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How to Measure a Chainsaw Bar?

Chainsaws are known to be highly effective tools for tasks like wood and tree cutting, pruning of branches, and more- but for them to function optimally, you need to have all the correct components available. Beyond this, you also need the right measurements. If you use the wrong bar or an ill-fitting chain on your chainsaw, it could be dangerous. Getting the measurements on your chainsaw bar and chain may seem easy at first, but with the several amounts of chain saw brands, types, and sizes available in the market, you’re bound to get varying measurements on your chainsaw.

How to Measure a Chainsaw Bar:

Measuring the chainsaw bar is easy and can be done with a tape measure. You’ll need to measure the bar from the tip of the chain to the point where the bar enters the chainsaw casing, then round your measurement up to the nearest even number, for instance, 10.5” and 11” should both be counted as 12”. Also understand that there are two sizes often used, the true Length and the effective cutting length. The true length is the actual length of the bar itself from both ends, the effective cutting length, is usually shorter than the actual length of the bar.

The bar measurement of a chainsaw is typically different compared to the actual length of the bar. It is important to know the bar measurement, especially when replacing a chain or purchasing a replacement bar. Generally, the bar measurement shows the effective cutting length of the chainsaw, but not the entire length of the bar, which is usually a few inches longer than the actual cutting length. We will explain in this blog post how to effectively measure a chainsaw bar.

Why Do You Need To Measure A Chainsaw Bar?

Before we go into details on how to do it, let’s briefly dive into the reasons why you need to measure a chainsaw bar. Ideally, if you maintain and care for your chainsaw well, it can last for a long time– and this goes for all the models regardless of their power source.

However, with time, the chains and bars of your chainsaw can become worn and will most likely need replacement. In some cases, chainsaw owners can also decide to fit a larger or smaller bar onto their chainsaw. Hence, you’ll want to know the correct size of the bar currently on your chainsaw to easily work out what size to buy as a replacement. Regardless of the reason for changing your chainsaw bar, you must know the current length of the bar and that of the chain that goes with it. Make it a note that, using a bar that is too long for your chainsaw can cause the machine to struggle, while using the wrong size of the chain may cause the chain to suddenly fly off, causing serious injury to the user.

How to measure the chain

Before you measure the chain, there are two measurements you need to be familiar with, and these are the pitch and the gauge. The pitch is the successive distance between three rivulets (the studs that hold the chain together) on the chain. If you want to work out the pitch, you need to measure the distance between the center of the first rivulet and that of the third one, then divide it by two. The common chain pitches you’ll find are 3/8” or 0.325”.

The gauge of the chain, on the other hand, refers to the width of the groove that houses the chain on the bar, and there is a special method you can use to work it out. All you need to get is a quarter, a penny and a dime. First clean out the groove with a rag, making sure there is no debris or dirt stuck in it, then simply try to push the coins into the groove to know the one that fits best.

  • If the quarter fits best, then the gauge is 0.063
  • If the penny fits best, then the gauge is 0.058
  • If the dime fits best, then the gauge is 0.050

Deciding How Long a Bar You Need

Another common problem related to bar measurements is knowing how long the bar you need should be. The usual or commonly used guideline is to consider the diameter of the wood you’ll often be working on and then mentally add extra two inches. For instance, if you most often cut trees with a diameter of 10”, then you will most likely need a bar of 12”. This additional diameter gives you enough bar to deal with trees within this size range comfortably and with just a single pass. As you know, it is very possible to cut through wood with a diameter twice the length of your bar, you can do this by making two passes and cutting from both sides. While this is possible, it is even more time consuming and, it may not be practical especially if you have to do it more often. Hence, it would be much better to have a longer bar.

● Don’t go for a bar longer than you need

A lot of people get tempted to buy the longest bar they find. While this may allow you to cut through thicker pieces of wood, it can be counterproductive especially if you’ve never used anything that long. Generally, longer bars are very hard to manage, are not comfortable, and can be dangerous in the hands of inexperienced users. They are not practical for smaller tasks such as pruning and are usually more expensive, which means that you’ll only be wasting money.

● Always use the right parts for the right chainsaw

While choosing the right length of the bar for your chainsaw is important, ensuring that you go with the right length of the chain will also help you run your tool with the minimum amount of risk. Also, you’ll find in your manual or the surface of the bar, the right measurements. However, if you happen to misplace the manual and you don’t find anything on the bar, then you’ll have to resort to measuring the bar and chain manually.

How to Measure a Bar Manually

Measuring a chainsaw bar manually is quite simple and can simply be done with just a tape measure. You’ll need to measure the bar from the tip of the chain to the point where the bar enters the chainsaw casing, then round your measurement up to the nearest even number, for instance, 10.5” and 11” should both be counted as 12”. This is known as the “called length” or sometimes the “useable length” (as this is the part of the bar that can be used for cutting).

When the time comes to replace the chain on your chainsaw, you’ll need to know the length of the chain. If you have lost the owner’s manual for your chainsaw, or the chain is broken or lost, then you’ll have to measure the bar.  Once you have gotten the right measurement, you can now proceed to buy the correct chain for your chainsaw. There are two ways to measure the length of the bar on your chainsaw.  You can measure the effective length or the true length. 

● Effective Length

The effective cutting length, also referred to as the chainsaw length, is usually shorter than the actual length of the bar, but it is the simplest measurement to work out. All you need is a standard tape measure. Since you’ll be doing the measurement and handling the chain yourself, you should follow some safety steps before you begin the measuring process. First, turn the chainsaw off, it’s only logical, then grab the rubber cap that covers the spark plug and remove the wire from the spark plug by carefully pulling it until it comes free. This will prevent the chainsaw from accidentally coming on.

Next, place the chainsaw on a level surface and put the end of the tape measure on the point where the bar emerges from the casing. Gently stretch the tape to the end of the bar and slightly past it. If you can’t find the chain of your chainsaw, you can add about 1/2″ further from the tip of the bar. Then round up the measurement to the nearest inch.  For example, if you measured 13-7/8″ round it up to 14″. 

● True Length

As the name suggests, the true length is the actual length of the bar itself from both ends.  If you want to get this measurement, you’ll need to use a socket driver or a wrench to remove the bolts that hold the cover on the chainsaw, then remove the cover completely. This will expose the entire length of the chainsaw bar and allow you to lift the chainsaw bar off the interior bolts.

Next, place the end of the tape at one end of the bar, then stretch the tape to the other end and take note of the measurement. Here, you won’t have any need to round off the measurement, and the readings gotten will be the true length of the bar.

Final remarks

Bring these measurements along when you go to the shop to purchase a new chain or bar, and if you’ll be purchasing it online, simply take a note of the readings and compare it to your options before choosing the bar. Once again, we trust that this article has helped you know how to measure a chainsaw bar.