How to Tighten a Chainsaw Chain

Chainsaw chains are the part of the chainsaw blade that cuts through wood. Over time, the chain can stretch slightly during use, which reduces the saw’s wood-cutting effectiveness, slows down the cutting process, and requires the user to exert more pressure on the saw. If the chain gets too loose, it can even come off the bar.

Loggers and DIY woodcutters are well aware that chains can loosen rather quickly during heavy use. Tightening a chainsaw chain is a simple task that can be done quickly so the user can get back to cutting wood.

All chainsaw chains can be tightened similarly, although some brands may feature a slightly different bolt and tension pin configuration from the one featured in this how-to. The following tools and supplies are required for this common maintenance task.

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BEFORE YOU BEGIN

Learn to recognize the signs that the chainsaw chain is getting loose, including the need to exert additional force on the chainsaw bar to cut through logs or the chain coming entirely off the bar. If it’s a new chain—or a new chainsaw—odds are you need to tighten the chain occasionally to keep the tool in good cutting order.

While just tightening the chain will alleviate cutting problems in many cases, when the chainsaw still isn’t cutting well after taking the following steps to tighten it, the chain may be dull—and will require chainsaw chain sharpening. Alternatively, the saw could be damaged and need the services of a professional repairperson. If so, contact the tool’s manufacturer for further guidance.

STEP 1: Locate the chain tensioning adjustment on the side of the chainsaw—near the bar’s base.

Most chainsaws feature a chain-tensioning adjustment on the side of the chainsaw case—near the bolts that secure the chainsaw bar in place. This resembles a flathead screw, although it is actually a pin that moves the chainsaw bar slightly to create more tension on the chain.

Depending on the individual chainsaw model, there may be one bolt, two bolts, or even three. These bolts are essential during the chain-tightening process, and they’re also instrumental in holding on the side plate that covers the chain and gear assembly.

STEP 2: Loosen the bolt(s) that secures the chainsaw bar before adjusting the chain tension.

Before adjusting the tensioning pin, you must loosen the bolts that hold the side plate in place. Use the socket end of a scrench (a screw/wrench combo) to loosen the bolts slightly.

These bolts also secure the bar beneath the side plate. Don’t take them off—that isn’t necessary—just loosen them slightly (about 1/2-turn, or so) until you can wiggle the chainsaw bar a little bit. Now, you’re ready to tighten the chain.

STEP 3: Use the screwdriver end of the scrench to turn the tensioning pin.

Once you’ve loosened the bolt(s) on the side of the chainsaw, you can tighten the chain. Insert the screwdriver end of the scrench into the flathead tensioning pin (the chain tightener) and turn it clockwise to tighten the chain. The chain isn’t actually becoming tighter—instead, as you turn the tensioning pin—it pushes the chainsaw bar out a little bit, which takes up the slack on the chain.

During a typical afternoon wood-cutting session that lasts 2 to 4 hours, you may need to tighten the chain two or three times. But, it’s quick and straightforward since you don’t need to disassemble the saw. Keep a scrench nearby for tightening.

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STEP 4: Test the chain’s tension to determine when it’s tight enough.

How tight should a chainsaw chain be? Chainsaws don’t come with gauges that indicate when the chain is at the correct tension, but there’s an easy test you can do to figure it out.

After adjusting the tensioning pin, grab the chain at the bottom of the saw blade between a thumb and finger and pull it downward. You should be able to pull the chain sufficiently to see a small space between the links and the bar. However, the inside tips of the links should still be positioned in the bar groove.

If you can pull the entire chain below the bar, it’s still too loose. If the chain doesn’t budge at all—it’s too tight, and you can turn the tensioning pin counterclockwise to loosen it a bit.

STEP 5: Retighten the bolts after adjusting the chain tension.

The final step in the process is to retighten the bolts after adjusting the chain tension. Using the socket end of the scrench, turn the bolts until they’re snug. This won’t take much—just 1/2 a turn, or so.

Now, you’re ready to get back to cutting wood. But be careful—chainsaws are powerful tools that demand care and respect.

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Final Thoughts

Chainsaws are formidable power tools. Although more battery-operated models are available today, many still run on gas or diesel and create earsplitting noise during operation. Operating one requires physical strength and attention to safety. When a chainsaw chain is too loose, it increases the risk of the saw kicking back or the chain coming off, both of which can lead to injury.

As a general rule, users should check the chain’s tension before using the saw every time and frequently during use. Once you master the chain-tightening process, it won’t take more than a couple of minutes, and the only tool you’ll need is a scrench.

Tightening the chain isn’t a cure-all for a worn-out chain, however. Over time, usually a few months of frequent use, the chain can wear out and the blade links can become dull or worn down. When you start tightening the chain twice as often as you did when it was new, it’s probably time for a new chain.