Figuring out how to measure a chain for a chainsaw is crucial for ensuring your saw runs efficiently and safely. A chain that’s too long or too short won’t fit your guide bar properly, leading to poor performance, excessive wear, or even dangerous malfunctions. This comprehensive guide will walk you through every step needed to accurately determine your chainsaw chain’s chainsaw chain dimensions, covering everything from chainsaw pitch to chainsaw drive links. We’ll help you understand chainsaw chain size so you can confidently replace chainsaw chain when needed.
Why Accurate Measurement Matters
Getting the right chainsaw chain length isn’t just about the chain fitting; it’s about the entire system working in harmony. A correctly sized chain ensures:
- Optimal Cutting Performance: A chain that’s too loose can jump off the bar, while one that’s too tight can strain the engine and bar. The right fit means smooth, efficient cutting.
- Reduced Wear and Tear: An improperly fitted chain can cause premature wear on your guide bar, drive sprocket, and the chain itself. This saves you money on replacements and maintenance.
- Enhanced Safety: A chain that jumps off the bar is a serious safety hazard, potentially causing injury. Accurate measurements contribute directly to safe operation.
- Proper Tensioning: The ability to tension the chain correctly depends on having the right length. Too much slack or too little can be problematic.
The Key Components of Chainsaw Chain Measurement
When you’re looking to measure a chainsaw chain correctly, you need to focus on three primary specifications:
- Pitch: This is the distance between the drive links, measured from the center of one rivet to the center of the next.
- Gauge: This refers to the thickness of the drive links, which must match the groove in your guide bar.
- Number of Drive Links: This is the count of the individual links that engage with the guide bar.
Let’s delve into each of these critical measurements.
Measuring Chainsaw Pitch
What is chainsaw pitch? Chainsaw pitch is one of the most important measurements. It’s a standardized measurement that determines how the chain links interact with the drive sprocket and the guide bar. It’s measured from the center of one rivet to the center of the next rivet on the same chain.
The most common pitches you’ll find are:
- 0.325 inches (8.25 mm)
- 3/8 inches (9.52 mm)
- 0.404 inches (10.26 mm)
There are other less common pitches like 1/4 inch and 3/8 low profile, but the three listed above are the most prevalent for general-purpose and professional chainsaws.
How to Measure Pitch:
- Using a Ruler or Caliper: Lay your chain flat on a hard surface. If you have a digital caliper, this is the easiest way to measure. Measure from the center of one rivet to the center of the next rivet. Repeat this measurement a few times to ensure accuracy.
- Using a Specialized Pitch Gauge: Many saw shops or online retailers sell specialized pitch gauges. These tools have notches corresponding to common pitches, making identification straightforward. You simply line up a section of your chain with the gauge to see which notch it fits perfectly.
- Counting Rivets: A common trick for determining pitch is to count rivets. Take any three consecutive rivets and measure the distance between the first and third. Divide that distance by two. This will give you the pitch. For example, if the distance between the first and third rivet is 1 inch, your pitch is 0.5 inches (which is not a standard pitch, so this highlights the need for precision). A more practical example: if the distance between the first and third rivet is 0.65 inches, then the pitch is 0.325 inches (0.65 / 2 = 0.325). This method is best used with a caliper for accuracy.
It’s vital that your chain’s pitch matches the pitch of your drive sprocket and guide bar. Using the wrong pitch can lead to severe damage to your saw.
Measuring Chainsaw Gauge
What is chainsaw gauge? The chainsaw gauge refers to the thickness of the drive links – the part of the chain that sits in the groove of your guide bar. This measurement is critical because the drive links must fit snugly within the guide bar’s groove. If the gauge is too thin, the chain will wobble and be unstable. If it’s too thick, the chain won’t fit into the groove at all.
Common gauges are:
- 0.050 inches (1.3 mm)
- 0.058 inches (1.5 mm)
- 0.063 inches (1.6 mm)
How to Measure Gauge:
- Using a Ruler or Caliper: The most accurate way to measure the gauge is with a caliper. Measure the thickness of a drive link. Ensure you’re measuring the thickest part of the drive link, where it enters the guide bar groove.
- Checking Your Existing Chain: Often, the gauge is stamped directly onto the chain, usually on the drive links. Look for a number like “050,” “058,” or “063.”
- Consulting Your Chainsaw Manual or Bar: Your chainsaw’s owner’s manual will specify the correct gauge for your saw. Alternatively, the gauge is often stamped on the guide bar itself, typically near the base where it attaches to the saw.
Always match the gauge of your new chain to the gauge specified for your guide bar.
Counting Drive Links
What are chainsaw drive links? Drive links are the small sections of the chain that have a “foot” or protruding piece on the bottom. These drive links are what engage with the drive sprocket on your chainsaw’s clutch and sit within the groove of the guide bar. The number of these links determines the chainsaw chain length and is essential for the chain to wrap correctly around your guide bar and engine sprocket.
How to Count Drive Links:
- Remove the Chain: It’s easiest to count the drive links with the chain off the saw. Lay the chain out in a straight line.
- Count One Side: Count each individual drive link along one edge of the chain. Start with the first drive link that has a “foot” and count until you reach the last one.
- Double-Check: Count them again to be sure. It’s a common mistake to miscount.
- Check Your Bar Length: While not a direct measurement of the chain, your chainsaw bar length is a strong indicator of how many drive links you’ll need. Chainsaws with longer bars generally require chains with more drive links. For example, an 18-inch bar might need a chain with 68 drive links, while a 20-inch bar might need 72. However, this is not a universal rule, as pitch and gauge can also influence the number of links for a given bar length.
Important Note: You are counting the drive links that sit in the guide bar and engage with the sprocket. Do not count the cutter links or the rivets connecting them.
Putting It All Together: Determining Your Chainsaw Chain Size
Once you have your pitch, gauge, and drive link count, you have all the necessary information to determine your chainsaw chain size. This information is usually presented together, for example: “3/8″ pitch, 0.050″ gauge, 72 drive links.”
Measuring a Chain On the Saw (When You Can’t Remove It)
If you need to measure a chainsaw chain but can’t easily remove it, there are still ways to get the information, although they are less precise:
- Pitch and Gauge:
- Pitch: You can try to measure the distance between rivets using a ruler, but this is difficult with the chain on the saw. The “count rivets and divide by two” method is still your best bet if you have a caliper.
- Gauge: Try to visually compare the thickness of the drive links to a known gauge (if you have a spare chain or gauge tool). Many guide bars will have the gauge stamped on them, which is a more reliable source if the chain is still on.
- Drive Links:
- Bar Length Indicator: Use your chainsaw bar length as a guide. While not exact, it’s a starting point.
- Counting with the Chain On: This is tricky. You can try to count the drive links as they pass over the sprocket or sit in the guide bar, but it’s prone to error. The most practical approach is to rely on your bar’s specifications or a known chain’s specifications if you have one.
The best chain length guide is often found in your saw’s manual or by looking at the markings on your existing guide bar.
Using Your Chainsaw’s Guide Bar for Measurement
Your guide bar is a treasure trove of information for determining the correct chainsaw chain size.
What Information is on the Guide Bar?
Most guide bars will have at least two, and often three, crucial pieces of information stamped or etched onto them:
- Length: This is the cutting length of the bar, usually measured in inches (e.g., 16″, 18″, 20″).
- Pitch: This will be indicated, often as “3/8” or “0.325”.”
- Gauge: This is also usually stamped, commonly as “.050,” “.058,” or “.063.”
How to Read Your Guide Bar:
- Locate the Markings: Look at the base of your guide bar, where it mounts to the chainsaw body. You should find the stamped information there.
- Example: You might see something like “18 .325 .050”. This translates to:
- 18: The cutting length of the bar is 18 inches.
- .325: The pitch of the chain required is 0.325 inches.
- .050: The gauge of the chain required is 0.050 inches.
Important Consideration: The guide bar length doesn’t directly tell you the number of drive links. You still need to count those. However, knowing the bar length and the pitch gives you a strong indication of the typical drive link count. For instance, a 16-inch bar with 0.325 pitch often requires around 56 drive links, while an 18-inch bar with 3/8 pitch might need 64 or 68 drive links.
Counting Drive Links on a New Chain
When you purchase a new chainsaw chain, the packaging will typically state its specifications. However, if you need to confirm the drive link count yourself:
- Unspool the Chain: Carefully unroll the new chain.
- Identify Drive Links: Locate the links with the protruding “feet” designed to sit in the guide bar groove and engage the sprocket.
- Count Meticulously: Count each of these drive links. It’s best to do this on a flat surface.
- Confirm Specifications: Compare your count to the specifications printed on the chain’s packaging or on the chain itself (sometimes marked on the tie straps between drive links).
What If Your Chain Information is Missing or Unclear?
If the markings on your guide bar are worn off, or you’re dealing with a chain that has no visible markings, here’s what you can do:
- Consult Your Chainsaw Manual: This is always the best first step. Your manual will specify the correct pitch, gauge, and often the required chain length (in drive links or total length).
- Identify Your Saw Model: If you don’t have the manual, find the make and model number of your chainsaw. You can usually find this on the saw’s casing or a sticker.
- Online Resources and Databases: Search online for your specific chainsaw model number. Manufacturers and parts suppliers often have detailed specification charts. You can find chain length guide information, pitch, and gauge for virtually any saw.
- Measure an Existing Chain (If You Have One): If you have an old chain that fits your saw, measure its pitch, gauge, and count its drive links.
- Visit a Local Saw Shop: Professionals at a reputable chainsaw dealer can help you identify the correct specifications for your saw by examining it or by using their expertise and diagnostic tools. They can also help you find the right chain to replace chainsaw chain.
Understanding Chain Length vs. Bar Length
It’s important to differentiate between chainsaw bar length and chainsaw chain length.
- Bar Length: This refers to the overall length of the metal bar that the chain runs on. It’s typically measured from the tip of the nose to the part where the bar inserts into the saw’s powerhead.
- Chain Length: This is determined by the number of drive links. A specific bar length will require a chain with a specific number of drive links to fit properly. For example, an 18-inch bar might need a chain with 68 drive links, while a different brand’s 18-inch bar might use a chain with 72 drive links, depending on the pitch and overall design.
Therefore, while the bar length is a good indicator, it’s the number of drive links that truly defines the correct chainsaw chain length for your saw.
Common Pitfalls to Avoid
- Mixing Up Pitch and Gauge: These are distinct measurements. Don’t assume they are the same or interchangeable.
- Ignoring Drive Link Count: This is the most common mistake when trying to measure a chainsaw chain correctly. Without the right number of drive links, the chain will not fit your bar.
- Assuming All Chains for a Bar Length are the Same: As mentioned, different pitches and designs mean that even for the same bar length, drive link counts can vary.
- Measuring from the Wrong Point: For pitch, always measure center-to-center of rivets. For gauge, measure the thickness of the drive link.
- Using a Worn-Out Chain to Measure: If your old chain is stretched or damaged, its measurements might be inaccurate. Try to measure a chain that was working correctly or a new one.
When Do You Need to Replace a Chainsaw Chain?
You need to replace chainsaw chain when:
- It’s Dull: Most commonly, chains are replaced when they become dull and can no longer cut efficiently.
- Teeth are Damaged: If teeth are chipped, broken, or worn down unevenly, the chain needs replacement.
- Chain is Stretched: Over time, chains stretch. If you find yourself constantly adjusting tension and the chain still feels loose, or the rivets are significantly worn, it’s time for a new one.
- It’s the Wrong Size: If you discovered you’ve been using a chain with the incorrect chainsaw chain dimensions, replace it with the correct one immediately to prevent damage.
- You Cut Through Contaminated Material: If you accidentally cut into dirt, rocks, or metal, it can severely damage your chain and may necessitate replacement.
Summary Table of Key Measurements
| Measurement | What It Is | Common Values | How to Measure | Importance |
|---|---|---|---|---|
| Pitch | Distance between drive links (center-to-center) | 0.325″, 3/8″, 0.404″ | Measure center-to-center of two consecutive rivets, or count 3 rivets and divide by 2. | Ensures proper engagement with sprocket and bar. |
| Gauge | Thickness of the drive links | 0.050″, 0.058″, 0.063″ | Measure thickness of drive link with caliper, or check chain/bar markings. | Ensures the drive links fit snugly in the guide bar groove. |
| Drive Links | Number of links that engage with the bar | Varies (e.g., 56, 64, 68, 72) | Count the individual drive links on the chain. | Determines the overall chainsaw chain length for your bar. |
| Bar Length | Cutting length of the guide bar | Typically 14″ to 20″ for common saws | Measure from tip to where bar inserts into saw body. (Often stamped on the bar). | Gives an indication of the likely drive link count needed. |
Frequently Asked Questions (FAQ)
Q1: Can I use a chain with a different pitch than my current one?
A1: No, you cannot. The pitch is dictated by your drive sprocket and guide bar. Using a different pitch will cause severe damage to your saw.
Q2: What happens if the gauge of my new chain is slightly different?
A2: If the gauge is too thin, the chain will be unstable and wear quickly. If it’s too thick, the chain won’t fit into the guide bar groove at all. Always match the gauge precisely.
Q3: How do I know if I have the right number of drive links?
A3: If the chain fits your guide bar correctly and you can tension it properly without the chain becoming too loose or too tight, you likely have the correct number of drive links. If the chain doesn’t reach around the bar and sprocket, or if you have excessive overlap, the count is wrong.
Q4: Is it okay to measure my chain with a standard tape measure?
A4: A standard tape measure is usually not accurate enough for the precise measurements required for pitch and gauge. A caliper is highly recommended.
Q5: My guide bar has wear, can that affect my chain measurement?
A5: Yes, a worn guide bar groove can make it difficult to accurately determine the original gauge. If possible, try to find the specifications for your chainsaw model or a new guide bar.
By following this guide and paying close attention to the pitch, gauge, and number of drive links, you can confidently measure a chainsaw chain correctly and ensure your saw is always equipped with the right parts for safe and efficient operation. Knowing your chainsaw chain dimensions is key to keeping your equipment in top condition.