How to Sharpen Lawn Mower Blades With a Bench Grinder?

It is essential to know 

when and how to sharpen lawn mower blades with a bench grinder. Sharpening a mower blade using hands would be more difficult and time-consuming as well. 

A dedicated bench grinder is one of the best convenient tools to sharpen a lawnmower blade. There are many ways to sharpen your lawnmowers, such as using a hand file, a rotary tool, and a bench grinder. 

But in this guide, we’ll focus on how to use a bench grinder properly to sharpen a lawnmower’s blade. 

Required Tools:

  • Wrench set
  • Safety glasses
  • Metal-grinding blade
  • Clamps
  • Work gloves

Steps to sharpen your lawn mower blades using bench grinder:


Firstly, disconnect the ignition wire from the plug. Doing so helps you to abstain from any accident while working on the mower. Plus, it drains the gas tank to spill with any fuel while removing the blades. 


Tip the mower onto its edge so you can explore the retaining bolt, which secures the blade under the side of the mower. A short wood block keeps the blade from turning around between the mowing deck’s inner surface and the edge. 

After that, use a socket and a large ratcheting wrench for loosening the bolt. Use penetrating oil, such as a liquid wrench, if the fastener is rusty enough. Now, wait for around 10 minutes before you make the next try.

It increases the leverage when you start loosening a specific stubborn fastener. 


After you remove the retaining bolt or nut, pull off the mower blade. In this step, find out which side of the edge has downward. The blade must get bolted back on the side of the same orientation. 


Carefully remove the blade and scrap, cleaning the mowing deck’s underside using a narrow blade putty knife. Start eliminating mud, all caked-on grass, leaves, as well as other kinds of debris. 

Moreover, you should clean both parts of the lawnmower blade. Use spraying with penetrating oil when you do so, and then scrub it with a stiff bristle brush.  


Typically, a mower blade comes with a cutting edge on each side positioned on the other side of the blade. Every cutting edge is only about 3 to 4 inches long; it means it doesn’t extend the blade length. 

Now clamp the blade at an angle in a vice with one of its cutting edges facing up. 


Afterward, it would help if you used a drill powered blade sharpener. It designs with a round abrasive stone, flat sharpening, and 0.25 inches diameter steel shank. This kind of abrasive stone has a beveled surface that grinds the cutting angle properly onto the blade.

Now chunk the sharpening rock into a drill and put in a few safety glasses. Start squeezing the trigger to run the training at full speed. Hence, slip the spinning sharpener over the blade edge. 

Make sure that the dull cutting edge meets the beveled part of the stone. And the flat surface of the guide should be against the rear of the blade. Now start moving the stone but slowly back and forth along with the cutting edge using mid-level pressure. 

After 4 to 5 back and forth strokes, you should stop doing it and check the blade sharpness. 

If you see it requires to be sharper, you can repeat this task until all the chips and nicks have ground off, and the blade gets sharper. Eliminate the sword from the vise and rotate it to make it sharpen the opposite cutting edge. 


Once you see both cutting edges get sharpened, then you should go for balancing both sides. Sharpening blades occasionally remove more metal from the blade that results in an unbalanced blade. 

Mowing with an unbalanced blade must create excessive wobbling that badly damages the motor and puts undue pressure on the mower. There is one way to detect if the  blade is balanced correctly. 

Slip the blade center’s hole only over a nail protruding. Now hold the edge in the position of horizontal. If you see it remains level, it means it’s balanced. 

However, if the end part of the blade rotates down toward a vertical position, it represents the unbalanced blade. Remove some metal depending on the necessary to make the knife sharpen and then retest it. 

Use a lawn mower blade balancer if you see the nail in the wall trick works with more precise results. Then place the balancer on the flat surface on the top pointed position with various diameter center holes. 

Remember: if it holds the same level, it means it keeps the proper balance. If it’s not, then find out which one is heavier than the other parts of the blade that needs additional sharpening. 


Once you make the blade balanced and sharpened, place it back onto the lawnmower in its original position. Use the wrench to tighten up the snugly retaining bolt or nut. Now reattach the ignition wire, which you disconnect. Fill the gas tank and take it to the newly sharpened mower out for testing. 

Top Recommended Bench Grinder for Lawn Mower Blades:

Though there are many kinds of bench grinders of many brands, they are not suitable to use. When you look for a good bench grinder for your lawnmower blade, consider the following points below:

  • The bench grinder must be well balanced.
  • Choose the 8-inch wheel but not the less than of it.
  • A heavy-duty bench grinder is more capable than other versions.
  • Consider that device which designs with a well functioned quieter motor.

Final Thought:

Mowing can be a regular household chore if you’ve got a lawn around the house you live in. Therefore, keeping the blade sharpener is essential as cleaning the grass. 

You can purchase a new blade for your lawnmower as always but keeping the blade sharpened and cleaned would be more comfortable and cheaper that can save a fair number of bucks yearly. 

Hopefully, you find this article well informative and understand how you can sharpen your lawn mower blade using a bench grinder. 

Lastly, make sure you’re using the ideal wheel for this task. Having the right wheel, you can quickly complete any grinding job.