clock menu more-arrow no yes

How to Sharpen Mower Blades

Cutting grass cleanly with This Old House landscape contractor Roger Cook.

In this video, This Old House landscape contractor Roger Cook shows how to convert a dull blade and cut grass cleanly.

Steps to Sharpen Mower Blades

  1. Disconnect the spark-plug wire from the spark plug to prevent accidental starting.
  2. Tip-up the lawnmower with its spark plug pointing vertically.
  3. Put on a leather work glove and grab hold of the lawnmower blade.
  4. Use a ratcheting socket wrench to remove the nuts holding the blade to the mower.
  5. Remove the blade from the mower.
  6. Clamp the blade in a vise and use a metal file to sharpen the cutting edges of the blade.
  7. Chuck a blade-sharpening stone into a drill/driver and use it to sharpen the lawnmower blade. Be sure to keep the stone's plastic guide against the rear of the blade.
  8. Sharpen the lawnmower blade using a bench grinder and get it “butter knife sharp.”
  9. Repeat to sharpen the opposite end of the blade.
  10. Set the sharpened blade onto a blade balancer. If the blade is out of balance, file or grind a bit more steel from the heavy end.
  11. Use a putty knife to scrape away any matted grass clippings from the underside of the mowing deck.
  12. Reinstall the blade, firmly tightening the nuts with a ratcheting socket wrench.
  13. Lower the mower and reattach the spark-plug wire.