Enhance your lawn by fine-tuning your mower’s blades
Uneven grass, torn blades, and frayed edges, oh my! If your grass looks a little worse for wear, your lawn mower blades might be telling you it’s time for a good sharpening. Luckily, if you have an hour to spare, our guide will show you simple ways to sharpen your lawn mower blades so you can get back to beautifying your yard in no time.
Not experienced handling mower blades? It’s best to hire a pro instead if you don’t have a strong DIY background to ensure your safety.
Sharpening your lawn mower blades provides many benefits. Not only will your lawn be healthy and free of diseases, but you’ll keep your lawn mower in good working condition for many years to come. We recommend sharpening your lawn mower blades twice per season or after 25 hours of use.
For DIY-savvy homeowners, the cost to sharpen your blades runs $20 to $60. It all depends on the type of mower you own—reel mowers require less tending, whereas gas and electric mowers require more prep and tools for blade sharpening.
If you don’t have the tools or experience handling sharp blades and working with a lawn mower, hiring a lawn mower repair pro is a great choice. A professional will ensure the job gets done without issue, and you’ll also have the option of adding additional tune-up repairs. You can expect to pay between $25 to $100 for a professional blade cleaning and tune-up.
If your lawn mower blades are dull, these are the telltale signs you need to give them a sharpening:
Torn, ragged, and uneven grass
Blades of grass are brown, especially at the tips
Lawn disease—fungus, patches, mildew, blighting, spots, or mold
You’ve hit rocks, sticks, or debris when mowing
Safety disclaimer: Working with any kind of blade poses a danger. If you don’t take the proper precautions, you could injure yourself. Wear safety goggles, gloves, pants, and a long-sleeved shirt to shield yourself from metal shavings and sparks. If you aren’t certain of your ability to handle this DIY project, contact a local lawn care service.
Don’t skip any steps when it comes to prep—your safety depends on it.
Turn your mower on its side (making sure the air filter and carburetor are lying face up) and prop it up with cement blocks.
Place a two-by-four piece of lumber between the blade and the lawn mower to keep the blade still.
Grab a clamp to hold the wood in place. Take a moment to mark the bottom of the blade with a marker, so when you put it back on, you’ll know which side faces up (this is a huge time saver).
Loosen the blade by locating the nut attached to the drive shaft. Turn the nut counterclockwise with a wrench until the blade comes off.
If your blades are rusted or full of debris, you’ll want to spray them with penetrating oil and scrub them clean with a brush or cloth before starting your blade sharpening project.
The most common lawn mowers are gas and electric models. You’ll simply need to remove the battery for an electric mower before you begin sharpening.
However, if you have a gas-powered motor, you’ll need to grab your safety glasses and gloves and disconnect the spark plug wire. Ensure you tape the wire to the outside of the mower with heavy tape so it doesn’t accidentally plug back in and turn on. Finally, you’ll need to drain the gas tank to prevent any fuel spills.
If you have the proper knowledge and experience, this DIY should take you under an hour. There are three blade-sharpening options to choose from below, but the final step applies to all.
Put on your gloves and safety glasses. Place the blade into a vise with the sharpening edge facing upwards.
Grab a 10-inch metal file and stroke the blade in one direction only at a downward 45-degree angle.
Apply pressure and continue stroking until your edge is as sharp as a butter knife (this can take up to 50 strokes).
Turn your blade over and repeat on the other side.
A blade sharpening stone fits on any standard electric drill, and you can purchase a kit (for around $15) at any local hardware store. The kit includes a 2-inch aluminum oxide angled wheel that sharpens your blades in minutes.
Put on your gloves, safety glasses, pants, and a long-sleeved shirt.
Place your blade in a vise.
Insert the blade sharpening stone into the drill and tighten.
Line up the stone with the blade—placing the flat part on the back edge and the curved part on the curved edge of the blade.
Run the stone over the blade (back and forth) for a few minutes until the blade is as sharp as a butter knife.
Turn the blade over and repeat on the other side.
Angle grinders cut through tile and are tough enough to remove grout and polish metal. They also provide a quick way to sharpen your mower blades.
You’ll see sparks fly for this option, so you’ll need gloves, protective eyewear, a long-sleeved shirt, pants, and ear protection.
Place your blade in a vise.
Choose a flap disc attachment (grind, blend, and finish all in one).
Place the grinder along the cutting edge of the blade.
Run the grinder along the edge, moving back and forth.
Sharpen until the blade is as sharp as a butter knife.
Turn the blade over and repeat on the other side.
After sharpening your blades, they can become unbalanced—which could damage your mower. We recommend purchasing a blade sharpening and balancing kit to perform a balance test. These kits are universal. You can find them at your local hardware store for around $12. If your blade is off balance, simply file it down until balance is achieved.
Clean the bottom of your mower with a brush, and scrape off any clumps of grass.
Reattach your blades, ensuring that the side you marked is face up.
Wedge your two-by-four under the blade and clamp it. Tighten the nut with a wrench.
Reconnect the spark plug, fill the tank with gas (or insert an electric charger), and you’re all set!
To keep your mower and blades in good condition, you should maintain a routine lawn mower maintenance schedule.
Track how long it takes to mow your lawn and keep a record. When you hit 20 to 25 hours, it’s time for a blade sharpening. Also, if your blades have cracks or dents, replacing them is a good idea instead of trying to sharpen them.
The quickest way to sharpen a blade is with an angle grinder. However, a blade sharpening stone is less hazardous and does a great, fast job at sharpening your blades.
You’ll want to use a 10-inch mill bastard file for sharpening your blades. These files are great for sharpening saws, chainsaw teeth, and knives. You can purchase them at any hardware store for around $7 each.
