper tension. Test the chain to check if it snaps back into position once released before moving on to the next step.
Secure the Chainsaw
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Keeping the saw stabilized will help you to properly sharpen the chain. Place the chainsaw in a bench vise with the clamps securing the guide bar. Release the chain brake so you can rotate the chain freely while the clamps are attached.
Identify the Shortest Tooth and Begin Sharpening the First Side
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To avoid double-sharpening the teeth, look for the shortest blade and mark it with a permanent marker to keep track of it while you’re sharpening. If your chainsaw’s teeth are the same length, you can start with any of the blades, but still mark the first tooth you choose to sharpen.
Using the file guide, file the first marked tooth from the inside towards the outside at a 30-degree angle, unless otherwise stated by your owner’s guide. Hold the file in your hands at a 90-degree angle, parallel to the ground. Remember, the file guide should always face away from the body of the saw to ensure you’re working in the proper direction.
Slide the tooth through the file guide, and only apply pressure on the stroke pushing outwards, not inwards, to avoid ruining the sharp edge.
File each tooth five or six times, or until the face of the cutting edge is shiny silver.
Moving In the same direction, file every other tooth until you’ve reached the marked tooth. Use the same number of strokes each time to maintain consistency.
If you’re using a round file, you will need to manually position the file at a 30-degree angle (unless otherwise noted), and place the file into the notch of the tooth. Applying pressure on the outwards direction, stroke the file five or six times, or until the cutting edge is shiny silver. File every other tooth the same amount of times, working in the same direction until you reach the first tooth. Be sure to knock shavings off of the file regularly as you work along the saw chain.
Sharpen the Other Side of the Chain
Once the first side of the chain has been sharpened, reverse the saw in the bench vise and begin working in the other direction using either the file guide or the round file. Keep filing every other tooth outwards, applying pressure only on the push stroke. Remember to maintain the same amount of strokes along each tooth.
Check the Depth Gauges and File
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To properly sharpen a chainsaw blade, it’s important to also check the depth gauge, sometimes referred to as the raker. The depth gauge controls how deep the chainsaw blade cuts into the wood. You likely won’t need to file the depth gauges every time you sharpen the chainsaw.
To check if it’s time to file the depth gauges, place the depth gauge tool over the chain so the rakers are exposed. If the raker is higher than the top of the depth gauge tool, you will need to file it down with the flat file. Using the same motion as you did with the file guide (applying pressure only on the outwards stroke), file each raker until it sits level with the depth gauge jig. If the file shakes or pulses as you file, switch sides of the chainsaw and file in the other direction. Once you complete this step, you should be left with a sharp chain that’s ready to take on your next woodworking project.