How do you measure the length of a chainsaw bar? You measure a chainsaw bar by counting the number of drive links on the chain that fit into the groove of the bar and then adding an inch for the tip. This process will be detailed further in this guide.
Knowing how to measure your chainsaw bar is crucial for several reasons. Whether you’re looking to replace a worn-out bar, upgrade to a longer one for bigger jobs, or simply want to ensure you have the correct parts, accurate measurement is key. This guide will provide a comprehensive chainsaw bar length guide to help you measure chainsaw bar size with confidence, ensuring you determine chainsaw bar length correctly every time.
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Why Accurate Chainsaw Bar Measurement Matters
Getting the right chainsaw bar is not just about aesthetics; it directly impacts performance, safety, and the lifespan of your equipment. An incorrectly sized bar can lead to a host of problems, including:
- Poor Cutting Performance: A bar that’s too short might not handle the size of wood you’re cutting, while one that’s too long might strain your chainsaw’s engine.
- Increased Wear and Tear: Using a bar that’s not compatible with your saw can cause premature wear on the engine, clutch, and drive sprocket.
- Safety Hazards: A bar that’s too long for the saw’s power can cause kickback, a sudden and violent upward and backward motion of the chainsaw, which is extremely dangerous.
- Chain Malfunctions: An incorrect bar length can affect chain tension and lead to the chain derailing, which can damage both the bar and the chain, and pose a safety risk.
Therefore, mastering the chainsaw bar measurement is an essential skill for any chainsaw owner.
Methods for Measuring Your Chainsaw Bar
There are a few reliable ways to measure chainsaw bar length. We’ll walk you through the most common and accurate methods.
Method 1: Counting Drive Links (The Most Accurate Way)
This is the industry standard for determining the chainsaw bar length of your current setup.
What are drive links? Drive links are the small tabs on the bottom of your chainsaw chain that sit inside the groove of the chainsaw bar. They are essential for keeping the chain engaged with the bar and the drive sprocket.
Steps to count drive links:
- Disassemble the Chain: Carefully remove the chainsaw chain from the bar and the saw. You might need a chain breaker tool if you’re disconnecting the chain for the first time.
- Lay the Chain Flat: Spread the chain out on a flat surface.
- Count the Drive Links: Starting from one end of the chain, count each of the small metal tabs that would normally sit inside the bar’s groove. Do not count the cutters.
- Record the Number: Write down the total number of drive links.
- Add an Inch: The actual advertised length of a chainsaw bar is typically one inch longer than the number of drive links. This accounts for the tip of the bar. For example, if you count 60 drive links, you have a 20-inch bar (60 drive links / 3 = 20 inches).
Important Note: Always count the drive links when the chain is off the bar. It’s easy to miscount if the chain is still on the saw.
Table: Drive Link Count to Bar Length Conversion
| Drive Links | Advertised Bar Length (inches) |
|---|---|
| 32 | 12 |
| 36 | 14 |
| 40 | 16 |
| 44 | 18 |
| 48 | 20 |
| 52 | 22 |
| 56 | 24 |
| 60 | 26 |
| 64 | 28 |
| 68 | 30 |
| 72 | 32 |
This is a general guide, and slight variations may occur between manufacturers.
Method 2: Measuring the Bar Directly
While counting drive links is the most precise method, you can also measure the bar itself.
Steps to measure the bar directly:
- Remove the Bar: Take the bar off the chainsaw.
- Use a Measuring Tape: Lay the bar flat on a surface. Measure from the tip of the bar down to the point where the chain mounts onto the bar (the nose sprocket or the mounting hole).
- Record the Measurement: Note the measurement in inches.
Caveats to Direct Measurement:
- Tip Inclusion: Be precise about where you start and end your measurement. The advertised length usually includes a portion of the bar’s tip.
- Wear: If your bar is heavily worn, the measurement might be slightly less than its original advertised length.
Method 3: Checking the Bar’s Markings
Many chainsaw bars have their specifications stamped directly onto them.
Where to look for markings:
- Near the Mount: The mounting end of the bar, where it attaches to the chainsaw body, often has a chainsaw bar numbering system that includes length, gauge, and pitch.
- On the Side: Sometimes, the length will be printed on the side of the bar itself.
What to look for:
You’ll typically see a number followed by an “inch” symbol (e.g., 20″). This refers to the advertised cutting length. You might also see other numbers which relate to the chainsaw bar gauge and chainsaw bar pitch.
Deciphering Chainsaw Bar Specifications: Beyond Length
While how long is my chainsaw bar is a primary concern, other specifications are equally important for ensuring compatibility and optimal performance. These are often found alongside the length marking.
Chainsaw Bar Gauge
What is chainsaw bar gauge? The chainsaw bar gauge refers to the thickness of the chain that fits into the bar’s groove. It’s measured in millimeters or inches.
- Common Gauges:
- 0.050 inches (or 1.3 mm)
- 0.058 inches (or 1.5 mm)
- 0.063 inches (or 1.6 mm)
Why gauge matters: The gauge must match the chain you are using. A chain with the wrong gauge will not sit properly in the bar groove, leading to poor performance, increased wear, and potential chain derailment.
Chainsaw Bar Pitch
What is chainsaw bar pitch? The pitch refers to the distance between the drive links of the chain. It’s a crucial factor for ensuring the chain meshes correctly with the drive sprocket and the bar’s nose sprocket. Pitch is usually stated as a fraction of an inch.
- Common Pitches:
- 3/8″ (often referred to as 0.375″)
- .325″
- 0.404″
How pitch affects compatibility: The pitch of your chain must match the pitch of your drive sprocket and the nose sprocket on the bar. Using the wrong pitch will cause the chain to skip or bind, damaging components and creating a safety hazard.
Chainsaw Bar Mounting
What is chainsaw bar mounting? This refers to the pattern of bolts and spacing used to attach the bar to the chainsaw body. Different chainsaw brands and models use different mounting systems.
- Importance of Mount Type: When looking for a chainsaw bar replacement size, you must ensure the mounting system matches your saw. If the mount doesn’t align, the bar simply won’t fit.
How to identify the mounting:
- Look for a Stamped Code: Manufacturers often use a letter or number code (e.g., “D025”, “E025”) stamped on the bar, usually near the mounting end.
- Consult Your Chainsaw Manual: Your owner’s manual is the best resource for identifying your saw’s specific mounting pattern.
- Compare with Old Bar: If you’re replacing a bar, compare the mounting holes and spacing with the old one.
Chainsaw Bar Numbering Explained
Many manufacturers use a system of numbers and letters on their bars to indicate specifications.
- Length: As discussed, this is usually the primary number (e.g., 20 for 20 inches).
- Pitch: Often indicated as a fraction or decimal (e.g., 3/8 or .375).
- Gauge: Shown as a decimal (e.g., .050 or .063).
- Mount Code: The specific code for the mounting pattern.
For example, a bar might be marked “20-3/8-.050 D025”. This would mean:
* 20: 20-inch length
* 3/8: 3/8″ pitch
* .050: 0.050″ gauge
* D025: Specific mounting pattern for certain saw models.
This detailed chainsaw bar numbering system is vital when searching for a chainsaw bar replacement size.
Factors to Consider When Changing Chainsaw Bar Length
While knowing how to measure is essential, deciding to change your bar length involves more than just measurement.
Chainsaw Engine Power
The engine size and power of your chainsaw are critical.
- Too Long a Bar: Installing a bar that is too long for your saw’s engine can overload it. This leads to overheating, reduced power, and potential engine damage. The saw will struggle to drive the chain efficiently, and you’ll experience slower cutting and excessive strain.
- Too Short a Bar: A bar that is too short might limit your ability to cut larger pieces of wood effectively. However, it’s generally less detrimental to the saw’s mechanics than a bar that’s too long.
General Rule of Thumb:
* For smaller homeowner saws (e.g., 30-45cc), typically 14-18 inch bars are recommended.
* For mid-range professional saws (e.g., 45-60cc), 18-24 inch bars are common.
* For larger professional saws (e.g., 60cc+), bars of 24 inches and longer can be used.
Always check your chainsaw’s owner manual for recommended bar lengths.
Safety Implications
The length of the bar directly affects the potential for kickback.
- Kickback Zone: Kickback occurs when the upper quadrant of the bar tip contacts an object or is pinched. The longer the bar, the larger this “kickback zone” becomes.
- Mitigation: Chainsaws designed for longer bars are built with more powerful engines and better anti-kickback features. If you increase your bar length, ensure your chainsaw’s safety features are in good working order, and always maintain proper cutting technique.
Cutting Chain Type
The type of chain you use is also dictated by the bar.
- Chain Speed: A longer bar requires more power to keep the chain moving at optimal speed.
- Chain Durability: Longer chains are heavier and can put more stress on the drive system. Ensure your chain is rated for the length of the bar and the power of your saw.
When You Might Need to Measure Your Chainsaw Bar
There are several scenarios where accurately knowing your chainsaw bar length is necessary.
Chainsaw Bar Replacement
This is the most common reason. Chainsaw bars wear down over time. The groove can widen, the rails can become uneven, or the nose sprocket can fail.
- Wear Indicators: Look for signs like uneven cutting, a chain that’s hard to keep tensioned, or visible damage to the bar rails.
- Matching Specifications: When buying a replacement, you need to match the original length, pitch, gauge, and mounting system.
Upgrading Your Chainsaw Bar
You might want a longer bar to tackle larger trees or a different type of bar for specialized cutting.
- Feasibility Check: Before purchasing a longer bar, ensure your chainsaw can handle it. Check your owner’s manual or consult with a dealer.
- Performance Considerations: A longer bar might require a different chain or adjustment to your cutting technique.
Buying a New Chainsaw
If you’re purchasing a new chainsaw, knowing the typical bar sizes available for different models can help you make an informed decision. This chainsaw bar length guide can help you understand the specifications.
Troubleshooting Chain Issues
If your chain is constantly coming loose or derailing, an incorrect bar length or a worn bar could be the culprit. Measuring your current bar will help diagnose the problem.
Frequently Asked Questions (FAQ)
Q1: How can I tell what kind of mount my chainsaw bar has?
A1: The best way is to check your owner’s manual. You can also often find a code stamped on the bar itself near the mounting end. Comparing the mounting holes and their spacing to pictures online or to an old bar from a known saw model can also help.
Q2: Can I put a longer bar on my chainsaw than what it came with?
A2: Generally, yes, but you must be cautious. Ensure your chainsaw’s engine has enough power to properly drive the longer chain. Overpowering the saw can lead to overheating and damage. Always consult your owner’s manual or a professional before making the switch.
Q3: What happens if I use a chainsaw bar with the wrong pitch or gauge?
A3: Using the wrong pitch will prevent the chain from engaging correctly with the drive sprocket and bar nose, causing it to skip or bind. The wrong gauge will mean the chain doesn’t sit properly in the bar groove, leading to increased wear on both the chain and bar, and potentially causing the chain to derail.
Q4: My chainsaw bar has a number like “18” on it. Does that mean it’s an 18-inch bar?
A4: Usually, yes. The primary number stamped on the bar typically refers to its advertised cutting length in inches. However, always confirm by counting the drive links for the most accurate measurement.
Q5: How do I know if my chainsaw bar is worn out?
A5: Signs of a worn bar include a chain that consistently runs loose even after adjustment, visible wear on the bar rails (they might look “hooked” or uneven), or a damaged nose sprocket. If your saw cuts poorly or vibrates excessively, a worn bar could be the cause.
By following these methods and keeping these important specifications in mind, you can confidently measure and select the correct chainsaw bar for your needs, ensuring safe and efficient operation of your equipment.