Do Brand New Lawn Mower Blades Need To Be Sharpened?

July 18, 2021

You may wonder why manufacturers ship mowers with seemingly copious amounts of paint on the blades.

There are good reasons for it; the gobs of paint on your mower's blades serve many purposes, including protecting you against injury, protecting the blade from damage, and preventing rust.

Brand New Lawn Mower Blades Need To Be Sharpened
brand new lawn mower blade

So, even though the protective coating can make blades feel as if they need sharpening, do not remove it!

So, are they actually dull or do brand new lawn mower blades need to be sharpened before use?

You might have also heard that lawn mower blades need to be sharpened even right out of the box.

This is because people see the thick coat of paint on these brand new lawn mower blades, feel how rough the paint is, and automatically assume that the blade needs work before the first use.

The finish over the edges of the new blades is even thicker than on other parts of the blade–causing many people to think that the blades are not sharpened when it is shipped to customers.

Don't worry about blades needing sharpening if you've just bought a brand new lawnmower, as manufacturers ship them sharpened right out of the factory.

Do Lawnmower Blades Ever Need Sharpening?

If you've ever used an old lawnmower, you've probably noticed that dull blades still cut grass, so you might have wondered if blades require sharpening at all.

The thing is, although worn blades can mow lawns, they rip rather than cut through the grass, producing uneven tips. Ripping up rather than cleanly cutting the grass leaves it less resistant to pests and diseases (think of the difference a sharp knife makes when you're in your kitchen, cutting up a steak).

Dull blades will leave the grass turning yellow or, worse, brown. Sharp edges make for healthier, less damaged grass, better able to recover swiftly, and leaving your lawn looking more neatly trimmed.

Something else to consider is that, apart from damaging your lawn, dull mower blades will pull on the grass and further exacerbate damage to the blades themselves.

Grass will wrap around these dull mower blades as your lawnmower rips them out of the ground, and this will produce more stress yet on the machine, reducing its lifespan and damaging individual components.

Worn blades will also cause you to spend longer mowing your yard (and nobody needs that), as well as putting additional strain on your mower.

Therefore, the answer to whether blades even need sharpening is a resounding "Yes", but that too raises other questions.

For example, how often should you sharpen your blades, and are there any downsides to doing so?

Life rarely gives without taking, so let us examine this latter question first.

How Can You Tell If Your Lawnmower's Blades Are Dull?

The simplest way to tell if your mower's blades are dull is to look at some grass blades after you have finished mowing. If their tips are torn-looking or ragged, it's time to sharpen the blades (or perhaps buy new ones).

You could also try cutting some paper on them, although this is also a perfect way to do yourself a nasty injury if you're not careful. The more easily the blades slice through the paper, the better.

What Downsides Are There To Sharpening Your Lawnmower's Blades?

The first should be apparent: the more you sharpen a blade, the less 'blade' you have.

Sharpening works by honing both sides of the blade, grinding the edge down to as thin a surface as possible. The only way to achieve this is by shaving off bits of each edge, making the blade itself thinner and weaker.

It isn't likely that a few sensible sharpenings will do much damage, but over time, inevitably, they will take their toll.

Another problem that sharpening blades can cause is to upset their balance. Blades arrive (or at least should come) from the factory well-balanced and not causing excessive vibrations when you operate your lawnmower.

What Blunts Lawnmower's Blades?

Commonly, your mower's blades quickly dull when they hit stones or other kinds of debris.

To maintain your blades and keep them sharp for longer, just run a quick eye over your lawn before you begin mowing, removing twigs, clumps of fallen leaves, and other junk.

Cutting the grass frequently is another excellent tip because short grass is easier to rake and keep clear of anything that could blunt blades.

How Often Should You Sharpen Your Blades?

Average homeowners will not need to sharpen their blades as often as lawn care professionals, who unsurprisingly sharpen their blades at least every week.

While this might sound somewhat excessive to you, we can use that information to figure out how often you should sharpen yours.

It turns out that lawn care professionals spend an average of 25 hours actually mowing lawns every week, so if they are sharpening their blades once in that period too, in effect, they are doing so every 25 hours.

This information gives us a handy standard to follow: sharpen your lawnmower's blades every 25 hours of use.

Now, you might be thinking, "That's all very well, but how do I know when I've used my mower for 25 hours?"

Easy! The next time you mow your lawn, remember to time how long it takes you, a feat you can accomplish with just the aid of your cell phone's timer.

Once you've figured out how long it took you to cut the grass, divide that into 25 hours, and there you are.

Most folks don't mow their lawns that often, so another handy rule-of-thumb is to sharpen your blades at the beginning of every season.

For example, if you take an hour and a half to mow the lawn, you'll need to sharpen your blades after every 16 outings.

How Should You Sharpen Your Blades?

No matter what type of lawnmower you use, whether it's a push mower or self-propelled, all mowers have the same thing: blades beneath.

To sharpen those blades, you must first access your mower's underside. However, before you turn your mower on its side, make sure you remove some spark plugs.

Next, unplug the power cable as you'd probably find it inconvenient if the motor accidentally kicked in and sliced off a piece of your 'personal real estate'. Always think about safety.

After you have reached the blade safely, mark the underside of the blade with a marker. Marking the blade that way is crucial because it could damage your mower if you put the blade back incorrectly.

Next, remove bolts or nuts that secure the blades, then sharpen them in any manner you like, either manually with a grinder or file or with your bench grinder.

No matter the method you choose, ensure you wear adequate protection: long sleeves, gloves that resist cutting, and goggles.

Take careful note of each blade's cutting edge. It is normally about 3 or 4 inches high, which is shorter than the blade. Only this bit needs sharpening on either side.

What About Balancing The Blades?

As mentioned earlier, your brand new lawnmower ought not to require its blades to be balanced. However, if you've just sharpened yours following the instructions above, you must ensure that every blade is balanced.

You can buy tools that can do this for you, but it is a bit of an overkill. To check a blade's balance, rest it with its center on anything narrow. A well-balanced blade will settle evenly.

If the blade tilts in one direction, then the lower edge shows which side requires more grinding.

Why Use a Sharpening Service?

There are three good reasons to use a sharpening service.

The first is, unless you are wealthy–or obsessed with DIY–the betting is fair that you cannot match the tools available to professional lawnmower sharpening services.

Professionals will use a wide range of sharpening wheels and high-precision grinders. They also have technology allowing them to set blades precisely against the mower's cylinder. Correctly set up, the gap between the cylinder and the blades is paper-thin.

A professional sharpening service will also set the pressure against the blades with exactness, as overdoing it could mean the mower's blades will produce heat and deteriorate quickly.

The second reason to use a sharpening service is that technicians should spot other problems which may crop up with your lawnmower occasionally.

"A stitch in time saves nine," as the saying goes, and a timely warning or intervention from the technician could end up saving you some money.

The other reason to use a sharpening service is perhaps the one which might strike the strongest cord in you: it is easier!

In A Nutshell, Do brand new lawn mower blades need to be sharpened?

Do brand new lawn mower blades need to be sharpened? No.

Your new lawnmower should mow your lawn cleanly and well-trimmed, leaving cut grass tips with sharp edges. Although some vibration is inevitable, vibrations should not be excessive.

Happy mowing!

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