How to Sharpen Lawnmower Blades

Have you ever mowed your lawn and been disappointed in the ragged, uneven cut? Are you unsure of what went wrong? One possible culprit is dull mower blades, which result in an uneven cut and can add extra strain to your mower’s engine.

In this step-by-step guide, we will walk you through the importance of sharpening lawnmower blades, when to do it, and the proper techniques for achieving a perfect cut every time.

Why is it important to sharpen lawnmower blades?

Dull blades tear the grass instead of cutting it cleanly, leading to a ragged appearance and making your lawn more susceptible to diseases and pests. Keeping your blades sharp ensures a clean and precise cut, promoting healthier grass growth and an overall better-looking lawn.

When should I sharpen my lawnmower blades?

Determining when to sharpen your lawnmower blades depends on the frequency of use and the grass you are cutting. Generally, it is recommended to sharpen your blades at least once or twice per mowing season. However, if your mower struggles to cut efficiently or the grass tips appear frayed, sharpen the blades immediately.

How do I sharpen lawnmower blades?

Sharpening lawnmower blades may seem daunting, but with the right approach, it’s straightforward. Let’s break it down step-by-step:

Preparation and safety

Before you begin, ensure you have the necessary tools: safety gloves, safety glasses, a socket wrench, and a blade balancer. Safety should always be a top priority.

How to remove mower blades

Start by disconnecting the spark plug to prevent an accidental engine start. Then, carefully lift or tilt the lawnmower and use a socket wrench to remove the blades. Note how the blades are positioned so you can reinstall them correctly later.

How to clean and inspect the blades

Once the blades are removed, clean them thoroughly with a wire brush to remove any debris, grass clippings, or rust. A clean blade will be easier to sharpen and maintain. Inspect the blades closely. Ensure the blades are still in good condition with no bends or dents. If there are flaws like these, it’s time to replace them with new blades. 

How to sharpen the blades

There are various methods for sharpening mower blades, and the right method for you depends on your skill level and the tools you have available.

How to sharpen blades with a hand file

Using a hand file is a traditional and effective method. Secure the blade in a vise and run the hand file along the cutting edge, maintaining the original angle. File in one direction only, away from your body, until you achieve a sharp edge. Once the top side is sharpened, move to the bottom side. With the blade still secure in the same position, begin filing the backside of the blade while keeping the file horizontal. This only requires a few strokes and will remove any burs created while sharpening the front of the blade.

How to sharpen blades with a hand grinder

A hand grinder can speed up the sharpening process compared to the hand file method. With the blade secured to the table with a strong vise or clamp, gently run the grinder along the blade at the original angle, being careful not to overheat the blade. A good tip is to count the number of back-and-forth strokes so you can use the same amount on the other side to help balance the blade. Once the front is sharpened, move the grinder along the backside of the blade with one swipe to remove any burs.

How to sharpen blades with a bench grinder

Depending on your resources and skill level, a bench grinder is another option for sharpening the blades. Carefully hold your blade at the original 45-degree angle and move the blade smoothly along the bench grinder. Remember to count your strokes to use on the opposite side. Once the front side is sharpened, flip your blade over to make one stroke along the backside to remove any burs.

How to balance and reinstall the blades

Before reinstalling the blade, check its balance using a blade balancer. Ensure both ends of the blade are at an equal height. Once balanced, reinstall the blade carefully, following the reverse steps of the removal process.

Where can I find lawnmower service near me?

If you prefer professional assistance with lawnmower maintenance or require replacement parts, the team at Koenig Equipment is here to help, regardless of your lawnmower brand. From John Deere to Gravely to Kubota and everything in between, the trained technicians can help service your lawnmower and sharpen your blades to keep your lawn looking great with every cut.

Contact your local Koenig Equipment to schedule your service today.

Additional Resources

Safety Tips for Riding and Walk-Behind Mowers

What are the Benefits of Pre- and Post-Season Mower Inspections?

How Long Do Lawn Mowers Last – Is it Worth a Repair?