How to Sharpen Lawn Mower Blades with A Grinder Professionally

how to sharpen lawn mower blades with a grinder

Is your lawn mower failing you to cut grass properly?  

It’s probably the lawn mower blades that require sharpening a bit! When the mower is in frequent use, especially during summer, the edges need to sharpen at least after a full day’s use. What happens if we don’t? It might cause grass disease and loss of mowing capacity of the machine. So, should you visit a mechanic every time? or learn how to sharpen lawn mower blades with a grinder by yourself to save up to $60 each time?   

While sharpening the lawn mower blades- there are two options, use manual sharpeners like handheld files or electric motor-based grinders for sharpening lawn mower blades.   

In comparison, electric grinders like an angle grinder or bench grinder consume less time than manual ones.   

So, if you’re a beginner and don’t know how to sharpen lawn mower blades with a grinder, our step-by-step guide will help you to understand the entire process. 

How to Sharpen Lawn Mower Blades with A Grinder  

It’s an excellent idea to sharpen lawn mower blades on your own as long as you know how to sharpen them with a hand grinder or bench grinder and be cautious to use protective eyeglasses and masks for safety.  

So, let’s gather all the necessary steps you’ll need to follow while sharpening the lawn mower blade. At first, we’ll look step by step at how to sharpen mower blades with angle grinder. 

How to Sharpen Mower Blades with Angle Grinder 

Step- 1 Ensure All the Necessary Tools  

A few things will be needed to start the sharpening process, including   

get prepare to; how to sharpen lawn mower blades with a grinder

  • Lawnmower Blade Sharpener (can be a manual file or motor-based grinder)  
  • Precautionary materials, like hand gloves, masks, goggles, and protection for ear   
  • A bench vice for holding the blade tightly  
  • Socket wrench  
  • Wire brush  
  • Sandpaper  
  • Wooden box (optional)  

Step-2 Carefully Remove the Blade  

Hand grinder or bench grinder, it doesn’t matter how you’re sharpening the lawnmower blades; the first step is to take the blade out of the machine.

Remove the spark plug wire to avoid the risk of a fire accident. Additionally, empty the fuel to prevent leakage.  

Now, access the blade under the deck of the lawnmower. A socket wrench will come in handy to remove the center nut of the blade. However, if it seems complicated, use a cleaner spray to remove the blade from the lawnmower easily.   

Step-3 Examine Lawnmower Blade  

Sharpening lawnmower blades depends on how many times it has been used, the quality of the blades, and how smoothly or roughly hitting stones or any other hard materials.  

We recommend checking the blades after using the lawnmower every 25-30 hours; if sharpening can prolong the usability, then go for it. Otherwise, it is better to replace the blade with a new one.  

Now, if you need to sharpen the lawnmower blade, follow the next steps.  

Step- 4 Fix the Blade on a Bench Vice  

Set the blade in the bench vice and tighten up the vice as much as possible. As a result, the blade will get a firm hold and won’t move while sharpening.  

fixing the grinder

Step-5 Prepare the Blade for Sharpening  

Remove the dirt, grass, and other things from the blade and clean it properly with a stiff wire brush. Use sandpaper if it’s difficult to clean all the dirt with the wire brush.  

Step-6 Prepare Angle Grinder  

Use an angle grinder or the hand-handled grinder to sharpen the lawnmower blade across its cutting edge holding the machine on hand.  

For the angle grinder, set a metal grinding disk with the angle grinder. Ensure the blade’s edge remains at the top while sharpening with the grinder.  

Caution: Use hand gloves, mask, and goggles for your safety.  

Step- 7 Run the Grinder  

Run the grinder along the blade’s cutting edge, abrasing it to the inside. Wheel the grinder from the tip and run it across the blade’s dull part; repeat the process for the edges of each side of the blade.  

You need to sharpen the blade edges as well as keep the cutting corner in proper shape. So, align the grinder disk with the angle of the blade from the inside. After that, move the grinder side-by-side along the blade’s bevelled edge.   

Pro tip: Thrust gently will bring the result by sharpening your lawnmower blades for the next mowing hours.  

Step-8 Inspect the Blade Balance and Readjust It with The Lawnmower  

Ensure that the blade sharpening is well-balanced. Otherwise, it may damage when you run the machine over the grass and won’t be able to cut correctly. To check the balance of the blade, place the blade horizontally on a wall nail.   

The heavier side will go down if the balance is not done properly. Then, grind this heavier portion of the blade. Once the balance is done, move out the blade, adjust it to the lawnmower, and fix it with the nut.  

How to Sharpen Lawnmower Blade with a Bench Grinder  

A bench grinder is made of a wooden bench containing a sharpening disk with it.  

So, sharpening a lawnmower blade with a bench grinder is almost similar to sharpening lawn mower blade with a hand grinder. The only difference is you have to move the blade instead of wheeling the grinder disk over it.  

Bench Grinder

How to Sharpen Mulching Mower Blade with Grinder   

To sharpen the mulching mower blade here is how to sharpen the lawn mower blade with a bench grinder:  

  • Ensure to take necessary protection measures before starting  
  • Start the bench grinder and carefully push the blade back and forth  
  • Make sure the blade has been sharpened at the right angle on both sides and the blade is well-balanced  


Depending on the use, your lawnmower blade must be sharpened after a certain duration. So, once you notice that the mower is not performing well, it’s a sign that the blade may need to be sharpened.  

It’s highly recommended not to use dull blades over the grass as it increases the risk of disease that can damage all the grass. Besides, cutting unevenly may bring a brownish colour across your lawn grass that will spoil the look and feel of the grass. So, why go to the mechanic if you can do it on your own?  

This informative guide will help anyone to learn how to sharpen lawnmower blades with a grinder. Hope this lawnmower blade sharpening guide helps you to keep your lawn green and full of life by yourself! 

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