It is no secret that chainsaws are indispensable tools, especially when it comes to cutting jobs. Whether you want to prune a few branches or fell an oak tree, you can rely on this tool to get the job done.
The bulk of this cutting task lies specifically on the chainsaw bar and chain. Over time though, these parts can start to wear out. When they do, the best thing you can do is to replace them.
Now to find all the correct components for replacement, you should first establish the size of the current bar and chain. This way, you don't end up installing an ill-fitting chain or bar. So here, we’ve provided a detailed guide on how to measure a chainsaw bar.
Why You Need to Measure a Chainsaw Bar
Before we get into the nitty-gritty of how to measure a chainsaw bar, let’s look at the reasons that might necessitate this action.
In a perfect world, chainsaws would last for a lifetime, especially if they’re well taken care of. Sadly, this is not the case as both the chainsaw chains and bars wear out over time. When this happens, it’s good to replace them with brand new ones to keep your chainsaw running smoothly.
Apart from that, there are other instances where an operator wishes to replace their current tool with either a larger or smaller bar. If this is the case, you’ll need to determine the size of your current bar so that you can buy the right replacement from a hardware store.
Whatever your reason is, a chain or bar replacement requires you to figure out the length of your existing bar as well as the chain that corresponds to it.
That said, keep in mind that the length of the bar can affect your chainsaw’s performance. If you use one that is too long for the saw, it may struggle. Similarly, using the wrong bar or chain can cause it to detach abruptly, leading to serious injury.
Now that you know why it's necessary, let's dive into the steps you should take to measure a chainsaw bar.
How to Measure a Chainsaw Bar
We’ll start with the basics. The guide bar is simply the blade or cutting tool of a chainsaw. It’s the long flat metallic piece, on which the chain moves over as it cuts.
As highlighted later in the guide, the length of the chainsaw bar depends largely on the type of saw you're using. For now, let's look at how to measure a chainsaw bar for a new chain.
How to Measure a Chainsaw Bar Manually
A chainsaw bar manually measuring process is quite simple.
All that’s needed is just a tape measure. Next, estimate the length of the bar, starting from the tip of the chain all the way up to the cutter closest to the chainsaw body. Finally, round up this figure to the nearest inch that’s an even number.
The distance you’ve just estimated is referred to as the “called length” or “useable length”. It is so-called because it’s the section of the bar that’s used to cut trees, limbs, and other items.
There are two other types of bar lengths that you should be keen on when measuring your chainsaw bar:
Effective Cutting Length
This is the distance of the bar as estimated from its tip to the point where it enters the chainsaw body. Follow these steps to determine the effective length:
- Take your tape measure and place it at the very end of the bar
- Next, use this measuring tape to estimate the distance from that tip to the point where the bar enters the chainsaw body
- If you get an odd number, round it up to the closest even number
Chainsaw bars are only described using even numbers. This is why it’s important to round the measurement to the closest even number to get the effective cutting length.
For instance, if you found the distance to be 13 inches, a suitable replacement chainsaw bar length would be 14 inches. Similarly, if you get the effective cutting length as 14 ¾ inches, then you’d look for a 16-inch bar.
True Length
This refers to the actual length of the chainsaw's bar because it's measured from one end to the other. As such, the actual length/true length will always be longer than the effective cutting length.
Truth be told, the true length is not as commonly used as the effective cutting length. However, you can still use this cutting length to estimate that of the new bar.
Follow these steps to determine the required length:
- Start by loosening the bolts that are holding the chainsaw bar cover in place. This should allow you to remove the cover completely, to expose the entire length of the bar.
- Now, gently remove the chainsaw blade/bar and put it on a level surface
- Then using a tape measure, estimate the length of the bar from one end to the other
Unlike the earlier method where you had to round up the result, this approach gives you pinpoint accuracy. So what you get is the right length of the chainsaw bar.
Once you’ve attained the true length and effective cutting length, the only thing left is to compare the two figures to get the ultimate fit.
If you own a Stihl chainsaw, the Oregon 105671 makes for an excellent bar and chain replacement combo. It’s pretty versatile and can be used with gas-powered chainsaws of up to 62cc. The cutting length of this chainsaw bar is 20 inches, and its chain measurements are as follows: gauge .063” and pitch .325”.
Safety Tips When Measuring Chainsaw Bar
On the surface, the procedure to measure a chainsaw bar might not appear risky. Still, you’ll want to adhere to a few safety tips, especially if you’ll be taking the measurements and handling the chain all on your own.
Turn off the chainsaw
This should be the first step you take. If it’s a battery-powered saw, then remove the batteries. And if it’s corded, then be sure to unplug it from the socket.
Remove the spark plug wire
To do this, first seize the rubber cap covering the spark plug. Then, pull the plug wire until it’s completely free. This step ensures that you can’t accidentally turn the chainsaw on.
Place the chainsaw on a flat surface
If you've decided to measure a chain manually, it's advisable to place the bar and chain system on level ground. This significantly enhances your safety.
Follow the owner's manual
The measuring process you undertake will also depend on the specific brand of chainsaw. For instance, Husqvarna requires users to disconnect the spark plug before placing your tape measure on the saw's housing where the bar emerges.
How to Measure Chainsaw Chain
Learning how to measure the size of the chainsaw chain is a little more difficult, but not entirely impossible. To determine what chain fits your saw, there are three elements that you’ll want to pay attention to, namely: gauge, pitch, and the number of links in the chain.
If you have the original chainsaw bar, you may find these chain and bar measurements printed on it. In the majority of chainsaws, these measurements are printed on the side of the bar just close to the user end. However, this placement may vary depending on the manufacturer.
If you’re new to the world of chainsaws, you may experience difficulty distinguishing between the printed metrics. So here are a few pointers:
- The chain pitch measurement is typically located below the brand’s name. It’s described in the form of inches. For instance, if you come across “⅜”, this means the chain pitch is ⅜ inch (0.95 cm).
- The gauge is described using both inches and millimeters. Often, it’s printed to the right side of the brand’s name. For example, if your chainsaw reads “.058’/1.5mm, it means your chain’s gauge is .058 inches.
- As for the number of drive links, the figure will likely have the letters “DL”. For instance, if you see “66DL”, this means your chainsaw has 66 links.
If you don't find any of these metrics next to the model number, consider checking the owner's manual. Every manufacturer is required to provide an accurate description of their chainsaw bar in the user manual. In case you lost your manual, follow these steps to determine your chain’s size:
1. Determine the Number of Drive Links
This is one of the few steps that can be a little tiring. But first, what are drive links? Well, these are the triangle-shaped extensions located underneath the chainsaw chain. They’re responsible for attaching the chain to the bar.
To access them, you’ll need to remove the chain first. Using a wrench, start by removing the cutting bar’s side panel. Next, loosen the chain’s tension with the help of a screwdriver. Finally, detach the chain from the bar and start counting the drive links.
The vast majority of chainsaws have drive links ranging from 66 to 72. Those with a 16-inch length have 66 links whereas 18-inch models have up to 72 links.
Quick tip: be sure to don safety gloves to avoid getting injured by the chainsaw chain links.
2. Determine the Pitch
Drive links are typically held in position by rivets. Not only do these rivets keep the links firmly attached but they also provide some wiggle room. The flexibility is what allows the chain to flex as it winds around the bar.
So how do you measure the pitch? Simply estimate the distance between any three consecutive rivets. While you’re at it, measure from the middle point of the first rivet to the middle point of the third.
It’s important that you measure this distance accurately. To achieve this precision level, it’s best to start at the 1-inch increment on your tape measure rather than its end.
Once you get the result, divide it by two and this will be the chain’s pitch. For instance, let’s say you’ve measured the distance and found it to be 6/8 of an inch.
The pitch will be ½ of 6/8”, which equates to ⅜ inches. On that note, the most common chain pitches are 0.325", 3/8", and 0.404" pitch.
3. Measure the Chain Gauge
The gauge is a measure of how thick the drive links are. The easiest way to determine this metric is to use the coin test.
Look for three types of coins: a dime, penny and a quarter. Using one coin at a time, try to fit each one into the chainsaw bar groove.
If it's the correctly-sized coin, then it will glide and fit right in the groove with minimal effort. If the coin ends up being too narrow, it will likely rattle around instead of fitting snugly. Conversely, if it’s too wide, then it won’t fit at all. Here are a couple of guidelines to help you determine the chain gauge size:
- Penny: .043-inch
- Dime: .058-inch
- Quarter: .063-inch
Ultimately, not every individual is a DIY enthusiast. Some may find the process of measuring the chain and bar a little tiring.
If this sounds like you, you can always take your saw to the nearest hardware store. Not only can they take these measurements for you but they can also do the replacement.
Chainsaw Bar Sizing Guide
Another crucial point that you should keep in mind is that not every chainsaw can handle just any bar length.
A longer bar will certainly require more power to run or operate. This explains why most electric chainsaws can’t handle any blade that’s longer than 18 inches. Their motors or rechargeable batteries just don’t have enough power to drive very long bar and chain systems.
This means that if you have projects that call for a massive cutting capacity, your best bet is a gas-powered chain saw. This power tool can easily power and drive the longest bar, which is usually a 72-inch chain bar. Here’s a quick summary to help you make an informed decision:
Gas Chainsaws
The length of such a chainsaw bar usually starts at 16 inches and can go all the way up to 72 inches. However, the maximum length you’ll find on most gas saws is 24 inches. This is ideal for felling larger trees.
Corded Chainsaws
These are the second smallest of the bunch. The chainsaw blade length typically ranges between 14 and 16 inches, which makes it ideal for felling small trees.
Battery-Operated Chainsaws
The bar length on these chainsaws can go up to 18 inches. This means they can be used to bring down medium trees.
Mini Cordless Chainsaws
The length on this chainsaw bar ranges from 6 to 9 inches. These are only good enough for light-duty tasks like pruning limbs.
Generally, the new chainsaw bar should be at least two inches longer than the diameter or thickness of the material you intend to cut. This extra wiggle room provides enough bar length to tackle the stock in one single pass.
Conclusion
Has your chainsaw bar and chain been showing signs of wear? If either of them has, you may want to start budgeting for a new one. But before you start window-shopping, you should learn how to measure a chainsaw bar and chain.
For the bar, you’ll want to estimate either the called length or true length. And when it comes to the chain, determine the pitch, gauge, and the number of cutting links on your existing chain.
Once you have all these estimates on hand, you can start shopping for the correct replacement bar.
While you’re at it, don’t forget to consider the type of chain saw you have. Electric chainsaws are best equipped with a maximum bar length of 14 inches. Gas-powered chainsaws that run on beefy engines can take much longer bars.
Don't skip this procedure of measuring your chainsaw bar. Using the right chainsaw for your DIY projects not only guarantees efficiency but also enhances your safety.
Similarly, always adhere to the size restrictions/guidelines provided by the manufacturer. Don't try to fit a bar longer than what's been recommended.