How to sharpen a chainsaw

How to sharpen a chainsaw

John, Passionate gardener, Cambridge

Guide written by:

John, Passionate gardener, Cambridge

57 guides

Chainsaws are handy tools that can be easily transported to a job site. However, the chain does need to be filed on a regular basis to keep it sharp. This is a fairly straightforward process but you do need to follow a few basic rules. Read on to find out how best to sharpen a chainsaw.

Important features

  • Securing the chainsaw and cleaning the chain
  • Filing the cutter teeth
  • Checking and/or adjusting the depth gauges
  • Tensioning the chain
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Sharpening a chainsaw: when, how often and why

How to tell when your chainsaw needs sharpening


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If you notice one or several of the following signs, it's time to sharpen your chainsaw.

  1. You have to apply force to push the chainsaw through wood (a properly sharpened chain should slide easily into materials).
  2. When you make cuts, the chainsaw creates fine sawdust instead of small wood shavings.
  3. The cutting line is squint; the chainsaw is pulling to one side. This is a sign that not all teeth are the same length and that some are more worn than others.
  4. The chainsaw 'jumps' on wood; this is usually caused by the depth gauges which require adjustment.
  5. Smoke is appearing as you cut; a sign of overheating.

How often to sharpen a chainsaw

The amount you have to sharpen a chainsaw depends on the types of cuts you make, the type of wood you cut and how often you use the tool. Don't wait until your chainsaw is no longer able to cut anything to sharpen it; a quick file every three or four times you top up the fuel is a good guideline to follow.

The advantages of a well-sharpened chainsaw

It is important to sharpen your chainsaw for a number of reasons.

  1. To ensure your chainsaw is working at its best (meaning you'll use less fuel).
  2. To improve its cutting precision.
  3. To make cutting tasks easier by limiting the amount of effort you have to apply.
  4. To prevent kickback.
  5. To enhance user safety.
  6. To prolong the service life of the machine (guide bar, chain and clutch).

Steps

  1. Securing the chainsaw and cleaning the chain
  2. Filing the cutter teeth
  3. Checking and/or adjusting the depth gauges
  4. Tensioning the chain

1. Secure the chainsaw and clean the chain


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Before you start sharpening, it's important to ensure your chainsaw is fixed firmly in place to prevent it from moving around as you work.

If you are working at home, you can secure the guide bar in a benchtop vice. Alternatively, you may find yourself having to sharpen your chainsaw on a job site. In this case, secure your chainsaw in a small portable vice designed to be fixed to a tree stump or another stable piece of wood.

No matter where you work, the chain must be able to slide freely around the guide bar. Clean the chain to get rid of any oil or resin residue.

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Chainsaws

2. File the teeth using the right type of file

How to choose the right file to sharpen your chainsaw


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Files vary in diameter so it's important to pick the right one depending on the size of your chain, or more specifically, the size of the pitch.

The chain pitch is usually noted on the guide bar. If not, you can simply measure the distance between three consecutive rivets and divide the result by two.

Pitch size
File diameter
6.35 mm
4 mm
8.25 mm
4.8 mm
9.32 mm
5.2 mm
10.26 mm
5.5 mm

Pick your point of reference

The shortest cutter tooth should be your point of reference. Mark out this out using permanent marker. This will be your starting point (to avoid sharpening the same tooth twice).

All other cutter teeth should be filed to match this size. After sharpening, all cutter teeth should be the same length to ensure they all cut the same amount of wood. If all your cutter teeth are the same length, you can start sharpening wherever you like.

File all right- and left-hand cutter teeth


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Chainsaw chains feature two different types of cutters: they alternate right-hand cutter teeth with left-hand cutter teeth.

Position the round file into the gap between the teeth and hold it at a 30-degree angle to the guide bar.

The cutter teeth of some chainsaws will be marked to help you find this angle. You can also purchase a guide to help you. The sharpening angle may be 35° or even 25° on some chainsaws; be sure to check the instructions for your model.

Holding the handle of the file in one hand, guide the end of the file with the other hand. Slide the file forwards along the cutting edge of each tooth, pushing down slightly on the end of the tooth. You should not file down the curved edge at the base of the tooth. The file will only work as you push it forwards; you should lift it each time you return to the tooth.

When you have filed one cutter tooth, slide the chain to move onto the next. If all your cutter teeth are the same length, count the number of times you pass the file over the tooth (generally two or three times) or adapt the number of strokes to obtain your desired length.

Sharpen in the opposite direction


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Once you've filed all the cutter teeth in one direction, turn your chainsaw around to get access to the cutter teeth in the other direction and proceed as described above.

You can find special sharpening tools designed to be fitted onto the guide bar as well as sharpening guides, file holders, roller sharpeners and so on. All these tools will help you to maintain the same angle as you sharpen.

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Sharpening tools

3. Check the depth gauges


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Depth gauges are used to check that your chainsaw is cutting to the right depth. A poorly adjusted depth gauge can cause kickbacks or damage to the chain and chainsaw. In turn, this can pose risks to the user.

Position the measuring tool on the teeth. If part of the depth gauges protrude over the measuring gauge, you will have to file them down using a flat file until you reach the measuring tool itself.

Repeat the same process for every depth gauge. Alternatively, you can simply file each depth gauge using the same number of strokes so they reach the same height (although this is not an exact science).

4. Check the chain tension


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A correctly tensioned chain should be held all around the guide bar but should be easy to move.

When pulled, the chain should not become disengaged with the guide bar.

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Guide bar

Final tips for sharpening a chainsaw

Manually sharpening a chainsaw is quick and will offer good results, provided you use the right tools. Alternatively, it is possible to pick from a range of electric sharpeners designed for chainsaws.

To use these sharpening tools, you'll have to adjust the settings before you start and the chain will have to be removed from the chainsaw.

How to sharpen a chainsaw

Required skills


Required skills

Sharpening a chainsaw is a delicate procedure that requires a lot of precision and attention.

While the task isn't that tricky in itself, you do need to be quite good with your hands, even if you use a few tools to help you out.

Time required


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15 minutes

Number of people required


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1 person

Tools and equipment


Tools and equipment
  1. Vice (fixed or portable)
  2. Round file
  3. Flat file
  4. Depth gauge
  5. Wrench/screwdriver to tighten chain
  6. Cloths and cleaning product
  7. Sharpening guide (optional)

Personal protective equipment (PPE)


PPE
  • Puncture-resistant gloves
  • Protective clothing

Please note: this is a non-exhaustive list; be sure to match your personal protective equipment to the job at hand.

PPE

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PPE

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Guide written by:

John, Passionate gardener, Cambridge, 57 guides

John, Passionate gardener, Cambridge

When I was young, I was already working in the family garden. Perhaps that is where my interest in plants and gardening came from. So, it was logical for me to study both plant biology and agronomy.   At the request of various publishers I have, over twenty-five years, written many books on the subject of plants and mushrooms (a subject that is close to my heart).They were mostly identification guides at first, but shortly after they were about gardening, thus renewing the first passion of my childhood.   I have also regularly collaborated with several magazines specializing in the field of gardening or more generally in nature. There is no gardener without a garden, I have cultivated mine in a small corner of Cambridge for the last thirty years and this is where I put into practice the methods of cultivation that will I advise you in as well.

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