The ease with which you cut with a chainsaw depends massively on the sharpness of its chain. When its chain is dull, a chainsaw loses a lot of its cutting power and it also becomes potentially dangerous to use it. A chainsaw chain should therefore be sharpened regularly.
With this guide, we want to share our experience in chainsaw sharpening to help you keep your chainsaw chain perfectly sharp so that it will last longer, perform better, and cut quicker and more safely.
There’s one main method for sharpening a chainsaw, which is by the way the most popular and the less expensive. That’s the one we’ll be mostly focusing on here.
Later in this guide, we’ll also be talking about a few other effective techniques that you can use to sharpen a chainsaw.
When to Sharpen a Chainsaw?
A chainsaw with a well-sharpened chain cuts wood easily.
With a dull chain, cutting wood with a chainsaw becomes a struggle. A dull chain is also dangerous as it is more likely to catch in the wood and thus increases the chances of kickback.
To keep your chainsaw cutting nicely at all times, you need to know when to sharpen the chain.
Here are a few easy-to-notice signs that indicate your chainsaw needs to be sharpened:
- Your chainsaw cuts slower.
- You’re pushing hard on your chainsaw when you’re cutting.
- There is smoke when you cut: your chainsaw burns wood instead of cutting it.
- Waste material: a dull chain produces dust; a sharp chain produces chips.
When the chain is rusty, damaged, or when the teeth are too short, it should be replaced.
Anatomy of a Chainsaw Chain
If you look closely at the saw chain, you’ll see a series of teeth set up in an alternating pattern. One tooth has its cutter oriented to the left and the next tooth to the right. Each cutter has a sharpened semicircular cutting edge, whose diameter varies from one chain to the next. This diameter is typically 5/32 in., 3/16 in., or 7/32 in.
Between each cutter, there is a piece of metal that’s shaped somewhat like a wave. These are called rakers. They are slightly shorter than the cutters. The purpose of a raker is to act as a depth gauge. It prevents the cutting edge of the cutter from biting too deep into the wood.
The difference in height between the raker and the top plate of the cutter determines the depth of cut for each pass of the tooth around the bar.
The gullet forms the space between the cutter and the raker.
Before sharpening, you need to be aware of two specific characteristics of your chainsaw chain:
- The diameter of the semicircular cutting edges.
- The pitch – or rake angle – of those cutting edges – most chains have a 30 to 35° rake angle.
You should be able to find those pieces of information in your owner’s manual. If not, use the chain identification number stamped on the drive link to check directly with the chain manufacturer.
What You Need
To sharpen your chainsaw properly, you’ll need a specially designed file kit for chainsaw sharpening. For about $20, you’ll have everything you need to start hand-filing your chainsaw. The kit should include:
- A round file.
- A flat file.
- A chainsaw chain sharpening file guide.
- A chainsaw chain sharpening depth gauge guide.
As you’ll see, it’s extremely useful to have a depth gauge guide and a file guide for sharpening your chainsaw. But, if you don’t wish to purchase the kit and thus decide to only use the files you already have, don’t use a standard rattail file. Its coarse teeth and tapered diameter will ruin your chain.
No Hazardous Energy
Before anything else, what you need to do is make sure your chainsaw is switched off.
If your chainsaw is electric, separate it from its power source:
- Unplug your corded electric chainsaw, or
- Remove the battery from your cordless electric chainsaw.
How to Sharpen a Chainsaw
Position the Saw and Clamp the Bar
The first thing you want to do is lock up the bar of the chainsaw in a vise or tabletop clamp.
- Engage the chain brake.
- Make sure to clamp the middle of the bar in the vise. Don’t clamp it near the edges of the bar nor too close to the body or tip of the chainsaw. Don’t overtighten it.
- If you don’t have a vise or a tabletop clamp, you can sharpen your chainsaw without it. But, make sure to keep the chainsaw steady while filing the chain.
Tighten the chain
Next, you need to prevent the chain from moving as you sharpen it.
- Use the tension-adjusting screw on your chainsaw to tighten the chain. It should be tight enough but you must still be able to move it around the saw with a little effort.
Mark the First Tooth You’re Going to Sharpen
If you take a close look at the chainsaw chain, you’ll notice that some of the teeth are pointing away, and some of the teeth are pointing in the opposite direction, towards you. The teeth pointing towards you are the ones you’re going to sharpen first. Then, you’ll flip the chainsaw around and sharpen the other teeth.
To know when you’ve sharpened every tooth on one side of the chainsaw and avoid sharpening a section twice, you need to make a mark.
- Grab a permanent marker or some white paint and mark the link or cutter of the tooth that you’re going to sharpen first.
Position the Round File
To sharpen your chainsaw chain properly, you need to position your round file accurately.
At this point, you should already have looked inside your owner’s manual to find the diameter and rake angle – horizontal angle – of your chain’s cutting edges.
- Select the round file with the appropriate diameter.
- Mount your round file in the file guide.
- Set the file guide on the saw chain with the file resting against the semicircular cutting edge of the tooth you’ve just marked.
- Use the lines on the file guide to set the appropriate rake angle. The line with the value of the angle you need must be parallel to the chainsaw bar.
- Keep the file guide at a right angle vertically.
File the First Tooth
- Maintain the angle and slide the file forward with sideways pressure across the cutting edge.
- Pull back the file towards you. Avoid touching the cutting edge while you do that.
- Repeat this process five or six more times with steady sideways pressure until the cutter is sharp and shiny.
- Keep count of how many strokes you’ve made.
File All the Other Tooth Facing Towards You
- Disengage the chain brake when you need to advance the chain. Re-engage it before filing the next tooth.
- Repeat this process for every tooth/cutter that faces you until you’ve reached your starting point.
- You must make the exact same number of filing strokes for each cutter. Otherwise, you may create an imbalance and your chainsaw would not be cutting straight.
Rotate the Chainsaw
Now, it’s time to sharpen the teeth facing the opposite direction.
- Unlock your chainsaw from the vise or tabletop clamp.
- Rotate it 180°.
- Lock it back up in the same way you did previously.
File the Remaining Teeth
File the Rakers
Once you’ve sharpened every cutter, you need to check the depth of the rakers.
- To do so, simply put the depth gauge guide on top of every raker and check whether they protrude above the guide or not.
- If they don’t, the depth is correct.
- If they do protrude, however, file them flush with your flat file.
How to Sharpen a Chainsaw – Alternatives to File Sharpening
File sharpening is great for occasional chainsaw users. It’s quite cheap and, with a little bit of practice, you’ll be able to sharpen any chainsaw in less than 15 minutes.
But, for professional chainsaw users or those seeking how to sharpen a chainsaw quickly, file sharpening might not be ideal. Luckily, there are quicker ways to sharpen a chainsaw. But, you guessed it, you’ll need to spend a bit more money.
Sharpen Your Chainsaw with These Handheld Power Tools
The first power tool you can use for chainsaw sharpening is the Rotary tool. Also called Dremel Tool, this very versatile device accepts – among many other attachments – a chainsaw sharpening accessory. That accessory includes a cylindrical grinding stone and an alignment guide.
- To use it, you simply need to adjust the alignment guide just like you would with a filing guide.
- Then, simply start the rotary tool and sharpen the cutting edge of the cutter for a few seconds.
- Repeat. Apply the same pressure and run the tool for the same amount of time for each tooth.
The second power tool option is specifically designed for chainsaw sharpening. It is a specific rotary grinder that comes with more than enough accessories to sharpen all kinds of chainsaw chains very quickly and well.
- Its design is a bit different from the rotary tool, but you pretty much use it in the same way.
Sharpen Your Chainsaw with This Stationary Power Tool
Benchtop Chainsaw Sharpener
A benchtop chainsaw sharpener is a stationary machine specifically and solely designed for chainsaw chain sharpening.
This tool is really for those who use and own several chainsaws or have spare chains waiting to be mounted. With it, you save a significant amount of time and energy and get very accurate and consistent results.
A benchtop chainsaw sharpener has a design somewhat similar to that of a miter saw – see our guide on how to use a miter saw.
But, instead of a blade, it uses a grinding wheel that tilts up to 35° left and right to sharpen any chainsaw chain angle.
- To use it, you need to first remove the chain from the chainsaw and clamp it into the tool’s vise.
- Set the sharpener’s grinder to the appropriate angle.
- Pull the trigger and bring down the grinder onto the cutting edge of a cutter for a few seconds. Count how many seconds you sharpen the tooth.
- Then, unlock the chain, reposition it and repeat for each tooth facing the same direction. Once again, apply the same pressure and run the grinder for the same amount of time.
- Readjust the grinding angle to the opposite side and sharpen all the remaining teeth.
More on Chainsaws
Check out our related article on how to use a chainsaw.