What is the correct way to measure a chainsaw bar? You measure a chainsaw bar by counting the number of drive links on the chain that fit into the bar groove and then referring to the bar’s stamped specifications for its length, gauge, and pitch. This guide will walk you through the entire process, ensuring you get the right chainsaw bar replacement.
Chainsaw maintenance is key to keeping your tool running smoothly and safely. One of the most common parts that might need replacing is the chainsaw bar, also known as the blade. Knowing how to accurately measure your current chainsaw bar is crucial for ordering the correct replacement part. Getting the wrong size can lead to poor performance, damage to your chainsaw, or even dangerous situations. This in-depth guide will cover everything you need to know about chainsaw bar measurements, from the basics to more specific details like gauge and pitch.
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Why Accurate Chainsaw Bar Measurements Matter
Before we dive into the “how,” let’s touch on the “why.” Accurate chainsaw bar measurements are essential for several reasons:
- Performance: A bar that’s too long or too short can affect the chain’s tension and the saw’s cutting efficiency.
- Durability: An incorrectly sized bar can put undue stress on the drive sprocket, clutch, and engine, leading to premature wear and tear.
- Safety: A loose or improperly fitted chain can fly off the bar, a serious safety hazard.
- Cost-Effectiveness: Buying the wrong part means wasted money and time.
Deciphering Chainsaw Bar Measurements: The Essentials
When you’re looking to replace your chainsaw bar, there are a few key measurements you’ll need to know. These are the core specifications that define the chainsaw bar size.
1. Counting the Drive Links: The Most Important Step
This is the simplest and often the most crucial measurement. The number of drive links is the number of small metal tabs on the chain that engage with the sprocket and sit inside the groove of the bar.
How to Count Drive Links:
- Remove the Chain: Ensure your chainsaw is off and cool. Carefully remove the chain from the bar and sprocket.
- Lay the Chain Flat: Spread the chain out on a flat surface.
- Count the Drive Links: These are the pieces of the chain that have a tab on the bottom, designed to fit into the bar’s groove. Count each of these tabs.
- Tip: It’s easy to miscount. Count them twice, or count every tenth link as you go.
Why this matters: While you might see a length stamped on the bar, the number of drive links is a universal indicator that works across different brands and models, making it a reliable way to identify the correct chain and, by extension, the correct bar.
2. Chainsaw Bar Length
The length of the chainsaw bar is typically measured from the tip of the bar to the point where the chain enters the bar mounting. However, this measurement isn’t as straightforward as it seems and can be interpreted in different ways.
The Standard Measurement Method:
The most common and reliable way to measure chainsaw bar length is to measure the cutting length. This is the length of the bar from the nose of the bar to the front of the drive sprocket housing.
How to Measure Bar Length:
- Remove the Chain: As before, remove the chain from the bar.
- Use a Measuring Tape: Place a measuring tape along the top of the bar.
- Measure from the Nose to the Sprocket: Measure from the very tip (the nose) of the bar straight along the top edge to the point where the chain engages with the drive sprocket.
- Round to the Nearest Inch: Chainsaw bars are typically sold in even-inch increments (e.g., 16 inches, 18 inches, 20 inches). Your measurement will likely be a bit longer than the stamped length due to the nose radius. Round your measurement to the closest common bar length.
Important Note: While you measure the cutting length, the overall length of the bar is sometimes used by manufacturers. It’s best to confirm this with the bar’s specifications or by counting drive links.
3. Chainsaw Bar Gauge
The gauge refers to the thickness of the drive links on the chain, and consequently, the width of the groove in the chainsaw bar. This is a critical specification that ensures the chain fits correctly onto the bar and into the sprocket.
Common Gauges:
- 0.050 inches (or 1.3 mm): This is a very common gauge for many homeowner and occasional-use chainsaws.
- 0.058 inches (or 1.5 mm): Often found on more professional-grade saws and larger bars.
- 0.063 inches (or 1.6 mm): Used for heavy-duty saws and demanding cutting applications.
How to Determine Your Chainsaw Bar Gauge:
- Check Existing Bar/Chain: The gauge is usually stamped on the base of the chainsaw bar (the part that attaches to the saw) or on the chain itself, often near the drive links. Look for numbers like “.050”, “.058”, or “.063”.
- Measure the Drive Link: If it’s not stamped, you can measure the thickness of a drive link with a caliper. Ensure you’re measuring the part that sits in the bar groove.
- Consult Your Chainsaw Manual: Your owner’s manual will list the recommended bar and chain specifications, including the gauge.
- Count Drive Links and Refer to Specs: If you know the drive link count and your saw’s model, you can often find the gauge in online specifications or by comparing with known chains.
Why Gauge Matters: Using the wrong gauge can prevent the chain from seating properly in the bar, leading to poor lubrication, excessive wear, or the chain not feeding correctly.
4. Chainsaw Bar Pitch
Pitch refers to the size of the chain’s drive links and sprockets. It’s defined as half the distance between any three consecutive rivets on the chain. Like gauge, it’s crucial for compatibility between the chain, bar, and sprocket.
Common Pitches:
- 3/8″ (9.5 mm): A very common pitch for a wide range of chainsaws, from smaller to mid-sized.
- .325″ (8.25 mm): Often found on smaller homeowner saws.
- .404″ (10.2 mm): Typically used on larger, professional-grade chainsaws for heavy timber cutting.
How to Determine Your Chainsaw Bar Pitch:
- Check Existing Bar/Chain: The pitch is almost always stamped on the base of the chainsaw bar or on the chain itself, usually near the drive links. Look for fractions like “3/8” or “.325”.
- Measure the Chain: If not stamped, you can measure the distance between three rivets. Measure from the center of one rivet to the center of the third rivet, then divide by two. Use a measuring tape or calipers.
- Consult Your Chainsaw Manual: Your saw’s manual will list the correct pitch.
- Count Drive Links and Refer to Specs: Knowing the drive link count and your saw’s model is often enough to deduce the pitch from manufacturer charts.
Why Pitch Matters: If the pitch of your chain and sprocket don’t match the pitch of your bar, the chain won’t engage properly with the sprocket, rendering the saw unusable and potentially damaging components.
How to Measure a Chainsaw Blade: Beyond the Basics
When we talk about how to measure a chainsaw blade, we are essentially talking about the bar. The blade is the chain itself, but the bar is the metal guide the chain rides on. Understanding all the chainsaw bar specifications ensures a perfect fit for your chainsaw.
5. Chainsaw Bar Type (Mount)
Chainsaw bars come with different mounting systems to attach them to the chainsaw body. This is called the “mount” or “mount type.” Different saw manufacturers, and even different models from the same manufacturer, can have unique mounting patterns.
Common Mount Types:
- Sprocket Nose Mounts: These are the most common and feature a replaceable sprocket at the tip.
- Hardnose Mounts: These bars have a solid, non-replaceable tip. They are generally less common and less durable.
- Roller Nose Mounts: Similar to sprocket nose mounts but with a roller bearing in the nose for reduced friction.
How to Identify Your Chainsaw Bar Mount:
- Inspect the Base of the Bar: Look at how the bar attaches to the chainsaw. You’ll see bolt holes and possibly a slot for a tensioning screw.
- Compare with Manufacturer Charts: Most chainsaw bar manufacturers provide charts or diagrams that show their various mount types. You can often identify your mount by comparing the shape and hole pattern of the base of your current bar to these diagrams.
- Look for Stamped Codes: Some manufacturers stamp a specific code on the bar indicating its mount type (e.g., “Husqvarna mount,” “Oregon mount type A,” “Stihl mount”).
- Consult Your Chainsaw Model: Knowing your specific chainsaw model is the easiest way to find out which bar mount it uses. Search online for “[Your Chainsaw Model] bar mount type.”
Why Mount Type Matters: The mount is what physically attaches the bar to the chainsaw. If the mount doesn’t match, the bar simply won’t fit onto your saw, regardless of length, gauge, or pitch.
Putting It All Together: Finding Your Chainsaw Bar Replacement
Now that you know the key measurements, let’s consolidate them for ordering a chainsaw bar replacement.
Step-by-Step Guide to Identifying Your Bar
- Count Your Drive Links: This is your most reliable starting point.
- Measure the Cutting Length: Get an approximate length, but remember drive links are primary.
- Identify Gauge and Pitch: Look for stamped numbers on the bar or chain.
- Determine Your Bar Mount: Inspect the base of the bar and consult your saw’s model information.
Where to Find This Information on Your Chainsaw Bar
- The Stamped Information: Most chainsaw bars have the length, pitch, and gauge stamped into the metal near the base where it attaches to the saw. Look for numbers like “18”, “3/8”, “.050”.
- Example: A bar might be stamped “18 3/8 .050”. This means it’s an 18-inch bar, designed for a 3/8-inch pitch chain, with a .050-inch gauge.
- The Chain: The chain itself will also have the pitch and gauge stamped on it.
- Chainsaw Manual: Your chainsaw’s owner’s manual is your best friend for all specifications.
- Manufacturer Websites: Most major chainsaw and bar manufacturers have online catalogs or compatibility charts.
Table: Common Chainsaw Bar Specifications Summary
| Specification | How to Measure/Identify | Why it Matters |
|---|---|---|
| Drive Links | Count the number of drive links on the chain. | Universal compatibility check for chain and bar. |
| Bar Length | Measure cutting length from nose to sprocket housing (round up). | Affects reach and cutting performance; ensure it matches saw’s power. |
| Bar Gauge | Look for stamped numbers (.050, .058, .063) or measure drive link. | Ensures chain sits correctly in the bar groove. |
| Bar Pitch | Look for stamped fractions (3/8″, .325″, .404″) or measure chain. | Matches chain and sprocket for proper engagement. |
| Bar Mount Type | Inspect base of bar; compare to manufacturer charts or know saw model. | Ensures the bar physically attaches to the chainsaw body. |
Common Pitfalls to Avoid When Measuring
- Confusing Bar Length with Chain Length: Remember, you’re measuring the bar, but the drive link count is for the chain. They must be compatible.
- Ignoring the Mount Type: This is a common mistake. Even if length, gauge, and pitch are right, a mismatching mount will prevent installation.
- Relying Solely on Stamped Length: Stamped length can sometimes be overall length, not cutting length. Always verify with drive links.
- Not Checking Drive Link Count: This is the most critical specification for chain and bar pairing.
- Assuming All Bars for a Brand are the Same: Different saw series within a brand can use different mounts, pitches, and gauges.
Can I Use a Different Chainsaw Bar Length?
Generally, you should stick to the chainsaw bar length recommended by your chainsaw manufacturer. While you might be able to fit a slightly longer or shorter bar, it’s not advisable without careful consideration.
- Longer Bars: A longer bar requires more power from the engine to drive the chain effectively. Using a bar that’s too long can strain the engine, leading to overheating and premature failure. It also affects the saw’s balance and can increase kickback risk.
- Shorter Bars: A shorter bar might seem harmless, but it can sometimes lead to a chain that’s too loose, even when tensioned correctly, or it may not be compatible with the drive sprocket.
Always refer to your chainsaw’s owner’s manual for the maximum recommended bar length.
Frequently Asked Questions (FAQ)
Q: I found a number stamped on my bar that looks like the length, is that all I need?
A: No, that’s only part of the picture. While the stamped length (e.g., 16″, 18″) is important, you also must confirm the drive link count, pitch, gauge, and mount type to ensure compatibility. The drive link count is often the most critical piece of information.
Q: How do I know if my chainsaw bar is worn out?
A: A worn bar will have a groove that is wider than the chain’s drive links, and the sides of the groove might be tapered. You might also notice the chain is difficult to tension correctly, or it tends to drift to one side when cutting. A worn bar can also cause accelerated wear on the chain and sprocket.
Q: My chainsaw manual is lost. How can I find the right chainsaw bar specifications?
A: The best approach is to:
1. Identify your exact chainsaw model number.
2. Count the drive links on your current chain.
3. Note any numbers or codes stamped on your current bar.
4. Search online using your chainsaw model number and terms like “bar specifications” or “compatible bars.” Many manufacturers and parts suppliers have lookup tools.
Q: Can I use an Oregon bar on a Stihl saw, or vice versa?
A: Yes, you can, but only if the specifications (pitch, gauge, mount type, and drive link count) are identical. Oregon is a major manufacturer of aftermarket chainsaw bars and chains that are designed to fit many different brands of chainsaws, provided the specifications match. Always verify these details before purchasing.
Q: What is a “skip tooth” or “full chisel” chain, and does that affect my bar measurements?
A: “Skip tooth” and “full chisel” refer to the design of the cutting teeth on the chain. Skip tooth chains have fewer teeth, spaced further apart, which is good for cutting in dusty or dirty conditions as it helps clear debris. Full chisel teeth are more aggressive cutters. These chain designs do not change the physical measurements of the bar (length, gauge, pitch, mount). They are chain characteristics that must match the bar’s specifications, but they don’t alter how you measure the bar itself.
By carefully following these steps and paying attention to all the chainsaw bar measurements, you’ll be well-equipped to find the correct chainsaw bar replacement and keep your chainsaw cutting efficiently and safely.