A chainsaw bar, or blade, is one of the key parts that perform the cut. There are many different types of chainsaw bars, detailed below.
You will need to know the length of your chainsaw blade if you wish to purchase a different type, or if it breaks and you need to purchase a replacement.
The bar length refers to the effective cutting length of the chainsaw, not the entire length of the bar.
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What are the different types of chainsaw bars?
Solid bars are the ones you will be most familiar with. They are a single length of steel that has been shaped and planed to form a smooth central platform for the chain to rest upon.
They are incredibly strong and tend to be used in tree felling as well as in conditions that are dusty, sooty, or sandy. They tend to be coated in an incredibly thin layer of water-based paint to protect them against scratches.
Longer solid bars are recommended to be used with a replacement blade tip. This reduces the load on the tip of the bar by transferring it to the roller bearing. These bars are also coated.
Solid bars can have either a hard or replaceable sprocket nose. Hard nose bars are less common. These bars are one solid metal structure all the way through.
They are very durable and are well-suited to sawing fence posts and working in dirty conditions.
Replaceable sprocket nose bars are the standard among chainsaw manufacturers. They are characterized by the presence of a sprocket at the tip of the bar. This has indents at the top that the chain rests in.
This helps to keep the chain in the right place and turning smoothly. This sprocket can be removed and replaced if it becomes damaged.
Laminated chainsaw bars are formed by conjoining 2 steel rails together. They will have a core made of steel and a sprocket trapped between them.
These are sometimes preferred to solid chainsaw bars, as what they lack in strength they more than make up for in flexibility. They do not tend to reach lengths in excess of 24”.
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How to measure a chainsaw bar
You should ensure that the chainsaw is switched off and unplugged before you attempt to measure the bar length.
A good way to be certain the chainsaw will not accidentally turn on is to remove the spark plug wire. To do this, grasp the cover of the spark plug and pull gently on the boot to take out the wire.
Grab a tape measure and place one end against the chainsaw handle casing where the bar comes out. Extend the tape measure to the tip of the blade.
Read the number that is in line with the cutting blade at the tip of the nose. Round this up to the nearest inch. For instance, a measured length of 14 6/8 inches would be rounded up to 15 inches.
Use a socket wrench to take the nuts out that attach the chainsaw body to the casing. Once you have done this, you should be able to remove the casing completely. This will leave you with the full length of the chainsaw bar exposed.
Measure the length from one end of the chainsaw bar to the other, including the now exposed section. This should come out about 2 – 3 inches longer than the first length. This is the actual length of your chainsaw bar.
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How do you measure the chain length?
When replacing the blade, you will likely need to replace the chain too. This is the moving belt that loops around the chainsaw blade and cuts through your material.
It is absolutely vital to get the correct chain length for your bar. Incorrect sizing will likely result in injury to the operator or damage to the chainsaw.
To accurately work out the chain length you will need 3 key measurements. These are the number of drive links, the pitch, and the gauge. The drive links are the individual link components on the chain.
The pitch is a measure of the distance between each drive link. The gauge is the width of the chain’s groove that rests on the bar.
There are 2 ways to find your chain measurements. The easier method is to look at the area of the bar covered by the chainsaw casing.
On this area manufacturers commonly print all of the measurements you will need to replace your chain.
This will be in the format ⅜” 72 1.3mm/.050”. This means it has a ⅜ inch pitch, 72 drive links, and .050” gauge.
If you cannot find this information, you will have to do a little work to find out the pitch and gauge values. To work out the pitch, measure the link between 3 rivets on the chain.
Rivets are the little round pegs that hold the drive links together. Divide this by 2 and you will get the pitch value. This is measured in inches, and common sizings include .404”, .325”, ⅜”, and ¼”.
There is a quick trick to work out the gauge. Grab 3 coins, a quarter, a dime, and a penny. Take each coin in turn and try to fit them into the groove on the blade.
The one that fits snugly and can be inserted with ease is the correct value. The quarter represents a .063” gauge, the dime represents a .058” gauge, and the penny represents a .043” gauge. Another common gauge size is .050”.
How do you know when to replace your chainsaw bar?
Chainsaw bars are fairly durable and will not need replacing too often, probably once every few years depending on usage.
If the bar appears damaged in any way, you should replace it before operating the chainsaw again. Keep an eye out for the bar bending, cracking, or pinching on the drive links.
If your chain moves from side to side while in operation, the bar needs to be replaced. Finally if you notice the nose sprocket is jammed or damaged please take your chainsaw for servicing.
