You can't just file a chain after it eats dirt

If your chain hit dirt or metal, don’t just run a file over it — you need to inspect for hidden damage first.

Dirt is the sneaky one. It doesn’t break teeth, it just dulls them and rolls the cutting edges, so you think a few passes with a file will fix it. Sometimes it does, but usually you need to file a lot more than normal to get past the damaged steel. So the first step is to clean the chain and look closely at every cutter under good light. If the edges are rolled or shiny and deformed, you’re not done after one pass.

Metal is a different story. Hitting a nail, fence wire, or rock can chip teeth, bend cutters, or create hairline cracks you can’t see without a magnifier. If you spot a crack, that chain is done — replace it. A small chip might be grindable back to shape, but don’t try to file a deep nick and hope for the best. It’ll dull fast and could throw a tooth at speed, which is not the kind of excitement you want.

Also check the depth gauges, because they take wear too, and glance at the bar rail and sprocket while the chain is off. The impact travels. It’s not just the chain that takes the hit.

Saving a chain that’s been through metal isn’t saving money — it’s borrowing trouble.