How Tight Should a Chainsaw Chain Be?

Wondering how tight your chainsaw chain should be?

How tight does it actually have to be?

Like any other tool, a chainsaw requires maintenance. There’s bar oil to refill, a carburetor to keep clean, and yes, a chain to keep tensioned. If the chain is too tight or too loose, the saw isn’t going to work as it’s intended. It might even pose a significant safety hazard.

If you’d like a better understanding of all the parts of the chainsaw, check out my article on The Parts of a Chainsaw (Explained in Simple Terms).

So, how tight should the chain be on a chainsaw, and how do you tighten it? Here’s everything you need to know about keeping your chain at the right tension.

Why Is Chain Tightness Important?

Before we go any further, let’s talk about why it’s important to have the chain properly tightened. To begin with, let’s assume you have a brand new saw with a perfectly-tensioned chain. As you operate your saw, the chain will be under stress, and it will slowly stretch out. After a while, it’s going to start to sag.

To begin with, this can cause the blade to move from side to side while it pulls through the wood. This makes for inefficient, irregular cutting, and causes the teeth to dull faster than they should. Not only that, but a loose chain can even come flying out of the saw, which is pretty dangerous.

So, why wouldn’t you just tighten the chain as much as possible? That way, you can go for even longer without it getting loose. This might sound smart, but an overly-tight chain poses some issues of its own. For one thing, it puts more stress on the motor, so your blade won’t move as quickly as it should. For another thing, the excess stress can cause the chain to snap and fly off, which is even more violent and dangerous than losing a loose chain.

As you can see, knowing how much to tighten your chainsaw chain is an essential skill. Whether you’re using an electric or gas-powered chainsaw, you’re going to save lots of money, time, and effort by doing the job yourself instead of having your chain professionally tightened.

What Tools Do I Need?

Most chainsaws will come with a tensioning tool you’ll use to adjust your chain. It has a hex socket at one end of a hollow tube that serves as a handle. Sticking out of the handle, in a T-shape, there’s a standard screwdriver. If you have one of these, it’s all you’re going to need to adjust the chainsaw.

That said, some manufacturers don’t include any tools, and you’ll have to buy them as an extra. Another alternative is to use your own standard screwdriver and a ratchet kit. To do this, simply locate the nuts that hold the bar cover in place, and find the appropriate socket; you’ll be all ready to go. Those are the only tools you’re going to need for such a simple job. There’s nothing else to it.

How Do I Tighten the Chain?

If you’ve been running your chainsaw, wait for it to cool down. A hot saw could burn you, and a hot chain is going to shrink slightly as it cools. Regardless of whether your saw is hot or not, disconnect the spark plug wire before you start adjusting. The last thing you want is to have the motor suddenly fire up while you’re working. If you have an electric saw, unplug it, or remove the battery on a battery-operated machine.

Now, loosen the bar cover nuts slightly. Don’t take them all the way, since the bar could come loose as you’re tightening. But you want it to be loose enough to let the bar slide freely forwards and backward. Now, you’ll need to locate the tension screw. This can be in several places, depending on your chainsaw. In most cases, it’s either directly beneath the bar, or on the side of the bar cover. If it’s not in either of those locations, check your owner’s manual.

To tighten the chain, first, hold the end of the bar so it’s level instead of sagging. As you tighten the tension screw, the bar will be pushed outwards, tightening the chain. As you loosen the screw, the tension on the bar will be relieved, relaxing the chain. Once you’ve gotten the correct tension, all you have to do is re-tighten the bar cover nuts. There you go! Your chain has been tightened!

How Tight Is Too Tight?

But how tight should the chain actually be? To find out, look at the inside part of your chain. There, you’ll see little shark fin-shaped teeth that fit in the groove in the bar. If those teeth can come out of the groove, the chain is too loose.

Start by letting go of the bar and setting the chainsaw on a level surface. Look at the chain underneath the bar. If it’s sagging, and there’s a gap between the chain and the bar, the chain is too loose and needs to be tightened more.

If there’s no gap, you can proceed to a snap test. Lift the chain from the top of the bar. It should lift easily, without you having to pry it up or use any tools. However, you shouldn’t be able to lift it to the point where the little fins come clear of the groove. If they do, you need to tighten the chain. If they don’t, and the chain snaps neatly back into place, you’ve found the perfect tension.

Closing Thoughts

Keeping your chainsaw under the proper tension is an integral part of maintaining your tool in proper condition. Just like filling your bar oil and sharpening your blades, it’s one of the things that keeps your saw safe and functional.

Not only that, but many shops charge a steep fee for what amounts to less than five minutes of work. Do you really want to pay a fee, over and over again, for something you can do yourself with tools you already own? Now that you know how to tighten your own chain, you don’t have to.

That concludes my article, I hope I answered any questions you may have had.

If you notice your chainsaw needs a good clean after you’ve tightened the chain, make sure to check out How To Clean a Chainsaw for some of my tips for getting it looking brand new again.

Happy sawing!

Your pal,

Chainsaw Larry