How To Sharpen Lawn Mower Blades

Sharpen Lawn Mower Blades Efficiently

Keeping your lawn short and trimmed can help prolong the life of the grass, ensuring it’s healthy and weed-free. However, you also need to maintain your lawn mower, so that you’re getting the very best out of it. Mowing your lawn with blunt blades can cause the grass to rip and tear, which can encourage brown and dead grass. Sharp blades ensure an even and slick cut, allowing your lawn to flourish.

But how do you keep your lawn mower blades sharp? Our quick guide below explains everything you need to know about how to sharpen lawn mower blades – and keep your lawn looking its best.

Mower maintenance

First things first, you need to make sure whether or not your blades need sharpening. Good mower tools maintenance can prolong the life of your blades, such as cleaning all grass and muck off once you’ve mowed your lawn, as well as storing it properly in a clean, dry space, such as an outdoor shed or garage. If you notice brown, broken blades of grass on your mower after you’ve used it, this is a good indication that your mower blades need sharpening.

A good rule to follow is ensuring your sharpen your mower blades twice every summer – as this is when you’re most likely to be using your lawn mower. If you mow your lawn often or have a large lawn, you may need to sharpen them a lot more often than this.

You should also check how well balanced your blade is. If it looks off-balance i.e. one side is higher than the other, your lawn may not be getting the best cut it could be. You can buy a balancer from a garden center or hardware store, but if you don’t have one, you should be able to look at the blade to see how well balanced it is. Simply remove the blade and realign it, tightening with a wrench.

Blades with cracks or dents will need replacing. Cracks are cause for concern as it means the blade could break at any moment, which is dangerous for you – and damaging for your grass.

Safety first

Before you begin sharpening your blades, you’ll need to make sure that the mower is switched off and removed from any kind of power source. This may mean removing the spark plug, just to be sure. You want to try and avoid the mower accidentally starting as you’re removing the blades. Wear eye goggles and gloves as a precaution.

Removing the blades

Before you remove the blade or blades from the mower, make a mark on the blade, so that you know which is the top and which is the bottom. This will help when reattaching the blade back on the mower. Lay the mower on the ground, so that you can easily access the bottom. If your mower is particularly heavy, you may need assistance with this. You should try and clean away as much debris and muck as possible before removing the blade. This will make it easier when turning the bolt.

Once clean, using a wrench, you can slowly remove the blades. Be careful when doing this that you don’t do it too quickly, as you may injure yourself.

Cleaning the blades

Remove as much dirt and grass as possible from the blades. Having excess muck on them will make them difficult to sharpen and you won’t have the best outcome. You can use an old towel or rag for this, and simply use warm water to remove the debris.

Sharpening your mower blades

There are two ways to sharpen mower blades: by hand and with a bench grinder. We’ll outline how to do both below.

1. Sharpening by hand

Using a file or grindstone, you should try to keep the blade at a 45-degree angle. The best way to achieve this is to clamp the blade securely on a workstation. Run the file along the edge of the blade, until the blade becomes clean and shiny. This means you’ve managed to sharpen efficiently. Although flying debris will be low if doing this by hand, we would still suggest you wear protective eye gear and a facemask. Although your lawn mower doesn’t have to be as sharp as the knives you use in your kitchen, it should be sharp enough to cut butter. The speed in which the blade spins is what helps cut the grass, not just the sharpness of the blade.

You should use a solid metal file to sharpen your blades. It doesn’t need to be large in size – around 2 inches across, and 10 inches in length.

2. Sharpening with a bench grinder

Before you begin, you must have the proper safety equipment available in order to use a bench grinder. This means a full face mask, including eye protection and mouthguard. You should also wear specialized gloves and a long-sleeved top for further protection.

Once you’re ready, use the bench grinder to move the blade back and forth on it. Ensure you maintain the original angle of the blade, as this may affect its cutting ability once placed back on the mower.

Reinstalling the blade

Once you are happy with the sharpness of your mower blades, it’s time to reinstall them and attach them back onto the mower. Using a lubricant, such as WD-40, spray this onto the bolt to avoid rusting in the future. Using the mark you made previously, check which way up your blade should go, then reassemble, with the correct washers, and tightening the bolt fully. You should only need a wrench to reattach the blade or blades, as a hammer will cause damage to both the blade and the mower.

Remember, if you’re ever unsure of how to sharpen your blades, speak to a professional. Lawn mower repair businesses will be able to assist you for a small price, which means you won’t risk damaging your mower – or yourself.