How to Measure Bar Length on a Chainsaw

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Learn to quickly & easily take bar length measurements
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The bar on a chainsaw is the metal part that the chain wraps around. You may need to determine the size of your chainsaw bar to replace either the bar or the chain. Luckily, measuring the bar is easy. We’re here with everything you need to know about measuring a chainsaw, including sizing a chainsaw bar , measuring and choosing a chain, and common mistakes to avoid along the way.

Quick Guide to Measuring a Chainsaw Bar

To measure the bar length of a chainsaw, make sure the chainsaw is unplugged. Then, use a tape measure to find the length from the tip of the chainsaw bar to where it meets the body of the chainsaw. Round that number up to the nearest whole, even number to get the standard bar size.

Section 1 of 5:

How to Measure Bar Length on a Chainsaw

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  1. Set your chainsaw down on a flat surface with the handle facing up. Use a screwdriver or wrench to loosen the screws or bolts holding the top cover on the chainsaw's body. Look for a black wire plugging into a circular port under the cover, and pull the wire out of the port to disconnect power from the spark plug. [1]
    • Unplugging the spark plug will ensure that the saw can’t start while you're working on it.
    • The location of the screws or bolts may vary depending on the chainsaw model you have—check your owner’s manual if you aren’t sure where to find it.
  2. Place the end of a tape measure where the bar goes inside the main chainsaw body. Extend the tape until you reach the tip of the bar and record your measurement. Round the measurement to the nearest even number to find the cutting length of your bar. [2]
    • For example, if the measurement you took is 13 1 ⁄ 8  in (33 cm), the cutting length is 14 in (36 cm).
    • The cutting length may also be referred to as the called length, usable length, or effective length.
    • The average cutting lengths on most chainsaws are 14 in (36 cm), 16 in (41 cm), 18 in (46 cm), and 20 in (51 cm).
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  3. Locate the 2 nuts on the right side of your chainsaw holding the clutch cover in place, and use a wrench to unscrew them. Once you take off the nuts, pull the cover straight off of the chainsaw to expose the rest of the bar. Move the bar forward so it releases from the clutch before pulling it off of the bolts.
    • If your chainsaw has a brake, make sure it's in the locked position before removing the clutch cover. Otherwise, it will be difficult to put back on.
    • Safety tip: Wear work gloves if you still have a chain on the saw so you don't accidentally cut yourself.
  4. Start your tape measure on one end of the bar and extend the tape to the tip on the other side to find the true length. Round the measurement to the nearest inch to know the true length of the chainsaw bar. [3]
    • For example, if the measurement is 16 1 ⁄ 3  in (41 cm), then the true length of the bar is 16 in (41 cm).
    • Standard chainsaw bar lengths are between 8–24 in (20–61 cm)
    • The true length of the chainsaw bar will always be longer than the cutting length.
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Section 2 of 5:

Measuring the Chain

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  1. Locate the two nuts on the right side of your saw that hold the clutch cover in place, and use a wrench to remove them. Take off the clutch cover so you can access the rest of the chain. Carefully pull the bar toward you to release tension on the chain so it hangs loose. Grab the chain and unloop it from around the clutch, which is the cylinder where the bar connects to the saw. [4]
    • Wear work gloves to help protect your hands from the chain's teeth since they can be sharp.
  2. 2
    Measure 3 consecutive rivets and divide by 2 to find the chain’s pitch. Lay the chain on a flat surface so you can see the rivets, which are the circular metal pieces that hold the chainlinks together. Start your tape measure at the center of any rivet on the chain. Pull the tape along the chain until you reach the center of the third rivet to take the measurement. Divide that measurement by 2 to find the chain's pitch. [5]
    • For example, if the distance between the 3 rivets is 3 ⁄ 4  in (1.9 cm), divide it by 2 to get a pitch of 3 ⁄ 8  in (0.95 cm).
    • The pitch may also be listed in inches on the right side of the chainsaw's bar.
  3. The gauge of the change refers to the thickness of the drive links that fit in the groove on the chainsaw's bar. Put one of the drive links, which are the pointed metal pieces on the inside of the chain, between the jaws of a caliper and slide the jaws closed so it grips the drive link tightly. Check the measurement reading on the caliper to know the gauge. [6]
    • The gauge measurement is usually listed on the side of the chainsaw's bar in inches if you aren't able to measure it.
    • The standard gauge sizes are 0.043 in (1.1 mm), 0.050 in (1.3 mm), 0.058 in (1.5 mm), and 0.063 in (1.6 mm).

    Variation: If you don't have a caliper, try sliding a penny, dime, and quarter into the groove on the chainsaw's bar to see which one fits snugly without forcing it in. Use the type of coin to determine the gauge size.

    Dime: 0.050 inches (1.3 mm)
    Penny: 0.058 inches (1.5 mm)
    Quarter: 0.063 inches (1.6 mm)

  4. The drive links are the pointed metal pieces that are on the inside of the chain. Lay the chain on a flat surface and put a small piece of tape on one of the drive links. Start counting the number of drive links along the length of the chain, starting with the one you marked. Continue counting the drive links until you reach the one you marked and write the number down. [7]
    • You can also place the chain on a flat surface and line up the links so they’re across from each other, then count the links by 2s.
    • You may be able to find the number of drive links on the side of the chainsaw's bar labeled with “DL” (drive links).
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Section 3 of 5:

Choosing a New Chain

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  1. 1
    Match the chain pitch and gauge. Always use the exact chainsaw chain recommended for your tool. Using a chain with the wrong pitch and gauge can do more than just affect the performance of your chainsaw—it can be dangerous. [8]
    • Using a chain with the wrong pitch or gauge could cause the chain to bind or come off track while you’re using it.
  2. 2
    Choose the right type of chain for the job you’ll be doing. There are four main types of chainsaw chains. Each is best suited to a particular job. Always check your operating manual to know which type of chains can be used on your chainsaw before choosing one. If your chainsaw accommodates different types of chains, here’s what to know about each one: [9]
    • Low-profile: These are lightweight, low-kickback ( not zero-kickback) chains. They’re usually recommended for chainsaws up to 42 cc and are intended for light-duty projects like trimming small branches.
    • Chisel: Chisels have a squared (or chiseled) leading edge and a rounded side plate. They cut quickly, but they also wear out faster than some chains. Both chisel and semi-chisel are good for moderate use, like cutting firewood.
    • Semi-chisel: Semi-chisels have a rounded leading edge and round side plate. They’re not quite as fast as a chisel chain, but they tend to last longer.
    • Square: Square chisels have a square leading age and flat side plate. This is a powerful, aggressive chainsaw often used for cutting lumber.
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Section 4 of 5:

Common Measuring Mistakes

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  1. 1
    Including the full bar length Chainsaw bar measurements are usually based on the cutting length—the usable portion of the bar when the chainsaw is fully assembled. If you measure the bar while it’s detached from the chainsaw, you’ll get the “true length,” not the cutting length.
  2. 2
    Not rounding to an even number Most chainsaw bar lengths are based on standard sizes. These are typically whole, even numbers. So if you measure your cutting length at 16 1 ⁄ 4  in (41 cm), that could technically be considered an 18 in (46 cm) chainsaw bar.
    • There can be some discrepancy in bar sizes—this may occur because of differences in the size and shape of the clutch cover between different manufacturers and models.
  3. 3
    Misreading or mis-measuring the pitch or gauge Having the wrong pitch or gauge on your chain can cause your chainsaw to malfunction. This leads to a very high risk of injury, so it’s important to be very careful when determining these measurements. [10]
    • If the pitch is wrong, the chain may be too loose or too tight.
    • If the gauge is wrong, the chain might be loose in the groove on the bar, or it might not seat properly.
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Section 5 of 5:

FAQs

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  1. 1
    What does 72 mean on a chainsaw chain? The number 72 probably refers to the number of drive links on your chain. However, it’s important to check your owner’s manual if you’re not sure about the specifications of your chainsaw.
  2. 2
    Can you use a .050 chain on a .042 bar? No, you should always use the correct gauge chainsaw for your bar. Using the wrong gauge can cause the chain to be too loose or not seat correctly in its groove, which is very dangerous.
  3. 3
    What does LP mean on a chainsaw chain? “LP” means low-profile, which refers to the chainsaw pitch. Note that LP and standard chains are not interchangeable—you can not use a 3 ⁄ 8  in (0.95 cm) chain on a 3 ⁄ 8  in (0.95 cm) LP bar.
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      Tips

      • Chain measurements may be printed on the right side of the saw's bar or in the saw's user manual.
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      • Check the user manual for your saw to see if there are specifications for what bar length you can use.
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      Warnings

      • Don't use bars or chains that are the wrong sizes since it could damage your chainsaw or cause injury.
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      • Make sure to disconnect the spark plug on your chainsaw before measuring it so it doesn't accidentally start.
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      Things You'll Need

      • Wrench
      • Tape measure
      • Caliper
      • Marker

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      References

      1. ↑ https://above.nasa.gov/safety/documents/Chainsaw/ABoVE_Chainsaw_Safety.pdf
      2. ↑ https://secure.caes.uga.edu/extension/publications/files/pdf/C+1208_3.PDF
      3. ↑ https://youtu.be/0aEd79YP4Ec?t=42
      4. ↑ https://youtu.be/nSU_ary56dA?t=22
      5. ↑ https://secure.caes.uga.edu/extension/publications/files/pdf/C+1208_4.PDF
      6. ↑ https://secure.caes.uga.edu/extension/publications/files/pdf/C+1208_4.PDF
      7. ↑ https://youtu.be/eDYUvn6tTIE?t=57
      8. ↑ https://www.carltonproducts.com/wp-content/uploads/2019/01/CarltonSafetyMaintManual_EN.pdf
      9. ↑ https://secure.caes.uga.edu/extension/publications/files/pdf/C+1208_4.PDF
      1. ↑ https://www.carltonproducts.com/wp-content/uploads/2019/01/CarltonSafetyMaintManual_EN.pdf

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