How do I sharpen a chainsaw?
A chainsaw blade can be sharpened by hand using an appropriate sized round file. Each tooth needs to be filed sharp by incorporating a few different techniques for sharpening.
There are numerous ways to sharpen chainsaw teeth, but hand sharpening is the quickest and easiest method.
Learning how to sharpen a chainsaw may seem like a daunting task the first time.
But once you learn how to sharpen a chainsaw, the process can be quite rewarding.
With knowledge and practice, you may find the process of sharpening your chainsaw very satisfying. Especially when you see beautiful, efficient, effortless cuts from your blade.
Being able to harvest and prepare bowl blanks from wood that may otherwise go to waste is one of the most satisfying feelings.
A sharp chainsaw is essential for efficient bowl blank preparation.
This site is dedicated to the process and art of turning wood bowls. However, everything shared in this article applies to sharpening chainsaws for any wood cutting purpose.
There are some specific steps and practices that need to be addressed and executed to achieve a properly sharpened chainsaw blade.
This article will detail everything you need to sharpen your chainsaw blade like a pro, or perhaps even better than a pro.
Let’s dive in and get our chainsaws as sharp as new!
When to Sharpen the Chain
When is the best time to sharpen a chainsaw blade?
This may seem like an obvious question, but let’s look a little closer.
The first easy answer to this question is to sharpen when the blade is dull and not cutting very well or taking a long time to complete a cut.
There are other times when we need to stop and sharpen the blade as well.
Chainsaw Not Cutting Straight
If you are seeing the saw pull or drift as it is cutting, this is a sign the chainsaw needs sharpening.
Often, when a chainsaw is not cutting straight, the cutting teeth have been compromised in one way or another.
The most common way to cause cutting issues with a chainsaw is to allow the chain to touch the ground. Sand, dirt, or rocks will immediately damage chainsaw blade cutting teeth.
When the saw touches the ground, the damage is never balanced, and the chain, like the tires on your car, is not running true, it’s wobbling.
This lack of balance causes the blade to perform inaccurately, and the issue needs to be addressed immediately to improve performance and save the chain from further damage.
Field or Shop Chainsaw Sharpening
The chainsaw blade can be sharpened in the field or at a bench.
Sharpening a chainsaw in the field can be a bit inconvenient, but there are ways of improving the experience.
If you have a log handy, turn it upright and use a stump vise to hold the chainsaw bar steady as you sharpen.
A stump vise can be hammered into the log and provide a secure mount as you sharpen.
The thumbscrew of the stump vise holds the chainsaw bar firm and allows a steady platform to perform the sharpening.
In The Shop Sharpening
In the convenience of your shop or garage, the chainsaw blade can be sharpened right on the bench or while held in a vise.
The chainsaw blade can be left on the saw, and the chainsaw bar can be clamped in a vise to hold it in place.
Be sure only to tighten the vise enough to hold the bar steady and not crush the chainsaw bar.
Another option is to take the blade off the chainsaw and hold it in the grip of a vise.
The chain will need to be unclamped and reclaimed as you move through the teeth.
Know Your Chainsaw Blade
Almost every chainsaw blade is different.
Between the length of the chain, the size and angle of the cutting teeth, the depth of the guide links, and other factors, rarely will you find two blades the same.
Because there are so many different chainsaw blade variables, you need to know your chainsaw blade exactly.
Take the time to read your chainsaw manual and make a note of your chain size.
You can usually find your chainsaw manual online by searching your saw make and model, then adding the word “manual” with the search.
Take your saw to a professional shop if you have no idea what size blade you need. They will usually be able to help you determine the exact chainsaw blade for your model.
If you have purchased an extra blade, look at the box, and you will see the details for your blade.
Teeth Diameter
The first item you need to know for sharpening is the cutting teeth diameter and angle.
Teeth diameter is also the size of the file you will need to sharpen the teeth.
Many blades use a diameter around 5/32” (4mm) 3/16” (4.75mm) or 7/32” (5.5mm). But there again, this can be different with your blade.
The angle of the teeth can also vary from around 10° to approximately 35°.
The chainsaw tooth diameter and cutting angle are the two main factors we will need to know to sharpen the blade.
Chainsaw Sharpening Gear
You will need some equipment to sharpen your blade properly, surprisingly minimal and straightforward equipment.
If you are sharpening in the field, I recommend having a stump vise handy to hold your chainsaw bar in place as you sharpen.
You will need a file in the proper diameter to match your cutting teeth. See above to determine the diameter of your teeth.
Here are links to files for three typical chainsaw diameters; 5/32″, 3/16″, 7/32″.
If you like, use a guide handle for the file. Also, mathe the file handle to the size of your file. It will help keep the file properly positioned when sharpening.
Once, the teeth are sharp, the raker guides need to be examined and filed down. A rake depth gauge and a flat-file are necessary for this task.
That is about all you’ll need to sharpen your chainsaw.
Safety and Visual Aid
Like everything we do in woodworking, we want to be safe and protect ourselves at all times.
Because we will be moving and handling the sharp chain, it’s best to wear heavy work gloves.
Eye protection is always essential to keep metal shavings or any foreign objects from our eyes.
In addition to protecting your eyes, you may also want to wear eye magnification of some sort.
I use a flip-down magnifier to increase my vision while sharpening.
Increased vision allows for easy assessment of each cutting tooth as you sharpen your chainsaw blade.
Mark and Start
If you know the chainsaw blade has been damaged by touching the ground or another foreign object, check the teeth to find the most damaged area first.
Mark the chain in the starting area with a marker or other method, to prevent double sharpening teeth.
Set The Chain
If there is any slack in the chainsaw blade, tighten the chain before you begin to sharpen.
You want the chain to be snug and firm in the chainsaw bar track with as little wiggle room as possible.
However, you will need to have the chain just loose enough to move it along the bar groove as you progress through the sharpening process.
Proper Chainsaw Cutter Angle
Every chainsaw blade is different, but many blades use a 20°, 25°, 30°, or 35° sharpening angle. Again, check your saw manual or blade packaging.
It is crucial to maintain this same angle as you sharpen the blade.
If you use a file guide, you will see the angles marked by a line that crosses the guide. Match the proper angle and make it parallel with your saw bar.
(straight down file guide pic)
When you sharpen freehand, without a file guide, you can make an angle guide with a piece of cardboard and place it under your blade.
You can also add the proper angle lines to the top of a vise if you are vise-clamping the chain down as you sharpen.
As you sharpen, you can look down on the file and check that it aligns with the angle below.
Built-In Angle Guide
Most blade manufacturers make a line right on the top of each cutting tooth. This line is the proper angle for the teeth.
You can freehand sharpen just by making sure your file runs parallel to the scored line on the top of each tooth.
Keep File Level
The file needs to be horizontal and perpendicular to the chainsaw bar at all times.
Do not allow the front of the file to dip down or rise as you file.
Keep the file nice and flat as you sharpen each tooth.
File Stroke Direction
OK, confession time. I used to do this step completely backward, and I thought it didn’t matter. It does matter.
The cutting teeth of a chainsaw are coated or hardened on the outer surface.
What this means is we need to sharpen from the inside out, not the outside inward.
The stroke of the file needs to go from inside out, away from the cutting tip of the teeth.
Also, the file only cuts on the push forward, not on the pull backwards. So, do not let the file touch the tooth on the way back or it will ruin the sharp edge.
File Depth on Cutter
The depth at which the file rides in the cutting tooth groove is critical.
Ideally, the file remains above the top of the cutting tooth by about 20% of the file diameter.
In other words, 4/5 of the file is down inside the cutting tooth, while 1/5 of the file sticks above the tooth.
This proportion is essential to keep the current shape of the cutting tooth.
If the file is entirely down inside the curved part of the cutting tooth, the tooth will have a hooked over appearance.
A hooked over chainsaw cutting tooth will be fragile on the top surface and prone to easy damage.
If you are having difficulty maintaining the 1/5 file above the tooth position, consider using the file guide sized to your teeth diameter.
The file guide is specifically designed to keep 1/5 of the file above the tooth as you sharpen the chain.
Chainsaw File Stroke
When you have the right size file and angle established, it’s time to start filing.
The file works on the push cut only, and you will only need to make a couple passes, in most cases, to sharpen a tooth.
Hold the file with both hands, one at each end. Place the file inline with the proper angle for the teeth and make a single stroke forward across a tooth.
As you file, add pressure back into the curve of the sawtooth, not downward.
The tendency is to apply pressure down onto the base of the tooth.
Instead, we need to apply pressure in the curve of the tooth to sharpen and remove any burrs.
There is no need to rotate or turn the file as you make each stroke. Instead, make smooth, level passes inline with the proper angle for your cutting teeth.
When each cutting stroke is complete, return the file to the starting position without touching the saw tooth on the way back.
Consistent Filing
Address the worst teeth on the chain first, then file all the remaining teeth the same amount.
If the first tooth takes five strokes to sharpen, apply five strokes to all the remaining teeth.
The reason for this practice is balance. Keeping all the teeth to similar shapes and sizes will make the chain balanced and run smoothly.
Flip and Repeat
Sharpen all the alternating teeth running in one direction on the chain until you return to the mark you made at the beginning.
Once all the teeth running in one direction are sharp, rotate the chain or the entire saw to access and sharpen the set of opposite direction teeth.
Use the same techniques to sharpen the teeth running the other way.
Chainsaw Raker Height
Between the cutting teeth are little bumps or projecting pieces of metal. These raised in-between sections are called rakers or depth guides.
The depth guides are positioned right in front of each cutting tooth and control how much wood material is allowed into the cutting tooth.
As the chainsaw blade teeth are sharpened, they are also reduced slightly in height.
To keep the same or proper amount of space between the depth guides and the cutting teeth, we also need to adjust the height of the depth guides.
Use a raker gauge to determine the proper height of each depth guide by placing the raker gauge across two cutting teeth.
The depth guide section height should be flush with the height of the raker gauge.
If a depth guide section sticks up above the gauge, use a flat-file to reduce the height of the depth guide.
I remove the raker gauge when I file because the indicator is made with hardened metal and will dull the file. Once I remove some material from the raker, I return and recheck the height.
When the top of the raker depth guide is flush with the gauge, remove the gauge and file over the front edge of the raker to assure smooth fluid movement.
Drive Link Performance
Under the chain are drive-links that ride in the bar of the chainsaw.
If you notice the chain is not moving smoothly in the chainsaw bar, there may be an issue with the drive links.
Debris or foreign objects in the chainsaw bar groove can scrape and damage the drive or guide links.
Remove the chain from the saw and inspect the drive links and look for any scratches or burrs. File any damaged areas on the links smooth.
Also, use the thin flat surface of your chainsaw tool, that looks like a screwdriver, to clear out the bar groove completely.
Use spray parts cleaner to remove fine debris from tight places.
Alternative Sharpening Methods
There are other ways to sharpen your chainsaw blade.
Probably the easiest, hands-free way to sharpen your blade is to drop it off and have a professional do it for you.
However, even if a pro sharpens your blade, you don’t have the assurance they are taking the same amount of time and attention you might.
Other options include sharpening devices that clamp to the chainsaw bar and act as a pencil sharpener, like the Timberline Chainsaw Sharpener.
Timberline Chainsaw Sharpener 5/32″
Timberline Chainsaw Sharpener 3/16″
Timberline Chainsaw Sharpener 7/32″
Oregon makes an electric bench chainsaw blade sharpener that can be adjusted to sharpen nearly any type of chainsaw blade. This model can be useful for production or if you have several chains.
You’ll need to remove the chain from the saw to sharpen with the Oregon sharpener.
Sharpen A Chainsaw Conclusion
We all know we have to have sharp tools to get good results. The chainsaw is no exception.
Taking the time to sharpen your chainsaw might not be the most convenient thing on your to-do list. But afterward, when you watch your sharp blade drop smoothly through a log, the results are well worth the effort.
Let me know if you sharpen your own chainsaw blades and if you do anything differently. Leave me a comment below.
You are going to want to see these related articles next:
• GREEN WOOD BOWL BLANK MAKING PROCESS
• BOWL TURNING GRAIN ORIENTATION – WOOD BLANK DIRECTION
• DRYING GREEN WOOD BOWLS – 6 METHODS FOR SUCCESS
• QUARTER SAWN WOOD BOWL – HOW TO MAKE
• 10 PLACES FIND FREE WOOD FOR BOWL TURNERS
Happy Turning (and Cutting),
Kent
