Chainsaw Not Cutting Straight – Common Causes

Updated July 22nd, 2022
Chainsaw Not Cutting Straight

A chainsaw is one of the most important tools for woodworking projects, but it may become faulty for some reason. Common reasons for a chainsaw not cutting straight include the chainsaw not being properly sharpened, the groove of the chainsaw bar being worn out, the rails of the chainsaw bar being uneven, the chainsaw chain being loose, and the chain not being wide enough.

Usually, chainsaws should be able to cut through various types of wood within seconds. However, when the saw bar is not correctly maintained, the chainsaw won’t cut straight. It will give an angled cut.

Here are common causes and their solutions.

Causes

the Chainsaw behind cut log

Uneven Sharpening of The Chainsaw

To determine why your chainsaw can’t cut straight is a dull chain, check the condition of your chain. If the chain isn’t adequately sharpened, you’ll notice that the cutting teeth aren’t balanced on both sides. One side will have longer teeth. This imbalance in length will prevent the chainsaw from cutting straight.

Fixing this problem is a no-brainer. Simply sharpening the chain will solve this issue. To prevent it from occurring in the first place, we recommend equally sharpening the cutter teeth of your entire chain regularly.

One incident that can prompt an imbalance in the length of your chain’s cutter teeth is when your chain hits a rock while the chain is running. The impact of this contact can damage the blades on either side of your chainsaw.

The Groove of the Chainsaw Bar is Worn Out

When you notice your chain still cutting sideways instead of cutting straight even when its breadth is proportionate to the groove, that’s a problem. Time and long-term use can cause this problem. The groove of your saw bar is bound to wear out when you use it over time.

This can also cause the default breadth of the chain groove to expand slightly. This again is bound to happen because each time you use the chainsaw to cut wood, its bar endures continuous impacts. Over time, this will make the chain wiggle in the groove. When this happens, it won’t be cutting straight anymore.

The Bar Rails are Uneven

The bar rails refer to the pair of edges forming the groove. They provide support on both sides for the sharp chain and ensure it stays vertical. When these rails get worked out due to fatigue and continued use of the chain, one rail will be lower than the other.

This will prompt the uneven chain to respond to gravity by leaning on the lower rail. This will turn the chain angled instead of its default vertical state. Naturally, a chain in an angled state can’t cut straight.

Loose Chain

This is another common reason your chainsaw is not cutting straight. When the chain is not fitted correctly on the bar, it tends to flip to the side, preventing the chainsaw from cutting straight. Thankfully, manufacturers now design most chainsaws to have a tension adjustment feature, ensuring the chain tightens automatically around the bar. Using this feature to adjust the tension of your chain will ensure that it becomes tightly fitted to the bar.

The chain isn’t Wide Enough.

Every chain has cutter tooth drivers that fit into the bar’s chain groove. When these drivers are thinner than the groove, it will result in the chain wiggling in the groove instead of fitting correctly. This will cause your chainsaw to tilt sideways when you try to cut straight, resulting in an angled cut.

Check the sides of your chain to ensure whether the width of the chain is proportionate to the groove. If the chain is easily moving forward and backward, then that means your chain is thinner than the groove.

Having established the various causes why a chainsaw is not cutting straight, let’s delve into the solutions.

Solutions

sharp chainsaw on wood log

Properly Sharpen the Chainsaw if it Cuts Crooked

Before you proceed with this curative measure, take a critical look at your chain links and the cutter teeth length first to determine if there’s lopsided sharpening or not. A cutter tooth length can easily be verified thanks to a small line that helps you compare its dimensions with the other tooth. This small line defines a lower limit for the point above which the cutter teeth cannot be filed or sharpened.

When you notice an obvious difference, use a file to sharpen the higher cutters. Follow the steps below to sharpen the chainsaw properly:

Step 1: Get the Tools you Need

Firstly, get all the tools you need to sharpen your chainsaw. Ensure you have a round file as well as a file guide. For safety purposes, we strongly advise that you get a file that has a safety handle.

Step 2: Chainsaw Bar Adjustment

The next step is to ensure your chainsaw bar is adjusted on a bench. This makes the process of filing your chainsaw more efficient and easier than if you’re holding your chainsaw with your hand. Put the longitudinal side of the bar between both fixtures and ensure the top part of the teeth is showing above. Also, ensure your chain can spin freely while it’s fixed.

Step 3: Filing the Cutter Teeth

Firmly push the round file in the file guide on the top part of the chainsaw’s tooth at 30 degrees. Then, use your dominant hand to move it and press it tightly across the entire cutter. Getting the correct angle and filing in one direction is very important. If you move the file forward and backward continuously, it can damage the teeth.

Ensure you move the file towards the tooth. Also, press it on the tooth till the metal peels away with each movement. When you’re done with one side, repeat the filing process on the other side till all sides have been completely filled. Ensure you maintain equal pressure on both sides.

Step 4: Filing the Depth Gauges

Once you’re done filing the teeth, this is the next area to focus on to retain cutting depth. For this area, we recommend using a flat file and a depth gauge tool for guidance. After filing, check that the upper part has been balanced. Repeat this process for the entire chain.

Ensure your Chain is Tighter

If you’ve sharpened your chainsaws properly and still they cut crooked, the next place to inspect is the tension. If the tension is not tight, you’ll notice that the chain will sag. Tighten your chain using the chain adjustment screw. If that doesn’t work, break the chain open and shorten the cutter link to keep its length at the right size to fit on the guide bar properly.

Get a New Chain with Complementary Thickness

This is the solution for a chain that shakes sideways in the groove. You can check for its thickness as well as the groove’s thickness. This information is usually in the instructions manual. Several bars generally have chains that are ⅝” thick. So if the chain you’re currently using falls short of that dimension, that means you need to get it replaced with the correct size on the guide bar. This can be purchased at a saw shop.

Turn the Groove Over

If you’ve changed the chain to the right size and it still shakes sideways, the guide bar is wearing out on one side. Typically, this happens to the lower side of the groove because that’s the side that touches wood during the cutting process. The fatigue experienced makes it prone to wear out.

To solve this issue, turn the bar over and reinstall the chain on it. This will position the less worn side of the bar on the lower side. Then flop the chain horizontally and see if it still shakes while in the groove. You should notice slight wiggling on the lower side and considerable wiggling on the upper side. It won’t matter if the upper side wiggles at this point because it won’t matter during the cutting process.

Grind the Rails to Correct the Imbalance

If the solutions mentioned above don’t work, inspect your rails. If you notice that the rails are uneven and one side of the rails is lower than the other, that means you’ll need to even them out by grinding them. To this effect, you’ll need a reliable grinding tool.

Keep your rails balanced and firmly press them against the grinding tool. Do this till some metal peels from the higher rail and both rails are even. If you can’t get your hands on a grinding tool, a flat file and bench-wise will make a good alternative.

How to Straighten your Chainsaw Bar

chainsaw bar on the table

Most chainsaw bars can be straightened with a particular technique. This is a tricky chore because not getting it right can damage your bar. Besides, this also depends on the type of bar (solid or laminated bar) and the extent of its damage.

Follow the below steps to straighten solid chainsaw bars:

Step 1 – Position the Bar into a Press

This involves applying steady pressure strong enough to straighten the bar. We recommend using a hydraulic or arbor press. If you can’t use a press, get an adjustable wrench (24 inches in size) and a bench wise to get the job done.

Step 2 – Use a Hammer on the Bar

Position the solid bar on a flat anvil and beat it with a 4-pound dead blow hammer. We don’t advise using a ball pen hammer because that will ruin the surface of your bar. In the absence of a flat anvil, use a bar hook tool.

Step 3 – Using a Bar Cleaner Handle

Using this eliminates the debris in your rails. It’s as thick as the width of the groove. Use this tool by placing it between both rails, then beat the link out with a dead blow hammer.

When it comes to laminated bars, which are thinner than solid bars, we recommend putting rubber padding beneath the bar before beating it with a dead blow hammer. The padding will protect the bar from damage that the hammer blows could have incurred.

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