How to Sharpen a Chainsaw

Whether a thunderstorm has snapped a large limb or an entire tree needs to be felled, your chainsaw is the tool for the job. However, if you find yourself really pushing on your chainsaw to get it to cut through that wood, then it’s time to sharpen your chainsaw chain.

While you can take your saw chain to a shop, you will save time and money sharpening your saw chain yourself. Once you have the right chainsaw sharpening tools and a little experience, you’ll be able to sharpen your chain in a matter of minutes.

Tools needed for sharpening a chainsaw:

While many chainsaw manufacturers offer proprietary sharpening tools that are specific to their brands, most chains can be just as easily sharpened using the following generic sharpening tools:

• A round file sized to match the pitch of the chain - use this file to sharpen each cutting tooth
  • For both 1/4 and 3/8 in. low-profile chains, use a 5/32 in. file 
  • For a 0.325 in. chain, use a 3/16 in. file.
  • For both 3/8 and 0.404 in. chains, use a 7/32 in. file
• Flat file - use this when you need to reduce the depth gauge before each cutting tooth
• File guide to help you hold the file at the correct height and orientation
• A depth-gauge filing guide 
• A stump vise (if you plan to do any sharpening in the field)
• Safety goggles and work gloves 

Not surprisingly, there are many chainsaw sharpening kits on the market. While you can piece together your own set of chainsaw sharpening tools, each kit will contain some version of this list.

When to sharpen your chain

A chainsaw's ability to cut wood comes from the sharp, opposing cutters spaced along its chain. Each cutter is made up of two components: a flat-faced depth gauge that controls the depth of the cut and a dual-profile cutting element. These two profiles (referred to as the top plate and side plate) contain three different angles that, when combined, quickly cut through wood and remove waste. If the chainsaw is no longer chewing through wood like it used to, or if the waste appears more like sawdust than small wood chips, the chain has probably become dull and needs to be sharpened.

A chain makes your work harder. On the other hand, a sharp saw chain is not only easier on you but will also help your chainsaw last longer. Furthermore, it’s safer to cut wood with a sharp chainsaw blade. With a sharp chain, there’s less chance of dangerous kickback. 

Whether you decide to sharpen your saw blade by hand or with an electric sharpener, sharpen your chain every two to three times you refill the gas tank. Some people even insist on sharpening their chainsaw chain every time they refuel. Either way, the chain should not get to a point where it is creating more dust than shavings. 

One its chain is sharpened, your chainsaw will be ready for more cutting action. But remember that if you're doing a lot of work in any one day, you may need to repeat this process a couple of times to keep the chain at its sharpest.

How many times you can sharpen a chainsaw chain

Conventional wisdom says a saw chain can be sharpened up to ten times or more. Once each cutting tooth on your chain has worn to about 4 mm in length, it’s time for a new chain.

One issue that can arise from a new chain is that the new chainsaw chain doesn’t always mesh smoothly with the chainsaw’s existing sprocket and bar. This is because these parts have worn during use whereas the new chain has not.

One way to avoid this is to purchase an extra chain or two when you buy your chainsaw. Then switch chains at regular intervals, like after every third tank of gas. This will ensure each chainsaw chain cooperates smoothly with the chainsaw’s guide bar. 

How to sharpen a chainsaw blade

Sharpening each cutter on a chainsaw chain is no different than sharpening a knife or a mower blade. Steady, smooth pressure moving in one direction is the key.

Sharpening a chainsaw blade by hand

1. Secure the chainsaw’s guide bar in a vise. If you’re out in the field, a stump vise comes in handy. If you’re in your garage or workshop, the vise on your workbench will do.
2. Engage the chain brake and check the chain tension.
3. Clean away any debris from each cutting tooth.
4. Use a piece of masking tape to mark the blade you will sharpen first.
5. Place the file guide over the chain.
6. Select the appropriate-sized round file. This file should be about 25 percent taller than the cutting tooth.
7. Following the appropriate angle on your file guide, file the cutting tooth in one smooth stroke. Use both hands to keep control of the file, and always file in one direction. Do not run the file back and forth over the tooth. Two or three strokes is enough, especially if you sharpen your chain regularly.
8. Skip the next tooth and move to the next cutting tooth that faces the same direction as the one you just sharpened. File this cutting tooth with the same number of strokes.
9. Proceed around the chain. Once you reach the piece of masking tape again, release the chainsaw, flip it around, and sharpen the other teeth. Again, use the file guide to ensure you’re filing at the right angle. Use both hands and the same number of strokes all the way around.
10. Once each cutting tooth is sharp, place the depth gauge guide over each depth gauge to determine if the gauge should be reduced. Each depth gauge should be just a bit shorter than the cutting tooth. The guide shows you how much each gauge needs to be lowered. Use the flat file and run a few strokes along the top of the depth gauge. Then check again. 

Using an electric chainsaw sharpener

Besides handheld files, there are many electric attachments that allow you to sharpen your chainsaw chain with a rotary tool. If you decide to sharpen with one of these, the sharpening process is largely the same. The difference is instead of sliding a file across each cutting tooth, you will use a spinning grinding stone.

Just as in sharpening with a file, the key is to hold your tool—a Dremel for instance—at the proper angle and for only a brief moment. It’s always easier to over file with an electric sharpener. Also, as in chainsaw sharpening by hand, be sure to give each tooth the same attention.

Taking your chain in to be sharpened

After a season of cutting, it is advisable to take your chain to a shop for sharpening. Many small-engine repair shops offer this service. The price often depends on the size of the chain and whether or not the chain is still on the bar. Anywhere from $6 to $25 is fairly typical for a saw chain sharpening.

Safety tips for chainsaw sharpening

A dull blade increases your chances of injury in multiple ways. However, sharpening a metal blade also creates opportunities for injury. Besides heavy-duty leather gloves and safety goggles, there are some other considerations you can make to stay safe.

Choose the right chainsaw

Using the right tool for the job is an effective way to reduce the risk of injury. This is especially true when it comes to power tools. Selecting the right chainsaw for both you and the job is an essential step to avoiding a painful if not deadly situation. 

Understanding your chainsaw

The most undervalued piece of safety advice comes from reading your chainsaw’s operating manual. Most manuals will inform you of the file size needed to sharpen your chainsaw chain. Many will also tell you the angle at which the file should be used. 

After the chain has been sharpened

Once you’ve finished sharpening, check the chain tension again. While it is unlikely, parts can and do shift while working.  

Once your chain is sharp and set to the appropriate tension, you’re ready to get back to work. Just continue to be safe by keeping a wide stance and two hands on your chainsaw. Never cut above your head, and don’t be in a rush. With your sharpened chain, you’ll finish soon enough.

When you’re ready to tackle sharpening a chain or finding the chainsaw best for you, Tractor Supply Company is here to help.