How To Sharpen Lawn Mower Blades Without Removing Them?

Disconnect the mower from power, tilt it for blade access, and secure the blade. Then, use a metal file or angle grinder at a 45-degree angle for sharpening.

How to sharpen lawn mower blades without removing them? Well, before answering this question, you must know the importance of maintaining the sharpness of your mower knife.

Sharpening lawn mower blades is an important part of maintaining the mower.

Without sharpening, you will have blunt ones, which can cause an uneven cut to your lawn. Such blades can also tear and bruise them, making them vulnerable to pests and diseases.

In addition, your lawn will have an unattractive visual due to its yellowing color and tends to turn brown due to improper cuts.

Furthermore, gardeners tend to sharpen the lawnmower blades by removing them during this time. But for some people, it is pretty tricky.

Hence, we provide a step-by-step guide on how to sharpen lawn mower blades without removing them. It will save you time and energy to maintain your mower blades to perform well in perfectly trimming down the grass.

The Reason to Keep Your Lawn Mower Blade Sharp

A fatal mistake often made by gardeners or homeowners who grow lawns in their front yard is to let the mower blade become blunt. And worse, they think it is okay as long as their grass is cut and the garden looks neat and clean.

In fact, dull blades can cause the cut to be irregular, leaving an unfinished cut. In many cases, the cut does not encourage healthy grass growth.

Instead, they will turn them yellow and brown, which is visually unattractive.

how to sharpen lawn mower blades without removing
Repairing Lawn Mower Blade

In addition, a mower with an improper blade of sharpness and angle can bruise and injure the grass, creating open wounds to the grass.

This event makes your grass more susceptible to pests and diseases.

Moreover, it also triggers stress on the plant, resulting in a shallow root system and slow growth, and, in worse cases, they will die.

From the mower’s perspective, such blades will waste their time trimming the lawn because the lawnmower will not make a perfectly trimmed lawn. In addition, trimming consumes a lot of fuel with minimum results. What a waste!

Hence, sharpening lawn mower blades is essential for grass and mowers. So, how to know when is the best time to sharpen your lawn mower blades? Find out the answer in our next section!

The Right Time to Sharpen Your Lawn Mower Blade

Grass grows silicate particles within the leaves, becoming its defense against herbivorous animals.

However, this section is detrimental for gardeners because it can quickly dull their lawn mower blades, leading to a ragged finish and uneven cut.

Instead of Replacing your mower blades, it is best to sharpen them. The blades will commonly work for 2-3 years, so changing them every time they get blunt is not worth it.

Generally, you will need to sharpen your blades 20-25 hours after using the mower to cut the grass. However, it depends on how often and long you use it to mow.

The point is that the longer you use the mower blade, the more frequently you must sharpen it.

how to sharpen lawn mower blades without removing
Cleaning Lawn Mower from Grass

You will probably need an hour to trim the grass if you have a large yard. In this case, sharpening is necessary after around twenty uses.

On the other hand, blade sharpening for a small garden can be done after forty uses as you will require only half an hour to finish the mowing. Moreover, the best time to sharpen the blades is when the mowing season comes in spring.

It is a fresh start to prepare for trimming the grass and encourage their growth later on.

How Sharp Should the Blades be?

Despite being so important to sharpen the lawnmower blades, it does not mean you have to make them extremely sharp like a razor.

Mower blades that are too sharp actually make them dull too quickly, making them have to be sharpened frequently. And in this case, the edge won’t last long.

how to sharpen lawn mower blades without removing
Sharp Lawn Mower Blades

In addition, they can also slip and roll over more often than those that are sharpened at the perfect sharpness. So, how do you know that your blades are sharp enough to mow the lawn?

To measure sharpness, ensure the edge won’t cut your fingers when you touch it. But please don’t grab it to avoid injury. Furthermore, sharp blades are also characterized by shiny metal files with a clean look and flat edge.

Meanwhile, the blunt ones commonly have a dull appearance with a darker color.

Easy Step to Sharpen Lawn Mower Blades without Removing Them

Now, it’s time to provide you with a complete step-by-step guide on how to sharpen lawn mower blades without removing them. Even though it sounds tricky, they are actually relatively simple and easy.

You can sharpen your lawn mower at home by preparing some equipment and following our instructions below!

Lawn Mower in Garden
Lawn Mower in Garden

1. Prepare The Equipment

For safety measures, you must prepare some equipment prior to the sharpening process. This will include:

  • Safety tools: Goggles and cut-proof hand gloves
  • Sharpening equipment: bucket filled with water to clean up, wire brush, wooden block, flat metal file, angle grinder, metal blade.
  • Next, park your mower on a flat surface to prevent accidental starting.

2. Unplug The Power Supply

Disconnecting the mower from a power supply like batteries or electricity is necessary to avoid the mower running while you are working on the blade.

For the gas mower, you must unplug the spark plug. To prevent a gas spill, remove the gas tank lid and replace it with a plastic bag on the top can of the gas.

3. Lean Over Your Mower

Some people don’t realize how important this step is. It allows you to access the blade as you wish.

Make sure the air filter and carburetor are facing up to ensure the oil and gas won’t spill everywhere. In addition, the mower should be in a balanced position before you start sharpening the blade.

4. Limit The Blade Movement

You can use 2 x 4 pieces of scrap wood and place them against the mower to prevent movement.

If you can’t find the scarp, wooden blocks will work great too! The idea is to ensure it stays in place and not moving in other directions.

5. Clean Up The Blade And Deck

Remember the wire brush you prepare? Use it to clean up the blade and deck from dust, specks of dirt, and grass.

Make sure to check under the deck too. Wash them off with water.

6. Sharpen Lawnmower Blades

And here is the main task, sharpening the lawnmower blades. You may use the metal file or angle grinder, as you prefer. Next, place it on the cutting edge of the blade.

Maintain a proper angle. For the common mower blade, the angle should be 30-45 degrees.

7. Complete The Process

Once you have finished sharpening, lower the mower carefully. Then, plug in the mower.

For the gas one, open the tank, and remove the plastic bag that covers it. Put back the lid on the top. And you are all set!

Things to be Aware Of (Important Tips)

You know how to sharpen lawn mower blades without removing them. But here, we would love to put other things to consider before and after sharpening the edges.

1. Sharpen Or Replace?

Lawn mower blades don’t have a specific lifespan. However, most of them last for about 2-3 years. After this time, you must replace them before hurting your lawn.

You can also check on the blade visually to determine whether they need replacement. If they have massive rust, it may be time to consider buying a new one.

2. Empty Gas Tank Before Sharpening

While covering the gas tank with a plastic bag is an option to prevent leaking, it is best to sharpen blades when the gas is empty. It also eases you in handling your mower while honing edges.

3. Beware Of Excess Vibration

Observe how your mower moves after the blades are sharpened. If they move with extreme vibration, you may have unbalanced blades. It can result in an uneven cut to your grass or, worse, damage your mower.

4. Notched Blades

Do you see notches on your blades? Don’t worry! As long as they do not show extreme rust all over the body, they may only need sharpening.

Final Thought

To sum up, you can sharpen your lawn mower blades without removing them easily at home. Make sure you follow our step-by-step guide to do it properly without damaging the blade, mower, and of course yourself.

Remember, safety precautions are a must while you are working on sharp equipment.

Check out the important tips before sharpening to help you understand the blade and not rush into the sharpening process.

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FAQs (Frequently Asked Questions)

Is it worth sharpening the mower blade?

Sharpening lawn mower blades give your grass an advantage because blunt blades can bruise them.

Not only does it harm your lawn, but dull mower blades also leave the tip of the leaves brown.

Thus, affecting their physical appearance. In addition, sharpening the blades can save fuel by 25%. Ideally, you need to sharpen the blades 25 hours after mowing your lawn.

Do you sharpen both sides of the lawn mower blade?

Yes! You are recommended to sharpen both sides of the blade for a proper lawn cut.

If you want to have long-lasting sharp blades, try to look for the top side of the cutting edge. Then, start sharpening from that point to the direction that meets resistance.

But please, be careful of your fingers!

How often do lawn mower blades need to be sharpened?

To keep it sharp and working properly, your lawn mower blades must be sharpened every 20 to 25 hours after use. Or, if you don’t have time, at least do it once a year.

The more often you move, the more often you have to sharpen it.

Usually, you will notice yellow, brown, and dull grass grows after mowing if your mower blades are blunt. Check the sharpness by cutting a piece of paper with the edges and observing the cut.

A fine blade will give you a clean cut. On the other hand, a blunt one may badly cut the paper or even won’t cut at all.

How do you sharpen a lawn mower blade by hand?

If you don’t have time to prepare the proper equipment to sharpen your lawn mower blades, you can try it by hand. How to do it?

  • Prepare safety gloves, sharp file, deep burring rod, sharpening stone, sharp knife, and bench vise.
  • Remove the blades. But before that, make sure to empty the gas tank and disengage the spark plug.
  • Find the flat file and start sharpening the chiseled side of the lawnmower blade.
  • Similar to the previous step, you need to use the flat file against the sharpening stone to sharpen the blade.
  • For an additional sharpening tool, you can try the sharpening rod. It helps you remove the irregularities on the blade.
  • The final step is to make sure that each side of the blade is clean and balanced.

What angle should lawn mower blades be sharpened at?

For industrial lawn mower blades, the common angle used for sharpening is 30 degrees.

However, it depends on the blades and how long you have used your lawn mower. The high lift blade needs 15 degrees, while the other is 45 degrees.

Despite the size, it is crucial to know the angle before sharpening the knife since the wrong one can tear and stress the grass.

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