If you own a chainsaw, chances are you have been warned to keep an eye on the chain and its tension. After all, the chain is one of the most important parts of any chainsaw.
The chain is a sneaky little fellow that tends to stretch and get loosened up at the wrong time and the wrong place. And this is dangerous. Nobody needs experience to know that, and there is no way of getting around the fact that any chain will get loose with time.
But why does that really happen?
Why do chainsaw chains stretch? Chainsaw chains stretch and become loose as they wear off due to time and usage. New chains that have not been used before are going to stretch a lot more in the beginning during the break-in period. Loose chains should always be tightened as they are posing a health and safety risk.
These are the important details at first glance.
But if you want to know more about it, I’ll go through some quick facts about how the chain on your chainsaw operates, what caveats there are, and what you can do to keep both your chainsaw and chain working for longer efficiently.
Why Do Chainsaw Chains Stretch, and Is This Normal?
It is completely normal for the chain to get loose and stretch with time and use.
This is especially true for brand new chainsaws that have never been used before: their chains may need to be tightened more often and generally speaking, will stretch a lot after the first few times you use the chain.
In the beginning, there is a break-in period where you will see the chain stretching the most.
The break-in period can vary from chainsaw to chainsaw and will depend a lot on how much you use it. Therefore, it’s recommended to always inspect the tension of your chain before working with the saw.
Another thing that affects the chain is heat.
While you work with your chainsaw, the chain will be experiencing tremendous amounts of pressure and friction, which will cause it to get extremely hot. The high temperature will loosen the metal a bit. But after it cools down, it should return back to its normal tension.
And last but not least, the chain loosens up because it wears off with time and through use.
If you have an old chainsaw, you may see the chain getting loose more frequently as a result of the wear off of both the chain and sprockets.
The older your chainsaw and the more you use it, the more you should keep an eye on the chain. Is it getting loosened way too often? Are the chain’s teeth dull? Is the chain difficult to move around the bar?
Make sure to inspect the condition of the chain regularly as it may be time for it to be replaced.
What happens if the chain doesn’t have proper tension?
A loose chain will cause your chain bar to wear off prematurely. This means that you may not only damage your chain but the guide bar, as well.
It also poses the risk of the chain coming off the guide bar while you work with the chainsaw, which can be extremely dangerous. Although most modern chainsaws have a chain catcher on their bottom for such cases, it’s better to be safe than sorry.
Can you prevent the chainsaw chain from stretching?
The chain will always stretch to some extent no matter what you do; this is why you have to make the necessary checks and inspections before working with your chainsaw.
Make sure to check the tension of your chain before each use!
This is a mandatory pre-operation check which is done for safety reasons for both you and your chainsaw.
How to recognize a stretched chain?
This is one of those things that may seem like something difficult to assess, that is until you actually see it. When it happens, you will both feel and see the difference. Anyway, here are the steps you should follow:
- Place the chainsaw on level ground or table;
- Make sure it isn’t running, and it’s completely switched off. If you have used it recently, let it cool down a bit;
- Take a look at the part of the chain that runs under the guide bar;
- Does it appear to sag down visually? Is there a space between the chain and the guide bar? If there is, then you need to tighten the chain;
- Does the chain appear to be close to, or touching the guide bar?
- Grab a part of the chain with your hands;
- Be careful and use gloves as the chain is very sharp, and it will most likely have some oil on it;
- Pull a little on the chain. Does it stretch? An adequately tightened chain should be able to stretch ever so slightly, but it should remain in the slides of the guide bar.
How to Tighten a Loose Chainsaw Chain
Luckily, tightening a loose chain is not a complicated task.
Before You Start
Before you start, make sure you have the chainsaw switched off. If you have worked with it or switched it on recently, leave the chainsaw for a couple of minutes to cool off. The bar and the chain may become very hot, and you are risking burning yourself.
You want to fix the tension of the chain while it is completely cold. If the chain is still hot, it will be more loose, which will lead to overtightening once it cools off.
Have the chainsaw on level ground, table or you can alternatively place it in a vice for better safety and stability. Keep in mind that you will be working in very close proximity to the chain, which is sharp and can be dangerous.
The Bolts and Adjustment Screws
Start by loosening the bolts that hold the bar in place. Don’t take them completely off, just loosen them a bit. You should feel the bar becoming a bit more loose.
Next, tighten the chain by operating the chain adjustment screw.
Different saws can have different adjusting methods. The tension adjustment screw is generally located in the base of the bar. However, the various models may have the screw placed in different locations:
- It can be on the outside between the two bolts;
- It can be on the inboard side; and
- Some have an adjustment dial which does not require any tools.
Continue using one hand to lift the bar as you very slowly adjust the chain tension. That way, you will be able to see and feel at the same time how tight the chain is.
Proceed until you have the chain properly tightened.
Once you are ready, make sure to tighten the bolts that are holding the bar in place.
There is just one more thing you need to do before you are ready, and that is rechecking the chain.
It is possible that by tightening the bolts that keep the bar in place, the chain gets overtightened. If that is the case, follow the steps again and loosen the chain a bit.
How Tight Should the Chainsaw Chain Be?
As you can see, you don’t need any special equipment to fix a loose chain. And you can do it all by yourself too. But how tight should the chain be?
First, let me start with the obvious, the chain should not be too tight, or too loose. Both extremes are dangerous to both you and your chainsaw.
How to properly test the tension of the chain
- Grab the chain with your index finger and thumb. You should be able to lift it up from the bar just a bit.
- In other words, you should be able to pull the chain just a little outside the bar. The chain guides – the bottom parts of the chain teeth – should still be in the bar. Or about 1/4th of them should remain in the bar.
- And when you release the chain, it should snap back in the bar nicely.
If the chain has been tightened and has proper tension, it should be easy to rotate around the bar.
An extra tip here is, never to rotate the chain backwards as this may cause it to jam, or you may cut yourself with the teeth.
Additionally, please do not forget to double-check this with your user’s manual that came with the chainsaw. There should be information provided by the manufacturer as to how the chain should be maintained and tightened for your particular model.
Can You Overtighten the Chain on the Chainsaw?
There is a good reason as to why I doubled down on the importance of tightening the loosened chain just enough, not too much and not too little.
You can overtighten the chain very easily, as it doesn’t require a lot of revolutions of the chain tightening screw. For example, sometimes you may need just half of a revolution.
If you tighten the chain too much, it will place a lot of pressure on the bar, particularly the tip and can wear it off much faster than expected.