Chainsaw Bar Measurement: How To Measure A Bar On A Chainsaw

If you’re wondering, “What is my chainsaw bar size?”, the easiest way to determine it is by looking at the existing bar itself or checking your chainsaw’s manual. Often, the size is stamped directly onto the bar, and a chainsaw bar size chart can help you decipher it. This guide will walk you through the process of measuring a chainsaw bar, a crucial skill for any chainsaw owner needing a chainsaw bar replacement size or simply wanting to know their equipment better.

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Deciphering Your Chainsaw Bar’s Identity

Knowing your chainsaw bar measurements is vital for a few key reasons. Firstly, it ensures you purchase the correct replacement parts, preventing compatibility issues. Secondly, it allows you to potentially upgrade your bar for better performance, like a longer chainsaw bar length for more demanding tasks. Finally, it’s a fundamental aspect of chainsaw bar identification. This detailed guide will help you navigate the world of chainsaw guide bar size, so you can confidently identify and measure your bar.

The Core Measurements of a Chainsaw Bar

When we talk about measuring a chainsaw bar, there are a few critical dimensions that define its size and compatibility. These are not just random numbers; they dictate how the bar fits onto your saw and how it will perform.

Drive Link Count: This is arguably the most important measurement for ensuring your new bar fits your saw. Drive links are the small tabs on the bottom of your saw chain that fit into the groove of the chainsaw guide bar. The number of drive links must match the bar you are replacing or the new bar you are purchasing.
Gauge: The gauge refers to the thickness of the drive links. This is a critical compatibility factor. Chainsaws are designed for specific chain gauges. Using the wrong gauge can cause damage to both the bar and the chain, and can be dangerous. Common gauges include .050″, .058″, and .063″.
Pitch: The pitch is the distance between the drive links, measured from the center of one rivet to the center of the next, then doubled. It’s a measure of how close together the teeth on the chain are. Like gauge, pitch is a critical compatibility factor. Common pitches include 3/8″, .325″, and .404″.
Bar Length: This is the measurement most people think of first. It’s the length of the cutting edge of the bar, from the tip to the front of the mounting bracket. However, it’s important to note that the actual cutting length is usually a few inches shorter than the stated bar length.

Methods for Measuring Your Chainsaw Bar

There are several straightforward ways to determine your chainsaw bar measurements. Each method provides the necessary information for selecting the right replacement or understanding your current setup.

Method 1: Reading Markings on the Bar

Many chainsaw manufacturers clearly mark the essential information directly onto the chainsaw guide bar itself. This is the most convenient and often the most accurate method.

Locating the Markings

Common Locations: Look near the base of the bar, close to where it attaches to the chainsaw body. The information might be stamped or engraved.
What to Look For: You’ll typically find the pitch and gauge clearly marked. For example, you might see “3/8 .050” or “.325 .058”. The bar length is also usually indicated, often in inches.

Interpreting the Markings

Pitch: This will be a fraction like 3/8″ or a decimal like .325″ or .404″.
Gauge: This will be a decimal measurement, typically .050″, .058″, or .063″.
Bar Length: This is usually a whole number of inches, such as 16″, 18″, 20″, etc. Remember, this is the nominal length.

Example Markings:

3/8 .050 - 18 means a 3/8″ pitch, .050″ gauge, and an 18-inch bar.
.325 .058 - 20 means a .325″ pitch, .058″ gauge, and a 20-inch bar.

Method 2: Measuring the Drive Links

If the markings are worn off or difficult to read, you can manually count the drive links on your chain. This is a reliable way to ensure you get the correct chain for your bar, which is crucial for proper fit.

Counting Drive Links

Remove the Chain: Safely detach the chainsaw chain from the bar.
Lay the Chain Flat: Spread the chain out on a flat surface.
Identify Drive Links: Drive links are the segments of the chain that sit inside the groove of the chainsaw bar. They have a smaller protrusion on the bottom.
Count Carefully: Count each drive link one by one. Ensure you count all of them.

Example:

If your chain has 68 drive links, you need a bar designed for a chain with 68 drive links.

Method 3: Measuring the Bar Length (Nominal vs. Actual)

While the nominal bar length is usually stamped on the bar, it’s good to know how to measure it yourself. However, it’s important to understand the difference between the nominal length and the actual cutting length.

Measuring Nominal Bar Length

Lay the Bar Flat: Place the chainsaw bar on a flat surface.
Measure from the Tip to the Mount: Measure the length from the very tip of the bar (where the chain goes around the sprocket) to the point where the mounting bracket begins to attach to the chainsaw.
Use a Measuring Tape: Use a reliable measuring tape for accuracy.

Understanding Actual Cutting Length

The actual cutting length is the part of the bar that extends beyond the chain cover and actively cuts wood. This is typically about 2 inches shorter than the nominal bar length. For example, an 18-inch bar will have an actual cutting length of approximately 16 inches. This distinction is important when considering the capabilities of your chainsaw.

Method 4: Using a Chainsaw Bar Size Chart

Once you have your pitch, gauge, and drive link count, a chainsaw bar size chart can be an invaluable tool to help you identify compatible bars.

How to Use a Chainsaw Bar Size Chart

Find a Reputable Chart: Many chainsaw manufacturers and parts suppliers provide these charts online or in their catalogs.
Match Your Specifications: Locate your chain’s pitch, gauge, and drive link count on the chart.
Identify Compatible Bars: The chart will then list the chainsaw bar model numbers and lengths that are compatible with your chain specifications. This is particularly useful when looking for a chainsaw bar replacement size.

What Information is on a Typical Chart?

Pitch	Gauge (in)	Drive Link Count Examples	Compatible Bar Lengths (in)
3/8″	.050	52, 56, 60, 64, 68, 72	14, 16, 18, 20, 22, 24
.325″	.050	56, 60, 64, 68, 72, 76	15, 18, 20, 22, 24, 26
.325″	.058	64, 68, 72, 76	20, 22, 24, 26
3/8″	.063	72, 76, 80, 84, 88	24, 26, 28, 30, 32
.404″	.063	76, 80, 84, 88, 92	24, 26, 28, 30, 32

Note: Drive link counts can vary by manufacturer, and this table provides common examples.

Method 5: Checking Your Chainsaw Manual or Manufacturer’s Website

Your chainsaw’s owner’s manual is a treasure trove of information about your specific model. It will detail the recommended bar size, pitch, and gauge.

Locating the Information in Your Manual

Specifications Section: Look for a section dedicated to specifications, parts, or maintenance.
Bar and Chain Details: The manual will usually list the exact chainsaw bar size and chain specifications recommended by the manufacturer.

Manufacturer’s Website

Model Lookup: Most manufacturers have websites where you can look up your chainsaw model and find a list of compatible parts, including the correct chainsaw guide bar size.
Parts Diagrams: They often provide detailed parts diagrams that clearly label the bar and its specifications.

Common Chainsaw Bar Measurements and What They Mean

Let’s dive deeper into the specifics of chainsaw bar measurements and why they are important for selecting a chainsaw bar replacement size.

Pitch: The Spacing of the Teeth

What it is: Pitch refers to the distance between the drive links on the chain. It’s measured from the center of one rivet to the center of the next, then doubled.
Common Pitches:
- 3/8″ (0.375 inches): A very common pitch for a wide range of chainsaws, from smaller homeowner models to professional-grade saws. It offers a good balance of cutting speed and durability.
- .325″ (0.325 inches): Frequently found on lighter to mid-weight chainsaws, often used for general-purpose cutting and trimming. It provides a good balance of power and maneuverability.
- .404″ (0.404 inches): Typically used on larger, more powerful professional chainsaws designed for felling large trees and heavy-duty cutting. It offers aggressive cutting and is often paired with a thicker gauge.
Why it Matters: The pitch of your chain must match the pitch of your sprocket and the groove in your chainsaw guide bar. Mismatched pitches will cause the chain to not seat properly, leading to poor cutting performance, premature wear, and potential damage to your saw.

Gauge: The Thickness of the Drive Link

What it is: The gauge is the thickness of the drive links on your chain. This thickness determines how snugly the chain sits in the groove of the chainsaw guide bar.
Common Gauges:
- .050 inches (1.3 mm): A very common gauge for many general-purpose chainsaws.
- .058 inches (1.47 mm): Often found on mid-range to professional chainsaws.
- .063 inches (1.6 mm): Typically used on heavier-duty professional chainsaws, often paired with larger pitches like 3/8″ or .404″ for more demanding tasks.
Why it Matters: The gauge of the chain must precisely match the groove width of your chainsaw bar. If the gauge is too thin for the groove, the chain will be loose and prone to derailing, which can be dangerous and damage your equipment. If the gauge is too thick, the chain will bind in the groove, leading to poor performance, overheating, and excessive wear. Always check your chainsaw bar model number and specifications for the correct gauge.

Bar Length: The Cutting Reach

What it is: The stated bar length is the nominal measurement from the tip of the bar to the front of the mounting bracket. The actual cutting surface is slightly less.
Common Lengths: Chainsaw bars come in a wide range of lengths, from 10 inches for small top-handle saws to over 36 inches for large professional saws.
Why it Matters:
- Cutting Capacity: Longer bars allow you to cut through larger diameter logs and trees.
- Maneuverability: Shorter bars are generally more maneuverable and lighter, making them suitable for limbing and smaller tasks.
- Chainsaw Power: Your chainsaw has a power limit. Using a bar that is too long for your saw’s engine can strain the motor, lead to overheating, and reduce cutting efficiency. Always consult your chainsaw’s manual to determine the maximum recommended bar length.
- Chainsaw Bar Replacement Size: When replacing a bar, it’s usually best to stick to the manufacturer’s recommended length unless you have a specific reason and understand the implications of changing it.

Drive Link Count: The Chain’s Foundation

What it is: As mentioned earlier, this is the number of drive links on your chain. This count is critical for the chain to fit properly onto the bar’s sprocket and within the bar’s groove.
Why it Matters: This is a non-negotiable specification. A chain with the wrong number of drive links simply will not fit or function correctly. It’s a primary factor when determining the correct chainsaw bar replacement size or purchasing a new chain.

Choosing the Right Chainsaw Bar Replacement Size

When it’s time to replace your chainsaw bar, having accurate measurements is key to a smooth and safe purchase.

Factors to Consider When Replacing a Bar:

Compatibility with Your Chainsaw Model: This is paramount. Ensure the new bar’s mounting shank matches your chainsaw’s drive sprocket cover. Different manufacturers and even different models within the same brand use different mounting styles.
Pitch and Gauge: These must match your existing chain or the chain you intend to use.
Bar Length: Consider the type of work you do. For general use, stick to the original length. If you need to cut larger logs, you might be able to go slightly longer, provided your chainsaw has the power to handle it.
Bar Type:
- Laminated Bars: Most common, made of three steel layers laminated together. Good balance of durability and cost.
- Solid Bars: Made from a single piece of high-strength steel. More durable and resistant to bending, but heavier and more expensive.
- Roller Nose Bars: Feature a sprocket at the tip that reduces friction, leading to less chain wear and kickback. Ideal for general use and professionals.
- Hardnose Bars: Have a solid tip with no moving parts. Simpler and less expensive but can cause more chain wear and are more prone to kickback.

How to Find Your Chainsaw Bar Model Number

If your bar is too worn to read markings, or you’ve inherited a saw without a manual, the chainsaw bar model number might be your next best bet.

Look for Manufacturer Logos: Most bars have the manufacturer’s logo stamped on them.
Search by Brand: Once you know the brand (e.g., Oregon, Stihl, Husqvarna), you can often find their product catalogs or websites.
Use Online Resources: Many online retailers have search tools where you can input your chainsaw model and find compatible bars. These tools often list the specific bar model numbers you need.
Consult a Dealer: Local chainsaw dealers are excellent resources. They can often identify the correct bar by sight or by looking up your chainsaw model.

Frequently Asked Questions (FAQ)

Q1: Can I use a longer chainsaw bar than what came with my saw?
While you might be able to physically fit a longer bar, it’s generally not recommended unless your chainsaw is specifically designed for it. Using a bar that is too long can overwork your chainsaw’s engine, leading to overheating, reduced cutting efficiency, and premature wear on the engine and clutch. Always check your chainsaw’s manual for the maximum recommended bar length.

Q2: What happens if I use the wrong pitch or gauge?
Using the wrong pitch or gauge is a serious issue.
* Wrong Pitch: The chain won’t engage properly with the sprocket or the bar groove, leading to poor cutting, excessive wear on the chain, sprocket, and bar, and potentially the chain derailing, which is dangerous.
* Wrong Gauge: If the gauge is too thin for the bar groove, the chain will be loose and can jump off. If the gauge is too thick, the chain will bind, causing friction, heat, and strain on the saw.

Q3: How often should I replace my chainsaw bar?
Chainsaw bars wear out over time. Look for signs of wear such as:
* Groove Widening: The groove where the chain sits can become wider and shallower.
* Burring: Metal shavings can build up on the edges of the groove.
* Wear on the Rails: The rails along the sides of the bar can become uneven or worn down.
* Bent or Damaged Tip: The sprocket at the tip can wear out, or the bar itself can become bent.

If you notice these issues, or if your bar is significantly worn, it’s time for a replacement. Many professionals replace their bars when they replace two or three chains, or when the bar groove is too worn to be cleaned up with a file.

Q4: What is the difference between a roller nose bar and a hardnose bar?
A roller nose bar has a replaceable sprocket at the tip that reduces friction as the chain moves around it. This leads to less chain and bar wear, more efficient cutting, and a reduced risk of kickback. A hardnose bar has a solid, non-moving tip, making it simpler and less expensive but less efficient and potentially more prone to kickback.

Q5: My chainsaw bar is worn. Can it be repaired?
Minor wear, such as burring on the edges, can often be addressed by filing the rails of the bar. You can use a specialized bar rail file to clean up the groove and restore its proper width. However, if the bar is significantly worn, bent, or the tip sprocket is damaged, it’s usually best to replace it entirely.

By following these guidelines and paying close attention to your chainsaw bar measurements, you can ensure you always have the right equipment for the job, whether you’re performing routine maintenance or looking for a chainsaw bar replacement size. Knowing your chainsaw bar identification is the first step to a safer and more efficient experience.