How to sharpen a chainsaw blade

How to sharpen a chainsaw blade

If you’re not already regularly sharpening your chainsaw blade, you should really start making it a part of your routine. Just like with hedge trimmer blades, or even the ones on your lawnmower, dull chainsaw blades make your tool so much less efficient.

The difference with chainsaw blades is that they are also highly dangerous when they lose their sharpness, increasing the probability of it getting jammed in the thing you are trying to cut much higher, or kicking back, and likely causing an injury. You should always have a first aid kit on hand when using cutting tools, but the possibility of you needing it will be increased if your chainsaw is blunt.

I know a lot of people are put off by tool maintenance, especially those of you who are new to this kind of thing but servicing your tools is an essential part of owning them, and they are usually much easier to take care of than you would think.

So, today’s article is all about how to sharpen a chainsaw blade and we will be doing our best to explain exactly how to do it, giving you the confidence to handle the upkeep of your chainsaw yourself, and prevent accidents that can occur as a result of blunt blades.

In this video, you’ll see how fast a chainsaw can kick back, and also exactly what NOT to do with your chainsaw: not a scrap of safety equipment in sight, and he was very, very, lucky to still have a face 😲

Tools that you’ll need for sharpening a chainsaw

To sharpen your chainsaw blade in the easiest and most efficient way possible, you’re going to need a flat surface like a table or workbench, either clamps or a vice to hold the tool in place, a screwdriver for adjusting the tensioner on the chainsaw, a thick pencil or marker so that you can clearly mark your start and finish point, a round file for sharpening the cutters, a flat file for the rakers, and a depth gauge and sharpening guide. Here’s all that in bullet points for clarity-

· Flat surface like a table or workbench
· Vice or clamps to hold the chainsaw in place
· Screwdriver
· Marker or pencil
· Round file (the same diameter as the chainsaw’s teeth)
· Flat file
· Depth gauge & sharpening guide

How to sharpen a chainsaw blade step by step

Here we will walk you through the steps required to sharpen a chainsaw blade with a couple of hand files. This is only one method of maintaining chainsaw blades, and there are others using Dremel tools and other products designed specifically for sharpening these blades. We chose to go with the hand filing method as these files are something that anyone can find in their local DIY shop and are inexpensive.

Get your space ready
Make sure you have enough space to work comfortably in your shed, garage, out on your patio, etc. Clear clutter away, especially from down below as you don’t want to have the chance of tripping over something and falling onto the chainsaw. Even without any power and lying still, you can still have a nasty accident.

You’re going to need elbow room to work those files, and some kind of lighting if working indoors or at night. Spend a little time getting your workspace set up properly and things will go a lot smoother in the long run.

Always make sure that the battery is removed from a cordless chainsaw, that an electric chainsaw is unplugged, and that you have removed the spark plug from a petrol chainsaw, before starting to work on them.

You don’t want the main body of the chainsaw moving all over the place while you sharpen the chain, so you need something to keep it stationary. I’ve used both clamps and vices in the past with success, but I realise that not everyone will have these, especially in the larger sizes needed to lock down a chainsaw. If this is the case, you can always remove the chain and secure that in a vice while you work on it, or as a last resort, get someone to hold the chainsaw steady.

If you’re going to be sharpening your chainsaw away from your home, you might want to look for one of those portable chainsaw sharpening clamps, as shown in the video below-

Get your chainsaw ready
Anything thing you don’t want moving around while you’re working on it is the chain itself, so grab your screwdriver and adjust the tensioner. Some brands and models of chainsaw might require something other than a screwdriver to do this, but if a special tool is required, they are usually included in the box with the chainsaw. You don’t want to overdo this part, and you should be able to move the chain around with your hand, it’s just that you don’t want it to slip away every time you touch it with the file.

After marking your starting point on the side of the tooth, take your round file and set it into the sharpening guide. This will allow you to accurately sharpen the cutters and to get some uniformity instead of having to guess how much you’ve filed down. The first time I tried to sharpen the blades on a lawnmower, I didn’t think about keeping things even and sharpened one side far more than the other. The results weren’t great, but I came away with experience and a ‘sharpened mind’ 😉

These sharpening guides usually have markings on them to help you with this and also give you the measurement of the angle at which you’ll be sharpening. What’s more, they can be picked up fairly cheaply from amazon and should last a long time before having to be replaced.

Sharpening at the correct angle is important when maintaining all cutting tools, no matter, if it is shears, loppers, or a pruning saw, that you’re dealing with, so make sure you find out what the best angle is before you go filing or grinding away.

Use the round file and sharpening guide on the cutters
After the round file is securely fixed in place in the chainsaw sharpening guide, you can place it so that it nestles next to the curved edge of the cutter. Using the lines on the guide, align it until the chainsaw’s bar sits parallel, and then simply push the file across the cutter multiple times until sharp and shiny.

It’s important to file only in one direction and not back and forth or it will not produce the results you want. Keep track of how many times you moved the file for this first edge and then do the same for all the other edges. 

As already mentioned earlier, your round file should be the same diameter as the cutters, and if you’re having problems finding the right size, you might have better luck buying a chainsaw sharpening kit like this one-

With the cutters sharpened, it’s now time to file the rakers down so that they are all level. These rakers are situated between the cutters and play the important role of controlling how deep your cuts will be, so getting them all leveled off at the same depth is going to improve the performance of your chainsaw.

Use the depth guide and flat file for the rakers
Place the depth gauge on top of the raker next to the first cutter that you marked earlier, and you should see that the top of the raker sits flush with the top of the gauge. However, if you notice that the raker rises up higher than the depth gauge, it’ll have to be filed down with a flat file or a grinder if that’s what you’re using. Once you’re happy with one raker, move onto the next, and then the next, until they’re all done.

The following clip is of a guy in the USA giving his tips on filing rakers, so take a look if you’re still not clear about what we mean-

Finally, grab your screwdriver again and set the tension back to a useable level, apply some oil to the chain, and also fill up the chainsaw oil reservoir on the tool itself. Your chainsaw should now be back to its best and ready to slice through anything you point it at.

As we already mentioned, this is just one method of sharpening a chainsaw blade and there are other tools that can do the job faster, such as Dremel tools and fixed benchtop sharpeners. These tools will cost more than just using hand files, but they do really speed up the time it takes to finish the job and require less effort, so some people prefer them.

Always remember to keep safety in mind when using a chainsaw, and wear proper chainsaw trousers and boots. With the right equipment and a little common sense, you can use these powerful tools safely.