Symptoms
- Cut curves to one side instead of going straight
- One side of the chain looks more worn than the other
- Wider or narrower kerf on one side of the cut
- Bar appears to lean during cutting
Likely causes
- CommonUnevenly sharpened chain teethFiling more off one side's cutters than the other makes them cut at different rates.
- CommonChipped or damaged tooth on one sideA single damaged cutter can throw off the whole side's cutting balance.
- PossibleWorn or bent guide bar railsUneven bar rails let the chain track slightly off-center.
- PossibleBar flipped inconsistently causing uneven wearNot periodically flipping the bar concentrates wear on one rail.
- Less commonChain tension too looseExcess chain slack can allow slight wandering during a cut.
What to do
- Engage the chain brake and remove the plug boot before inspecting the chain.
- Compare cutter lengths on both sides of the chain by eye; look for one side visibly shorter than the other.
- Sharpen all cutters evenly, using the same file size, angle, and stroke count on both sides.
- Check depth gauges are uniform across all cutters after sharpening.
- Inspect the guide bar rails for uneven wear and flip the bar end-for-end if only one side shows wear.
- Verify chain tension is correct, neither too tight nor sagging.
- Test cut on scrap wood to confirm the saw now tracks straight.
Tools and parts
- Round chainsaw file
- Flat file
- Depth gauge tool
- Bar wrench
Replacement chainSearch: “chainsaw replacement chain”
Guide barSearch: “chainsaw guide bar replacement”
When to call a pro
If the bar rails are significantly worn or bent, have a small-engine shop replace the guide bar.
Safety
Use caution
Wear cut-resistant gloves and engage the chain brake before handling the chain for inspection or sharpening.