Remember the first time you used your chain saw, how well it cut through anything you threw it at? Your saw should work that well everytime you use it, even if it’s several years old. If not, you’re not only making your saw work harder than it should – putting excess wear on it in the process – you’re also putting yourself in danger of accidents or injuries. Let’s look at why chain saw sharpening is important, and how it’s done.
In order to properly sharpen your cutting chain, you should understand the principles behind how it works. There are five components to the typical saw chain:
- Left-hand cutters
- Right-hand cutters
- Drive links
The cutters are the part that do the actual cutting, so that’s what we’re going to focus on in this article. These cutters have two important features – a raker, or depth gauge at the front and another cutting element, much like a gouge, at the rear. The space between the two is known as the gullet.
There are two surfaces on the cutting element – the top plate and the side plate. The top plate angle is the one you’ll probably recognize more easily. When you’re looking down at the cutter, it’s the roughly 30 degree rake you’ll see. Underneath the top plate is another bevel that works much like a chisel, with a roughly 60 degree angle. The final angle is the side-plate, which is generally about 85 degrees, sometimes less depending on the brand of chain.
These angles combine to do the cutting when you’re chopping wood. The sharp corner where the angles meet slices through the grain of the wood. The alternating left and right cutters work each side of the cut, while the angle beneath the top plate essentially “scoops” out the chip to keep the cut clear.
You’ll know it’s time to sharpen your chain when several things happen:
The chain starts to look “shiny.” If you look at the top and side plates and the chrome plating is worn off, you’ll see the steel underneath it which will appear shiny. To sharpen the cutting edge of the saw chain again, you’ll need to file the steel down until you see a thin bit of chrome.
The chain stops self-feeding. This is probably the most common signal that it’s time to sharpen your chain. When sharp, your saw chain will pull itself down through your cut. If you find you have to put pressure on the saw and push it through the cut, your chain probably needs sharpening.
The discharge from your saw is dusty. A sharp saw chain will discharge square wood chips. If you find your saw is discharging dust instead, the chain likely needs sharpening.
If you find your chain is getting dull, it’s important to take the time to sharpen it properly. Forcing a dull chain through the wood puts excessive strain on the chain, sprocket, guide bar and engine. It has been shown that dull chains are the most common source of bar failures.
Having a dull chain saw also puts excessive strain on you as the operator, which can cause you to tire faster and can lead to poor decisions, accidents and injuries.
Don’t take any chances with your health and well-being. Take the time to do proper chain saw sharpening when needed. The job will actually wind up taking less time, in spite of the time you take to sharpen your chain, and you’ll be much safer in the long run.