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How To Sharpen a Brush Cutter Blade? 10 Steps!

Have you ever been through a situation where you were cutting through a weed, and your blade suddenly vibrated or jumped out of its groove?

Well, I’ve witnessed this situation many times. It is common for a brush cutter blade to become dull during operation due to constant friction against tough weeds and grasses.

If this happens, you will need to hone the teeth on the blade to work like new again. The process of shaping metal using abrasive stones or pastes to sharpen them is not easy, especially when you don’t know where to start.

This article is a complete step-by-step guide on How to Sharpen a Brush Cutter Blade.

It has been the weapon of choice by foresters, tree trimming professionals, and anyone who needs to clear an area of tall grass, weeds, and light brush quickly.

However, like any other piece of equipment, it needs regular maintenance to perform at its best while landscaping. So what kind of care does a blade require? Sharpening is required. Let’s dive deep into the blade sharpening world.

How To Sharpen a Brush Cutter Blade 1
Machine Sharpening Saw Blade via Flickr

Preventive Measures To Be Followed

It’s a good idea to take some precautions before we begin. If nothing else, you should put on a pair of thick cut-resistant hand gloves and protective boots. In addition, when sharpening the blade with a machine, you must wear eye protection that automatically darkens when exposed to light.

Essential Things

  • A workbench
  • A file guide
  • Wrench/Socket set
  • A wire brush
  • Clean rag
  • A moderate amount of Lubricating oil
  • Soapy water
  • Bucket
  • Sharpening machine
  • Metal file/Whetstone (for manual sharpening)

How To Sharpen a Brush Cutter Blade

Step 1: Prepare Your Work Area and Tools

Make sure that you work in a well-ventilated area with enough light and away from children. Also, make sure you’re far enough away from any flammable materials.

To make cleanup easier, it’s also a good idea to spread a drop cloth over the work area. Now that you have all the tools mentioned earlier and safety equipment ready, start by looking at how to properly hold the brush cutter blade.

Step 2: Remove The Power From The Brush Cutter

You may have turned off the switch, but it’s critical to ensure that the machine won’t start in any way. For example, when removing the blade, you may need to turn the blade side up, and you can imagine how bad things may get if the switch is unintentionally pressed.

Step 3: Remove the Blades from the Brush Cutter

Remove the blades according to your brush cutter’s type. Unless you have a brush cutter with a fuel tank, turn the brushes upside down and take the blade out.

Make a distinguishable imprint on the bottom side of the blade before removing it. So, making a mark will reveal which side is the bottom, and you won’t need to reinstall the blades.

The blades are fastened to the cutter with a bolt in the center. You won’t remove the blade if you don’t immobilize it before using a wrench or ratchet since it will turn with the wrench.

A sturdy wood board can be used to immobilize the blade. To keep the entire blade from turning when you loosen the bolt, place a piece of wood between the blade and the deck.

You can also use a clamp or a vise instead. Finally, you should be able to unscrew the bolt once you’ve stopped the blade from rotating.

Step 4: Clean the Blade

After the blade has been removed, clean it since there’s supposed to be a lot of grime and clipped grass on the blade. Remove any trimmed grass or mud with a soft-bristled brush, and then thoroughly wash with water.

After rinsing the blade with water, massage it with a dry rag and, if possible, soak it in soapy water for a more thorough cleaning, especially if the stains and debris aren’t easy to get rid of.

Step 5: Assess The Blade’s Condition

Sharpening blades can be done by hand or with a machine. Sharpening by machine is quite effective, but doing it by hand could also be acceptable, which requires a good amount of handwork.

This is important to determine which procedure should be used to sharpen your blade. A few strokes with a flat-file or on a whetstone should usually be enough to restore normal sharpness on a slightly dull blade.

On the other hand, blades with serious symptoms of wear will almost certainly need to be sharpened using a grinder.

Step 6: Sharpening The Blade

  • Manual Sharpening Using Metal Flat-File

Place the blade on the workbench and secure it before you begin sharpening it. When you press the stone against the blade, it should not move an inch. A vise or clamp can be used to keep the blade steady.

Because whetstone sharpening is difficult to obtain the optimum angle due to their construction, this procedure is great for bent edges.

Pick up the metal file and run it back and forth across the blade’s cutting edge. Rub the cutting edge with the metal file until it shines brightly.

Next, sharpen the other side of the blade in the same way. Do not stop until you see the shiny stuff on the blade; it should shine like a new blade.

  • Manual Sharpening Using Whetstone

For sharpening the blade, you’ll need two types of whetstones.

  1. Medium-grain
  2. Fine-grain

First, you’ll need to angle your blade on the whetstone at a 45-degree angle to utilize it. Then, slowly pull and push the blade inward and outward. You’ll start with a medium-grain whetstone and then end with the fine-grain whetstone. This should be done on both sides of the blade.

  • Sharpening Using A Grinder

A bench grinder is a great choice when it comes to restoring a damaged bevel edge in the shortest period. However, it would be best if you first secured the grinder on your workbench in a sturdy position.

Then, begin grinding the blade back and forth on each side of the running stone as soon as it is turned on. This will sharpen the blade to the point that you won’t have to do it again anytime soon.

Step 7: Check The Balance

When sharpening, it’s crucial to keep the blade balanced. This confirms that the blade has been correctly honed and that neither side is heavier than the other.

You can test this by changing the blade on a nail. Ascertain that it will be hung in the center. Your blade is not precisely balanced if one side dips lower than the other. To restore balance in the blade, merely sharpen the dipping side again.

Step 8: Test Your Blade

Once you have sharpened all of your notches, test the blade on a patch of weeds to check for any additional adjustments that might need to be made. If you notice any additional notches that need to be filed, repeat the sharpening process for those notches as well.

Step 9: Clean Your Blade

The best way to clean your brush cutter blade after sharpening is to use compressed air. Remove the blade from your brushcutter and blow off any metal filings that might be stuck to it.

If you don’t have access to compressed air, you can also use a paintbrush or wet rag to clean away any dust or grit on the blade.

Step 10: Test Again

After cleaning your brush cutter blade, test it again to ensure sharp and ready for use. If you notice any spots where the notches are sharp or uneven, make sure to go back and file them down with your metal file.


On a concluding note, sharpening a brush cutter blade is not necessarily difficult. However, it will take some time to achieve the sharpness that you are looking for.

Make sure that you practice first before tackling your first real blade. As with all tools, always maintain, clean, and store it properly after using it.

If you have made this far in this article, I am sure you have found my user-friendly step-by-step guide on properly sharpening brush cutter blades helpful. I’m confident that you’ve learned everything there is to know about sharpening brushes.