The most common reasons a chainsaw drifts or cuts at an angle, from uneven sharpening to a worn or bent bar.
A chainsaw that pulls to one side during a cut, producing a curved or angled kerf instead of a straight line, almost always points to an imbalance somewhere in the cutting system rather than a problem with technique. The good news is that the causes are limited to a small handful of mechanical issues, and most are inexpensive to diagnose and fix.
Uneven sharpening is the most common cause
A chainsaw chain has cutters on both the left and right side of the loop, and each side needs to be filed at the same angle and to the same length for the saw to cut straight. If one side is sharper or longer than the other, that side removes more wood per pass, and the bar gets pulled toward the duller side as the saw works through the cut. This typically happens gradually over several hand-sharpening sessions where slightly more pressure or a few extra strokes are applied to one side without noticing. The fix is to resharpen carefully, counting strokes and checking angle consistently on both sides, or to have the chain professionally sharpened until it is restored to even length. Our guide on sharpening frequency covers how to build a consistent sharpening habit that prevents this drift from developing in the first place.
Uneven raker or depth gauge height
Each cutter has a depth gauge, sometimes called a raker, just ahead of it that controls how deeply the cutter bites into the wood. If the rakers on one side of the chain are filed lower than the other, that side takes a more aggressive bite and again pulls the cut toward that side. Depth gauge filing should be checked with a gauge tool after every few sharpenings, since rakers need periodic adjustment as the cutters themselves wear shorter, and this step is often skipped by chainsaw owners who only file the cutting edge.
A bent or unevenly worn bar
The bar itself can develop a slight bend from being dropped, pinched in a cut, or twisted while cutting, and a bent bar will steer the chain off a straight line regardless of how well the chain is sharpened. The bar rails can also wear unevenly over years of use, particularly on the side that contacts the wood most often. You can check for a bent bar by sighting down its length like a rifle barrel, or by flipping the bar over on the saw; if the crooked cut direction reverses after flipping, the bar is the cause rather than the chain.
Chain tension issues
A chain that is too loose can wander in the bar groove during the cut, contributing to an uneven or wandering kerf, especially on longer bars. Confirming correct tension before each session rules this out as a contributing factor; see our guide on correct chainsaw chain tension for the standard check.
How to diagnose which cause applies to you
Start with the simplest test: flip the bar over. If the cut direction reverses, the bar is bent or worn unevenly and should be replaced. If the crooked cut stays the same direction after flipping, the problem is in the chain itself, either uneven cutter length or uneven raker height. Inspect both sides of the chain closely under good light and compare cutter length side to side; a visible difference of even a millimeter is enough to cause noticeable drift over a long cut. If the chain looks even but is simply worn out overall, it may be past the point where hand sharpening can restore straight cutting, and replacement is the more reliable fix; see this roundup of chainsaw chains for replacement options matched to your saw.
Safety note: always shut off the engine or remove the battery, and engage the chain brake, before inspecting, adjusting, or touching the chain in any way. Wear cut-resistant gloves when handling the chain, and never test tension or sharpness with a bare finger run along the cutting edge.
Preventing crooked cuts going forward
Once a crooked-cutting chainsaw has been corrected, whether by resharpening evenly, adjusting rakers, or replacing a bent bar, the best way to keep it cutting straight is a consistent maintenance routine rather than reacting only after drift becomes obvious. Sharpen both sides with the same number of strokes at the same angle every time, ideally using a filing guide that clamps onto the bar to keep the angle consistent by hand. Check raker height with a gauge tool every two or three sharpenings rather than only when cutting performance noticeably drops. And inspect the bar periodically for straightness, especially after any incident where the saw was pinched, dropped, or twisted during a cut, since those are the moments most likely to introduce a bend that will not be obvious just from looking at the saw.
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FAQs
The most common cause is uneven sharpening, where cutters on one side of the chain are sharper or longer than the other side, so that side removes more wood and pulls the bar toward it. Uneven raker height and a bent bar are the other common causes.
Flip the bar over on the saw and make the same test cut. If the direction of drift reverses, the bar is bent or unevenly worn and should be replaced. If the drift stays the same direction, the problem is in the chain, not the bar.
A uniformly dull chain usually causes slower cutting and burning rather than crooked cuts. It is unevenly dull or unevenly sharpened cutters, sharper on one side than the other, that cause the saw to drift toward the duller side.
Yes, if the cause is uneven cutter length or raker height. Carefully filing both sides to equal length and angle, and checking raker height with a gauge tool, typically restores straight cutting. If a bent bar is the cause, sharpening will not help.