The body or casing of the chainsaw holds the 2-stroke (gas) or 3 phase AC motor (electric) and a multitude of other parts. However, the more important parts are the ones that protrude for cutting: the bar and the chain.
It’s important to note that not every bar or chain will work for every saw. For instance, larger chainsaw bars work well with more powerful motors because it takes more energy to drive the chain around the bar. This is also why most electric chainsaws are typically smaller at around 12-14”. They don’t have the necessary amperage to drive the chain effectively.
A chain that doesn’t fit properly on your chainsaw presents a dangerous hazard. If you are unsure in any way about the sizing of your chain, you should have it serviced by a professional. Before you take out your tape measure, you should also consult your chainsaw’s owner manual. If you’ve lost it, you can likely find the manufacturer’s website and locate it online.
If you aren’t interested in finding the model number and finding the details, don’t fret! You can determine the length on your own.
How to Measure a Chainsaw Bar
Measuring the Chainsaw Bar Length
To preface, the standard bar lengths for chainsaws are 16, 18, and 20 inches. However, longer bars do exist and can exceed 24 inches. When taking a measurement, you should round to the nearest even whole number.
Note: Bar lengths and other metrics like pitch, gauge, and drive links can be found on the existing bar in some cases.
- Using your tape measure, measure from the front tip all the way back to the cutter closest to the body.
- Round the measurement to the nearest even number in inches. For instance if you measured 15”, you’ll need a 16” bar. If you record 18.75” you’ll need a 20” bar.
It’s as simple as that. Once you have the bar length you can simply buy a replacement bar that meets that length requirement.
Measuring the Length of your Chainsaw’s Chain
In addition to determining the bar length of your chainsaw, you should be able to measure your chain’s pitch, gauge, and drive links.
To start, you should count the number of drive links that the chainsaw has.
Note: While these numbers are usually indicative of the noted length, certain brands like Stihl like to be different. For instance a 16” chain will usually have 66 drive links. Stihl however, can use 67.
In order to determine the pitch or chain size, you’ll need to measure the distance between the centers of three consecutive rivets and then divide this by 2. The rivets are the small, round studs that hold the chain segments together. The resulting quotient is the size of the chain’s pitch. The standard sizes for pitch are 0.375” and 0.325”.
For a simple computation of the chain pitch, this is a shorter formula:
Chain Pitch = [distance between 3 consecutive rivets] / 2
The chain’s gauge is a measure of the thickness of the drive links. Ideally, you can confirm this measurement by using calipers and checking the width of the drive links. However a quicker way of doing so is using a quick trick with coins.
- Grab a quarter, a penny, and a dime.
- Clean the debris from the bar’s groove.
- Slide each coin into the chainsaw bar groove without being forced.
Determine which fits and associate the coin with a specific gauge measure below.
Quarter = 0.063
Penny = 0.058
Dime = 0.050
If you add up the pitch and gauge, you are now able to determine the size of your chain, where the size of your chain pitch plus the number of your drive links is indicative of the required length.
You are now prepared to purchase the replacement bar and chain for your saw.