6 Steps to Sharpen Your Mower Blade- Experts Opinion

What happens when you are trying to mow the lawn’s grass with a dull blade? The dullness of the blade will result in the spoilage of time and also the person’s mood. All you need to take a break and let your dumb and dull blade turn into a lustrous and sharp blade. The sharpening of blades is not just only the matter of blade but also a matter of lawn care. In a grass mower, there are one or two rotating blades that rotate to cut the grass to an even height.

In everyone’s mind, a question will arise why there is a need of sharpening the blades? The plant pathologists consider it to be the most convenient and most appropriate action to sharpen it before use. The dull blade will pull the grass, leaving the surface with ragged tears which may be harmful to plants’ growth and also increases the vulnerability of fungal attack, which in turn will weaken the plants. Moreover, the shredded grass will no longer be able to heal itself even within the next 24 hours, the blades will take on a brown, straw-like appearance. 

6 Steps to Sharpen Your Mower Blade

Even if you sharpen the blades of your lawnmower every year before the spring season it could still get dull midway through the season when you will need to mow a larger yard and also the blades get scalped with the ground or hit the rocks during mowing. In that case, you will need to sharpen the blades of your lawnmower again.

Steps to Sharpen Your Lawn Mower Blade

Many different ways have been used by house owners to sharpen the lawnmower blades such as sharpening with a bench grinder, filling with the rotary tool, hand-filling, and also using the angle grinder. But the most accurate and easiest method to sharpening the blades is to use a drill and a sharpening stone that is specially designed to give a sharp cutting edge to your dull lawn mower blades. 

Tools needed to sharpen your lawnmower 

Some essential tools are mandatory during lawn mowing :

  1. Gloves and pieces of equipment for eyes safety 
  2. An angle grinder, hand metal file or a sharpener for the lawnmower blade
  3. Wrench which will remove and reattach the blade
  4. Wood blocker
  5. Screwdriver or nail 
  6. Dedicated blade balancer (how to balance mower blade)

It is recommended that you should sharpen your lawn mower’s blade every year before the mowing season. Many house owners think that sharpening the mowers blade every year is unnecessary when they could still mow their lawn with those dull blades but that is not the right way to do it as it could be harmful to both your lawn and for the lawnmower.

You must take off the blades from the mower before sharpening as it gives you greater access to the cutting edges of the mower and allows you to inspect any debris or damage to the blade such as excessive wear. You can easily remove the blades of your lawnmower following these simple steps and could easily sharpen the mower blade by hand filer. Some lawn mowers also allow you to sharpen the blade without removing it and it will also save your time. 

Step 1: Prepare for removing the dull blade

 Before you even try to remove the dull blade make sure that you have disconnected the ignition wire from the spark plug. (If it’s a cordless mower, remove the battery pack), tie them back so it does not come in contact with the spark plug. Removing the spark plug eliminates the risk of accidentally starting the engine and eliminates the risk of harming your hand. Also, drain all the fuel from the fuel tank and keep it dry unless you are done sharpening the blades.

Step 2: Unscrew bolts and blade

Turn the mower at its one side that exposes the retaining nuts or bolts and keep the carburetor or air filter side up while the blades on the underside of the grass mower. This will protect the air filters in case of dripping of fuel and gas. While you are unscrewing the blades, blades could get turned and may harm you, to avoid this place a wedge of 2×4 woodblock and place it between the end of the blades and also inside the mowing deck. You will need a large ratcheting wrench and socket to loosen the bolts or nuts. Now move that wrench in a counterclockwise direction to loosen the bolt on the side of the blades. If the nuts and bolts are rusted, apply some oil or grease and wait for a few seconds and then try again. And if it still does not open up try to slip a metal pipe over the wrench handle.

Before removing the nut make sure to mark the blade with spray paint or something else to remember which way to uninstall as the most common mistake the house owners make is that they reinstall the blade upside down and that the blades won’t cut the grass. The blades must be reinstalled in the same orientation.

Step3: Clean the blade surface

After removing the blades, keep a narrow blade putty knife and scrape all the deck of your lawnmower, remove all the caked in grass, mud, leaves, and other debris. Once you are done with scrubbing spray the penetrating oil all over the surface and start scrubbing the whole surface with a compact bristle brush.

The lawnmowers have cutting edges on each side of the blade and they are opposite to the sides of the blade. These cutting edges are about 3 to 4 inches long and do not extend the total length of the blade. And after cleaning the surface of the blade briefly examine whether to sharpen the blade or to replace it.

Step4: Sharpen the blade

Sharpening the blades is the most important step and to sharpen the blade held the same cutting angle as before. Place the blade into the vice and start filling the blade with the mill bastard file. Lawn Mower blades are mostly made of fairly soft steel and you can easily fill it with a fine and sharp mill bastard filler by applying almost 50 strokes in the direction of the original cutting angle. If you keep sharpening the edge from the top this will give you a long-lasting edge. This file cuts into just one direction and if you can’t feel it bite into the steel while pushing stroke you are probably doing it the wrong way or maybe your file is dull or you are not pushing hard enough.

File until your lawn mower’s blade is butter-knife sharp, don’t try to make it razor-sharp as it does not last long. You can also use grinders for sharpening the blades but these grinders are harder to maintain as they may overheat and ruin your blade. Sharpening mulching blades are also very difficult as they have curved cutting edges and you’ll need different types of filers to file them.

Step5: Balancing of blades

Once you have sharpened your lawnmower blades you should also check whether the blades are balanced or not as some time sharpening of the blades removes more metal from one end of the blade than the other and the blade appears to be unbalanced. To check whether the blades are balanced or not hang it onto the nail and if one side of the blade dips and file that side more unless the blade remains horizontal.

And if you mow with those unbalanced blades, It may cause excessive vibration that could also ruin the bearings and the shaft. Unbalanced blades may also result in excessive wobbling that may damage the motor of the mower.

Step6: Reinstall the blade as removed

Once the blade is sharpened and also balanced check out which side of the blade you have marked up with the paint and place it with the same orientation and face. After placing the blades at their appropriate position use a wrench to tighten the nuts or the bolts. Your lawnmower is just ready to mow your lawn but before taking it for the test drive place the ignition wire in the spark plugs and fill the fuel tank of gas and you are just ready to go.


It is always necessary that you sharpen your lawn mower blades every year in the spring season as you just can’t mow well with those dull blades. We have guided you with some awesome and effective troubleshooting techniques that you could use to sharpen the blades of your lawn mower before even considering buying a new one. If you follow these tips as mentioned above you can mow your lawn easily without wasting much time and also money.

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