2018 Buyer's Guide

How to measure a chainsaw bar

2018 Buyer's Guide

How to measure a chainsaw bar

by Ollie Robinson

Knowing how to measure your chainsaw bar properly is important, but the first thing you have to understand is what a chainsaw bar actually is. The chainsaw bar is the middle part of your chainsaw that the chain actually runs along. It is a track that rotates the chain quickly to allow for cutting. Chainsaw bars come in several different lengths and in order to perform maintenance on your chainsaw and keep it running perfectly you need to be able to measure your chainsaw bar properly. This guide will take you through the entire step-by-step process as well as cover some basics like the tools that you will need and the safety precautions that you need to take in order to perform this measurement.

Why is it Important to Measure Your Chainsaw Bar?

It is important to measure your chainsaw bar because that is going to be how you figure out the length of the chainsaw bar that you are going to purchase to replace it. Your chainsaw bar does have to be replaced periodically, just like many of the other components of your chainsaw, and although the information needed to replace your chainsaw bar and purchase the correct size is located in the manufacturer specifications that came with your chainsaw, most people do not save this information and it can be a struggle to find it online.

That’s why it is useful to know how to measure your chainsaw bar yourself. The process is pretty straightforward, and learning how to do it will give you a valuable skill that you can use to maintain your chainsaw and not have any excuse not to replace the chainsaw bar or chain when they start to wear out.

What to Measure

One of the things that you will learn is that there are two different measurements that you need to take. The first measurement is the effective cutting length of the bar, while the other is the entire length of the chain bar. Let’s look at these in more detail.

Effective Cutting Length: You probably already know that the entire length of your chainsaw bar is not used for cutting. That’s because part of the bar is hidden within your chainsaw. When you remove the bar, you will be removing the fasteners that keep it locked to the chainsaw and those are located beyond where the cutting area starts. The distance from where the bar protrudes from the chainsaw to the tip is known as the effective cutting length.

Entire Chain Bar Length: You also want to have a measurement of the entire chain bar length. This is accomplished by removing the bar and then measuring it from one tip to another. Both of these measurements can be useful when it comes to deciding which new chainsaw length or chainsaw bar that you need.

What Tools do You Need to Measure Your Chainsaw Bar?

There are a few tools that you’re going to need to gather up and have on hand if you want to measure your chainsaw bar. These are pretty standard tools that you already have around the house – especially if you already perform maintenance on your chainsaw. However, knowing what these tools are will make sure that you are prepared when it comes time to change your chainsaw chain or bar.

A Flat Surface: The first thing that you’re going to need is some kind of flat surface that you can say your chainsaw down on that can be scratched or damaged. Obviously, if you have a tool bench in the garage that you normally use to work on stuff, then this is going to be the best choice. However, if you do not have a workbench, then putting a piece of plywood on a couple of sawhorses will do the trick nicely.

A Measuring Tape: You will also need a measuring tape. This can really be any kind of measuring tape, but you may want to consider going with the type of measuring tape that is soft and folds up into a little package instead of the measuring tape that you normally clip your belt that is retractable.

Chainsaw Tools: Depending on the type of chainsaw that you have, you might need various tools in order to remove the chain and the bar. This will depend upon how your chainsaw comes apart. If you have taken your chainsaw part before, then you know what tools you need, and if not, check the manufacturer specifications or look online to find out.

Work Gloves: You are going to need work gloves as well. You do not want to be removing chainsaw chains and working with a potentially sharp chainsaw bar without work gloves because you can cut yourself quite deeply. They should always be a part of your standard equipment when you are doing any maintenance on your chainsaw.

How to Measure a Chainsaw Bar in 7 Steps

Here is a step-by-step guide that will show you exactly how you can measure your chainsaw bar as well as perform the types of maintenance that go with this measurement. There really isn’t all that much to measuring your chainsaw bar, but it can be useful to see the various steps that you need to accomplish broken down in a way that makes it very clear what needs to be done.

Step One: Prepare Your Measuring Area

The first step that you are going to perform is preparing your measuring area. If you are going to be working on the tool bench or some type of surface that you don’t care get scratched then all you need to do is set up that surface and place your chainsaw onto it. However, if you are going to be working on your kitchen table or some other surface that can get scratched then you may want to lay down a blanket to protect that surface.

Step Two: Gather Your Tools

Next, you will gather up the tools that you will be used to perform the measuring. This includes a sturdy pair of work gloves, a measuring tape that is flexible enough readability use on your chainsaw bar and whatever tools are required for you to remove the chain from your chainsaw and remove the bar from where it is fastened underneath your chainsaw as well.

Step Three: Remove the Chainsaw Chain

You will want to remove the chainsaw chain next. Generally, there are two nuts that hold the side plate onto the chainsaw. Unscrew the nuts and remove the plate so that you can access the chain. Sometimes the chainsaw brake is attached to the guide bar side plate. If this is the case, make sure to unlock the brake before you remove the sprocket. It can be extremely difficult to remove the chain if the brake is in the locked position and it can be almost impossible to reinstall it. You also need to release the chain tension. Pull the nose of the chainsaw’s bar away from the chainsaw to release it from the tensioner. Now remove the chain. If you are not replacing the chain at this time, you can put it back on after you replace the bar.

Step Four: Measure the Cutting Length of the Bar

The first measurement that you will be taking is the cutting length of the bar. You can actually take this measurement while the chainsaw bar is still attached to the chainsaw if you want, although it is possible to take this measurement after you remove the bar as well. If you have left the bar on the chainsaw, then all you need to do is measure from the very beginning of where the bar comes out to the tip. You may not get an exact measurement with this, but you need to be able to round it off to an even number and fit it into one of the standard lengths of chainsaw cutting sizes. So, rounded to the nearest even number and it should come to be 10, 16, 18 or 20 inches.

Step Five: Measure the Full Length of the Bar

The second measurement you will take is the full length of the chainsaw bar. To get the length of the entire chainsaw bar, you are either going to have to remove it from the chainsaw or you’re going to need to take off some of the parts so that the entire length of the chainsaw’s exposed. This will probably require that you use a ratchet and socket. Once you have exposed the bar or taken it off of the chainsaw completely, then you can measure it by simply using your tape measure from one side of the chainsaw to the other – from one tip to the other tip.

Step Six: Measure the Number of Drive Links & Pitch

If you are going to replace your chainsaw chain, then you’re going to want to measure the number of Drive links and figure out the pitch of the chain. The drive links are the links in your chain that are protruding from the underside and they grab the drive cog which allows you to use the chainsaw to cut. They are sometimes referred to as lugs. Count the number of drive links that are on the chain. To figure out the pitch of the chain, all you have to do is measure the distance between any of the three consecutive rivets that are holding the chain assembly together. You will be measuring from the center of the rivet on one side all the way to the center of the rivet on the other side and dividing by two. Once you remove the chain, you will probably be able to determine what the rivets are easy.

Step Seven: Put on the New Chainsaw Bar or Chain

Finally, you will need to put your new chainsaw bar or chainsaw chain back on the same way that you removed the old one. This is where those chainsaw tools will come in handy, and it is usually a fairly straightforward process, although if you have trouble then you may want to look up a tutorial online for your particular chainsaw model. There probably videos from other people who have replaced the bar or chain on that particular model that you can use to guide your own efforts.

When to Replace Your Chainsaw Bar

Knowing when you should replace your chainsaw chain is definitely useful information to have. First of all, you want to inspect the rails on the bar’s heel. Turn the bar and look at the profile in the heel. You will notice that worn bars have narrow tails and it is one of the warning signs that your bar needs replacement.

Another sign is that the inside rails are more visible. With a brand-new chainsaw bar, they are hard to see. With the chain on the bar, hold a strange edge against tooth side plate in the body bar. Good side rails hold the bar. If worn down, then the chain tends to lean. You definitely want to replace your bar right away if the inside rails are worn because this can be dangerous.

However, the most common and telling sign that a chainsaw bar needs to be replaced is that your chainsaw will not cut straight anymore. There is very little else that can cause the chainsaw angling away from your cut as you are working, so this is the case then it’s probably due to needing to replace your bar.

What is Chainsaw Chain Pitch and Gauge?

Let’s look at a couple of different subjects that you should be aware of: chain pitch and gauge. Understanding these are important parts of replacing your blade properly.

Chain Pitch: Chain pitch is a measurement of the three consecutive rivets that hold the chain assembly together. The way that you measure pitch is by starting your tape measure right in the center of one rivet and then measuring to the center of the third rivet on the far side. You will then divide that number in half. This will give you your pitch measurement.

Gauge: Gauge is the measurement of the width of the groove in your chainsaw bar. Measuring gauge accurately might require some special tools, but there is a way that you can estimate gauge by using standard coins. Simply clean as much wood chip debris as you can out of the chainsaw bar groove and then see if a penny, quarter or dime fit the best in that groove without being forced. If it is a quarter, then the gauge is around .063, a penny is .058 and a dime is .050.

Safety Precautions to Take

There are definitely some safety precautions that you need to take when you’re working with your chainsaw. First of all, remove the chainsaw spark plug so that it cannot start up accidentally. This is very difficult when you have a pull start, but it becomes much more possible with the push-button start. Removing the spark plug will make sure that even if the start mechanism is activated that the chainsaw does not fire which could result in serious injury.

The other thing you want to do is keep in mind that the chainsaw chain, the chainsaw bar and various other components of the chainsaw are very sharp. You always want to be wearing a thick pair of leather gloves whenever you are working with your chainsaw. That’s why it is recommended in the list of tools above.

Final Thoughts

The bottom line is that there plenty of things to keep in mind when it comes to measuring your chainsaw bar and replacing your bar or chain. However, this guide should give you some pretty clear instructions and other information that you need in order to measure your chainsaw bar correctly and to do this required maintenance. Chainsaws do need their chains and bars replaced periodically, so this is an important thing to learn.

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