How to Sharpen Lawnmower Blades

A lawnmower can cut grass if it has a dull cutting edge, yet the result won’t be the best. Once you mow your lawn, you will see ragged clumps where the blades rip rather than cut.

While it isn’t pleasing to the eyes, it causes grass blades to brown and can make it easier for pests and disease to spread.

When you have a lawnmower that has sharp blades, it will cut clean through your grass to leave an even finish, and a healthy lawn.

Learn how to sharpen a lawnmower blade

It is a recommendation to sharpen your lawnmower blades at least twice during the grass growing season because you never know what stones or sticks they hit, which can impact the blades cutting edges.

Here, we show how easy it can be sharpening mower blades at home, so you can have the best looking lawn without spending on finding someone who does lawn mower blade sharpening.

How to Sharpen Mower Blades Like a Pro

Once you decide to learn how to sharpen a lawnmower blade, you will be surprised how easy it can be to get professional results.

There are three stages to accomplish this, so here are the guidelines you need for each.

Removing Your Mover Blade

In this first stage, it is as much to do with safety, as it is to do with accessing any cutting part of the blade.

  1. Disconnect the spark plug on petrol engine mowers. Electric mowers won’t use a spark plug and only need disconnecting from the mains
  2. Drain any gasoline from the tank
  3. Tip your lawnmower onto its side to expose your mower blade. You may have to remove a lot of dry grass that accumulates underneath
  4. Once you have access, use a block of old wood, and use it as a wedge to stop the mower blade spinning as you use the wrench
  5. Check the blade fastening; some come with three bolts while some use a single one. If it has seized, use a squirt of WD40 or an equivalent. If your bolts are still tight, you may need to add a tube over the end of your ratcheting wrench handle for extra torque to loosen the nuts before removing the blade
  6. Be sure to check which way the blade fits before you remove the blade from the mower. Many mower models have a specific method that lawnmower blades and the retaining brackets fit, although it is wise to be sure.
  7. Once you remove the blade, check all the parts that cut the grass. You may see you have a dull blade, and there are small dents or nicks along the edge. If you have any significant dents or it looks bent, then you may have to replace it.

Working the Edge of Your Blade

One thing you will learn when you see how to sharpen lawn mower blades is the number of ways you can do this.

After showing you the steps to sharpen the blade, you can see the different tools you can use to accomplish this task.

If you sharpen your blades on a regular occasion, you may find they only need a light sharpening to bring them back to peak efficiency.

Use a vice to hold the blade with the cutting edge of the blade facing upward. The mower blade should be at an angle rather than being horizontal.

Take a fine-tooth file that is designed for metal use, and then start your gentle strokes working your way to the end of the blade. You do need to follow the cutting angle or bevel that is already there.

After several strokes and you can see new metal, you will spot a burr. Flip the blade and gently run the file along this to remove these rough pieces of metal.

Mower blades cut from both ends, so once you do one end, spin the blade around and sharpen the opposite end.

DEWALT Bench Grinder, 8-Inch (DW758)

Alternative Lawnmower Blade Sharpener

Using a file can take a while, so it isn’t always the best solution for everyone. Luckily, there are alternative ways you can sharpen a lawnmower blade if you are used to doing any home improvement projects.

Here are the other ways you can sharpen lawn mower blades.

Bench Grinders: A bench grinder is a quick way to obtain a sharp edge on your lawnmower blade.

Be sure to wear gloves and goggles because there can be sparks. Make sure your grinding wheel is a fine stone, or you can remove too much material.

Rotary drills: if you have a dull mower blade, then a drill with a sharpening stone attachment can make light work of removing dents and putting a sharp edge back on your blade.

You will need a steady hand using these as your lawn mower blade sharpener because of the high RPM and hand-holding nature of your drill.

Balancing Your Blade

One thing often overlooked it to be sure your blade is balanced. If you remove more metal on one side, then it won’t spin evenly, and you can face extreme vibrations.

To find the heavy end just needs a nail in a wall and suspend your blade. If your blade sits level, it is balanced. However, if one end drops, you will need to remove a bit more metal to even it out.

It may just take a quick pass with any of the sharpening methods you used on your dull mower blade when you first sharpened.

For the best in lawn care; all you need to do is reinstall the blade and tighten the fasting bolts.
Once they are secure, you can flip your mower back over and then connect the plug and fill it back up with gasoline.

You are now ready to put your tools away, head to your lawn, garden equipment at the ready, and off you go for cleanly cut grass.

Read more about lawnmowers:

How to Sharpen Lawnmower Blades

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