4 signs it’s time to replace chainsaw bar

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A chainsaw bar has to handle a lot of heat and friction due to the chain spinning around it. Eventually, there comes a point when the bar of your chainsaw gets worn out and it stops working properly. But the bars are made with tough materials and it can be difficult to know when it is time to replace the bar of a chainsaw. Not to mention it can be hard to tell a worn-out bar apart from a good one at a glance. So what are some telltale signs which indicate that it is time to replace your chainsaw bar?

Some common signs that indicate it is time to replace the chainsaw bar are:

  1. Damaged or Bent bar
  2. Chain wiggles side to side on the bar
  3. The edges of blades are tilted at an angle
  4. A jammed or damaged bar nose sprocket
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A chainsaw bar that is showing the above-mentioned issues means that your chainsaw is going to need a new bar. But to be certain about whether these signs indicate a worn-out bar or not you will have to take a closer look at your chainsaw bar. That is why in this article we are going to explain how you check for the signs of a worn-out chainsaw bar.

Sign 1. Damaged or Bent bar

This is the most obvious sign of a worn-out bar and it is also the first step in finding out whether you need a new bar or not. Now to do a proper visual inspection of your chainsaw bar, you will have to take the bar out and remove the chain swell. A damaged bar cannot only reduce the efficiency and cutting power of your chainsaw but it can also be dangerous to use. A bar can get damaged due to a variety of reasons including a loose chain or lack of lubrication. If the bar is missing a chunk or there is a broken rail edge then it is an obvious sign that you will have to replace the bar immediately. But other than this obvious sign here are some types of damages you need to look for in a chainsaw bar after removing the bar from chainsaw:

  • Cracks in the rails of the bar: Look along the rails of your chainsaw bar for any cuts or cracks. Pay close attention to the middle of the bar when looking for cracks. In case you notice any cracks in the chainsaw bar it is time to get a new bar, period. Apart from cracks, if the bar has some pointy edges, file them down so that they don’t cause the chain to get caught in them while the chainsaw is running.  
  • Bent bar: A bent bar is something even experienced chainsaw users can face occasionally. Although chainsaw bars are solid and don’t bend easily there is always a chance that a bar might get bent under certain circumstances or heavy load. To be certain whether your chainsaw bar is bent or not you can perform this simple test:
    • With the bar removed from the chainsaw and chain took off, hold the chainsaw at your eye level and look straight along the groves of the bar.
    • Look for any bends on both sides of the bar.

If you find any minor bends in the chainsaw bar they can be easily fixed by hitting the bent area with a rubber mallet. But if the bar has been bent too much, the only solution is to replace the bar altogether.

  • Pinched grooves/Rails: A pinched area on the chainsaw bar means that the rails in this area are going to be narrower than the rest of the bar. A pinch in the rails is going to cause excess friction with the chain because there is simply not enough room for the chain to move freely between the rails at this pinched spot. Not to mention a pinch in the rails can even cause the bar to heat up excessively or the chain may get stuck in the pinch. Luckily a pinch is easily repairable and you can use a screwdriver with a flat head to open up the pinch so that it matches the normal thickness of the bar rails. 

Sign 2. Chain wiggles from side to side on the bar

We are not talking about a loose chain here because a chain is loose when the chain hangs at the bottom and doesn’t sit tightly against the bar. What we are looking for is left to right movement of the chain even when the chain is properly tightened. If your chain is wiggling between the grooves of the bar you will find it difficult to get a clean cut because the chain will not be able to stay in the same place to provide a straight cut. There is a simple test you can do to confirm if the chain is wiggling on the bar or not and here is how to perform the test:

  • Before starting the test make sure that the chain is not worn or loose because a worn-out chain can also cause itself to move left and right between the grooves.
  • Apply tension to the chain so that it sits snuggly between the grooves of the bar.
  • Try to move the chain from left to right to see if the wiggle of the chain is noticeable or not.

If the chain is moving left and right a lot then it is a clear sign that the grooves of the bar have widened up significantly compared to their normal gap. If you try to use a bar with widened up grooves you are not going to be able to cut properly no matter how sharp or new the chain is. Some shops do offer the service to fix the gap between the grooves of the chainsaw but it is always best to replace the bar if the chain is wiggling excessively on a bar.

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Sign 3. Edges of blades are tilted at an angle

Another telltale sign of worn-out grooves on a chainsaw bar is when the blades of the chain are not pointing straight up instead they are tilted at an angle. This is also a sign that the grooves on the bars are either worn on one or both sides and the chain is tilting causing the blades to tilt along with it. If you want to confirm whether the chain is tilting or not you can find that out with this simple method:

  • Grab a ruler or any straight item.
  • Place the chainsaw on a flat surface before you begin the test.
  • Take the ruler or any straight item you have picked and place it on the side of the bar.
  • Press the ruler against the bar and the side of the chain and notice whether there is a gap between the ruler and the surface of the bar or not

If you notice that there is a gap between the ruler and the bar when it is pressed against the side of the chain then it is an indicator that the groves on the bar are not worn and the chain isn’t tilting to the side and so isn’t the blade. But if the ruler lays flat against the side of the bar when pressed against the side of the chain then it is an indicator that there is too much space between the rails of the bar and the chain and blades are tilting to one side. You can perform this test at multiple locations on the bar and on both sides as well. If the chain is tilting at an angle the blades will be cutting at an angle as well which means irregular cuts or no cutting power at all if the blades are tilting too much. If that is the case your best bet is to simply replace the bar and buy a new one.

Sign 4. A jammed or damaged bar nose sprocket

 Nose sprocket is a gear located at the front of the chainsaw bar and it allows the chain to move in a fixed place between its teeth. The nose sprocket of the bar gets oil from the bar oil reservoir located near the motor of your chainsaw. If there isn’t proper lubrication being provided to the nose sprocket then it can get seized due to increased friction and it can cause the chain to break. Or another scenario might be that a person is cutting a tree and the weight of the tree caused the bar to pinch at the edge jamming the sprocket along with it. And finally, the nose sprocket might break a tooth or two which means the chainsaw will not be able to run at all. If your chainsaw bar has a replaceable nose sprocket you can easily swap it for a new one and get on with cutting but if you own a chainsaw without a replaceable nose sprocket you will have to get a new bar. The best way to avoid a jammed sprocket is to keep the oil reservoir filled and periodically grease the nose sprocket to prolong its life and prevent it from jamming.     

How to replace a chainsaw bar?

Once you have identified that you need to replace the bar on your chainsaw the next step is the actually replace the bar itself. Luckily the bar replacement process is pretty similar for most chainsaws and it can be done without any difficulties. If you are looking for a general idea for how often you should replace a chainsaw bar, a rule of thumb is to replace the bar of your chainsaw once after you have gone through three chains on the same bar. But before you can start the bar replacement process make sure that the replacement bar you have is the exact same length as the one you are replacing it with. And if the chain is worn out you should also replace the chain as well. Once you are sure that you have the correct size replacement bar for your chainsaw you can follow these steps to replace the bar:

Step 1. Safety first, before starting, make sure to wear a pair of heavy-duty working gloves and ensure that the bar is facing away from you before you start the bar replacement process. Also, make sure that the kill switch is turned off and if you have a gas-powered chainsaw the spark plug wire is disconnected.

Step 2. If you have the chain cover on the bar of your chainsaw remove it and then you will have to undo the 2 nuts in order to remove the sprocket/clutch cover. Most clutch cover nuts can be removed with a 13mm socket but the size of the socket required can be different depending upon the size or type of chainsaw.

Step 3. With the nuts removed you can take the clutch cover off and put it aside. Now you are ready to start removing the bar.

Step 4. Before removing the bar you have to push the bar backward to reduce the tension on the chain and simply remove the now loose chain and bar completely by sliding the bar off the adjustment posts.

Step 5. With the bar removed you can clean the area around the sprocket and inside of the sprocket cover as well.

Step 6. Slide the new bar onto the adjustment posts and then reinstall the chain on the bar. Make sure the chain is properly adjusted on the bar nose sprocket and the main driving sprocket as well. When installing the chain, the sharp end of the blades of the chain should be pointing forward towards the front of the bar. Finally, make sure that the chain is properly adjusted into the rails or grooves of the bar.

Step 7. Pull the bar forward to create tension in the chain and after that, you will have to tighten the chain to proper tightness and there are two ways you can do it. But before tightening the chain, install the cover and put the nuts on the adjustment posts without tightening the nuts all the way. Some chainsaws will have a chain adjustment screw located in between the adjustment posts and in order to tighten the chain you will have to tighten the screw until it is not hanging too low at the bottom of the bar. While for some chainsaws you will have to adjust the tightness of the chain with the help of an adjustment screw located at the front of the sprocket cover. Once you have adjusted the chain tightness make sure to tighten the nuts of the sprocket cover properly to secure the sprocket cover in place.

Note: When you are adjusting the tightness of the chain make sure you don’t overtighten the chain as it will cause the bar to wear out quickly. A good rule of thumb is to tighten a chain until the drivers of the chain are not coming out of the rails when you pull them down at the bottom of the bar. And make sure that the nuts of the sprocket cover are loose when you are tightening the chain.

After installing a brand new bar on your chainsaw make sure that the bar oil reservoir is full so that it can lubricate the new bar properly. But since it takes some time for the lubricant from the reservoir to circulate to the front sprocket of the bar it is a good idea to lubricate the front sprocket after installing a brand new bar to the chain. There is a small oil hole near the nose sprocket of the bar and you can pour some bar oil in this hole to lubricate it. And for good measures, get some bar oil on a piece of cloth and apply the oil to the chain as well. After making sure everything is nice and snug, reconnect the sparkplug wire if you had taken it off, before starting the bar replacement process and your chainsaw is ready to be used again.

 Conclusion

If your chainsaw is not performing as it should despite the chain being sharp and tight it is a good idea to look for these 4 signs of a worn-out bar. While physical damage to the bar can be visible the signs of wear are not that easy to detect which is why chainsaw operators can’t spot a worn-out bar in time. But with the help of the techniques we have explained in this article, you can easily identify and confirm the symptoms of a worn bar and save yourself the worry. Also, make sure to keep the bar clean and periodically remove any debris stuck between the groves of the bar to make the bar lasts a long time.