How To Sharpen a Chainsaw

Over time, chainsaw blades become dull, making the tool less effective and potentially dangerous. Learning to sharpen your chainsaw can save you time and money while ensuring your equipment performs at its best. This Old House landscaping contractor Roger Cook demonstrates the proper technique for sharpening a chainsaw blade, and we’ll review them below.

Understanding Chainsaw Sharpening

While there are services that will sharpen your chainsaw for you, it’s a good idea to at least understand why cutting with sharp blades is important and when to sharpen.

Why Sharpen Your Chainsaw

A dull chainsaw blade can lead to the following issues.

• Inefficient cutting
• Increased fuel consumption
• Greater physical strain on the operator
• Higher risk of kickback and accidents
• Unnecessary wear on the chainsaw’s engine and components

By keeping your chainsaw sharp, you ensure clean, fast cuts and reduce the risk of injury.

When To Sharpen Your Chainsaw

Whenever possible, you should sharpen the blades before you start to notice any of the following signs—once per year at the beginning of spring is usually sufficient. However, you’ll definitely know it’s time to stop and sharpen if any of these things happen.

• The chainsaw produces sawdust instead of wood chips.
• You need to apply increased pressure to cut through wood.
• The chain pulls to one side while cutting.
• You notice smoke while cutting, even with proper chain lubrication.
• The cut edges appear rough or uneven.

Tools and Materials Needed To Sharpen a Chainsaw

Before you begin sharpening your chainsaw, gather the following tools and materials.

• Round file (matching the diameter of your chain’s cutters)
• Flat file
• File guide or sharpening jig
• Depth gauge tool
• Work gloves
• Safety glasses
• Owner’s manual for your specific chainsaw model

All these items can typically be found at your local home center or hardware store, or you can purchase them online as part of a chainsaw sharpening kit.

Safety Precautions When Using Chainsaws

Safety should always be your top priority when working with chainsaws. Follow these precautions:

• Ensure the chainsaw is turned off and cool before sharpening.
• Wear work gloves to protect your hands from sharp edges.
• Use safety glasses to shield your eyes from metal filings.
• Work in a well-lit area and a stable surface.
• Consult your chainsaw’s manual for specific safety guidelines.

Above all, always wear gloves when handling a chainsaw, even when it’s not running.

Step-by-Step Chainsaw Sharpening Process

Follow these steps to sharpen your chainsaw effectively.

1. Clean the chain thoroughly to remove debris and oil.
2. Engage the chain brake to prevent movement during sharpening.
3. Identify the leading cutter, which is typically the shortest one.
4. Set your file guide to the correct angle (usually 25 or 30 degrees, see below for details).
5. Place the file in the cutter at the marked angle.
6. Push the file across the cutter with steady, even strokes.
7. File each cutter the same number of times to maintain balance—three is usually enough unless the cutters are substantially worn down.
8. Repeat the process for all cutters on one side of the chain.
9. Turn the saw around and sharpen the cutters on the other side.

Pro tip: Maintain consistent pressure and angle with the file for best results.

Using a File Guide

Unless you have substantial experience with chainsaw sharpening, you’ll want to use a guide to maintain the correct angle while filing. These typically cost between $10 and $20 and are available online or in hardware stores. Here’s how to use one.

1. Select the appropriate file guide for your chain size.
2. Align the guide with the chain’s sharpening angle markings.
3. Insert the round file into the guide.
4. Follow the contour of the cutter while keeping the guide flat against the chain.

Lowering the Rakers

The rakers, also known as depth gauges, are crucial for controlling the depth of each chainsaw cut. To maintain proper cutting performance, the rakers should be slightly shorter than the cutters. Here’s how to adjust the rakers to the correct height.

1. Use a depth gauge tool to check each raker’s height.
2. If the raker protrudes above the cutter, file it down using a flat file. File carefully to avoid removing too much material.
3. Check the height again with the depth gauge tool.
4. Repeat for all rakers on the chain.

Common Mistakes to Avoid When Sharpening a Chainsaw

When sharpening your chainsaw, be aware of these common pitfalls.

• Using the wrong file size for your chain
• Over-filing, which can weaken the cutters
• Inconsistent filing angles, leading to uneven cutting
• Neglecting to sharpen all cutters equally
• Forgetting to adjust the rakers

Maintaining Your Sharpened Chainsaw

After sharpening, proper maintenance is key to keeping your chainsaw in top condition.

• Clean the chain thoroughly after each use.
• Keep the chain properly tensioned.
• Ensure adequate lubrication during operation.
• Store the chainsaw in a dry place when not in use.
• Regularly inspect the chain for damage or wear.

Additional Chainsaw Maintenance Tips

A well-maintained chainsaw is far safer and easier to use. In addition to sharpening, keep an eye on these features.

• Inspect and clean the air filter: A clean air filter ensures efficient engine performance.
• Check the spark plug: Periodically inspect and clean or replace the spark plug.
• Tighten loose parts: Regularly check and tighten any loose screws or bolts to ensure the chainsaw operates smoothly.
• Inspect the fuel system: Ensure there are no leaks and that the fuel mix is correct.

Costs of Chainsaw Sharpening

Conducting your own chainsaw maintenance can save you money, but understanding potential costs is helpful.

• DIY sharpening kits: Available for around $13–$40 and include files, a file guide, and a depth gauge. Some include a small rotary power tool.
• Professional sharpening: Typically costs $12–$35 per chain.
• Replacement chains: New chains can vary in price, generally costing between $9 and $43 depending on the size and brand.

Environmental Impact and Recycling

Maintaining and sharpening your chainsaw also has environmental benefits. Obviously, sharpening a chain instead of buying a new one saves money and resources. It’s also true that properly sharpened tools work more efficiently, reducing fuel consumption and emissions. 

When possible, consider recycling old chains and other metal parts to minimize environmental impact. Most hardware stores have recycling programs for tools and machinery parts. By participating in these programs, you contribute to sustainability efforts and ensure that metal components are reused or disposed of responsibly.