How do you sharpen a chainsaw by hand?
Sharpening a chainsaw by hand takes a round file matched to your chain's pitch, a flat file and depth-gauge tool, and cut-resistant gloves. The file removes the least metal of any method, so a hand-filed chain lasts through more sharpenings, and the tools are cheap and portable enough to carry into the field. Follow the steps in order to keep every cutter even.- Stop the engine, remove the battery or pull the spark-plug boot, and engage the chain brake.
- Clamp the bar in a vise or wedge it firmly so the chain cannot move, and put on gloves.
- Choose the round file size that matches your chain pitch, from 5/32 inch on small chains to 7/32 inch on large ones.
- Set the file into the first cutter at the top-plate angle marked on the tooth, usually about 30 degrees.
- Push the file across the tooth two or three times in one direction only, lifting on the return stroke.
- Move to the next cutter facing the same way and repeat with the same number of strokes.
- Turn the saw around and file the cutters facing the other direction.
- Every few sharpenings, lay the depth-gauge tool over each raker and file any protruding fin flat with the flat file.
Mark your first tooth with a paint pen so you know when you have gone all the way around, and keep the strokes equal so no cutter ends up longer than the rest. If you struggle to hold the angle, a file guide or a 2-in-1 file tool from our sharpener picks sets it for you. The full method and file-size chart are in our chainsaw sharpening guide. This is general guidance, not a substitute for the safety instructions in your saw's manual.
How many file strokes does each tooth need?
Most touch-ups need only two or three file strokes per cutter, because a chain sharpened little and often never gets dull enough to need more. Count the strokes on the first tooth and give every other cutter exactly the same number so they stay even.If a cutter is chipped or was dragged through dirt, it may take more strokes to reach clean steel, in which case bring every other tooth to the same length rather than leaving one short. The goal is uniform cutters, not one perfect tooth, since it is the shortest, dullest cutter that sets how the saw cuts.
How do you keep both sides of the chain even?
Keep both sides even by using the same file size, the same angle, and the same number of strokes on every cutter, then checking that the left and right teeth are the same length. Uneven cutters make a saw pull toward the sharper, longer side and cut in a curve.If the saw already cuts crooked, eyeball the cutter lengths on each side, file the longer side back to match the shorter, and reset to equal strokes from then on. A marked starting tooth stops you double-filing or missing cutters as you work around the loop.
What are the common mistakes when filing by hand?
The common mistakes are pressing on the return stroke, letting the angle wander, using a worn or wrong-size file, and forgetting the depth gauges. Each leaves the chain cutting slowly or roughly even though the teeth look sharp.A round file cuts only on the push, so lift it on the way back rather than sawing it to and fro. Keep the file level and at the marked angle, replace it once it stops biting, and lower the rakers every few sharpenings so the sharp cutters can reach the wood. Filing a loose or dirty chain undoes good technique, so tension and clean the chain first, as covered in our chainsaw maintenance guide.
When is a chain too worn to sharpen by hand?
A chain is too worn to keep sharpening once the cutters reach the wear line stamped on each tooth, when it will no longer hold tension, or when cutters are cracked or missing. At that point no amount of filing restores a safe, lasting edge, and a new chain cuts better and safer.Hand filing removes the least metal of any method, so a hand-filed chain reaches this point later than one repeatedly ground on a machine. Our chainsaw chains guide explains how to read the wear line and choose a replacement.
