Why Does a Chainsaw Not Cut Straight?

Why Does Chainsaw not cut straight ?

A chainsaw that fails to make straight cuts can be immensely frustrating. I recently struggled with my trusty Stihl chainsaw inexplicably pulling to one side while cutting firewood. The angled and crooked cuts not only made my work slower but also more dangerous with increased chances of kickback. Determined to get to the root of the problem, I dove into troubleshooting and maintenance to get my chainsaw cutting straight again.

Proper chainsaw function and cutting ability is vital for efficiency and safety. In this comprehensive guide, I’ll share the common issues that cause chainsaws not to cut straight and provide tips for maintenance, troubleshooting, and prevention.

Why Does the Chainsaw Not Cut Straight?

Why Does a Chainsaw Not Cut Straight?

There are a few key reasons why your chainsaw may cut crooked instead of nice, straight lines:

Dull or Damaged Chain

The chain is one of the most important components on a chainsaw, and a dull or damaged chain is a common culprit behind crooked cutting. The sharp cutter teeth on the chain do the actual cutting through the wood. As the teeth wear down over time and use, the cutting ability declines. Blunt cutter and raker teeth force you to apply more pressure to cut, increasing the risk of kickback from the chainsaw blade binding or pinching in the wood. This struggle can pull the saw to one side. Damaged or improperly sharpened teeth can also lead to uneven, inefficient cutting.

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Uneven Wear on the Guide Bar

The guide bar provides critical support and guides the movement of the chain around the bar. If the bar has uneven wear, such as more wear on one side of the bar’s rail, groove, or nose, it can cause the chain to travel crooked. This throws off the entire cutting motion.

Chain Tension Issues

Proper chain tension is crucial for straight cuts. Chains naturally stretch over time and use. If the chain becomes loose it can wobble from side to side while cutting and easily jump out of the guide bar groove. An overly tight chain strains the bar and engine. Either under or over tensioning prevents the chain from tracking straight.

Regular maintenance helps identify issues before they lead to cutting problems. At the first sign of the saw veering off course, investigate with these potential causes in mind.

Dull or Damaged Chain

Sharp cutter teeth are essential for efficient, straight chainsaw cutting. Here’s what you need to know about maintaining and sharpening the chain:

How a Dull Chain Affects Cutting

As the cutter and raker teeth on the chain lose their sharp edge, performance immediately suffers. The dull surfaces require more force to sever wood fibers. This added pressure forces the saw left or right, leading to angled cuts. Binding and pinching can also occur.

Signs of a Damaged Chain

Look for cracked, bent, or missing cutter and raker teeth. Damage occurs over time through wear and improper sharpening techniques. Gaps between adjacent teeth or uneven tooth length indicates issues.

Proper Chain Sharpening Techniques

Regular sharpening extends chain life. Follow a few rules to properly sharpen cutters and rakers:

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Sharpening Techniques

  • Use the correct round file size for your chain – match file diameter to chain gauge.
  • Maintain the manufacturer’s specified filing angle, usually 30°. File perpendicular to the guide bar with even strokes.
  • Sharpen all cutters on one side first, then flip and do the opposite cutters. This prevents tilting or angling teeth.
  • Lower rakers evenly after several sharpenings so cutters can penetrate wood.

Uneven Wear on the Guide Bar

The condition of the guide bar is key for straight chainsaw cutting. Here are some signs of wear and steps for maintenance:

Causes of Uneven Wear

Friction naturally wears the guide bar’s rail where it contacts the chain. Debris buildup accelerates local wear. Running a loose chain exacerbates issues on one side.

How Uneven Wear Affects Cutting

Wear reduces rail thickness and the bar groove depth. This allows increased side-to-side chain movement and flexing during cutting. The chain eventually tracks to the worn area and makes angled cuts.

Replacing or Maintaining the Guide Bar

Inspect bars regularly, especially the underside. Replace excessively worn bars for optimal function. Lubricate and clean the bar to reduce friction. File down burrs or flat spots. Consider side-to-side rail swap or bar reversal to distribute wear.

Chain Tension Issues

Proper chain tension prevents many cutting issues:

Proper Chain Tension

Check tension frequently since chains stretch over time. The chain should seat snugly in the bar groove but still pull freely by hand. About a dime’s thickness of slack beneath the drive links works for most saws.

How Tension Affects Cutting

Loose chains wander in the bar groove, causing crooked cuts. Overly tight chains drag and strain the bar, engine and cutter components. Either under or over tensioning reduces control.

Adjusting Chain Tension

First check the owner’s manual for model-specific steps since adjustment methods vary. Typically loosening bar nuts allows tweaking tension by turning the tensioning screw. Tighten nuts and recheck pull-by-hand tension.

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Why is my chainsaw pulling to one side while cutting?

A dull or damaged chain with uneven tooth sharpness can cause the saw to veer as it works too hard cutting. Binding and kickback risks go up. Also inspect the guide bar for uneven rail/groove wear which leads to chain drift.

How do I know if my chainsaw oiler is working?

Check for adequate oil flow with the chain running but not cutting. Oil should fling off the tip in a steady stream. If not, clean the bar and ports thoroughly. If flow remains low, the pump or lines likely need repair or replacement.

How do I adjust the chain tension on my chainsaw?

First consult your model’s manual. Typically, loosen the bar and clutch nuts, then turn the tension adjuster to tighten or loosen as needed. Leave slack under drive links when pulling chain around by hand. Tighten nuts and recheck tension.

How often should I sharpen my chainsaw chain?

Sharpen after 25-30 hours of use as a general rule. More often when cutting dirty or sand-laden wood. Inspect for rounded cutters, slow cutting, or increased effort which signal dullness. Keep extra chains on hand for quick change outs.

How do I clean the oiler holes on my chainsaw?

Regularly use a small wire to clear the oil inlet hole behind the bar nose sprocket and outlet ports along the guide bar rails. Flush with solvent spray. Proper oiling prevents excessive wear from friction.

How do I choose the correct file size for my chainsaw chain?

Use a file that matches your saw chain’s gauge measurement. The package or owner’s manual typically provides the gauge in inches or millimeters. Using a properly sized file ensures correct sharpening angle and depth.

How do I replace the guide bar on my chainsaw?

Check for excessive, uneven rail wear or damage. Remove old bar and chain. Clean the mounting surface. Install new bar and lightly lubricate. Install adjusted chain and tension properly. Tighten mounting nuts firmly. Confirm smooth chain rotation.


A chainsaw that cuts crooked is frustrating and dangerous. In most cases, the underlying causes are preventable with proper saw maintenance and care. Keep chains sharply sharpened. Monitor and address guide bar wear. Maintain proper chain tension. Clean the saw thoroughly and regularly. With practice and vigilance, you can troubleshoot problems and keep your chainsaw cutting straight for years to come.


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