What is the best way to measure a chainsaw blade for replacement? The most accurate way to measure a chainsaw blade for replacement involves identifying specific measurements printed on the bar or chain, and if those aren’t clear, physically measuring the chain’s pitch and gauge, and counting the drive links. Can you use a measuring tape to measure a chainsaw blade? While a measuring tape can give you the overall bar length, it won’t tell you the crucial chain specifications like pitch and gauge, which are essential for a correct replacement. Who is this guide for? This guide is for any chainsaw owner who needs to replace their saw chain and wants to ensure they purchase the correct one.
Replacing a chainsaw chain might seem straightforward, but getting the right fit is crucial for performance and safety. A chain that’s too loose can fly off, a chain that’s too tight can cause excessive wear, and a chain with the wrong pitch or gauge can damage your saw. This in-depth guide will walk you through precisely how to measure your chainsaw blade (or more accurately, your saw chain) to ensure you buy the perfect replacement. We’ll cover all the vital measurements and how to find them, even when they aren’t immediately obvious.
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Deciphering Your Saw Chain’s Identity
Before we dive into the measuring process, let’s clarify what we mean by “chainsaw blade.” In chainsaw terminology, the “blade” is actually called a “guide bar.” The moving part with the teeth is the “saw chain.” When people say “chainsaw blade,” they almost always mean the saw chain. So, from here on, we’ll refer to it as the saw chain.
Why Accurate Measurement is Essential
- Performance: A correctly sized chain cuts efficiently. An incorrect chain will bind, drag, or not cut at all.
- Safety: A loose chain is a major safety hazard. It can derail from the guide bar, causing serious injury.
- Durability: The wrong chain can damage your guide bar, sprocket, and the saw’s engine due to increased friction and stress.
- Cost Savings: Buying the wrong chain means wasted money and time trying to return it or find the correct one.
Locating Key Measurements: The Easy Way
Most chainsaw manufacturers make it relatively simple to find the necessary information for a replacement chain. It’s usually stamped directly onto the guide bar or sometimes on the chain itself.
Examining the Guide Bar
The guide bar is the metal bar that the chain travels around. Look closely at the base of the guide bar, where it attaches to the chainsaw. You should find a series of numbers and letters stamped into the metal. These are the specifications you need.
- Chain Pitch: This is the distance between drive links. It’s usually expressed as a fraction (e.g., 3/8″, .325″).
- Chain Gauge: This refers to the thickness of the drive links – the part that sits in the groove of the guide bar. Common gauges are .050″ or 1.3mm, and .058″ or 1.5mm.
- Number of Drive Links: This is the count of the individual links on the chain that sit inside the guide bar’s groove.
Table 1: Common Stamped Measurements on Guide Bars
| Measurement | Typical Format | Meaning |
|---|---|---|
| Chain Pitch | 3/8″, .325″, .404″ | Distance between rivets (drive links) |
| Chain Gauge | .050″, .058″, .063″ (or 1.3mm, 1.5mm, 1.6mm) | Thickness of the drive links |
| Bar Length | 16″, 18″, 20″ (in inches) | The usable cutting length of the guide bar |
What if the Markings are Unclear or Worn?
It’s not uncommon for these markings to become worn down over time due to dirt, oil, and general use. If you can’t clearly read the numbers on the bar, don’t worry. We’ll cover how to measure these yourself.
Measuring Your Saw Chain: The Detailed Approach
If the markings on your guide bar are unreadable, you’ll need to take precise measurements of your existing saw chain. This requires a bit more care but will give you the accurate data needed to select the correct replacement.
Step 1: Counting the Drive Links
This is the easiest and most crucial measurement to get right if the markings are gone.
- Remove the Chain: Safely detach the saw chain from your guide bar.
- Lay the Chain Flat: Spread the chain out in a straight line, as flat as possible.
- Count the Drive Links: A drive link is the part of the chain that has the small tabs extending downwards. These tabs fit into the groove of the guide bar and engage with the drive sprocket. Start counting from the first drive link and count every single one until you reach the end.
- Important Note: Do not count the cutters or the teeth. You are only counting the flat, narrow pieces that sit inside the guide bar groove.
- Double-Check: It’s highly recommended to count the drive links at least twice to ensure accuracy. Getting this number wrong will mean you buy the wrong chain.
Step 2: Measuring Chain Pitch
Chain pitch is a critical measurement that determines how the drive links engage with the drive sprocket and the cutters engage with the wood. It’s the distance between any three consecutive rivets, divided by two.
How to Measure Pitch Manually
You’ll need a ruler or caliper that has fine markings, ideally in inches or millimeters.
- Locate Three Consecutive Rivets: Find a section of your chain where you can clearly see three rivets in a row on the same side of the chain.
- Measure from the Center of the First Rivet to the Center of the Third Rivet: Place the zero mark of your ruler or caliper on the center of the first rivet. Extend it to the center of the third rivet.
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Divide by Two: The measurement you get is the distance between two rivets. Since pitch is defined as the distance between three rivets divided by two, you will divide your measurement by two.
- Example: If the distance from the center of rivet 1 to the center of rivet 3 is 1.5 inches, then your chain pitch is 1.5 inches / 2 = 0.75 inches, which is equivalent to 3/4″ or .750 inches.
Common Pitch Measurements:
- .325″ (0.825 cm): Found on many homeowner saws and smaller professional saws.
- 3/8″ (0.95 cm): Very common on mid-size to larger professional saws. Often written as .375″ in some contexts, but 3/8″ is the standard notation for saw chains.
- .404″ (1.016 cm): Used on very large, heavy-duty saws for aggressive cutting.
Using a Ruler to Estimate Pitch
If you don’t have calipers, you can often get a good estimate with a ruler marked in 1/16th of an inch.
- Align: Lay the chain flat and align the start of a drive link’s rivet with a clear inch mark on your ruler.
- Measure to the next rivet: Carefully measure the distance to the center of the next rivet.
- Measure to the third rivet: Measure the distance to the center of the third rivet.
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Calculate: Add the distance between the first and second rivet to the distance between the second and third rivet. Then, divide that total by two.
- A quick visual check: If the distance between rivets is roughly 1/4 inch, it’s likely .325″. If it’s closer to 3/8″ (slightly more than 1/4″), it’s 3/8″. If it’s significantly larger, closer to 7/16″ or a bit more, it’s likely .404″.
Step 3: Measuring Chain Gauge
Chain gauge refers to the thickness of the drive links. This measurement is critical because the drive links must fit snugly into the groove of the guide bar. If the gauge is too thick, the chain won’t fit. If it’s too thin, it will be loose, leading to premature wear and potential derailment.
How to Measure Gauge Manually
This measurement is best done with a caliper for accuracy, though a good ruler can sometimes provide a reasonable estimate.
- Identify a Drive Link: Select one of the drive links on your chain.
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Measure the Thickness: Measure the thickness of the part of the drive link that sits in the guide bar groove.
- Using Calipers: Open the jaws of your caliper and place them on either side of the drive link’s width. Close the jaws until they firmly touch the sides of the drive link. Read the measurement.
- Using a Ruler: If using a ruler, try to align it with the side of the drive link and estimate the thickness. This is less precise.
Common Gauge Measurements:
- .050″ (1.3 mm): A very common gauge for many homeowner and mid-range saws.
- .058″ (1.5 mm): Also common, especially on some professional and performance-oriented saws.
- .063″ (1.6 mm): Typically found on heavy-duty saws designed for demanding work.
Table 2: Pitch vs. Gauge Combinations
| Pitch | Gauge | Common Use |
|---|---|---|
| .325″ | .050″ (1.3mm) | Homeowner, occasional use, smaller pro saws |
| .325″ | .058″ (1.5mm) | More aggressive cutting for some homeowner saws |
| 3/8″ | .050″ (1.3mm) | General purpose, occasional pro use |
| 3/8″ | .058″ (1.5mm) | Professional use, faster cutting, demanding tasks |
| .404″ | .063″ (1.6mm) | Large sawmills, felling large trees, heavy-duty |
Step 4: Determining the Guide Bar Length
While not a measurement of the chain itself, the guide bar length is essential for compatibility. This refers to the cutting length of the bar, not the total length.
- Look at the Stamped Measurement: As mentioned, the bar length is usually stamped on the guide bar itself (e.g., 16″, 18″, 20″).
- Measure the Cutting Length: If the stamp is unreadable or you want to be absolutely sure, measure the length of the guide bar from the tip of the nose to the point where the chain is held by the mounting studs. This is the usable cutting length.
- Important Note on Bar Length: When buying a chain, you need a chain designed to work with a specific bar length. A 16-inch bar typically requires a chain with a specific number of drive links that wraps around that particular bar. The bar length dictates the total length of chain needed, but pitch, gauge, and drive link count are the critical compatibility factors for the chain itself.
Putting It All Together: Finding the Right Chain
Once you have your measurements, you can confidently shop for a replacement saw chain.
Using Your Measurements to Shop
When you visit an online retailer or a local parts store, you’ll typically see chains listed with their specifications:
- Pitch: e.g., 3/8″ Low Profile, .325″
- Gauge: e.g., .050″, .058″
- Drive Links: e.g., 56 DL, 72 DL
You’ll also need to ensure the chain is compatible with your chainsaw’s model and its guide bar length.
Example: What to Look For
Let’s say you measured your chain and found:
- Drive Links: 66
- Pitch: .325″
- Gauge: .050″
- Bar Length: 18″
You would then look for a replacement chain specified as: .325″ Pitch, .050″ Gauge, 66 Drive Links for an 18″ Bar.
What About Other Compatibility Factors?
While pitch, gauge, and drive link count are the primary measurements, other factors can influence compatibility:
- Chain Type: Different chains are designed for different purposes (e.g., general cutting, ripping, aggressive bucking). Ensure the chain type matches your needs and saw’s capabilities.
- Bar Mounting: Chainsaw bars have different mounting patterns to fit specific saw models. This is usually determined by your saw’s model, not a chain measurement, but it’s vital to ensure the bar fits your saw.
- Sprocket Size: The drive sprocket on your chainsaw’s clutch needs to match the chain pitch. If you’ve replaced the sprocket or are using an aftermarket bar, ensure pitch compatibility. Most often, the chain pitch and sprocket pitch will be the same.
Common Pitfalls to Avoid
- Confusing Bar Length with Chain Measurements: Bar length tells you the size of the bar, but pitch, gauge, and drive links are what define the chain’s fit.
- Inaccurate Measuring: Take your time and double-check your measurements, especially the drive link count and pitch.
- Guessing: Never guess your chain specifications. It’s a recipe for disaster.
- Ignoring Manufacturer Recommendations: Always consult your chainsaw’s owner’s manual. It will list the correct chain specifications for your model.
Frequently Asked Questions (FAQ)
Q: Can I use a chain with a different pitch or gauge than what’s stamped on my bar?
A: No, you generally cannot. Using a chain with the wrong pitch or gauge can cause serious damage to your chainsaw, guide bar, and sprocket, and is a significant safety hazard. Always match the pitch and gauge exactly.
Q: How do I know if I have a “Low Profile” chain?
A: “Low Profile” (LP) chains are designed for smaller, lighter-duty chainsaws. They typically have a 3/8″ pitch but a narrower gauge (.049″ or .050″) and often a shorter drive link. The stamping might specify “LP” or indicate a pitch like “3/8″ Low Profile.” If your saw is a small homeowner model, it likely uses an LP chain.
Q: Does the number of teeth on the chain matter?
A: The number of teeth is related to the number of drive links and the pitch, but the definitive measurement is the number of drive links. Counting the drive links is the most reliable way to ensure you have the correct chain length for your guide bar.
Q: What if my chainsaw manual is lost?
A: If you’ve lost your owner’s manual, you can usually find a digital version on the chainsaw manufacturer’s website by searching for your specific chainsaw model. Alternatively, identifying the brand and model number of your saw will allow you to search for replacement chain specifications online.
Q: I measured my bar, and it’s 20 inches. What else do I need to know for the chain?
A: While the 20-inch bar length is important for the chain’s overall circumference, you still absolutely need to know the chain pitch, chain gauge, and the number of drive links that fit on that specific 20-inch bar. A 20-inch bar from one manufacturer might use a different drive link count or pitch than a 20-inch bar from another. Always prioritize pitch, gauge, and drive link count.
By following these steps and paying close attention to the details, you can confidently measure your chainsaw chain and select the perfect replacement, ensuring your saw performs at its best and safely for many cuts to come.