How to Sharpen Mulcher Blades


Your mulching lawn mower works hard to mulch the grass up into small particles so that it can effectively decompose back into the soil. As the blade repeatedly cuts the grass, it slowly dulls over time. Also, if your lawn mower picks up any twigs and small stones, these will hasten the dulling of your mulching blade. At least once a season, it is recommended to sharpen mulcher blades---more often if you run into twigs or small stones regularly.

Step 1

Turn the lawn mower off and take it to a well-lit and level surface. Disconnect the spark plug wire from the spark plug.

Step 2

Lay the lawn mower on its side and remove the mulching blade from the lawn mower. It is easily removed by loosening the nut that holds it to the engine shaft. Use an adjustable wrench for this.

Step 3

Use a wire brush or steel wool and remove any rust from the lawn mower blade.

Step 4

Put the lawn mower blade in a table vice to keep it stable. Use a metal file or angle grinder to sharpen the mulching blade. Follow the natural angle of the blade and sharpen until there is a nice, smooth and sharp edge on the blade.

Step 5

Remove the blade from the table vice and check its balance. Support the blade in the middle and notice if it tips either direction. If it does, remove a little more material from the blade on the side that tips down.

Step 6

Reinstall the blade back on the lawn mower by putting the bolt in and tightening it back up with your adjustable wrench. Stand the lawn mower back upright and reattach the spark plug wire.

Tips and Warnings

  • Wear gloves when handling lawn mower blades. The edge can be extremely sharp and cause serious cuts to bare skin.

Things You'll Need

  • Adjustable wrench
  • Steel wool or wire brush
  • Table vice
  • Metal file or angle grinder
  • Gloves


  • Weekend Gardener: How To Sharpen Lawn Mower Blades
Keywords: sharpen mulcher blades, table vice, well-lit and level surface, engine shaft, pits and nicks

About this Author

Robin Gonyo has been writing for several years now. She has a deep love for gardening and has spent a vast amount of time researching that subject. Previously she has written for private clients before joining Demand Studios. She hopes to share her knowledge with others through her writing.