Sharpening Bush Hog Blades – 3 Easy Methods

Sharpening Bush Hog Blades

Bush hogs are the perfect tools to whack through dense plant growth. They attach to the mower deck and clear bushes that may inhibit the lawn grass.

Unfortunately, there’s common confusion on whether you should sharpen bush hog blades. Additionally, many homeowners struggle to sharpen the blades properly.

This guide explains everything you need to know about sharpening bush hog blades.

What are Bush Hog Blades?

Brush hogs, also known as Bush Hogs (the biggest brush hog brand name), are multi-functional rotary mower blades attached to the back of a farm tractor.

You don’t attach them rigidly like a mower blade. Instead, smaller ones mount to the three-point hitch while larger ones attach to the drawbar, so the hydraulic system raises and lowers the head as necessary.

A small bush hog can pass 4-5 feet, while larger ones cover up to 15 feet. Extra-large brush hog blades are only found on large tractors.

How Do Bush Hog Blades Work?

Brush hog blades are purpose-built to knock down vegetation and weeds to create a more even lawn or garden.

It’s also ideal for trimming weeds around your property, mowing grazing paddocks, and clearing hayfields that have gotten too mature.

The “rough-cut” machines easily cut down mature weeds and grasses, and small bushes, a task you cannot accomplish with the traditional lawn mower blade.

Are you Supposed to Sharpen Bush Hog Blades?

Yes, you should sharpen bush hog blades. The blades handle many rough projects, from tree saplings to bushes and tall grass.

Thus they become blunt quickly. Moreover, rocky or rough terrain can nick, crack, or dislodge the blades. Therefore, routine sharpening is very important.

Sharp blades enable faster mowing, whereas dull blades tear the grass. Moreover, sharpening fixes misaligned cutting angles and cracks on the blade.

Fortunately, the blades are easy to remove and sharpen. More importantly, you don’t need special tools to sharpen brush hog blades.

How Often Should You Sharpen Brush Hog Blades?

Most brush hog users prefer to sharpen or whet their blades every five years. We recommend more frequent sharpening, ideally every spring, if you use the brush hog a lot.

Alternatively, you can sharpen your blades whenever you notice significant dulling or blade chipping. One of the signs of a dull blade is shredding. It rips plants rather than slicing them.

The blade is also extremely dull if you notice uncut bush patches on the lawn. Finally, the sharpening frequency depends on the type of blade.

Chisel blades with teeth on the edges are easy to judge – sharp teeth are triangular, while dull teeth are rounder.

Meanwhile, knife-edge and mulching blades are ripe for sharpening if the edges are irregular, crooked, or chipped.

What is the Best Way of Sharpening Bush Hog Blades?

The best way to sharpen a brush hog blade is using an angle grinder or bench grinder. Both are powerful tools that work exceptionally fast and guarantee great results if you follow the manufacturer’s guidelines.

Alternatively, consider a file sharpener. File sharpeners are manual tools. However, they give you greater control over the sharpening process. They’re also safer.

How to Sharpen Bush Hog Blades

The three main ways to sharpen a bush hog blade are by using an angle grinder, bench grinder, or a sharpener file. Begin by detaching the blade from the lawn mower.

Then clean it with a wire brush, pressure wash, and allow it to dry before sharpening. Most homeowners sharpen or whet their brush hogs every five years.

1. Using an Angle Grinder

The following is a step-by-step guide to sharpen your brush hog blade using an angle grinder and a grinding stone disk.

  1. Wear safety equipment, including a protective face mask and hand gloves.
  2. Clean the blade to remove soil and debris. We recommend scrubbing it with a wire brush.
  3. Secure the blade to a workbench or table with a vice or clamps.
  4. Select the right grinding stone disc. Alternatively, use a diamond grinding wheel.
  5. Attach the grinding disc to the angle grinder and secure it tightly to avoid slipping.
  6. Plug in the angle grinder and align it with the brush hog blade at the factory-recommended angle.
  7. Start the angle grinder and make several passes along the blade edge in smooth motions. Don’t round off the blade corners, as this is where most of the cutting happens.
  8. When done, remove the blade from the vice and flip it over to sharpen the reverse edge.

2. Using a Bench Grinder

Sharpening brush hog blades using a bench grinder is similar to the angle grinder process, except that a bench grinder is fixed to the workbench.

Here’s how to proceed;

  1. Wear protective gear, including eye goggles to protect your eyes from sparks and hand gloves to protect your hands from heat.
  2. Remove and clean the blade. Unfortunately, you cannot sharpen the blade with a bench grinder without removing it.
  3. Load the bench grinder with the appropriate grinding wheel, such as the Norton White Aluminum Oxide grinding wheel.
  4. Plug the bench grinder into the power outlet and push the start button.
  5. Hold the blade at 45 degrees (or the factory-recommended angle) and lightly pass the cutting edge against the rotating grinder wheel. Again, don’t round off the corners. Maintain even pressure for an evenly sharpened blade.
  6. When done, flip the blade to sharpen the opposite edge.

3. Using a sharpener file

If you cannot readily access an angle or bench grinder, a sharpening file will do. Here’s how to sharpen your brush hog blade using a sharpening file;

  1. Secure the blade on the workbench using a vice or clamps.
  2. Hold a 12-inch or 14-inch flat or bastard mill file against the blade.
  3. Adjust the file angle to match the original factory bevel setting. It’s typically 40-45 degrees.
  4. Begin sharpening by pushing the file against the blade away from your body. You should feel the file grinding away material from the blade.
  5. Make repeated passes as you work your way from one end of the blade to the other.
  6. Reposition the blade to sharpen the opposite edge.
  7. File away the burrs using gentle strokes.

Bush Hog Blade Sharpening Angle

Does the blade sharpening angle matter? Yes, it does.

You should sharpen bush hog blades at a 45-degree angle, though some blades are sharpened at 40 degrees. The idea is to match the original cutting edge.

Remember that sharper angles result in sharper blades, which cut more easily but dull faster. Meanwhile, wider angles produce less sharp blades, which dull less fast.

How to Remove Bush Hog Blades

Removing brush hog blades is easy. First, park the lawn mower in a flat place in the shade and switch off the engine.

Then tilt the cutting deck to access the underside. You’ll notice that a center bolt holds the blade to the deck.

Wearing proper safety equipment, including eye goggles and hand gloves, loosen the bolt using an impact wrench. Then remove the bolt and washer and gently remove the blade.

Can You Sharpen Bush Hog Blades Without Removing Them?

Yes, you can sharpen brush hog blades without removing them. Indeed, many owners are excited to skip the blade removal part.

However, Bush Hog recommends removing the blade before sharpening it. It allows you to sharpen the blade equally along the length.

In addition, It gives you a chance to balance the blade for even cuts.

When to Replace Brush Hog Blades

It’s time to replace your bush hog blade if the blade fractures plant stems and twists grass rather than slicing the stems.

This is one of the reasons some homeowners replace their bush hog blades every season. A new blade arrives factory-sharpened and easily lasts a season without resharpening.

To replace the bush hog blade, proceed as follows;

  1. Park the lawn mower in a flat area.
  2. Turn off the mower engine, set the parking brake, and remove the key.
  3. Remove the old blade from the cutting head.
  4. Install the new blade.


What’s the best STIHL brush cutter blade sharpening tool?

STIHL recommends various files and filing gauges to help you achieve optimum brush cutter blade sharpness. These include triangular sharpening files, flat files, and mill saw files. You can also purchase a sharpening template for greater accuracy. Consult the company before committing your money.

Can you sharpen the blades on a rotary cutter?

Yes, you can sharpen rotary cutter blades. Angle grinders and bench grinders are the best tools for the trade. However, you can also use a sharpening file to sharpen rotary cutter blades. Remember to follow the factory-recommended sharpening angle. Also, clean the blade before sharpening.

How sharp should bush hog blades be?

Ideally, your brush hog blades should be sharp enough to cut bush stems without shredding. However, you don’t want a razor-sharp edge. First, overly sharp blades dull fast. Additionally, a very sharp blade can create spikes that may go through a tire or someone’s foot.


Bush hog blades, formally known as brush hog blades, are easy to sharpen. Detach the blade from the mower deck, secure it to a workbench using a vice, and sharpen with an angle grinder or file sharpener.

Alternatively, sharpen it with a bench grinder. Consult your owner’s manual for the sharpening angle.

Interesting read: How Sharp Should Lawn Mower Blades Be?