How to Sharpen a Lawn Mower Blade

To sharpen the blade on your lawn mower:

  1. Remove the spark plug wire.
  2. Tilt the mower up on one side.
  3. Clamp a block of wood to the mower deck to prevent the blade from turning.
  4. Loosen the bolt holding the blade in place with a wrench, turning it counterclockwise.
  5. Mark the blade so you’ll know which side is up.
  6. Sharpen the blade on the beveled side—following the angle of the bevel—using a file, grinder, sharpening stone, or belt sander.
  7. Remove any burs on the flat side of the blade with a file or sharpening stone held flat against the width of the blade.
  8. Put the blade back on the mower with the beveled side of the blade facing up.
  9. Tighten the bolt with a wrench, turning it clockwise.
  10. Turn the mower back upright.
  11. Reattach the spark plug wire.

Watch this video to find out more.

Further Information

If you want an attractive lawn, it’s important to keep your mower blade sharp. Begin by removing the spark plug wire so there’s no chance of accidental starting. Then clamp a block to the deck to hold the blade in place while you loosen the retaining bolt with a wrench. Pay close attention to which side is facing down.

To sharpen the blade you can use a hand file, a bench grinder, or even a belt sander. Whatever tool you use, you want to work the beveled edges down to a point and remove any burs or nicks. When you put the blade back on, be sure the retaining bolt is nice and tight before reconnecting the spark plug.


  1. i didn’t hear you say to make sure the blade is re-balanced after sharpening. i always recommend to re-balance a blade because it is spinning at high rpm and will shorten the life of the engine’s bearings if it is not.

  2. References lawnmower blade sharpening. If you purchase a new mower blade its sharp butt not that sharp; however if you take a blade to a have it sharpened they will make it razor sharp. Is razor sharp too sharp or should the blade be similar to a new blade sharp? Thanks


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