Which Way Does a Lawn Mower Blade Go On?

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Although it is relatively easy to replace the blades or blade on a lawn mower, sometimes it is hard to determine which side of the lawn mower blade is supposed to face the ground and which side is supposed to face the lawn mower. If you want to know how to determine which side faces what, you’re in the right place.

The sharpened edge of a lawn mower blade spins in the direction of the rotation of the lawn mower, sometimes bending towards the grass. Pull the starter to see which direction the blade rotates. The dull edge of the blade bends towards the lawn mower. The blade will wobble if installed incorrectly.

Now that you know which edge of a lawn mower blade goes closest to the grass, you are likely wondering about how you can determine if you put the blade on upside down and how to change the blade(s) on a lawn mower. Keep reading to learn more details.

Which Way Does a Lawn Mower Blade Go On?

Sometimes it is hard to tell which side of a lawn mower blade is supposed to face the grass and which side is supposed to face the lawn mower itself, especially because they typically aren’t marked with “this side down” or this side facing etc.” like other products are.

On a lawn mower blade, there is a dull side and a sharpened side. The blade itself is sometimes bent so the sharpened side is closest to the grass and the dull side is closer to the lawn mower itself. If the lawn mower blades that you have purchased are bent in this way, hold the blade so the sharpened edge faces you, then put the blade on the lawn mower to install it in the correct way. (Source)

Basically, the sharp edge of a curved lawn mower blade should point towards the ground and the dull side should point towards the sky when the lawn mower is upright. (Source)

If the lawn mower blade that you purchased isn’t bent or angled in this way, figure out which way the blade on your lawn mower spins. If you have a lawn mower that needs to be cranked in order to start, pull the crank while you can see the blade of the lawn mower and watch which way it spins. The sharp edge of a lawn mower blade needs to spin in the direction of rotation so it can cut grass properly.

Sometimes there will be a stamp, etching, or some other type of marking or sticker that tells you which side of the blade should be closest to the grass when installed. If that is the case, use those markings to determine how to put on the lawn mower blade correctly. (Source)

Nowadays many lawn mowers only have one blade, but others have two blades that need to be replaced periodically. Lawn mower blades on a dual-bladed lawn mower typically have a notch in the blade that needs to be put on first. This enables the second blade to fit into place so they are flat against each other and can move together when the lawn mower is being used.

When you are replacing multiple blades on a lawn mower, this notch needs to be facing you and point towards the ground when the lawn mower is upright.

If you turn on your lawn mower while you can still see the blades and they wobble, then they may be upside down. It’s also possible that the bolt that ensures the blades stay on the lawn mower may be loose and need to be tightened before you start mowing your lawn with the new sharp blades on your lawn mower.

Now that you know how to tell which side of a lawn mower blade goes where, you are likely wondering what will happen if you use your lawn mower when the blades are upside down. This could lead to serious problems, so it’s. important to discuss.

What Happens If I Put the Lawn Mower Blades On Upside Down?

If you install the blade or blades of your lawn mower upside down, then a few things can happen.

Things that Can Occur When Lawn Mower Blades are Installed Upside Down:

  • Grass is cut unevenly
  • Blades become damaged
  • Mower become damaged

Grass Cut Unevenly

If you put the blades of a lawn mower upside down and mow your lawn, the grass will be cut unevenly and it will likely take longer to finish mowing your lawn because the grass won’t be cut properly. If this happens, all you need to do is flip the blades that you recently installed and mow the longer spots of your lawn again until you are happy with the length.

Blades become Damaged

The blades that you recently installed will become damaged and dull quickly if you install them upside down because they are wobbling and possibly hitting the metal of the lawn mower. This movement causes the blades to become chipped and possibly cracked.

They will also wear out faster than you expect them to because the dull side that is cutting the grass will become even duller, and will eventually stop cutting grass altogether, so you will have to replace the blades before you want to.

Lawn Mower becomes Damaged

If you put lawn mower blades on in an upside down orientation, your lawn mower is likely to become damaged. When lawn mower blades are put on upside down, they wobble. When the blades wobble, they hit the metal of the lawn mower as it is being used, which will cause the interior of the lawn mower to become nicked and damaged, as well as the blades themselves.

If you hear clanging when you are mowing your lawn after you have replaced the blades, you likely put them on upside down, or didn’t tighten the bolt holding the blades onto the lawn mower tight enough to hold them securely.

If your lawn mower is hit many times by the blades and you don’t fix the issue, then you will likely have to replace your lawn mower eventually because of the amount of damage that it has sustained. Lawn mowers can be expensive, so it is much easier and cheaper to simply make sure the bolt is tight and the lawn mower blades are installed correctly.

Although it is easy to accidentally put lawn mower blades on upside down, it is also easy to fix the issue before irreparable damage occurs. If you hear anything concerning when you are mowing your lawn, make sure that you installed the lawn mower blades correctly and make sure there aren’t any rocks on your lawn when you are mowing it.

Now that you know what can happen if you don’t install lawn mower blades correctly, you are likely wondering how often you should replace them. We’ll discuss that below.

When Should I Change Out Lawnmower Blades?

When someone purchases a lawn mower, they often don’t think about how frequently they should replace the blades. Luckily, lawn mower blades don’t need to be replaced frequently. Lawn mower blades typically need to be sharpened after they are used for a total of 25 hours and replaced after more than 200+ hours.

It is relatively easy to determine when you need to replace the blades on your lawn mower because they will be worn out. When a lawn mower has dull blades that need to be replaced, your lawn mower will likely become clogged more often than usual, the grass will look torn rather than cut, it will take longer to finish mowing your lawn, and there will be uneven patches of grass on your lawn.

Luckily, you won’t have to replace the blades on your lawn mower frequently unless you have a large lawn or you mow your lawn every week. (or multiple times per week). It might be a good idea to change out the blades at the start or end of the mowing season so you’ll be prepared for the future. Setting a regular maintenance schedule is always a good idea because it’s easy to forget steps like this.

Now let’s talk about how to replace lawn mower blades and how much you should expect to spend.

How to Replace Lawn Mower Blades

Although it sometimes seems like it is complicated to replace the blades on a lawn mower, it really is a simple process once you know how to do it. The exact steps that you need to follow will vary depending on the model and make of your lawn mower, but below are general instructions that you can follow. If you want to know exactly how to change the blades of your lawn mower, look at the Owner’s Manual and search for the instructions.

Necessary Materials:

  • Cut-Resistant Gloves
  • Wrench
  • New lawn mower blade(s) that will fit on your lawn mower.

How to Put on New Lawn Mower Blades:

  1. Gather needed materials.
  2. Lower your lawn mower onto the ground so you can access the blades.
  3. Clean out all leftover grass that may get in the way.
  4. Put on cut-resistant gloves.
  5. Use wrench to remove the bolt(s) that are holding the blade(s) on the lawn mower.
  6. Set aside the bolt(s) once removed.
  7. Remove the old lawn mower blade(s).
  8. Set the old blades aside where they won’t accidentally cut anyone and won’t be stepped on.
  9. Pick up new blades.
  10. Determine which side needs to face towards the grass and which side needs to face towards the lawn mower.
  11. Remove any stickers or removable markings that the manufacturer attached to the blades.
  12. Place the new lawn mower blades onto the lawn mower.
  13. Take the bolt(s) and tighten them until you can’t tighten them anymore.
  14. Make sure that the blades don’t wobble when spinning.
  15. Put away lawn mower and the tools used, or use your lawn mower.
  16. Throw away the old blades in an area where no one will be cut by them.

Now that you know how to replace old lawn mower blades, you are likely wondering where you can purchase new lawn mower blades and how much they typically cost. Keep reading to find out.

Where to Purchase New Lawn Mower Blades

You can purchase new lawn mower blades at nearly any hardware store. They are very easy to find both in-store and online, so it won’t take long for you to purchase new lawn mower blades after you realize that the ones that are currently on your lawn mower are worn out and dull.

Stores Where You Can Purchase New Lawn Mower Blades:

  • Walmart
  • Target
  • Home Depot
  • Lowes
  • Hardware Store
  • Lawncare Supply Company
  • Online Retailers

How Much Do New Lawn Mower Blades Cost?

New lawn mower blades cost between $12 and $31. The cost varies depending on the length, sharpness, and the manufacturer of the lawn mower blades. Sometimes, they come in a pack of two, which will increase the overall price of the blades, but that typically only occurs when your lawn mower requires two blades in order to function properly.

When you purchase new lawn mower blades, make sure you are getting the right size of blade and make sure that the blades are compatible with your lawn mower. You can determine what length of blade you need by looking in the Owner’s Manual that came with your lawn mower when you purchased it. If you can’t find your lawn mower’s Owner’s Manual, you will likely be able to find the product information online.

Overall, it is very easy to determine which side of a lawn mower blade needs to face the grass and which side needs to face the actual lawn mower when it is being used, so it won’t take long for you to do so. Many companies nowadays add stickers or other types of markings to lawn mower blades so it is easy for people to determine which side goes up, so you will be able to replace the blades on your lawn mower easily.


I am always happy to share all my knowledge about how to keep your garden in good condition and make it special.

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