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How To Tighten a Chainsaw Chain

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Chainsaw chains stretch and become loose during operation. This article's maintenance steps explain how to properly tension a chainsaw chain in under a minute.

Chainsaw chains stretch during normal operation and begin to sag on a saw's guide bar. If a chainsaw chain is allowed to become too loose, it can easily come off the bar during operation and create an unsafe situation for the user.

Chainsaw Chain Maintenance

Chainsaw chain tension should be checked and tightened often. We explain simple steps for how to tension a chainsaw chain below.

 

Correct Chainsaw Chain Tension

Before explaining the tensioning steps, we should explain what proper chainsaw chain tension looks like.

 

Good Tension-

A properly-tensioned chainsaw chain should still be just a little loose on the chainsaw guide bar, but the chain needs to be tight enough that you can't pull the drive links out of the bar nose.

Good Chainsaw Chain Tension

To determine whether or not your chainsaw's chain tension needs to be adjusted, pull the chain away from the guide bar a little to see if the drive links remain engaged or not.

 

Bad Tension-

A loose chainsaw chain will look like the one pictured below when it is pulled away from the guide bar. If the chain's drive links are disengaged from the guide bar when pulled, then it's time to tighten it up.

Bad Chainsaw Chain Tension

Chainsaw chains can also be overtightened.

There should be at least a little play in the chain, just not enough for the drive links to leave the guide bar. Tightening a chainsaw chain too tightly risks breaking it during operation.

 

Steps to Tension a Chainsaw Chain

Even though tensioning a chainsaw chain is easy and takes less than a minute, it's important to do each step carefully and correctly. Forgetting to do something like lift the guide bar nose when tightening it can seriously affect your tool.

Most chainsaws come with "scwrench" (screwdriver/wrench) that matches their side plate nut and tension adjustment screw size. 

 
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mugget10 months ago
Good info! Just got a chainsaw and pinched the chain, pulling it loose. Tried to adjust it but the manual didn't say to loosen the two nuts holding the bar first! Hope I didn't strip out the tensioning screw... now to go and do it properly...
I to am a Small engine tech that works at a dealer ship that sells a full line of Honda and Stihl power equipment. I could probably give you little tips about everything for everything I have seen, But by the time you check them all it would be night time and you wouldn't want to cut wood.

Toolrepair has a good basis down for tightening your chain, Once you do a thousand of them you might develop your own technique, But until then, follow the directions put forth in your owners manual. They write them for a reason and one of the reasons is so you have a reference of how to correctly tension your chain. If you own a Stihl chainsaw and don't have an instruction manual, you can go to your local Stihl dealer and they should be able to order you one. The book costs nothing to order (least here in Canada it doesn't) but maybe they will charge you some shipping. Then cover basic maintenance, starting, operating and safety. If you are worried about have a cracked impulse line, or a gas tank that is vapour locking, or your unit only idles, then take it to your (enter whatever brand here) dealer and get them to check it or get a service (tune up) done on your saw every year or two. and if you're not going to use it within 3 months drain all the gas and run the unit dry. Gas does go bad and the 2 dollars in gas that you save by nothing getting rid of it, isn't worth the hundred dollar bill you will get for repairing your unit.

If anyone has questions.. thats what the question section is for. If you want my help, feel free to question me if you really want.. maybe i'll even divulge some of my secrets
toolrepair (author) 3 years ago
@Peeet - I definitely agree you. Never tighten a hot chain and leave it in cold conditions. These are some very good tips to keep in mind when performing a chainsaw tensioning.
Peeet3 years ago
Good idea to post this quadracer!

But I have a real problem with the idea that "I dont want to give too many secretes, " . This really is nonsense. You will always get a better reputation if you provide all the best information you have than if you keep hold of information.

Some chainsaw businesses I know routinely profit from not providing good preventative information. I think it's utterly unprofessional and downright wrong.

VERY IMPORTANT re chain tension: NEVER tighten a hot chain & bar then leave it overnight in very cold conditions. The contraction and tightening of the chain with the cold can apparently bend or brake a crankshaft, especially if you overtighten.
quadracer3 years ago
Keep a eye on your bar wear.allways file off the burs, and then flat file the rails with a new chain.
toolrepair (author)  quadracer3 years ago
Nice advice on this one @quadracer, I should add that in as a good tip :) Thanks!
quadracer3 years ago
I find it best to grab the handle and lift up until bar tip on on the bench, and then tighten the rear bar stud first
Dr Qui3 years ago
Good Ible, but you did not mention that once you set the blade you should check the chain oil reservoir and top it up if needed.

You now need do one on how to keep the air filters cleaned out.

My dad worked at chainsaws and mowers for a living, I'm surprised how much I did pick up from just watching him.  I always give the chain about 1/4" of slack, my dad always says you should be able to slide the chain along the bar without effort if its a struggle then the chain is to tight.

One tip for the Electric Chain saw owners is to keep about 1/4" or more of slack in the blade, if the blade is to tight it WILL strip the nylon gear in about 5mins of use


toolrepair (author)  Dr Qui3 years ago
Thanks for the tips @Dr Qui -> I will definitely see if we can get something on how to keep the air filters cleaned out. That would be a great addition here.
Clogged filters was one of the most common cause of why the saws would not start.
toolrepair (author)  Dr Qui3 years ago
Which makes perfect sense :) Would be a good repair to show. Thanks again.
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