Can you measure a chainsaw chain by counting the drive links? Yes, counting the drive links is the most accurate way to determine chainsaw chain length. This blog post will guide you through the process of correctly determining your chainsaw chain length, covering all essential aspects from identifying key measurements to replacing an old chain.
When your chainsaw chain needs replacing, getting the right length is crucial. A chain that’s too long won’t fit properly and can cause damage, while a chain that’s too short won’t engage the guide bar. This guide will help you master the art of chainsaw chain sizing, ensuring you select the perfect fit for your saw.
The Importance of Correct Chainsaw Chain Length
Using the wrong chainsaw chain length can lead to several problems:
- Poor Cutting Performance: A chain that’s too short will not reach the sprocket, meaning it won’t cut effectively. A chain that’s too long might not tension correctly, leading to skipped teeth and inefficient cutting.
- Damage to Your Chainsaw: An improperly fitted chain can put undue stress on the drive sprocket, clutch, and guide bar, leading to premature wear and costly repairs.
- Safety Hazards: A loose chain can fly off the guide bar, posing a significant safety risk to the operator and anyone nearby. Conversely, a chain that’s too tight can overheat and break.
Key Measurements for Chainsaw Chain Sizing
To accurately determine chainsaw chain length, you need to know three critical measurements: pitch, gauge, and the number of drive links. These measurements are often found together as the “chainsaw chain number” or specification.
1. Chainsaw Chain Pitch
Chainsaw chain pitch is the distance between the drive links, measured from the center of one rivet to the center of the next rivet, then divided by two. It’s a vital measurement because it dictates the size of the drive sprocket and the overall spacing of the cutters. Chainsaws are designed to work with specific pitches.
Common chainsaw chain pitches include:
- .325 inches
- 3/8 inches (often referred to as 0.375 inches)
- .404 inches
How to Find Your Chain’s Pitch:
- Check Your Chainsaw Manual: This is the most reliable source. Your manual will specify the exact pitch required for your model.
- Look on the Guide Bar: Most guide bars have the pitch stamped on them, usually near the base where it attaches to the chainsaw. It might be preceded by a decimal point (e.g., “.325”).
- Measure: If you can’t find this information, you can measure it. Take a new or old chain and measure the distance from the tip of one drive link’s tooth to the tip of the next tooth. Divide this measurement by two. For example, if the distance is approximately 0.65 inches, your pitch is .325 inches. This method is less precise but can be helpful in a pinch.
2. Chainsaw Chain Gauge
Chainsaw chain gauge refers to the thickness of the drive link that fits into the groove of the guide bar. This ensures a snug fit, preventing the chain from wobbling or coming off the bar. The gauge is usually measured in millimeters or inches.
Common chainsaw chain gauges include:
- 0.043 inches (1.1 mm)
- 0.050 inches (1.3 mm)
- 0.058 inches (1.5 mm)
- 0.063 inches (1.6 mm)
How to Find Your Chain’s Gauge:
- Check Your Chainsaw Manual: Again, the manual is your best friend here.
- Look on the Guide Bar: The gauge is often stamped on the guide bar near the pitch marking. It might be a number like “1.3” or “1.5”.
- Measure: You can also measure the drive link. The easiest way is to look at the drive link on the chain. You can compare it to a known gauge measurement or use a caliper for precise measurement.
3. Chainsaw Drive Links
The drive links are the small tabs on the bottom of each chain segment that fit into the guide bar’s groove and engage with the drive sprocket. The number of drive links directly determines the total length of the chain.
How to Find Your Chain’s Drive Link Count:
- Count Them! This is the most direct method. Lay your old chain flat and carefully count each drive link. Ensure you count consistently from one end to the other.
- Check the Chainsaw Chain Number: Sometimes, the drive link count is part of the chain’s model number or specification. For example, a chain might be designated as 72 drive links.
Fathoming the Chainsaw Chain Number
The “chainsaw chain number” is often a combination of the pitch and gauge. For instance, a common specification might be “3/8″ pitch, .050″ gauge.” Some manufacturers use specific codes that incorporate drive link counts as well. Always refer to your chainsaw’s manual or the markings on your existing chain and guide bar to correctly identify the chain specification.
Determining Chainsaw Chain Size Without a Manual
If you’ve lost your manual or the markings on the chain and bar are unreadable, you can still determine the correct chainsaw chain size.
Method 1: Measuring an Existing Chain
This is the most common method when the manual is unavailable.
What You’ll Need:
- Your old chainsaw chain (even if broken)
- Measuring tape or ruler (preferably with fine markings)
- A flat surface
Steps:
- Lay the Chain Flat: Gently lay the old chain on a flat surface. If it’s broken, try to piece it together as closely as possible, aligning the drive links.
- Measure the Pitch:
- Identify a starting drive link.
- Measure from the center of the rivet on this drive link to the center of the rivet on the next drive link.
- Divide this measurement by two. This is your pitch.
- Example: If the distance between the centers of two consecutive rivets is 0.65 inches, the pitch is 0.65 / 2 = 0.325 inches.
- Measure the Gauge:
- Examine the drive link. You need to measure its thickness where it sits in the guide bar groove.
- The easiest way is often to compare it visually to known gauges if you have them available, or use a caliper for precision. If you have a ruler with very fine markings, you can try to measure the thickness directly. Common gauges are 1.1mm (0.043″), 1.3mm (0.050″), 1.5mm (0.058″), and 1.6mm (0.063″).
- Count the Drive Links:
- Carefully count each drive link from one end of the chain to the other. A drive link is the piece that protrudes downwards and engages with the guide bar.
- Be precise. Make sure you count every single one.
Once you have these three measurements (pitch, gauge, and drive link count), you have all the information needed to purchase a chainsaw chain replacement.
Method 2: Measuring the Guide Bar
While less reliable for pitch and gauge than measuring the chain itself, the guide bar can provide clues.
What You’ll Need:
- Your guide bar
- Measuring tape or ruler
- Magnifying glass (optional)
Steps:
- Check Markings: As mentioned earlier, look for stamped numbers on the guide bar. These usually indicate the pitch and gauge. You might see something like “.325 – .050” or “3/8 – 1.3”.
- Measure Bar Length: This is not directly for chain length but is crucial for compatibility. Chainsaw bar length is measured from the tip of the bar to the point where the chain engages the clutch drum (not the total length of the metal bar). This is important because a chain designed for a 20-inch bar might not work optimally on an 18-inch bar, even if pitch, gauge, and drive links are correct, due to differences in the groove and overall design.
Matching the New Chain to the Guide Bar and Saw
It’s not enough to just know your chain’s specifications; you must ensure they match your guide bar and chainsaw model.
- Pitch and Gauge Match: The new chain’s pitch and gauge must match the guide bar and the drive sprocket on your chainsaw. If they don’t match, the chain simply won’t work and could cause significant damage.
- Drive Link Count and Bar Length: The number of drive links on your new chain should be appropriate for the length of your guide bar. Generally, longer guide bars require more drive links. Manufacturers design chains for specific bar lengths.
Buying a Chainsaw Chain Replacement
When purchasing a new chain, you’ll typically provide the following information:
- Chainsaw Model: This is often the easiest way to ensure you get the right chain. Many retailers can look up the correct specifications based on your chainsaw’s make and model.
- Pitch: e.g., .325″, 3/8″, .404″
- Gauge: e.g., .043″, .050″, .058″, .063″
- Drive Links: The exact count of drive links.
You might also see chains referred to by a chain number or part number specific to the manufacturer or a universal numbering system. Always cross-reference this with your chainsaw’s requirements.
Common Pitfalls to Avoid When Measuring Chainsaw Chain
- Inaccurate Measurements: Using a faulty ruler or measuring incorrectly (e.g., not measuring from rivet center to rivet center for pitch) can lead to buying the wrong chain.
- Confusing Chain Length with Bar Length: Remember that chain length is determined by drive links, while bar length is the cutting length of the guide bar. They are related but not the same measurement.
- Ignoring Gauge: Pitch and drive links are important, but if the gauge doesn’t match your guide bar’s groove, the chain won’t function correctly.
- Not Checking the Sprocket: While less common, if your drive sprocket has been replaced with an aftermarket one, ensure its pitch matches the chain you intend to buy.
Replacing Your Chainsaw Chain
Once you have the correct chain, replacing it is a straightforward process.
What You’ll Need:
- New chainsaw chain
- Screwdriver or chain adjustment tool
- Gloves
Steps:
- Safety First: Ensure the chainsaw is turned off and the engine is cool. Wear protective gloves.
- Loosen the Bar Nuts: Loosen the nuts that hold the guide bar in place. You don’t need to remove them completely.
- Release Tension: Most chainsaws have a tensioning screw. Loosen this to release tension on the old chain.
- Remove the Old Chain: Slide the old chain off the guide bar and clutch sprocket.
- Place the New Chain: Position the new chain around the guide bar, ensuring the cutters are facing the correct direction (they should point forward on the top of the bar).
- Engage the Sprocket: Fit the drive links of the new chain into the groove of the guide bar and onto the drive sprocket.
- Tension the Chain:
- While holding the guide bar up slightly, tighten the chain tensioning screw until the chain is snug but can still be moved by hand.
- A properly tensioned chain should be tight enough not to sag off the bar, but loose enough to be pulled around the bar by hand with a gloved hand. It shouldn’t feel stiff or jammed.
- Tighten the Bar Nuts: Tighten the bar nuts firmly.
- Final Tension Check: Re-check the tension after tightening the bar nuts. The chain might have tightened slightly. Adjust as needed.
- Run the Chainsaw: Start the chainsaw and let it run for a moment. Check the chain tension again. New chains can stretch slightly as they seat themselves.
Troubleshooting Chain Tension
- Too Loose: The chain will sag and may come off the bar. Tighten the tensioning screw.
- Too Tight: The chain will be difficult to move by hand and may bind or overheat. Loosen the tensioning screw.
- Proper Tension: The chain moves freely by hand, but there’s no slack.
Frequently Asked Questions (FAQ)
Q1: Can I use a longer or shorter chain than what my chainsaw is designed for?
No, it is strongly advised against. Using a chain with the wrong number of drive links will prevent it from fitting correctly, leading to poor performance, damage, or safety hazards.
Q2: What happens if I use a chain with the wrong pitch?
If the pitch is wrong, the chain will not engage properly with the drive sprocket or the groove in the guide bar. This will prevent the saw from cutting effectively and can cause severe damage to the sprocket, bar, and chain.
Q3: What happens if I use a chain with the wrong gauge?
If the gauge is too thick, the chain will not fit into the guide bar groove. If it’s too thin, the chain will be loose and wobbly, leading to poor cutting and potential damage. The drive sprocket may also not engage correctly.
Q4: Where can I find the chainsaw chain number?
The chainsaw chain number is typically found in your chainsaw’s owner’s manual. It might also be stamped on the guide bar itself. If you’re unsure, counting the drive links and measuring the pitch and gauge of an existing chain is the most reliable method.
Q5: Is it okay to buy a chain from a brand different from my chainsaw manufacturer?
Yes, as long as the pitch, gauge, and drive link count are identical. Many reputable aftermarket chain manufacturers produce high-quality chains that are compatible with various chainsaw brands. Always double-check specifications.
Q6: How do I know if my guide bar is worn out?
A worn guide bar can have a rounded groove, frayed edges, or be bent. You’ll notice a loss of cutting performance, and the chain may not sit correctly. It’s recommended to replace the guide bar along with the chain if it shows significant signs of wear.
By following these steps and paying close attention to the key measurements, you can confidently determine the correct chainsaw chain length for your saw, ensuring efficient and safe operation for all your cutting tasks.