Does your lawn look ragged at the tips after you mow? That is not the grass. That is a dull blade tearing instead of cutting, and it makes the whole yard more vulnerable to disease.

You Do Not Need to Remove It

Most people put off sharpening because removal sounds like a hassle. If you have a jack, a socket set, and a file, you can do it in place safely.

1. Disconnect the spark plug. Do this first, not after. A mower can start if the blade turns.
2. Tip the mower on its side with the air filter side up. Tipping it the wrong way floods the engine with oil.
3. Block the blade so it cannot spin. A piece of 2×4 wedged between the blade and the deck works fine.
4. File the cutting edge at the original angle, about five strokes, following the existing bevel.
5. Check the balance. Hang the blade on a nail through the center hole. If one side drops, file a little off the heavy end.

Sharpen or Replace

File it once a season, or every twenty hours of mowing. If the blade is badly nicked, bent, or missing a chunk, replace it. A bent blade vibrates and that wears out the spindle. Blades are cheap compared to a spindle.

I skipped a season once and the grass looked chewed for a month before I worked out why. Now it is a ten minute job in the spring and the lawn looks better all summer.