How To Measure Chain For Chainsaw: Get It Right

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What is the correct way to measure a chainsaw chain? Measuring your chainsaw chain correctly is crucial for its proper function and longevity. The key measurements you need are the pitch, gauge, and the number of drive links. Incorrect measurements can lead to poor cutting performance, premature wear on your chainsaw and the chain, and even dangerous situations.

Why Accurate Chain Measurement Matters

A chainsaw chain is a precisely engineered component. Its ability to cut efficiently and safely relies entirely on its compatibility with your chainsaw’s guide bar and powerhead. Think of it like a bicycle chain and gears; they need to mesh perfectly. If the pitch, gauge, or length are wrong, the chain won’t engage with the drive sprocket or the bar properly. This can cause:

  • Slipping: The chain might slip off the sprocket, stopping your cut and potentially causing damage.
  • Excessive Wear: The wrong size chain can cause the sprocket, clutch, and even the guide bar to wear out much faster than they should.
  • Poor Cutting Performance: A chain that’s too loose or too tight won’t cut effectively. It might bog down, vibrate excessively, or produce uneven cuts.
  • Safety Hazards: A chain that doesn’t track correctly on the guide bar can fly off, presenting a serious safety risk.

Deciphering the Key Chain Measurements

To get your chainsaw chain right, you need to know three fundamental measurements: pitch, gauge, and drive links. These three factors, along with the correct bar length, define the correct chain loop for your saw.

1. Chain Pitch: The Tooth Spacing

What is chain pitch? Chain pitch is the distance between any three consecutive rivets on the chain, divided by two. It’s essentially the size of the drive sprocket that the chain engages with. This is the most critical measurement for ensuring your chain fits your saw’s drive mechanism.

How to measure pitch:

  • Locate Three Consecutive Rivets: Find three rivets in a row on your chain.
  • Measure from the Center of the First Rivet to the Center of the Third Rivet.
  • Divide the Measurement by Two: This is your chain’s pitch.

Chainsaw chains come in standard pitches, most commonly:

  • .325″
  • 3/8″ (also known as 3/8 inch standard)

  • .404″

  • Note: Some less common pitches exist, like 1/4″ and 3/8″ low profile, but the above are the most prevalent.

Where to find your chain pitch:

  • On the Guide Bar: Many manufacturers stamp the pitch directly onto the guide bar, usually near the base or the tip. Look for markings like “.325” or “3/8”.
  • On the Old Chain: Sometimes, the pitch is stamped on the drive links of your existing chain, though this can wear off over time.
  • Chainsaw Manual: Your chainsaw’s owner’s manual will specify the correct pitch for your model.
  • Manufacturer’s Website: You can usually find this information by searching for your chainsaw model online on the manufacturer’s website.

Example: If the distance between the center of the first rivet and the center of the third rivet is 1 inch, your chain’s pitch is 1 inch / 2 = 0.5 inches, which is 1/2 inch (or 3/8″ in common chainsaw parlance). Wait, that’s not right. Let’s re-clarify. If the distance between the first and third rivet is 3/4 of an inch, then 3/4 divided by 2 is 3/8 of an inch. So the pitch is 3/8 inch.

2. Chain Gauge: The Thickness of the Drive Link

What is chain gauge? Chain gauge refers to the thickness of the drive links – the parts of the chain that sit in the groove of the guide bar and engage with the clutch sprocket. It’s essential that the gauge matches the groove of your guide bar and the teeth of your drive sprocket.

How to measure gauge:

  • Measure the Thickness of a Drive Link: The drive links are the parts of the chain that extend downwards from the cutters.
  • Use a Ruler or Caliper: Measure the thickest part of one of these drive links.

Common chain gauges are:

  • .043″ (often referred to as thin kerf)
  • .050″ (the most common gauge)
  • .058″
  • .063″

Where to find your chain gauge:

  • On the Guide Bar: Like the pitch, the gauge is often stamped on the guide bar, usually next to the pitch marking.
  • On the Old Chain: It might be stamped on the drive links of your existing chain.
  • Chainsaw Manual: Consult your owner’s manual for the recommended gauge.
  • Manufacturer’s Website: Check the specifications for your chainsaw model.

Important: Using the wrong gauge can cause the chain to fit too loosely in the bar groove, leading to excessive wear and potential chain derailment. A gauge that’s too thick won’t fit into the groove at all.

3. Drive Links: The Length of the Chain

What are drive links? Drive links are the sections of the chain that have a small “foot” or “tab” that extends downwards. These drive links fit into the groove of the guide bar and engage with the drive sprocket on the chainsaw. The number of drive links determines the total length of the chain loop.

How to measure drive links:

  • Count Them! The simplest and most accurate way is to count the number of drive links on your current chain.
  • Start with the first drive link and count each one sequentially until you reach the last one. Ensure you count the entire loop.

Why the number of drive links is important:

The number of drive links is specific to the combination of your guide bar length and the chain’s pitch. A chain with the correct pitch and gauge but the wrong number of drive links will either be too short to fit around the bar and sprocket, or too long, preventing it from being tensioned properly.

Example: You might see a chain referred to by its pitch and drive link count, such as “3/8″ .050″ 72DL chain” (meaning 3/8″ pitch, .050″ gauge, and 72 drive links).

Putting It All Together: Finding Your Chain Size

Once you have these three key measurements, you can confidently identify the correct replacement chain for your chainsaw. Here’s how these measurements combine and where to look for specific brand information.

Associating Measurements with Bar Length

While pitch and gauge are absolute measurements, the number of drive links is directly correlated with the bar length and the overall chain pattern. For instance, a 20-inch guide bar on one chainsaw might use a chain with a different number of drive links than a 20-inch guide bar on another model, depending on the pitch and gauge.

  • Example: A 16-inch bar for a smaller saw might use a 52-drive link chain with a 3/8″ pitch and .050″ gauge. A larger saw with a 20-inch bar might use a 72-drive link chain with the same pitch and gauge.

Brand-Specific Sizing: Oregon and Stihl

Leading chainsaw chain manufacturers like Oregon and Stihl often have their own naming conventions or chain number systems that incorporate these measurements. Knowing these can be helpful when purchasing.

Oregon Chain Size

Oregon is a very popular brand for replacement chainsaw chains. Their chains are often identified by a numerical code that implies the size.

  • Common Oregon Series:

    • 91 Series: 3/8″ low profile pitch, .050″ gauge. Often used on smaller homeowner saws.
    • 20, 21, 22 Series: .325″ pitch, .050″ or .058″ gauge. Common for general-purpose saws.
    • 70, 72, 73, 75 Series: 3/8″ standard pitch, .050″, .058″, or .063″ gauge. Used on professional and larger saws.
    • 27, 28 Series: .404″ pitch, .063″ gauge. For heavy-duty, large-bore saws.

  • How to find your Oregon chain size:

    1. Check the Bar: Oregon often stamps their pitch and gauge on the guide bar.
    2. Check Old Chain Packaging: If you still have the original packaging.
    3. Use Oregon’s Website: Oregon has an excellent “chain finder” tool on their website where you can input your saw’s make and model, or your bar’s specifications, to find the exact Oregon chain you need. You’ll typically see options like “Oregon 72LPX066G” where:
      • “72” indicates the pitch and drive links (often the first two digits relate to pitch/drive link count).
      • “LPX” signifies the chain type and cutter type (e.g., “LPX” often means low-vibration full chisel).
      • “066” indicates the gauge (.063″) and the number of drive links (66).

Stihl Chain Size

Stihl is another major chainsaw manufacturer, and their chains also have specific designations.

  • Common Stihl Pitches and Gauges:

    • 3/8″ P: Stihl’s designation for 3/8″ pitch.
    • .325″ P: Stihl’s designation for .325″ pitch.
    • .404″ P: Stihl’s designation for .404″ pitch.
    • Gauge: Often stamped as .063″, .050″, .058″, etc.

  • How to find your Stihl chain size:

    1. Check the Bar: Stihl typically stamps the pitch and gauge on their guide bars.
    2. Check the Old Chain: Look for markings on the drive links.
    3. Consult Stihl’s Resources: Stihl’s website or your local dealer can help you find the correct chain by your saw’s model number.
    4. Stihl Chain Designations: Stihl chains often have names like “Stihl Picco Duro 36 RS” or “Stihl Rapid Micro 325”. The important part is finding the pitch and gauge. The numbers often relate to pitch and drive link count. For example, a “36 RS” chain might be for a certain bar length and pitch. The “RS” indicates a full chisel cutter for fast cutting.

Comprehending Chain Type and Cutter Type

Beyond the core measurements, different chain types and cutter types exist for various applications.

  • Chain Types:

    • Standard: Regular chains for general use.
    • Low Profile: Smaller pitch and gauge chains for smaller, lighter-duty saws.
    • Full Chisel: Aggressive cutters for fast, efficient cutting in clean wood.
    • Semi-Chisel: More rounded cutters that are more durable and forgiving in dirtier conditions, though they cut slower.
    • Skipper Chains: Designed to prevent kickback.

  • Cutter Type: This refers to the shape of the cutting tooth.

    • Full Chisel (Round or Square Ground): Sharp, aggressive corners for fast cutting. Prone to dulling faster and require more frequent sharpening, especially in dirty conditions.
    • Semi-Chisel (Round Ground): More rounded cutting corners. More durable, less prone to dulling from dirt and grit, and more forgiving for less experienced users, but cut slower.

When you buy a replacement chain, you’ll often see designations that describe these, such as Oregon’s “LPX” (low profile, full chisel, low vibration) or Stihl’s “RS” (Rapid Super – full chisel).

Practical Steps to Measure Your Chainsaw Chain

Let’s break down the process into actionable steps.

Step 1: Gather Your Tools

You don’t need much, but having the right tools makes it easier.

  • Measuring Tape or Ruler: A metal ruler or measuring tape is ideal for accuracy.
  • Calipers (Optional but Recommended): For precise measurement of the chain gauge.
  • Pen and Paper: To record your measurements.
  • Gloves: For safety when handling the chain.
  • Magnifying Glass (Optional): If markings on the bar or chain are faint.

Step 2: Safely Remove the Old Chain

  • Always ensure the chainsaw is off, the spark plug wire is disconnected, and the chain brake is engaged before attempting to remove or adjust the chain.
  • Loosen the bar nuts that hold the guide bar in place.
  • Release the tension on the chain by loosening the tensioning screw or mechanism.
  • Carefully slide the guide bar forward and off the mounting studs.
  • Remove the old chain loop from the bar.

Step 3: Measure the Pitch

  1. Lay the old chain on a flat surface.
  2. Find any three consecutive rivets on the chain.
  3. Using your ruler, measure from the center of the first rivet to the center of the third rivet.
  4. Divide this measurement by two. This is your pitch. For example, if you measure 0.75 inches (3/4 inch), your pitch is 0.375 inches (3/8 inch). If you measure 0.65 inches, your pitch is 0.325 inches.

Step 4: Measure the Gauge

  1. Identify a drive link (the part of the chain that sits in the bar groove).
  2. Using your ruler or calipers, measure the thickness of this drive link. It’s best to measure the widest part of the “foot” that goes into the bar groove.
  3. Record this measurement. Common gauges are .043″, .050″, .058″, .063″.

Step 5: Count the Drive Links

  1. Take the chain loop you removed.
  2. Starting from the first drive link, count each drive link sequentially around the entire loop.
  3. Record the total number of drive links.

Step 6: Consult Your Chainsaw Manual or Bar Markings

Before you go out to buy, double-check your findings.

  • Bar Markings: Look closely at the base of your guide bar. Many manufacturers stamp the pitch and gauge directly onto it. This is often the most reliable indicator.
  • Owner’s Manual: Your chainsaw’s manual will contain specifications for the correct chain size.
  • Online Resources: Use the manufacturer’s website or look up your chainsaw model online. Many retailers also have chain selection guides.

What If My Measurements Don’t Match Standard Sizes?

This is rare for most modern chainsaws, as manufacturers tend to stick to common standards. However, if you find your measurements are unusual, double-check your work.

  • Re-measure: Ensure you measured from the center of the rivets for pitch and were precise with the gauge.
  • Check the Saw Model: Make sure you have the correct saw model number.
  • Consult a Professional: If you’re still unsure, take your old chain and guide bar to a reputable chainsaw dealer. They can help you identify the correct specifications.

Buying the Right Replacement Chain

Once you have your pitch, gauge, and drive link count, you can purchase a replacement chain.

  • Look for Identical Specs: Find a chain that matches your pitch, gauge, and drive link count.
  • Consider Brands: Oregon and Stihl are excellent choices, but other reputable brands also offer quality chains.
  • Match Chain Type (Optional but Recommended): If you know what type of cutting you do most often (e.g., fast cutting in clean wood vs. occasional use in dirtier conditions), you can select a chain type that suits your needs. For example, if your old chain was a full chisel and you liked its performance, try to find a replacement with a full chisel cutter.

Maintaining Your Chainsaw Chain

Measuring correctly is only half the battle. Proper maintenance ensures your chain lasts and performs optimally.

  • Sharpening: Keep your chain sharp. A sharp chain cuts efficiently and reduces wear on your saw.
  • Tensioning: Ensure the chain is properly tensioned. It should be snug but still able to move freely around the bar. A chain that’s too loose can derail; one that’s too tight causes excessive wear.
  • Lubrication: Always ensure your chain is adequately lubricated with bar and chain oil. This reduces friction and heat.
  • Cleaning: Keep the chain, bar, and sprocket area clean to prevent debris buildup.

Frequently Asked Questions (FAQ)

Can I use a chain with a different pitch than what my saw specifies?

No, you cannot. The pitch is determined by the drive sprocket and guide bar groove, and using an incorrect pitch will prevent the chain from engaging properly, leading to damage and unsafe operation.

Can I use a chain with a different gauge than what my saw specifies?

No, you should not. A gauge that is too thick will not fit into the guide bar groove, and a gauge that is too thin will fit loosely, causing premature wear on the bar, sprocket, and chain, and potentially leading to the chain derailing.

How often should I replace my chainsaw chain?

Chainsaw chains need replacement when they are significantly worn, have damaged teeth, or cannot be sharpened effectively anymore. You’ll notice a decline in cutting performance, the chain might stretch more frequently, or the cutters may become irreparably damaged. It’s generally better to replace a worn-out chain than to try and push it too far.

Does the number of drive links always correspond to the bar length?

Not always directly in terms of the number itself, but rather the combination of pitch, gauge, and bar length dictates the required number of drive links for a specific chain loop. A 20-inch bar on one saw might use a 72-drive link chain, while a 20-inch bar on a different saw model might use a different number if the pitch or gauge is different. The key is to match all three specifications.

Where can I find the chain number for my specific chainsaw?

The best places to find the correct chain number or specifications are:
* Your chainsaw’s owner’s manual.
* The guide bar itself (look for stamped markings).
* The manufacturer’s official website for your specific chainsaw model.
* The packaging of your old chain (if you still have it).
* A local authorized dealer for your chainsaw brand.