A chainsaw can be split into three parts; the engine, the chain, and the guide bar. The guide bar is an integral part of the chainsaw that supports and provides a track for the chain, that is, it helps the chain move around the guide bar.
Chainsaws are not just for cutting down trees. Many people use them to cut wood, branches, and other things on their property. This is a guide about chainsaw bars and whether they should be universal or not.
Guide bars are primarily made of steel bars that are laser cut, welded together, and hardened by an induction process. They are also referred to as chainsaw blades. They are available in various types depending on the manufacturer.
The major classifications of guide bars are –
- Solid bars
- Laminated bars
- Specialist bars
They are called solid bars because they are just a single and sturdy steel core. They offer strength to the chains when cutting hardwood. They are a popular option because they are long-lasting and do not corrode or scratch easily. Solid bars are further classified into many categories. We have the hard nose bars, sprocket nose bars, replaceable sprocket nose bars, carving bars, and narrow nose bars.
Hard nose bars are typically used for cutting in dirty environments such as sooty, dusty, and sandy places. For instance, they are used to cut fence posts or the roots of trees. Sprocket nose bars allow for easier movement of the chain and as a result, the amount of heat generated as well as power consumed is greatly reduced.
You could call it a power-saving bar.
Replaceable sprocket nose bars, as the name implies, are those bars with replaceable sprocket noses. They allow easy adjustment of the chainsaw’s pitch. Lastly, we have narrow nose bars which offer the advantage of a significantly reduced kickback when in operation.
Laminated bars are comprised of several layers of steel joined together and are essential for situations where flexibility is prioritized over strength. Laminated bars having a nose wheel offer improved cutting control and a significantly reduced kickback.
The main function of a chainsaw’s bar is to guide the teeth on its chain around logs or through trees as it cuts through them. The bars should always be replaced when they become worn out and start producing less cutting power. This often happens due to excessive wear on chainsaw bars from use over time or from improper sharpening techniques which cause uneven wear along the length of the blade.
Specialist bars include carving bars (which are used for fine detailed woodwork such as boring and carving of wood), narrow kerf bars (which are popular among arborists because they are lightweight and require less power), extra-light bars (as the name implies they are very lightweight), extra-long bars (these are very long at about 44″ – 84″), and the double-ended bars (which are used for milling).
Technical Features and Functions of a Guide Bar
Before replacing a chainsaw’s bar, several features and their functions have to be understood. This way you will know if the bar you are about to replace it with is appropriate for your chainsaw.
Kickback Control: Kickback is the backward motion of your chainsaw in an arc while you cut. This motion is quite forceful and it mostly occurs when you try to cut with the tip or nose of your chainsaw. It could result in instability, serious injuries, and loss of control of your chainsaw. The guide bar offers strength and stability to the operator when using the chainsaw.
Bar Length: The length of the guide bar determines the number of drive links that could fit on your chainsaw. This inevitably determines its application too. These guide bars come in various sizes, from 12 – 14 inches, 14 – 18 inches, 18 – 22 inches, and 22 – 36 inches. The sizes depend on the manufacturer because not all of them produce all the blade sizes. To measure the length of your guide bar, simply use a measuring tape to mark the distance between the tip and base of the bar. Ten, round it up to the nearest even inch.
Available Number of Teeth on the Sprocket Nose: Replaceable sprocket noses allow you to easily adjust the pitch of your chainsaw. This feature is very important because the more the teeth on the sprocket nose, the higher the kickback and cutting performance.
Pitch: Mathematically, the pitch of your chainsaw is defined as
The higher the pitch, the shorter the distance between the drive links on a chain. This inherently means you have a great number of teeth on your chainsaw and just as we discussed above, the cutting performance of your chainsaw will be vastly increased. The table below shows the five standard chain pitches.
Chain Pitch (inches)
Chain Pitch (cm)
3/8 low profile
3/8 full profile
Groove Width: This is otherwise called the gauge and it is where the chain fits into the bar. It is used to provide lateral control of the chain and create a path for oil flow for the chain. Keeping your chain properly lubricated while in operation is a must. Usually, a professional is required to measure the size of your gauge simply because they are rather small and errors could be easily made but there is a trick used to determine the size.
- Get a penny, a quarter, and a dime.
- Clean out the groove
- Try to fit each coin perfectly into the grove.
- A penny equals 0.058”, a dime 0.050” and a quarter 0.063”
I must mention that this is simply a trick and you should let a professional measure it. The five standard groove widths are 0.043″, 0.050″, 0.058″, and 0.063″. The higher the groove width, the stronger the drive links, and the lower the cutting performance.
Replacing the Chainsaw Bar
Your guide bar is due for a replacement when the following issues occur:
The chain does not sit on the bar: When this occurs, it is a sure sign that the grooves have widened. A loose chain can simply be corrected by increasing its tension. However, a jiggling chain that does not sit right poses a lot of problems. You would be unable to cut straight if you operate a chainsaw having this fault.
The nose sprocket is damaged: The nose sprocket must be properly lubricated during use. If not, it seizes and breaks. If you are using a replaceable nose sprocket bar, then that is the only part that needs to be changed. Otherwise, the entire guide bar will have to be replaced.
Your chainsaw’s grooves have worn out: This is noticeable when the bar tilts at an angle. To confirm this, simply grab a ruler and press it against the side of the chain and bar. If you see a gap between the ruler and the bar, it means that the grooves have worn out and you must replace the bar.
There are cracks along the bar rails: If you notice cracks along the rails of the bar, then your bar has been greatly damaged and is due for replacement.
Your guide bar is visibly bent: Guide bars are designed to be strong or flexible. If it happens to be bent then it is due for a replacement.
Chainsaw bars could be interchangeable but this is not applicable for all chainsaws. Whether chainsaw bars are universal will often depend on how well the components match.
Inherently, it boils down to four main factors.
- The bar size
- The tensioner hole
- The oil hole
- The bolt slot
For instance, bar sizes must be the same. By bar size, I am referring to its length and width. If they both match, then you can proceed with assessing the remaining components. The tensioner hole is used to adjust the chain’s tension. The oil holes lubricate the chain and the bolt slot firmly secures the bar to the chainsaw.
It makes sense to have universal parts for a chainsaw but sadly this is not reality. Most manufacturer’s designs vary and the components suited for one chainsaw would not apply to the other.
The guide bar mainly wears off at the underside of the bar. This is because it is the side that mostly gets used when cutting.
Tips on Maintaining a Chainsaw Bar
- Always keep the chains well lubricated.
- To prevent the sprocket from jamming ensure that the oil tank is filled and the sprocket is well greased.
- Dress the bar rails with a rail dresser.
- Regularly clean the bar grooves so they do not wear out easily.
- Always ensure that the chain has been tensioned properly before use.
- Periodically check for cracks along bar rails.
In conclusion, chainsaw bars are not universal and you might find a compatible blade from a different manufacturer. However, there are various disadvantages to doing so. Your cutting performance would be affected and kickback could be increased. Besides, you might require a lot more effort to control your chainsaw.
Chainsaws can be an expensive piece of equipment that requires constant maintenance to keep them operating at their best. However, the most important part of your chain saw is often overlooked: the bar.
Remember to read your instruction manual for the recommended parts and consult a professional when replacing the bars.