Here's How Sharp Your Lawn Mower Blades Should Be

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Imagine you just finished mowing your lawn, but it still looks awful. What went wrong? After all, the mower was working just fine. And then it clicks: The blades must have been extremely dull. You'll need to sharpen them, but just how sharp should they be? Here's the answer: Mower blades don't need to be razor sharp like a surgeon's scalpel to cut grass. They just need to be moderately sharp, like a butter knife.  You should be able to touch its edge without cutting yourself.

The reason lawn mower blades should not be very sharp is because they move at very high speeds, and since grass is very fine and soft, it doesn't take much to get the job done. And if you try to make your mower blades razor sharp, it can backfire fast. Twigs, pebbles, thick weeds, among other things in the lawn, can make a razor-sharp blade become dull extra fast, so you would need to sharpen them more often.

Plus, a very sharp blade is also more likely to chip or crack, and once that happens, it will not cut grass properly and be more expensive to repair. A chipped and cracked blade is sometimes also the reason your lawn mower might be vibrating. With that said, let's break down the signs it's time to sharpen your lawn mower blades and explain how to do it right.

So now that you know how sharp your lawn mower blades should be, let's also talk about how to do it right. First of all, start simple. For instance, if your lawn mower blades just need a light refresh after a few mowing sessions and they have no major nicks, a handheld sharpener is usually more than enough. All you have to do is grab a mill file, clamp the blade in a vice, and sharpen the blade. Just make sure to sharpen the blade at the right angle. Not doing so is one of those mistakes everyone makes when sharpening lawn mower blades.

If, however, your mower blade is genuinely beat up and it has visible chips and dents, a mill file won't be enough. Instead, you'll need something more powerful, like an angle grinder or bench grinder. Just keep in mind that using such tools requires a bit of skill, so if you have no experience working with either of them, it is better to leave it to the professionals. However, if you can confidently use an angle or bench grinder, make sure to keep the blade balanced. The reason being is because if one side of the mower blade becomes heavier than the other, your mower will start vibrating. This will not only ruin the mowing experience but will also put stress on the mower engine. Don't worry, though! A lawn mower blade balancer is pretty cheap. Lastly, make sure you understand when it is time to replace lawn mower blades. If a blade is too damaged, sharpening it is just a waste of time and effort.