When the saw teeth become chipped, damaged or dull, the chainsaw likely won’t cut straight, especially if more teeth are affected along one side of the chain. Sharpen the teeth uniformly using a file and file guide, or take it to professional for sharpening. Madsen’s recommends using a grinder rather than a file, if you want to avoid taking it to a professional.
Dull cutters damaged by rocks can cause a chain to cut crooked. It’s important to remove all damage from cutters prior to cutting. Cutting with a dull chain can accelerate wear to the bar and chain.
The most probable reason why a chainsaw pulls either to the right or left during a cut is because it was sharpened unevenly. Keep working the side which you feel lacks attention, and eventually the chainsaw should start going as straight as new. The teeth have to be equally sharp on each end to make the chainsaw work straight.