How to Sharpen Your Lawn Mower Blade

Over time, lawn mower blades can become dull and work harder, and the chance of the machine breaking down increases. In this article, you will learn how to sharpen your lawn mower blades to their original sharpness.

If you mow your own grass, you need to understand how to sharpen the blade on your mower. A sharp blade saves time and energy while mowing, makes sure a clean cut, and even helps to minimize the spread of lawn fungi. This job will take about fifteen minutes per blade, and the only devices required is a wrench, a 24″ piece of 2×4 or 3″ diameter pipe, a vice and a file. Keep these few items close at hand and you can make quick work of it.

How Do You Understand if Your Blade Requires to Be Sharpened?

lawn mower - sharpening blades

Here are some signs that you ought to sharpen your mower blade:

  • The mower leaves a rough, ragged surface.
  • The blades of yard appearance torn instead of cut.
  • A day or so after cutting, the yard has brown tips.
  • It’s been at least a year given that it was sharpened.

How Often Should You Sharpen Your Mower Blade?

lawn mower - sharpening blades

If the mower is utilized routinely, intend on sharpening at least once a year. An annual sharpening ought to go hand-in-hand with an oil, filter and spark plug change, to keep your baby purring like a kitten. If it is used greatly or there are a lot of weeds, sticks, or other debris in the turf, as much as numerous times per summer may be needed. If multiple sharpenings per season are required, consider purchasing a second blade (or set of blades) to have on hand for a fast change out that can save time on cutting day and allow sharpening to be done when it’s most practical.

Mower blades should last a very long time, possibly the life of the mower. Nevertheless, an unsafe or broken blade must be discarded and replaced with a new blade matching producer requirements for your mower. Discard a blade when it is bent, split, worn thin on the back edge (opposite the cutting edge), deeply rusted, or otherwise structurally deformed.

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Sharpening a Mower Blade

Detach the spark plug or eliminate the battery to prevent an unintentional start.

Suggestion the mower up on its side.

The side with the carburetor and air filter ought to be on top.

Block the blade with the piece of 2×4 or place a piece of 3″ pipeline through the side discharge and over the blade to hold it in place.

lawn mower blade detachment

Set the bolt and washer aside where they will not be lost.

Use the wrench to remove the bolt which holds the blade in place.

Clamp the blade in the vice, in “cutting position” with the first end to be sharpened extending 3 or 4 inches beyond the jaws of the vice.

Following the initial angle of the cutting edge (roughly 30 degrees), and with long consistent strokes, use the file to smooth the rough cutting edge back to a flat sharp surface.

For fast grinding action, a double-cut file will remove a great deal of material quickly.

For sharpening and developing a last edge utilize a single-cut file.

sharpening lawn mower blade

Double sided files are available with one side single-cut and the opposite double-cut.

When the first end is total, re-position the blade and sharpen the other cutting edge.

Once both sides are sharp, examine the balance of the blade by hanging it on a nail through the bolt hole.

If it hangs horizontally, it’s prepared to re-install.

If one end hangs lower than the other, file a bit more off that end’s edge up until the blade balances on the nail. This will guarantee that the mower runs efficiently.

Re-install the sharpened, well balanced blade.

Keep in mind to utilize the 2×4 or pipe to support the blade as you tighten the bolt.

Reconnect the spark plug wire. You’re prepared to cut your grass again!


While old-fashioned cylinder or reel lawn mowers — those with a cutting bar and multiple-blade assembly that cuts forward as the operator presses it — most likely requirement professional servicing, the more normal gas- or electric-powered rotary mower can be taken care of in a do-it-yourself fashion. These utilize a single blade that spins horizontally around a vertical spindle — easy to eliminate and keep in your home. If yours is a riding mower, you’re in luck, too: These machines generally have two rotary blades, which can be gotten rid of and honed just the same. 

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Reyus Mammadli (Tech Support Leader)

Being a bachelor in electronics, an engineer in the field of biotechnical and medical devices and systems, Reyus Mammadli has been running a technical blog for many years, expressing his expert and user opinions on various devices and software.

Tech for Life