what side of the lawn mower blade is up

Which Side Of The Lawn Mower Blade Is Up?

If you own a lawn mower then you’ll know that, from time to time, you need to remove the blade to perform cleaning and maintenance. However, if you don’t put the blade back on properly and it’s in the wrong position then this will affect the performance of your mower. But how do you know which way lawn mower blades go on?

You’ve got a 50% chance of putting the mower blade the wrong way so it pays to familiarize yourself with your blade. The sharp edge of the lawn mower blade is what cuts the grass so this needs to be facing down while the dull side faces into the mower deck.

If you’re currently in the yard scratching your head and wondering what the correct lawn mower blade position is, worry no more. We’ve got you covered with this handy guide.

Knowing which way to put your lawn mower blades on is incredibly important. If they aren’t the way up then they aren’t going to cut the grass as you’ll just be running a dull edge over the lawn. So, when you take them off for maintenance or are installing new blades, it’s worth noting the position before taking the old ones off. However, if it’s already too late then here are some easy ways to tell which way around the need to go.

Check The Stamp On The Blade

It might seem really obvious now that we’ve pointed it out but oftentimes, there will be a stamp on the blade that tells you exactly which way round to install it. You should look for markings that likely say something like grass side and this will make life a hell of a lot easier for you.

However, while this is, without a doubt, the easiest way to tell which way is up, these stamps don’t appear on all blades so you might need to rely on other methods.

Sharp Side Of The Blade Faces Down

sharp side - faces down

Lawn mower blades only have one sharp side. Take a look at the blade in front of you right now and you’ll see that one side is sharp while the other would have a hard time cutting through hot butter.

It’s easy to tell which side is which as the dull side is normally raised at the edge. In fact, it kind of looks like a wing and it is this design that helps to lift the grass clippings from the ground and blows them into the mower deck before being passed into the collection bag or out of the chute.

When it comes to putting your blade back in, or installing a new one, make sure that the wings are facing upwards to the inside of the mower deck. The sharp side of the blade should be pointing down so that it is close to the grass and can cut it.

Sharp Side Of The Blade Moves Towards You

To install a new lawn mower blade, you’re going to need to have the mower tipped over so you can access its deck. The blade is secured using a bolt in the center and once you have tightened this, it’s a good idea to check the blade to make sure it’s been installed correctly.

The easiest way to do this is to keep the lawn mower on its side and then move the blade towards you. Of course, which way it moves will depend on which side the mower is tipped onto. If you’ve laid it on the right side then you’ll move counterclockwise while if it’s on the left side, you’ll need to move it clockwise.

As you do this, mimicking how the blade will move when cutting, the sharp cutting edge should be moving towards you. If the dull side approaches you first then you’ll need to take that blade out and reinstall it the other way around.

Which Way Do Lawn Mower Blades Spin?

Which direction the lawn mower blade moves depends on where you’re looking at it from. If the lawn mower is the right way up and you were looking down on it, imagining the deck was transparent, then the blade would move in a clockwise direction. However, if you were to look at it from underneath, it would be moving counterclockwise.

But this isn’t always the case with every model so you may need to look at the side discharge chute, if your mower has one. This will tell you all you need to know about the direction of the blades.

For mowers with their discharge chute on the left hand side, the blades will rotate counterclockwise. If your lawn mower’s side discharge chute sits on the right then the blades will move clockwise. The position of the chute is just so that the blades will help to send the clippings out.

How To Know If Mower Blade Is Upside Down

All it takes is to have a look at how your lawn mower has cut the grass and this will tell you a lot about the position of the blade. When you are removing a lawn mower blade, you’re doing so for one of two reasons; to sharpen and maintain it or replace it. In both cases, you would expect the final result to be a mower that cuts better than it did before.

However, if you have replaced or sharpened your blade, put it back in and find that the cut is worse or not improved then there’s a good chance that you’ve put it in the wrong way. The reason that the performance is affected is because the dull side of the blade is what’s now making contact with the grass and it’s not cutting it.

So, one of the easiest ways to tell whether a lawn mower blade is installed the wrong way is to simply assess the performance. If the cut is anything but crisp and clean then we’d recommend halting what you’re doing, flipping the mower over and double checking the blade installation.

bermuda grass aerate

What Happens When The Blade Is Upside Down?

We cannot stress enough how bad it is to cut your lawn with a mower whose blade is on the wrong way. But you’d be amazed at how many people do this and they’re not even aware of it!

So many people complain that their lawn mower doesn’t cut properly and end up chucking it or selling it for spares and repairs. When in reality, they could have taken the time to consider that the lawn mower just wasn’t set up properly.

So, that leaves us with the question of what happens if you mow with the blade upside down. Well, let us tell you that there’s a few problems which might arise.

It’s Bad For The Grass

One of the worst things about using a mower with an incorrectly installed blade is that it’s terrible for your grass. Instead of delivering a nice even cut, the blade will hack at the grass which puts a lot more stress on it and it won’t heal as quickly. As a result of this, you may find that the lawn becomes more prone to diseases and pests.

It’s Bad For The Blade

Earlier, we talked about the winged shape on the dull side of the blade. These should be facing up into the mower deck but when they point to the ground, there is a risk of them being damaged. This might happen if they collide with a rock, stone, piece of wood or anything else that may be lying on the lawn.

This risk increases even more if you use a lower cutting height as the blade will be even closer to the ground. While a single impact might not do too much damage, repeated bumps can cause the blade to bend and chip which means you’ll end up having to buy a new one.

You Could Seriously Mess Up Your Mower

Should you mow over something like a stone or a stump or the like then it might not only be the blade that suffers. In the worst cases, you may end up breaking the crankshaft.

This isn’t a problem that you’ll be able to fix and it’s unlikely that even a mower specialist would be able to do much. That’s because getting a crankshaft realigned after it’s been bent is often so expensive that it’s typically better to just replace the entire lawn mower. In some cases, fixing it might not even be possible and you’ll be left with having to fork out for a new tool.

Final Thoughts

sharpen lawn mower blade

It is unavoidable to have to take the blade out of your mower; unless you’re going to buy a new mower every time the blade needs to be sharpened or replaced. But that would cost a fortune!

However, so many people struggle with putting the blade back into the mower in the right position and this results in a poor cut as well as potential damage to your lawn mower.

It’s important to install the blade with the sharp side facing you and being closest to the ground. In a lot of cases, there is a marker on the blade which tells you which way to install it so there’s no need for any detective work.

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Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.

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