How to Sharpen Your Lawn Mower Blades Like a Pro

A Lawn Mower blade has to be sharpened whenever you find the machine’s blades are dull. Cutting the grass evenly and neatly is easier if they are light. So, there is a process to sharpen the blades of the mowers, which is given in the article below.

How to Sharpen Your Lawn Mower Blades

Reasons that Lawn Mower blades become dull:

Due to some reasons and our maintenance, Lawn Mower blades become dull and lose their sharpness. They are,

  • If the blades of the machine are continuously used without proper care.
  • The blades become dull when they are not cleaned after every use. The dust and debris on the blades may make the blades go dull after staying for longer.
  • Do not take care of the mower properly.
  • The common reason is that you may only use the machine for a while.
  • Storing the mower in rainy or wet areas can allow the blades to get rusted and becomes dull.

Signs that Lawn Mower blades became dull:

Lawn mower blades become dull due to many reasons. But you can identify that they are dull by noticing the below signs. They are,

Uneven grass after mowing:

The obvious sign that blades are dull is uneven lengths even after mowing the grass. With the dull blades, it becomes difficult to cut the grass evenly.

Mowing the same areas multiple times:

Suppose you notice that you mow the same area multiple times, even after cutting the grass. This is because the blades became dull enough that it became difficult to pass the area.

Needs stronger push:

A normal mower with sharp blades completes the work with an easy push. But if the blades are dull, it will become to push the mower because it doesn’t pass on the grass.

If the blade dent or bent:

Due to some strong jerks, the blade may dent or bend. If you find this sign, you must sharpen the blade and recover the bend.

Patches on the lawn:

If the blades are dull, then you will find dry patches where you find uneven grass after mowing.

The machine pulls up dirt or grass chucks:

A sharp blade cuts the grass evenly, but the dull blades pull out huge grass chunks or dirt from the surface.

Tools to sharpen Lawn Mower blades:

Some tools are needed to sharpen the Lawn Mower blades. They are,

  • Wrench or screwdriver
  • Bench clamp
  • Clean rag
  • Penetrating cleaner
  • Gloves
  • Eye protection glasses
  • A filer or grinder
  • Mask

How to sharpen Lawn Mower blades?

Follow the below steps to sharpen Lawn Mower blades if they are dull. They are,

Step:1 Disconnect the spark plug of the mower

Always make sure to disconnect the spark plug before sharpening the blades. If you do not disconnect, the mower can turn on, and the blades move automatically. This can cause accidents while sharpening the blades, which is the last thing we want.

Step: 2 Tip the mower

After turning off the sparker, tip the mower to its side to get the blade. You must tip it away from the carburetor and air filter because this can lead to oil leakage and damage the machine.

Remove blades:

Take a screwdriver or wrench in your hands and rotate the bolts to remove the Lawn Mower blades. Point a mark on the blade to identify the front and back sides of the blade when inserting them back. If the bolts are tight, use a penetrating cleaner or lubricant to loosen them.

Clean the blade:

The removed blade may already have rust, dirt, or debris. So clean the blade with a clean rag or cloth before sharpening it. Use a penetrating cleaner to clean it with wiping if it is too stubborn.

Clamp blades securely:

Place the blades in a bench clamp to sharpen them because you need to use both hands while sharpening.

Sharp the blade with a filer or grinder:


Using a filer to file the blade is easy if you have yet to gain experience in sharpening. Take the blade in your hands and place it at a 40 to 45 degrees angle on the filer.

Apply enough pressure and move the file back and forth to shape it. To get enough sharp, you need 50 strokes, and you can do more if you want more sharp.


Grinding the blade is easier than filing, but the blade can lose shape with grinding. Due to heat, if you do not know how to use it, the blades can change their shape. Bring the blades only if you have experience.

Take the Lawn Mower blades in your hand and run them through the grinder. If the grinder is overheated, wait a few minutes to cool it down. Again run the blade with enough heat.

Check the balance of the blade:

When we remove the blade to sharpen, then the balance of the Lawn Mower blades can change. So, you can check the balance by hammering the nail into the wall and threading it. Once you thread it to the center of the hole, the blade should look like a propeller.

If it shakes or doesn’t look like a propeller, take enough time to file it again.

Re-assemble the blades:

After completing the sharpening process:

  1. Take your bolts and blades in your hand.
  2. Re-assemble the blades into the mower carefully.
  3. Make sure that the spark is connected.
Check if it is working or not:

When you finally assemble all the parts, the last step is to check whether the mower is working properly. If you are okay with it, you can use it. If you find any faults, you can make other changes.

Tips to sharpen the blades of a Lawn Mower:

Some safety tips that you have to follow to sharpen Lawn Mower blades are,

  • Only sharpen the blades with wearing gloves or goggles.
  • Make sure to disconnect the spark before sharpening.
  • Avoid the blades as much as possible because they may be sharp enough to harm you.
  • You have to calm the blade to put the blade in a stable position.
  • Keep your fingers away from the blades.


Lawnmowers work to cut the grass in the lawn with the help of blades. But the Lawn Mower blades can become dull for usage, unused, or put in moist places, etc. You can sharpen the blades by using a filer or grinder. If you have yet to gain experience in sharpening, use a filer; if you are experienced, you can use a grinder.


Doesn’t the lawn mower blades become dull?

Yes, the blades will be sharp when they are brand new, but after a long time, they can become dull for many reasons.

What are the reasons that the blades of a lawn mower become dull?

Some of the reasons the blades become dull are that you have used the machine for a long time, without proper maintenance and care, storing it in moist places, not using it for a long time, etc.

How can we sharpen the blade? 

You can shape the baldness of a lawn mower with the help of a file or grinder.

Is it easy to sharpen the blades with a grinder?

The blades are easy to sharpen when using a grinder, but if you are a beginner, use a filer to sharpen. With the grinder, there is a chance that the blades change their shape due to overheating.

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