How do you match a chainsaw chain to a bar?

Matching a chainsaw chain to the correct bar is crucial for optimal performance and safety. The chain must fit the bar properly in terms of pitch, gauge, drive links, and length. Taking the time to ensure you have the right components will result in easier cutting, longer bar and chain life, and prevention of dangerous kickback events.

What factors determine chainsaw chain and bar compatibility?

There are 4 key factors that determine the compatibility between a chainsaw chain and bar:

• Pitch – The distance between any 3 consecutive rivets divided by 2. Measured in inches or millimeters. Chain and bar pitch must match.
• Gauge – The thickness of the drive links. The gauge of the bar must match the gauge of the chain.
• Drive links – The number of drive links the chain has must match the length of the bar.
• Chain length – The overall length of the chain must fit the bar with some slack for proper tensioning.

Getting any one of these wrong means the chain will not properly fit and function on the bar. Be sure to check the specifications of both your bar and replacement chain to ensure compatibility in all 4 areas.

How to measure your chainsaw bar

To find out what size replacement chain you need, you’ll first need to determine the specifications of your existing bar. Here’s how to measure it:

1. Remove the bar from the saw if currently installed.
2. Locate the chain pitch – Check the metal rivets on your existing chain and measure the distance between any 3 consecutive rivets, then divide by 2. This is your pitch measurement.
3. Find the gauge – Use a gauge tool or micrometer to measure the thickness of the drive links.
4. Count drive links – Count the number of drive links your current chain has. This determines the length you’ll need.
5. Measure bar length – Use a tape measure to determine the length of the bar from one end to the other.

Once you have these measurements, you can use them to find a compatible replacement chain.

How to match chain pitch

Chain pitch must exactly match the pitch of the bar. Mismatching the pitch is a common mistake that will make the chain not fit the bar at all. Chainsaw bars are manufactured in pitch sizes of:

• 0.325 inches
• 0.375 inches
• 0.404 inches
• 3/8 inches

Metric pitch sizes include:

• 8 millimeters
• 9.32 millimeters
• 10 millimeters

Consult your bar’s documentation or measure between rivets as described above to determine the pitch. Then get a replacement chain with a matching pitch measurement.

Matching chain gauge to the bar

The gauge of a chainsaw chain refers to the thickness of the drive links. Gauge is measured in millimeters or hundredths of an inch. Common gauges include:

• 0.043 inches
• 0.050 inches
• 0.058 inches
• 0.063 inches
• 1.1 millimeters
• 1.3 millimeters
• 1.5 millimeters

The groove along the bar that guides the chain is matched to specific gauge sizes. Using a mismatching gauge will result in a loose chain that can derail from the bar.

Use calipers or a gauge tool to precisely measure the drive link thickness and match to the same gauge chain.

Getting the right chain length

The length of the chainsaw chain must fit the circumference of the bar with a bit of additional slack to allow proper tensioning. Chains that are too tight or too loose on the bar will both negatively impact cutting performance.

To get the right length:

• Count the number of drive links on your existing chain – this gives you the length you need for full bar coverage.
• Or, measure the actual length of your existing chain from pin to pin using a tape measure.

With the drive link count or precise length measurement, you can match a new chain that will fit the bar properly.

Checking the number of drive links

Drive links are the part of the chain that engage the teeth on the bar sprocket to move the chain around the guide bar. Counting the drive links gives you the information needed to get a chain that will cover the full length of the bar with correct slack.

Chains have a range of drive link counts depending on the length of bar they are designed to fit:

Bar length	Drive link count
10″	40-45 links
12″	52-56 links
14″	58-62 links
16″	66-72 links
18″	74-80 links
20″	82-90 links
24″	100-108 links

Match your measured drive link count to a chain designed for your bar length. Having too few drive links results in a chain that won’t reach, while too many packed onto the bar results in tight chain with no room to tension properly.

How to find the right replacement chain

Once you have measured the key specifications of your existing bar, finding the right replacement chain involves 3 simple steps:

1. Match the pitch – Get a chain with the same pitch measurement as your bar, e.g. 0.325 inches.
2. Match the gauge – Replace with a chain that has the same gauge or thickness of drive links.
3. Get the correct length – Use your count of drive links or precise chain length measurement to get the right size.

Consult manufacturer catalogs and reference the pitch, gauge, and length information to select the appropriate chain. Keep in mind that chains are often sold based on the bar length they are designed to fit, so you can use your measured bar length to easily find the right chain.

Be sure to reference the manufacturer and model specifications of your saw to ensure you get a chain designed for optimal use on that model.

Why proper chain tensioning is critical

Installing a matched chain and bar set is only half the battle – proper chain tensioning is also crucial for performance and safety. Chains require some slack to allow for needed lubrication and movement around the bar.

Here are key reasons why tensioning the chain correctly matters:

• Loose chains derail easily, interrupting cuts.
• Overly tight chains bind and lead to increased wear.
• Correct tension allows bar grooves to properly lubricate the chain.
• Proper tension maintains drive link contact with the bar for maximum power transmission.
• A loose chain can slacken upon kickback, leading to more severe saw damage or operator injury.

Always refer to your saw operator’s manual for the proper procedure to tension the chain. This typically involves loosening a bar nuts, adjusting the tension adjuster to get about 0.5 inches of vertical deflection in the chain, then tightening down the nuts.

Check tension periodically while cutting and re-tension as needed to maintain optimal function and safety.

Signs you need a new chainsaw bar

Over time, the constant friction of the chain running along the bar can cause wear. This wear eventually makes it necessary to replace the guide bar to restore optimal performance. Here are key signs indicating your bar needs replaced:

• The chain derails from the bar frequently
• You notice damage such as large nicks or gouges in the bar rails
• Rail thickness feels significantly reduced from prior new condition
• The bar groove appears significantly worn or deformed
• You have difficulty tensioning the chain properly
• Sawdust buildup in the bar groove occurs persistently
• You observe faster chain wear than expected or excessive elongation
• The bar noticeably lacks straightness from side to side

Replacing a worn bar provides a fresh surface for the chain to run on and prevents accelerated chain wear. Use a bar gauge tool to periodically measure rail thickness and watch for thinning exceeding 0.020 inches compared to a new bar’s thickness.

Tips for extending bar life

You can maximize the lifespan of your chainsaw bar and minimize premature wear by following these maintenance practices:

• Hand-file chain to keep cutters sharp – dull cutters increase friction with the bar.
• Ensure chain is tensioned properly per manufacturer specs.
• Lubricate bar groove and chain regularly with bar oil.
• Keep rails free of nicks and burrs with a flat file.
• Clean bar groove periodically with solvent and compressed air.
• Avoid hammering logs or objects with the bar tip.
• Replace chain at end of usable life to prevent accelerated bar wear.
• Select bars with durable, wear-resistant rail materials such as hardened steel.
• Check and correct rail straightness if the bar begins to skew in the cut.

With proper care and maintenance, a quality chainsaw bar should last at least 2-3 chains before requiring replacement. Periodically inspect for wear and replace as needed to keep your saw running optimally.

Conclusion

Matching your chainsaw chain to the correct bar requires getting the right pitch, gauge, length and drive link count combination. Take measurements from your existing setup before buying replacement components. Tension the paired chain and bar per the saw manufacturer’s specifications. Maintain the bar by keeping rails clean and free of damage, replacing the chain regularly, and practicing proper saw operation. Follow these steps and you will be able to install a properly matched chain and bar set that performs safely and reliably.