How to Properly Sharpen a Chainsaw
If you have a house with a yard or property that contains trees and heavy brush, you already know that it can be tough to keep all of that foliage at bay. Pruners, hedge clippers, and loppers work well for smaller diameter limbs. But for trees, stumps, and larger limbs, you need a chainsaw.
Electric- and gas-powered chainsaws cut those large items like a dream. When the cutting gets tough again, it just might be time for a sharper chainsaw chain. New chains can get expensive, but fortunately, you can sharpen your own chainsaw with just a couple of simple, low-cost tools.
Basics of Sharpening a Chainsaw
A chainsaw's chain rotates clockwise if the saw is viewed from the right side. Or, when viewing the chainsaw from above, the chain moves forward (away from the user) along the top of the bar. Under the bar, cutting teeth bite into and abrade the wood.
With heavy wear and tear, the chain will dull quickly. It is important to sharpen your chainsaw because a dull chainsaw forces you to press harder on the saw, a dangerous move.
So, sharpening your chainsaw should be incorporated into your routine. There are three ways to go about this:
- Electric Sharpener: If you use your chainsaw more than a few times a year, it might be worth purchasing an electric sharpener ($50 to $100). Electric sharpeners have built-in angle guides to automatically situate the sharpener in the correct position.
- Guide and File: Metal files with matching guides help you to manually file the chainsaw teeth and the chain's depth gauges.
- File: You can use a file only, determining the angle with a Speed Square and estimating how far to file down the depth gauges.
When to Sharpen Your Chainsaw
Take a visual check of your chainsaw's chain while it is in place. When the leading edges of the teeth are rounded or out of the required angle, they should be sharpened. When the depth gauges on the chain are too high, this also is an indicator that it is time to sharpen the chain.
You can also lightly run your finger down the length of the chain, toward the cutting edges of the teeth. A sharp chainsaw will feel similar to the dull point of a paring knife: sharp but not quite sharp enough to cut your finger. A dull chainsaw's teeth will feel smooth.
When working on an electric chainsaw, always do so with the saw unplugged (or with the battery removed). With a gas-powered chainsaw, make sure that the chain brake is engaged. Wear heavy gloves when handling the chain.
What You'll Need
Equipment / Tools
- Metal file
- Speed Square
- Chainsaw user manual
- Protective gloves
- Vise (optional)
Examine the Chain
Before sharpening the chain, first remove it from the chainsaw and examine all parts of it. If some parts of the chain are in bad shape, it is dangerous to continue using the chain.
- Rivets that connect the cutting links should all be in place and tight enough that the chain does not bend from side to side.
- Intermediate tie straps that connect cutting links should all be in place and should be loose enough to move.
- The piece at the bottom of each drive link (called the tang) should still have a crescent shape in order to properly mesh with the sprocket driver.
If only the cutting teeth need sharpening, it is safe to sharpen the chain. If any other parts of the chain are defective, discard the chain and purchase a new chain.
Determine the Angle
Your chainsaw's user manual may indicate the proper filing angle for the teeth. Or some chains have hashmarks on top that show the angle. A Speed Square can help you file at the proper angle. Hold the square directly against the chain to ensure the proper angle.
File the Chainsaw Teeth
Clamp the chainsaw's bar into a vise if one is available. File the leading edges of the teeth. Note that chainsaw teeth alternate, so you will need to turn the file in opposite directions as you move through the chain.
File the Depth Gauges
File down the depth gauges on the chain to the level indicated by your chainsaw's user manual.
Tips for Properly Sharpening a Chainsaw
- File the same number of strokes per tooth.
- Use more strokes if the chainsaw has hit a nail or has been cutting muddy wood, as both actions will dull the chain more.
- Be sure to mark your starting point on the chain.