How long do lawnmower blades last?


To keep Lawnmowers, giving an attractive and stunning look to your garden, you need to maintain them well. But even well-maintained machines can cut the grass unevenly. Dull and faulty blades are the most likely cause behind your mower not mowing cleanly. You can sharpen dull blades; in fact, we would recommend you sharpen the blades now and then. But after a long period of use, the blades start losing their health, develop chips and dents and bends. When this is the case, further sharpening won’t help. Eventually, you will have to replace them with a new set of blades.

How long do lawnmowers blades last:

On average, most mower blades last up to 100 to 200 hours under normal conditions. The number of hours can be as high as 400 if you use high-quality blades. When blades get dull, you can sharpen them with a grinder or metallic file, but the blade sharpening will only work for 2 to 3 times. Eventually, you will have to replace them. Replacement is also needed if the blade is chipped and dented after hitting a rock, boulder, or another strong object.

The right time for blade replacement depends mainly on the user’s judgment. We advise you to check the blades every time before or after you mow and clean the blades and cutter area. While cutting, thoroughly examine the grass behind you. If the grass height is uneven, it means blades are dull and need some maintenance.

Signs of Lawnmower Blade wear and tear:

Blades are the most important part of a lawnmower. If the blades are not working properly, you will not be getting the desired results. To check if your mower blades are malfunctioning, you need to look for two things:

● Grass height

Lawnmowers with fine blades cut the grass evenly on each trip. If your lawnmower is cutting the grass unevenly, it means the blades of the mower are faulty. All you need to do is to examine the grass height in your lawn after every mowing. Uneven grass height indicates blade malfunction.

● Grass edges:

If the grass tips are torn, then maybe it is time to sharpen the blades or replace them. Dull blades rip the grass edges, which makes them turn brown quicker. Uncleanly cut grass not only makes your lawn look ugly, but it can also enhance the chances of grass diseases.

Sharpen the Blades, or Replace Them?

You have to sharpen the blades each time they get dull, but how would you know if they had reached their end?

Obviously, you cannot keep sharpening a single set of blades forever. There is a stage when further sharpening of blades will not do any better, and you will have to replace them. Let us look at the possible situations, which will show that it is time for a replacement.

  • Bends and dents in the blade
  • Cracks on the blade surface
  • Worn surface and edges

These are the conditions in which the blades must be replaced because there will be no benefit in sharpening them. Yard debris wears down a blade over the years, resulting in thin, weak metal whose surface can be cracked easily. If your blades are overused, replace them quickly to stay away from breakage. On the off chance that blades break while you are cutting, they can cause injury.

Besides, it is recommended that you should not wait for your blades to go bad beyond repair to get a replacement. Predictive or preventive replacement is better than replacement after a complete failure has occurred. Having multiple substitution blades close by is helpful, especially if you need to utilize the sharp edges for various purposes.

Why do the Lawnmower Blades Lose their Health:

The rotating speed of the blades is very high; if they hit a rock at this speed, it will break them. Thus, if you hear the sound of something hitting the cutting blades, stop the mower and quickly look for dents in the blades. See if the blades are curved or warped. If you find such contortions in the blades, then it is time to replace them.

Corrosion is another common source of blade damage. Rusted blades can be cleaned with a metal file. If the rust layer is too strong and thick to be filed off, you should replace the blades.

Tips to Increase the Lifespan of Lawnmower Blades:

Apart from sharpening, which will prolong the blade life, let us look at other factors that most people ignore.

● Peripheral parts:

Look after the other parts of the mower. If the rest of your mower is not functioning well, it will affect the blades. Change the oil, oil the moving parts, change the fuel channel, and ensure the elastic fittings are not exhausted.

● Look out for rocks in your lawn:

Clear your yard, and look for things that can cause damage the blades, such as rocks, metals, and twigs, before you begin mowing. As previously explained, these things will damage the blades, and you will have to replace them.

Also, try to be more attentive while mowing, making sure you don’t hit a rock and break your mower blades.

● Storage:

Store the mower indoors, and use a waterproof cover for it. Water can affect the mower causing rust in the blades; thus, blades will become weak and thin.

Replace your Lawnmower Blade:

The replacement procedure is relatively easy and can be performed at home. Ensure that the replacement set matches the set being replaced. Most important are the center hole’s thickness and diameter. The user manual can provide you with the correct blade dimensions for your lawnmower.

Given below is a step by step guide on how you can replace your lawnmower blades:

● Step 1: Seal the gas tank/cut the power

  1. Safety: Wear safety gloves before performing the replacement procedure.
  2. Seal the gas tank: Remove the gas tank’s lid and place a plastic bag over the gas can’s top, sealing it. After doing this, replace the lid in its previous position. This is to ensure that no gas spillage occurs while the mower is in the tilted position.
  3. Electric lawnmower: In case you are working on an electric mower, make sure it is not plugged in.

● Step 2: Tilt the Lawn Mower

Park the mower in an open flat area with the parking brake applied. You’ll need to tilt the mower to access the blades. When you tilt the mower, make sure that the carburetor and the fuel tank are on the top side to avoid leakage.

Place a wooden block diagonally at the mower’s far side to make it more stable in the tilted position.

● Step 3: Remove the Old Blade

Use a socket wrench to loosen the nut holding the old blade in place. Turn the wrench counterclockwise to loosen and remove the nut. Before removing the blade, please take a picture of it on your phone. This will help you later to put the new set in the correct position.

● Step 4: Install the New Blade Set

Refer to the photo you took earlier and installed the new blade set. The direction of the cutting edge is crucial and should match the photo. Consult the manual for the correct cutting edge direction for your model.

Use the socket wrench to tighten the nut, turning it clockwise this time. Make sure that the nut is tight, or else the blade would vibrate and not cut properly or even fall off.

● Step 5: Finishing

Once you have completed the replacement procedure, lower the mower carefully and slowly. In case of a gas mower, reopen the mower fuel tank lid, remove the plastic bag, and put the lid back again. With this done, the replacement procedure is finished. Your mower is now equipped with a set of fresh, sharp blades and is ready to be used.

Blade precautions and safety:

  • Make sure to wear good quality protective gloves to avoid injury from sharp edges.
  • Make sure that the blade replacement does not nullify your mower’s warranty. Consult the warranty card or contact the manufacturer for more info in this regard.
  • When tilting to excess the blades, make sure that the carburetor is on the top side.

Types of lawnmower Blades:

Lawnmower blades are interchangeable; however, you must ensure that the center hole and the new set’s blade length match the one you are replacing.

Most blades fall inside the range of about 16.75 inches to 22 inches in length. Most mowers can facilitate blades as long as 21 inches or 22 inches too.

Lawnmower BladesTypeSizeMaxpower Commercial Mulching BladeMulching Blades21 inchesEGO Power+ Lawn Mower BladeHigh-Lift Blades21 inches8Ten Lawn Razor Hi-Lift BladeN.A20.75 inches
Honda Lawn Mower BladeHigh-Lift blades20 inches

Related Questions:

● How much does a new set of lawnmower blades cost?

The blade price is moderate; they are not too expensive. Prices can vary from $10 to $50, or even higher. The cost will vary significantly according to blade size, brand, and quality/material. 

● How to find the size of lawnmower blades?

You will have to take a few measurements to find out the size of your lawnmower blades, the length of the blades measured diagonally, and the diameter of the center hole. After measuring the length, measure the blades’ width, measure the blades’ thickness at the center point.

The new blades should fit correctly in your lawnmower; you can use smaller or bigger blades, as long as they should tightly fit in and don’t touch the cutter area boundary while rotating. 

Final Remarks:

Good condition of lawnmower blades is crucial for having a well-mowed lawn. Dull blades will not cut the grass properly, so sharpening now and then is recommended. Sharpening increases blade life, but after multiple sharpens, the blades will become weak and thin. This is the stage where you must replace them. The replacement procedure is not too complicated. The guidelines presented in this blog post will help you replace your old lawnmower blades with a new set.

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