Reasons Why Chains Jump Off Chainsaw Bars
Chains coming off the bar of the chainsaw is a common complaint heard especially from first time owners of chainsaws.
And when you look at a chainsaw, you can understand why this baffles some people.
The chain on the chainsaw is very tightly integrated into the tool design! One therefore tends to forget (or have never known) that it is a completely separate entity.
In other words, the chain and chainsaw can be bought separately as stand alone items.
This means that, at some point, the chain has to be fitted to the chainsaw in order for the chainsaw to cut anything.
This gives rise to a number of possible errors that can result in the chain coming off!
Reasons for Chains Coming Off The Bar
– The chain is the wrong size/length. Unless the chainsaw comes with the chain already fitted, you need to make absolutely sure that the chain is suitable for the bar length of the chainsaw.
– New chains stretch! Even if you buy a chainsaw with the chain fitted, a new chain will always stretch after the first few uses. Yes its metal, but it will still stretch!
– Old chains stretch!
– Chains can be incorrectly tensioned.
– Chain put on back to front. Yep, it is possible to put the chain on facing the wrong way!
Lets look at each of these briefly:
Wrong Size Chain
Chainsaws come in a range of sizes with bar lengths. These range from 4 inches to 20 inches plus. If you buy a new chain you need to make sure you get the correct length chain.
Obviously a chain that fits a 4-inch bar mini saw is easily distinguished from one designed for a 20 inch bar chainsaw. The potential problem comes in when you misjudge the length by an inch or two.
You should pick the mistake up when you try to fit the chain.However if you have never done it before, then a slightly longer chain might just seem like it needs a bit of adjustment! It will almost certainly jump off if you get as far as actually trying to get the saw to work.
NB. Its the correct length chain or nothing! Do not try to adjust an obviously incorrect length chain to fit the bar. That is dangerous and could well result in injury.
New Chains Stretch
Can a chainsaw chain stretch?
New chainsaw chains in particular stretch a bit when first used. So even if you fit a new chain correctly, you need to keep an eye on the chain tension and adjust it as required as the saw is used and the chain “beds in”.
If you don’t do this then the chain is likely to jump off the chainsaw bar when it starts spinning.
Also be aware that if you buy a new chainsaw with the chain already installed, it still needs to be correctly tightened before you use it.
This is because the manufacturer doesn’t know how long its going to be between when the chainsaw leaves the factory and when it is sold and first used!
So in order to maximize the life of the chain, they will put the chain on, but leave it loose.
Old Chains Stretch
At some point your chain will stretch past the point where further tensioning of the chain is feasible.
At that point, if you do not replace the chain, you will likely run into a range of issues, one of which will be the chain either breaking or jumping off the bar…..or both!
Chain Incorrectly Tightened
Its an unfortunate reality, but the chain on your chainsaw can be too loose OR too tight!
So unfortunately its not a case of just tightening it as tight as possible and getting on with it.
The video below will help you sort the chain tightening issue out (which as you will see, is not straight forward – unfortunately)
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This might sound absurd, but it isn’t! If you have never dealt with a chainsaw before, or never changed a chainsaw chain before, then this mistake is easy to make!
Needless to say, even if the size and tension is correct, this situation is not going to end well!
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And here is how you make sure the chain is facing the right way!
In Conclusion
As you can see, there are several reasons why a chain might jump off a chainsaw.
The good news is that all of them are very easy to sort out or prevent!