What do I need to measure for a chainsaw chain? To measure for a chainsaw chain, you’ll primarily need to determine the chain’s pitch, gauge, and length (in drive links). You can find this information on your old chain, the chainsaw bar, or by physically measuring the chain itself.
Replacing a worn-out or broken chainsaw chain is a common maintenance task for any chainsaw owner. But how do you ensure you get the right size chain? Buying the wrong one can lead to poor performance, damage to your chainsaw, or simply a chain that won’t fit at all. This comprehensive guide will walk you through every step of determining chainsaw chain size, making your chainsaw chain replacement a smooth and successful process. We’ll cover how to interpret markings, perform accurate measurements, and avoid common pitfalls.
Why Accurate Chain Sizing Matters
Using the correct chainsaw chain size is crucial for several reasons:
- Performance: The right chain ensures efficient cutting, smooth operation, and optimal power transfer from the engine to the cutting surface.
- Safety: An improperly sized chain can snag, break, or cause kickback, posing significant safety risks.
- Durability: A correctly fitted chain reduces stress on the chainsaw’s drive system, bar, and engine, prolonging their lifespan.
- Preventing Damage: A chain that is too loose can derail, causing damage to the bar and casing. A chain that is too tight can cause excessive wear and heat, potentially seizing the engine.
Identifying Your Chainsaw Chain: Deciphering the Markings
Most chainsaw chains have important size information stamped directly onto them, usually on the drive links (the part of the chain that sits in the bar groove and engages the sprocket). Sometimes this information is also found on the chainsaw bar itself. Learning how to identify chainsaw chain size is the easiest way to ensure you buy the correct replacement.
1. The Chainsaw Chain Pitch
The chainsaw chain pitch refers to the distance between the rivets on the chain. It’s a critical measurement that dictates how the chain meshes with the drive sprocket and the bar groove. Pitch is measured from the center of one rivet to the center of the next rivet, then divided by two.
Common chainsaw chain pitches include:
- .325 inches (8.25 mm)
- 3/8 inches (9.53 mm)
- .404 inches (10.23 mm)
- 1/4 inches (6.35 mm)
Where to find the pitch on your chain: Look at the drive links. You’ll typically see numbers like “.325”, “3/8”, or “.404” stamped on them. For example, a chain with “.325” stamped on its drive links is a .325 inch pitch chain.
What if the stamping is worn off? If the markings are illegible, you’ll need to measure it manually.
2. The Chainsaw Chain Gauge
The chainsaw chain gauge refers to the thickness of the drive link’s “rail,” which is the part that sits in the chainsaw bar groove. The gauge is essential for ensuring the chain fits snugly into the bar without excessive play.
Common chainsaw chain gauges include:
- .043 inches (1.1 mm)
- .050 inches (1.3 mm)
- .058 inches (1.5 mm)
- .063 inches (1.6 mm)
Where to find the gauge on your chain: The gauge is also stamped on the drive links, often near the pitch. It’s usually a three-digit number preceded by a decimal point (e.g., “.050”).
What if the stamping is worn off? Again, manual measurement is your next step.
3. The Chainsaw Chain Length (Number of Drive Links)
The chainsaw chain length is not measured by its overall circumference, but by the number of drive links. Drive links are the small, protruding parts of the chain that engage with the drive sprocket and sit within the groove of the measuring chainsaw bar.
How to count drive links:
- Lay your old chain out flat.
- Count the number of drive links. A drive link is the part of the chain that extends downwards and fits into the groove of the chainsaw bar.
- Important Note: Don’t count the cutter teeth. Only count the drive links.
Where to find the drive link count: Sometimes, the number of drive links might be stamped on the chain, but it’s more common to have to count them yourself.
Example: Reading Chain Markings
Let’s say you find “.325 .050 72” stamped on your drive links. This tells you:
- Pitch: .325 inches
- Gauge: .050 inches
- Drive Links: 72
This is your chainsaw chain sizing guide for purchasing a new chain.
Manual Measurement: When Markings Aren’t Enough
If the markings on your old chain are too worn to read, or you don’t have an old chain, you’ll need to measure your chainsaw bar and chain directly. This section provides a chainsaw chain sizing guide for manual measurement.
Measuring the Chainsaw Bar
The chainsaw bar plays a vital role in the sizing process. Its specifications directly correspond to the chain you need.
1. Measuring the Pitch
The bar’s pitch is determined by the size of the drive sprocket it’s designed to work with, and the groove width. While not always explicitly stamped, you can infer it.
- From Sprocket: If you know the sprocket size (which should match the chain pitch), you have your pitch.
- From Bar Groove: The width of the bar groove should match the chainsaw chain gauge.
2. Measuring the Gauge
The gauge is the width of the groove in your chainsaw bar.
- Visual Inspection: Compare your bar’s groove width to known standards or use a caliper for accuracy.
- Markings on the Bar: Many bars have the gauge stamped on them, usually near the base where the chain enters the bar. Look for numbers like “1.3mm,” “1.5mm,” or “.050.”
3. Measuring the Bar Length
The bar length is measured from the nose of the bar to the mounting point where it attaches to the chainsaw body. It’s usually measured in inches. Common lengths are 14″, 16″, 18″, 20″, etc.
- Important: The bar length doesn’t directly tell you the chain’s drive link count, but it’s crucial information for compatibility. A bar designed for a 16-inch chain will require a chain of a specific length that fits that bar.
Measuring the Chain Manually (If No Old Chain or Clear Markings)
If you need to measure the chain itself without relying on markings, follow these steps carefully. This is a critical part of determining chainsaw chain size.
1. Measuring Pitch Manually
- Tools Needed: A ruler or measuring tape that can measure in fractions of an inch or millimeters.
- Process:
- Lay your chain flat.
- Find three consecutive rivets.
- Measure the distance from the center of the first rivet to the center of the third rivet.
- Divide this measurement by two. This will give you the pitch.
- Example: If the distance between the first and third rivet centers is 1 inch, then the pitch is 1 inch / 2 = 0.5 inches, which is equivalent to 1/2 inch or .500 inches. The most common pitches are .325, 3/8, and .404. If your measurement is close to one of these, that’s likely your pitch.
2. Measuring Gauge Manually
- Tools Needed: A caliper is the most accurate tool for this. A thin ruler might suffice in a pinch, but accuracy can be compromised.
- Process:
- Locate a drive link on the chain.
- Use the caliper to measure the thickness of the part of the drive link that sits inside the bar groove.
- This measurement will typically be in millimeters (e.g., 1.1mm, 1.3mm, 1.5mm, 1.6mm) or fractions of an inch (.043″, .050″, .058″, .063″).
3. Counting Drive Links
- Process:
- As mentioned before, lay the chain flat.
- Count each individual drive link. These are the parts of the chain that extend downwards and fit into the bar’s groove.
- Ensure you count all of them to get the total chainsaw chain length in drive links.
What If I Have the Chainsaw Model Number?
Knowing your chainsaw’s make and model is often the easiest way to find the correct chain.
Finding Your Chainsaw Model Number
- Check the Chainsaw Body: The model number is usually located on a sticker or plate on the main body of the chainsaw, often near the handle or engine housing.
- User Manual: Your chainsaw’s user manual will clearly state the model number.
- Manufacturer’s Website: You can often find information about your chainsaw by entering its serial number or model number on the manufacturer’s website.
Using the Model Number for Chain Sizing
Once you have the make and model, you can:
- Consult Your User Manual: The manual will often specify the recommended chain pitch, gauge, and length (in drive links) for your specific model.
- Check the Manufacturer’s Website: Many manufacturers have online parts lookup tools where you can enter your model number to find compatible parts, including chainsaw chains.
- Contact a Dealer: Local chainsaw dealers or power equipment shops can help you identify the correct chain if you provide them with your chainsaw’s make and model.
Matching the New Chain to Your Bar and Saw
Once you have determined your chain’s pitch, gauge, and drive link count, it’s time to select a new chain.
Pitch, Gauge, and Length: The Holy Trinity
- Pitch: This must match your drive sprocket and the bar groove.
- Gauge: This must match the groove in your chainsaw bar.
- Drive Links: This determines the total length of the chain and must match the length required for your bar to achieve proper tension.
Example Scenarios: Putting It All Together
Scenario 1:
You have an old chain with “.325 .050 72” stamped on it. You need a new chain.
* Action: Purchase a new chainsaw chain with .325 pitch, .050 gauge, and 72 drive links.
Scenario 2:
Your chainsaw bar has a groove width of 1.5mm and the pitch stamped near the mounting is “.404”. You counted 68 drive links on your old chain.
* Action: Purchase a new chainsaw chain with .404 pitch, .058 or .063 gauge (depending on the exact thickness, 1.5mm is typically .058 or .063, check carefully), and 68 drive links.
Scenario 3:
You found your chainsaw model number (e.g., “Stihl MS 250″). You check the manual and it states the required chain is 3/8″ pitch, .063” gauge, and 56 drive links.
* Action: Purchase a new chainsaw chain with 3/8″ pitch, .063″ gauge, and 56 drive links.
Other Important Chainsaw Parts Measurement Considerations
While pitch, gauge, and drive link count are paramount for chainsaw chain replacement, other chainsaw parts measurement can be relevant for overall saw maintenance.
The Drive Sprocket
The drive sprocket engages the chain. Its tooth count and pitch must match the chain. If your chain is excessively worn or you’re changing chain types, you might need to replace the sprocket as well to ensure proper engagement.
The Chainsaw Bar
- Mounting Type: Chainsaw bars have different mounting types (e.g., Stihl, Oregon, Husqvarna). The new bar must have the same mounting type as your chainsaw.
- Rail Height: While less common for chain sizing, bar rail height can affect cutting performance.
Frequently Asked Questions (FAQ)
Q1: Can I use a chain with a different pitch or gauge than my current one?
A1: No, you generally cannot. The pitch must match your drive sprocket, and the gauge must match your bar groove precisely. Using the wrong pitch or gauge will prevent the chain from running correctly and can cause significant damage to your chainsaw and bar.
Q2: What happens if my chain is too long or too short?
A2:
* Too Long: You won’t be able to achieve proper tension. The chain may derail, causing damage, or it might not engage the sprocket correctly, leading to poor cutting.
* Too Short: You won’t be able to get the chain onto the bar and sprocket in the first place, or it will be impossible to achieve proper tension, leading to excessive wear and potential derailment.
Q3: How often should I replace my chainsaw chain?
A3: Chainsaw chains wear out over time. Look for signs of dullness (producing sawdust instead of wood chips), skipping teeth, uneven cutting, or the need to constantly tighten the chain. Most users replace their chain when it shows significant wear, which can be anywhere from a few months to over a year depending on usage intensity and maintenance.
Q4: What are drive links?
A4: Drive links are the bottom portion of each chain segment that engages with the drive sprocket and sits in the chainsaw bar’s groove. The total number of these links determines the chain’s length.
Q5: Is there a standard chainsaw chain size?
A5: No, there isn’t one single standard size. Chainsaw chains come in various pitches, gauges, and lengths to suit different chainsaw models and applications, from small home-use saws to large professional felling saws.
Q6: Can I measure the chain from the outside?
A6: Measuring from the outside of the cutters is not accurate for determining pitch or gauge. You must measure from rivet center to rivet center for pitch and the thickness of the drive link for gauge.
Q7: My chain has numbers like 56, 60, 72. What do these mean?
A7: These numbers typically represent the chainsaw chain length in the number of drive links. For example, “72” means the chain has 72 drive links.
By following this detailed chainsaw chain sizing guide, you can confidently measure for and select the correct replacement chain for your chainsaw, ensuring safe, efficient, and durable operation. Always double-check your measurements and consult your chainsaw’s manual for the most accurate information.