Mower Blade Lessons from the Pros

Those of us in the North can’t quite think about lawn care until the glaciers covering the properties recede. But for the rest of us, there’s no better time to ensure that the season’s first mowing sets the tone for a healthy lawn to last all the year.

It starts with your mower’s blade, and some advice from equipment maker Toro explains well why the blade must be sharp…but not too sharp. If you shave—or, hipster, know someone who does—you’ll appreciate the comparison.

When shaving, think about the difference between the times you use a brand-new razor blade compared to when you are trying to get one last shave out of an old blade. When using an old blade, your skin is more prone to cuts, infection and irritation. When using a brand-new blade, you get a nice, clean shave.

The same thing happens with your grass. If the blades are dull or nicked, they will smash the edge of the grass blade, leaving a torn end rather than a clean cut. This torn end will usually turn brown a few days after mowing and become more susceptible to pests and diseases. But if the blades are nice and sharp, the grass will get a clean cut, with greatly reduced damage and stress.

In a nutshell, this explains why it matters. Here, with guidance from the same Toro pros, is how to get there.

Inspect the blade. Few of us record how much time we spend pushing a mower (tractors and riders have hour meters or even apps), but a blade needs a good check every eight to 10 hours of service. Have no idea how long you run your mower each season? We didn’t think so. Before the grass begins to grow, then, is a good time of year to do it.

With the gas tank empty, remove the mower’s spark plug cap, use eye protection such as safety glasses, and wear thick gloves. Take the blade off (check the manual if you’re unsure) and inspect it for nicks, dents and any other imperfections. Deep nicks, perhaps from mowing leaves, could make the blade no longer usable; they tend to last one to three years of regular use. Having a spare on hand will keep you prepared, and you’re best off buying blades specific to the model you own.

The blade you remove must be not only sharpened but balanced, and you can either do this yourself or take it to a local shop.

Sharpen it at home. Check the mower manual for any tips particular to your model’s blade. If you have a bench vise, secure the blade and smooth nicks with a metal file. A bench grinder works well, too, but for either you need to sharpen in one direction only, not back and forth. A tool sold in both Lowe’s and Home Depot for about $8, the Arnold Sharpener/Balancer, helps you grind using any drill/driver.

Toro and other manufacturers advise that sharpening can go too far. Think of the blades on a pair of scissors, not that of a knife. Sharpen the mower blade like a knife, and you’ll need to sharpen (or even replace) it much sooner.

Is your mower ready for spring?
A sharp blade is indeed necessary for a lush lawn, but you also need to ensure your mower will fire up in the first place. Here’s how to make that happen.

Do that balancing act. It’s easy to take off more on one side than the other when you’re sharpening a blade yourself. If you do, you could throw off the blade’s balance. How to tell? You’ll find your mower noisier, from the extra vibration, but the greater concern is wear and tear on the cutting deck and even the engine.

So after sharpening the blade, test its balance. The same Arnold tool mentioned above will help you balance the blade, but you can check out balance even without that tool. Hammer a nail partly into a wall and hang the blade by its center hole. If the blade hangs level, with neither side drooping, you’re good to go. If one half is heavier than the other, you’ll need to secure the blade and grind off a little. Grind only from the very end of the blade in the sail area—the part that sticks up like a sail.

Walk the walk. Once your blade is sharpened and balanced, you’re ready to go, right? Not quite. Anytime you’re about to mow, you should walk around your lawn once to check for rocks, branches and other debris. Even if you have never done this—sometimes property size discourages it—do it once a year, before that first mow of the season.

You never know what that glacier left behind, after all.

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