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Are Lawn Mower Blades Worth Sharpening?

Dull mower blades rip grass, resulting in ragged ends or failing to cut it entirely. This causes your grass to be uneven, with white or brown tips that are susceptible to disease. You don’t want this to happen, do you?

To keep your lawn clean, you need to sharpen your lawn mower blades. While you might want to sharpen your blades, sometimes the blades are so worn out that you might have the impression that they aren’t worth sharpening.

In such a case, you might think about replacing the blades.

To sharpen or replace

Most manufacturers include guidelines in their equipment manuals indicating how thick the cutting edge should be before replacement.

Besides this, there are a number of things you can look out for to tell whether your blades are ripe for replacement or whether you should sharpen them.

Cracks: Any degree of cracking is unsafe for both the mower and the user. If your blades have any cracks, you should replace them.

Chips: A few small chips, rocks, or other debris are typically not an issue and can be ground out with a file. So, you don’t need to worry too much about them.

Bends: Place your blade on a level surface to see if it’s still straight. A bent or dented blade will be poorly balanced, resulting in inefficient grass mowing. If your blades are bent, simply replace them.

Thin Edges: The other side of the sharp cutting edge is referred to as the trailing edge or fin. A new blade will have a thick fin that is slightly bent upward to provide lift.

The fin will wear down with use, becoming thin and sensitive. If your blade’s fin is thin and corroded, it could be time to replace it.

How do you know your blades are ready for sharpening?

Sharp blades cut grass cleanly, allowing the grass to recover faster and remain green.

A dull blade will most likely rip the grass blades, causing ragged tears that damage the grass and increase grass disease. Mowing with sharp blades will also shorten your mowing time.

In most cases, you only need to sharpen your blades twice every season. One decent sharpening at the start of the season and one toward the middle of the mowing season should be enough.

If you mow over materials like sticks or rocks, you may need to sharpen your blades more than once.

How do you know it’s time to sharpen the blades? There are a few signs that you can look out for:

The first thing to look for is unevenness on your lawn. Your grass should be cut at the same height with a single pass of the mower.

If your grass seems uneven after one pass, your blades are most likely dull and you need to sharpen them.

Inspecting the grass blades is another approach to identify whether it is time to sharpen your mower blades. If the tips of the grass blades are ripped and not cleanly slashed, it’s probably time to sharpen. Torn grass tips can ruin grass health and cause it to turn brown.

Finally, you can inspect the blade itself. Check for major chips or dents on the cutting edge. Inconsistencies in the blade are more likely to shred the grass than to cut it evenly.

Also, examine the thickness of your lawn mower blade. Dirt, sand, and other materials can erode the blade over time, weakening the metal and making it paper-thin.

If you notice this, replace the blade immediately because it can break while mowing and injure someone.

How to sharpen the lawn mower blades

Sharpened blades allow your lawnmower to slice through grass more easily, resulting in a healthier lawn. Here’s how to sharpen your lawn mower’s blades:

  • Disconnect the spark plug wire from the spark plug to keep the engine from starting accidentally.
  • Turn the mower on its side with the air cleaner facing up.
  • Remove the blade bolts with a wrench or socket and ratchet.
  • Remove the mower blade.
  • Use a file or rotary tool to remove any nicks or burrs from the blade’s cutting edge. Be sure to work slowly and carefully to avoid damaging the blade.
  • If the blade is severely dull, you may need to use a grinding wheel to restore its sharpness. Again, do it gently and cautiously.
  • After you’ve restored the blade’s sharp edge, use a honing stone to hone it even further. This ensures that your lawnmower cuts cleanly and effectively.
  • Install the sharpened blade, making sure the bolt holes are lined up correctly.
  • Tighten the bolts firmly with a wrench or socket and ratchet.
  • Re-connect the spark plug wire to the spark plug.

Parting shot

If you are wondering whether it’s worth sharpening the lawn mower blades, you need to consider the nature of the blades.

If the blades are worn out or have cracks, it’s worth replacing them instead of sharpening them, but if they are simply dull, you should sharpen them instead of replacing them.

On my 15th birthday, I became the designated gardener in my home.

Now at 32, I have a small garden and every day I'm out trying different plants and seeing how they grow. I grow guavas, peaches, onions, and many others. Want to know more about me? Read it here.

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