Uneven filing is the usual suspect

Uneven filing is the usual suspect when a chain starts pulling to one side after sharpening, but it’s not the only cause.

Most of the time, you just took more metal off one side than the other. Longer cutters dig deeper and pull the saw hard in that direction. The fix is boring: count your strokes, match your angles, and check every cutter with a depth gauge.

But if your filing is consistent and it still pulls, check the chain for burrs on the cutters, look at the depth gauges (they can be uneven too), and inspect the bar. Worn rails or a bent bar will pull a perfectly filed chain every time.

A quick way to tell which one it is: swap the chain side-to-side on the bar or flip the bar over. If the pull follows the chain, it’s the chain. If it stays on the same side, it’s the bar.

Get a filing guide and stop guessing.