Which Side Of The Lawn Mower Blade Is Up?

Lawn mowers are the most useful and crucial tool of yards in terms of maintenance and landscaping. Their demand and use rises with the onset of the warm season and continue till the end of the season. 

While mowing the grass, you should never be out of mind about the lawn mower blades that get spinning away down the whole season. With the continuous wear and tear, the blades get dull and lose their efficiency of smoothly cutting the grass blades. 

A dull or unsharpened mower blade starts butchering the grass and exposing it to more disease attacks, which could increase more investment in form of lawn fungicides that might lead to bare patches and eyesores.

Furthermore, the dull mower blade puts extra stress on the mower’s engine by forcing it to provide more power to cut through the tough grass.

Dull mower blades need to be sharpened or replaced immediately to save the grass and mower’s engine from further damage. But the crucial thing in replacing the mower blade is to set it correctly, as most users don’t know which side of the lawnmower blade is up.

In this article, we are going to discuss the whole process of the lawn mower blade replacement method to the correct mower blade position. Additionally, the types of lawn mower blades with their true replacements are also discussed in detail.

Let’s start.

Importance of lawn mower blades in the smooth cutting of grass

Lawn Mower blades are the metallic blades fitted down in the mower’s deck that help to cut the grass with their sharp edges and spinning movement. 

The Lawn Mower blade has two sides, one is the cutting side and the other is the trailing side. The sharpened edge of the blade is a cutting edge, also known as a beveled edge, that is angled and sharp edge to cut the grass. Its cutting side or sharp side faces the ground while the tapered side towards the sky.

While the other side is a trailing edge or dull edge that is bent or typically arcs to create a draft to lift the grass clippings away.

The sharpened side determines which side of the lawn mower blade is up and which is down.

If the lawnmower blades are fitted in the correct position with a sharp edge facing towards the ground surface, it will give a smooth and uniform cutting.

lawn mower blade

Which side of the lawn mower blade is up?

Lawnmower blades have two dissimilar edges and both edges have different functions to perform. The sharp edge cuts the grass while the trailing edge that arcs to create a draft to lift the grass clippings away. 

But it is difficult for a newbie to know the correct position of mower blades and the wrong blade fitting can be damaging for the mower’s engine and the users. 

Here is the quick way to determine the right orientation of lawn mower blades. 

Lawn mower blades are fitted in the mower’s deck in such a way that the sharp edges of the blade should be closest or towards the ground while the curved or tapered side of the blade should be pointed towards the sky.

But it is necessary to know the up and downside of lawn mower blades to finish the job faster and ensure efficiency. Here are some methods to determine the upside of a lawnmower blade.

1. Stamps or stickers

Most lawnmower blades have a stamp or sticker on one side of the blade. This sticker or marker shows the correct side of the blade. 

Go check for the stamp or sticker “This side down” or “Cut grass”. The stamped side of the mower blade indicates which side the instrument should be facing.

Some blades have engraved wordings onto the blade to indicate the correct side of the blade.

If your mower’s blade does not have any sticker or mark, you can put any sticker on your own to remind you of the correct side in the future.

2. Locate the “cutting” or “sharp” edge

Blades have tapered and sharp edges on one side. This side of the blade cuts the grass while the other side is totally flat or partially arcs for collecting the grass blades. 

To fix the blade’s incorrect orientation, the first thing to do is recognize the cutting edge of the blade and fix it in such a way that the tapered side should be upside while the sharp edge towards downwards to the grass.

Make sure to replace the blade with a truly similar blade having the same center hole and length of the instrument. Using any blade other than true one could lead to a whole new slew of performance issues.

Keep checking the edge of the blade from time to time as the sharp edge wears out with time and becomes dull and leads to choppy lawn cutting.

3. “Wobble” test or blade wobble

After finishing the blade installation, ensure that the blade should be rigid. It will create new problems in case of any flexibility or wobbling. The flexibility or wobbling can also be the reason for incorrectly fixed blades.

In other instances, it can also correct by tightening the bolts.

Wobble test ensures the efficiency of mowing with a new blade and the liability of the blade.

Here are some simple steps to perform wobble test:

  • Hold the lawn mower blade with one hand and the deck in the other hand.
  • Now give the blade a tug and pull it downwards gently.
  • It will not wobble if it is fixed on the right side by sharp edges facing towards the ground.

Wobble test ensures that the blade is secure and ready to mow the grass safely and smoothly.

What happens if I install my blade the wrong way?

Installing the lawn mower blade is not as simple as it seems. The true orientation of the blade is a sharp edge facing out towards the grass. 

But the wrong installed blade can be a great hassle for you in the form of damages to the mower’s engine and the person itself. 

Here are some significant issues of installing the blade the wrong way:

Uneven or choppy grass cut

If the blade is upside down, it means that the sharp edge is opposite to the ground while the tapered side is facing the grass. When you use such a blade, the grass blades will miss the direct sharp edge and it will chope the grass unevenly.

Blades damaging

Installing the blade in an incorrect position will cause them to wear and tear in less time. The wrong installed blade will start to wobble with few mowings and cause cracks in the blade. The blade will get dull faster and make it harder to cut the grass.(Source)

Damages to mower

Blade wobbling can cause serious damages to the other parts of the mower. The wrong installed blade will knock the stone loose and the stone may hit another part of the mower and damage it.

Engine heats up

If you accidentally installed the lawnmower blades in the wrong orientation, it will consume more power to cut the grass as the sharp edges are not facing the ground directly. This way the engine may get heated and cause adverse damages to the engine.

When to Change Your Lawnmower Blade

It doesn’t matter how often you mow your lawn or how much is the size of the yard, the lawnmower blades are worn out with time. If you will not replace or sharpen the blades from time to time, it will end up in the form of uneven and sloppy grasses.

The dull blade takes more power to cut the grass as it needs to do work harder to cut the grass blades.

Here are some particular tips on time to replace the lawnmower blades.

Uneven patches

When you notice the uneven grass patches in your yard after mowing, it means that blades replacing time have come up.

Ragged tips

A dull blade will start tearing and chopping the grass instead of cutting it. When you notice such things in your freshly cut lawn, it’s likely the time to replace or sharpen the lawnmower blade.

Manufacturer’s recommendation

Most good tool manufacturers recommend the replacing time of the particular tool or parts. In the case of lawnmower blades, the replacing time is almost 25 hours or so. 

The lawnmower blade can go a bit longer, depending on the condition of the lawn and the sharpness of the blade.

How to replace a lawn mower blade?

Replacing a lawnmower blade is not a technical task that needs some technical knowledge or specific tool kits. With a little knowledge of the correct lawn mower blade sides, one can easily replace the blade in a few minutes.

Here are a few simple steps to replace the lawn mower blade.

Step 1

Firstly, remove the spark plug to ensure personal safety. Then turn the mower on its side to prevent the spilling of fuel and saturation of oil from the air filter.

Step 2

Wear the gloves and secure the mower by lodging a 2×4 block between it and the mower deck. Now loosen the blade from the drive shaft with the help of a wrench.

Step 3

After removing the blade safely, take the blade to the shop for sharpening or do yourself by following a few simple steps of blade sharpening.

In the case of replacement, take the blade to the nearby shop and get a new one of the same hole size and length.

Step 4

Now start assembling the mower parts together. This is the crucial time in lawnmower blade replacement to fix the blade in the correct position. 

The sharp edge of the cutting side should be facing the ground while the tapered should be upwards.

In the case of a mulching blade, the wings of the blade will be orienting the mower deck and the writing side will be facing the ground.

Step 5

Tighten the bolt to prevent any wobble of the blade. Reinsert the wooden block and tighten the bolt with the help of a wrench but ensure to not break the bolt with extra tightening.

Now clean the mower deck to remove the dirt and apply the silicone spray coating. It will help to prevent the build-up of clippings through airflow.

Can I sharpen my blades instead of changing them?

Yes, you can sharpen the law nmower blade instead of replacing them every time. Only the cracked lawnmower blade needs to be replaced. You will need a grinder to sharpen the blade. Many other sharpening tools are present in the market that costs much less than shop cost. 

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