How do you sharpen mower blades with angle grinders? - Angle grinder 101 (2023)

If you have a lawn mower, you should expect your blade to dull sooner or later. When your machine reaches its inevitable faith,an angle grinderit can be your savior. If you are curious aboutHow to sharpen mower blades with angle grinders, keep reading our article.


  • Signs that mower blades need sharpening
  • How to sharpen cutting blades with angle grinders?
    • Step 1: Check the blades
    • Step 2: Set the grinding angle correctly
    • Step 3 - Plug in the grinder
    • Step 4 - Adjust Motor Forward/Reverse Switch
    • Step 6 – Remove Material With Each Pass
    • Step 8 - Check for Accurate Blade Balance
    • Step 9 - Cleaning the grinder
    • Step 10: Finish your work
  • Sharpens mower blades without removing them
    • hold the blade
    • wash the blade
    • sharpen the blade
    • Only sharpen when the gas tank is empty
    • The blades must be balanced correctly.
  • frequent questions
    • 1. At what angle do you sharpen lawn mower blades?
    • 2. How often should you sharpen your slicer blades?
    • 3. Should mower blades be sharp?
    • 4. Why is it important to keep the blade balanced?
  • Last words

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Signs that mower blades need sharpening

Normally, you need to sharpen the cutter blades once.after 25 hours of useto prevent damage to the turf. However, if you don't want to keep track of how long you've mowed, there are several signs of dullness to check for:

  • After being mowed, the grass is still uneven.
  • Your grass clippings have brown tips or frayed edges.
  • Your cutter blades appear to be dull.
How do you sharpen mower blades with angle grinders? - Angle grinder 101 (1)

How to sharpen cutting blades with angle grinders?

Below is the step by step guide to help you sharpen lawn mower blades with angle grinders.

Step 1: Check the blades

Check if the cutting blade is left or right handed. Place the blade on a level surface with the bottom side down against the surface.

Each end of the sheet should be positioned at the "12" and the "6" on a clock. Make sure it extends away from you. The mower blade is right-handed if the end of the cutting edge is to your right. On the other hand, the cutter blade is left-handed if it is on your left.

How do you sharpen mower blades with angle grinders? - Angle grinder 101 (2)

(Video) How to Sharpen Lawn Mower Blades With a Grinder

Step 2: Set the grinding angle correctly

The angle at which the grinder is placed is determined by the blade that needs to be sharpened.

Place the blade on a table and align its angle with the face of the stone. The grinding edge should appear to be directly touching the stone. If you are not touching edge to edge, you need to adjust the angle. To change the grinding angle, loosen the 2 turret bolts and turn the top nut to lower or raise the stone and motor.

For more information, consult your manual. After the correct angle is achieved, recheck the shroud and plate settings and retighten the turret bolts.

Step 3 - Plug in the grinder

Plug the power cord into an approved outlet. Insert the safety lock pin into the ignition switch.

If there is a light on your grinder, make sure it is in the right place.

Step 4 - Adjust Motor Forward/Reverse Switch

Move the engine switch forward if your mower's cutting blade is to the right. With this selection, the blade is pulled toward the stone while the stone rotates counterclockwise, causing sparks to fly to the other side of the cutter blade.


Always stand in front of your angle grinder, not to the side. The front of the abrasive wheel should face you. This position helps to avoid any material being thrown by the abrasive wheel.

Step 5 – Turn it on and start cutting

Turn the grinder on and let the stone and motor come up to full speed. Hold the blade with your hands positioned at each end of the sharp area.

Place the blade level on the table at 90 degrees to the 1-inch stone face with the motor running at full speed.

(Video) Grinding Disc VS Flap Disc For Lawn Mower Blade Sharpening

How do you sharpen mower blades with angle grinders? - Angle grinder 101 (3)

Step 6 – Remove Material With Each Pass

With each pass, remove material by moving the edge of the blade back and forth toward the grinding wheel. Hold the blade so the surface of the grinding wheel is parallel to the cutting edge.

As a result, sparks will fly to the right of the worktable if you have selected the 'forward' option for the motor switch.

If you have a sand trap, you can attach it to the side of the grinder. This will make it much easier to make your desktop more organized.

Step 7 – Slide Back and Forth for Both Blades

Continue sliding the blade back and forth across the stone until all nicks and dull areas of the edge have been removed. However, the cutter blade should not be sharp. Instead, you should aim for a 0.030 to 0.045-inch edge.

Rotate the mower blade and do the same at the other end. Pass the second end the same number of times as the first.

How do you sharpen mower blades with angle grinders? - Angle grinder 101 (4)

Step 8 - Check for Accurate Blade Balance

Remember to turn off the angle grinder before checking the mower blade for accurate balance.

Use a blade balancer. The blade should be centered in the cone after the magnetic unit is pushed back. The magnetic retention component should snap into place.

Then hold the blade horizontally and release it. If either end of the blade falls off, the extra material must be removed from that end. Remove the balancer blade, noting the heavier end.

(Video) Lawn Mower Blades 101: Understanding Proper Blade Maintenance

Step 9 - Cleaning the grinder

Return to the grinder and remove excess material from the heavier end slowly. You should grind excess material only on the sharp edge of the blade and never on the tips or back. Also, you should frequently check the balance of your blade to hit the sweet spot.

Step 10: Finish your work

When finished sharpening, remove the safety pin from the angle grinder. This removal helps prevent the grinder from being turned on accidentally or used without authorization.

Then turn off the light and sweep the sand and dust from your work area.

How do you sharpen mower blades with angle grinders? - Angle grinder 101 (5)

Sharpens mower blades without removing them

You can also sharpen the cutter blades without removing them. However, this method is not as effective as the method that requires blade removal.

In general, both sharpening methods share the steps, but there are some points that you need to pay attention to.

hold the blade

You need to make sure it is secured which will prevent any movement when trying to sharpen the blades. So you can wedge a 2x4 under the blade and over the mower deck to make sure the blade doesn't move while you're mulching.

wash the blade

How do you sharpen mower blades with angle grinders? - Angle grinder 101 (6)

The blade must be properly cleaned to remove rust, hardened grass, and other debris. After that, you will have full access to the cutting edges of your blade.

sharpen the blade

In order to shape mower blades without removing them, you must carefully implement the following steps:

(Video) How to sharpen lawn mower blades with a grinder + Basic Grinding tips

  • Keep a proper angle;
  • As you move away from the center, use consistent movements;
  • Never back down;
  • Switch to another edge after finishing one and start sharpening it.

Only sharpen when the gas tank is empty

This helps avoid wasting fuel.

The blades must be balanced correctly.

If this is not accomplished, strange noises will emanate from under the mower deck.

frequent questions

1. At what angle do you sharpen lawn mower blades?

A proper angle during the grinding process plays an important role in ensuring the longevity and performance of cutting blades.

The angled edge of lawn mower blades is manufactured at a certain 30 to 35 degree angle, the most common angle for lawn mower blades. You need to maintain this angle as you sharpen the mower blades over time.

2. How often should you sharpen your slicer blades?

The frequency depends on how often you use your mower. If you just use it at home, you can only sharpen your blades once a year. On the other hand, you need to sharpen more often if you are a professional.

It's usually time to sharpen your clipper blades if you notice a drop in cutting performance. This usually happens after 25 hours of use. Also, you should replace damaged blades immediately.

3. Should mower blades be sharp?

The blades on your lawn mower need to be very sharp, but very sharp. It must be possible to touch their blades without cutting yourself. Contrary to many people's perception, a sharp edge does not make your mower any better. In fact, it tends to roll, causing the blades to cut and chip.

In addition, cutting blades that are too sharp dull and wear down faster, requiring more frequent sharpening and resulting in shorter blade life.

4. Why is it important to keep the blade balanced?

Maintaining the balance of your mower blades is critical as it prevents damaging vibrations and wear that damages the mower.

Last words

We believe that our article should help you to have a better understanding of theprocesses for sharpening mower blades with an angle grinderwith or without removing these blades. However, our recommendation is to remove them, as you will have better inspection of blade damage and better access to the cutting edges.

(Video) How To Use An Angle Grinder - Ace Hardware

If you carefully follow our step-by-step instructions, your task of sharpening the blade will be successful.

Related Posts:

  1. How to sharpen drill bits with angle grinders?
  2. Can the angle grinder cut metal? How does it work?
  3. 11 Safety Tips for Angle Grinders to Avoid Accidents
  4. Angle Grinder Vs Reciprocating Saw: In-Depth Comparison


Can I sharpen my lawn mower blade with an angle grinder? ›

There are several good ways to sharpen lawn mower blades, but one of the quickest and easiest methods is with an angle grinder, an inexpensive, versatile hand-held power tool.

What grinder disc to sharpen mower blades? ›

What kind of grinder wheel should I use? We recommend a 36 or 40 grit flap disc OR a hard disc. Either straight or beveled wheels work equally well. Type 29 or 27 flap discs will work equally.

What angle do you grind mower blades? ›

Lawn mower blades come from the factory with a specific angle on the angled edge. This angle should be kept as you grind your blades over time. The most common lawn mower blade angle is 30-35 degrees. When sharpening your mower blades it is important to keep this 30-35 degree angle over time.

What is the best method for sharpening lawn mower blades? ›

The fastest way to sharpen a lawnmower blade is with a bench grinder. Wearing protective eyewear, earplugs, and work gloves, grind the edge of the blade against the spinning wheel. It'll be loud and you'll see sparks, but you'll be able to sharpen the blade in a matter of a few minutes.

Do you only sharpen one side of a lawn mower blade? ›

Lawn mower blades are only sharp on one side (unlike, say, a knife). So be sure to only sharpen the chiseled side.

Can you sharpen mower blades wrong? ›

You'll need to tip your mower on its side to get to the blade. Always tip it away from the air filter and carburetor. If you tip it the wrong way, fuel and oil can leak into your filter and carburetor and can damage them.

Can you sharpen a mower blade too much? ›

Don't Sharpen Your Mower Blades Too Often

It can make them dull faster which makes for poor-quality cuts that could damage your lawn. Sharpening blades too often can also cause excess wear on the engine since mower engines need to work harder to pull duller blades through the grass.

Should you sharpen the bottom of mower blades? ›

At the very least your mower blade needs to be sharpened at the start of every new season, and more often if your yard is stony or large. Setting your mower cutting deck to the lowest level will cause the blade to impact objects more often and will obviously need more regular sharpening. What is this?

What angle should you use an angle grinder at? ›

For surface grinding, use the flat part of the wheel, maintaining a 20°-30° angle between the tool and the work surface. Position the blade guard at the back toward your body. Use a smooth back-and-forth motion to guide the flap disc over the material.

How thin should I grind before sharpening? ›

Rule of thumb for general purpose chef's knives once finished: Thickness immediately behind the bevel 0.2mm; at 5mm from there 0.5mm; at 1cm 1mm.

Should lawn mower blades be sharp like a knife? ›

Mower blades should be aggressively sharp, but not as sharp as a razor's edge. You should be able to touch the blade with your hand without getting cut. Contrary to popular belief, a lawn mower blade with a razor sharp edge will not cut grass better.

Which sharpening method is better and why? ›

However, we prefer an edge sharpening technique for most output. Edge sharpening avoids emphasizing noise or other artifacts. In addition, edge sharpening holds up better if an image is resized slightly — which is often an unavoidable occurrence when image files are put into page layouts.

Is it better to sharpen a lawn mower blade or buy a new one? ›

Sharpen your regular blades on schedule to help them last as long as possible, but have a replacement set on hand in case of sudden damage. If you happen to hit a rock, you won't have to wait to sharpen your blades before you can continue mowing.

Does Backlapping sharpen the Bedknife? ›

Backlapping hones the reel and bedknife to the same cutting plane. Also, when a reel is ground, it's common for a burr to exist on the backside of the reel blade.

Can you sharpen tools with an angle grinder? ›

Angle grinders are versatile tools that can grind metal and cut tile, stucco and pavers, rout out mortar, plus they can sand, polish and sharpen. Learn to use an angle grinder to cut tile, mortar and pavers; make quick work of rust and loose paint removal; sharpen blades and cut or grind steel.

Can you use a flap disc to sharpen lawn mower blades? ›

I use this flap disc to sharpen mower blades. It is more user friendly than a grinding disc and removes less material so you can sharpen blades easily and frequently.

Do mower blades need to be balanced? ›

Balancing your lawn mower's blades will avoid wear and tear damage to its other components. An unbalanced lawn mower blade can lead to a significant amount of vibration while the mower is operating, which can slowly damage the entire structure and all other parts over time.

How many times can you sharpen mower blades before replacing? ›

Most landscapers report sharpening their blades 10 times or more. The amount of cuts you can get out of a blade can be determined by a variety of factors including terrain. For example, in sandy areas, like those in Florida. A set of blades may not last long enough to sharpen more than a handful of times.

Are dull or sharp lawn mower blades better? ›

Dull mower blades shred grass leaves that appear uglier, harder to mow and susceptible to disease. Sharp blades cut evenly, giving your lawn a smooth appearance.

Does Ace Hardware sharpen lawn mower blades? ›

We sharpen a wide range of edges, from lawn mower blades to paper scissors, we're here to make your cutting experience safe and easy.

How often do landscapers sharpen lawn mower blades? ›

Lawn care professionals sharpen their blades once a week or about every 25 hours of yard mowing. This means that you can follow the same advice and sharpen your blades every 25 hours of cutting your yard.

What happens if mower blades are dull? ›

A dull blade can make your lawn appear yellow, brown and raggedy. A dull lawnmower blade may even pull up portions of the grass because it actually pulls on the entire plant instead of slicing through the blades of grass cleanly.

What happens if you sharpen a blade too much? ›

The edge gets thicker.

Eventually, the edge will become thick and wedge-like behind the main bevel. The blade itself may be very sharp, but it won't seem sharp because a wedge shape doesn't cut well. To prevent this, you'll need to thin the blade a little bit each time you sharpen it.

Do you sharpen both sides of a mower blade? ›

Always sharpen from the top side of the cutting edge; this will give you the longest-lasting edge on the blade. Note: The file cuts in one direction only, on the push stroke; you'll feel it bite into the steel on the blade.

What should you not use an angle grinder for? ›

For example, if you use an angle grinder near a refuelling station or close to the storage or use of flammable or explosive substances, you are creating a risk of fire and explosion. If there are flammable materials in the work area, they may catch fire from the flying sparks.

Do you push or pull an angle grinder? ›

Allow the wheel to pull itself through the workpiece rather than trying to force it through. This minimizes friction and force, and helps extend the life of the cutting grains. Don't push too hard.

How much does it cost to have lawn mower blades sharpened? ›

Depending on the type of your mower, you can expect to pay anywhere between 20 dollars to 60 dollars. If it's a reel lawn mower you might not even need to take the blades off the mower and sharpen them while they're attached.

How do I know if my blade is sharp? ›

The technique is simple… gently tap the edge of the blade against your fingernail. Your knife is sharp if the blade bites in, and dull if it deflects or slides. Start from the heel (closest to the handle) and tap to the tip, looking for any areas that are not sharp.

How many foot pounds does it take to tighten a lawn mower blade? ›

To tighten the bolt or nut use a torque wrench and tighten it to proper torque specification. Walk behind mower blades should be installed between 38 and 50 foot pounds of torque. Riding mower blades should be installed between 70 and 90 foot pounds of torque.

Is it worth sharpening lawn mower blades? ›

If you want an attractive, well-kept lawn then sharpening the mower blades is worth it. Dull blades will leave the tips of grass burnt and leave your lawn susceptible to disease and lawn pests. Dull mower blades may leave your lawn unevenly cut.

Can you use a grinder to sharpen? ›

Bench grinders provide another way to sharpen a knife. These tools feature a high-speed spinning wheel that can be used to trim wood, plastic, metal, and other materials. You may already have one in your workshop or garage, in which case you can get right to work maintaining the edge of your knife blade.

Can you sharpen a lawn mower blade without removing it? ›

It is thus clear that your lawn mower needs to have well-sharpened blades. However, is it possible to sharpen the lawn mower blades without removing them? Yes, it is, and whereas this method is not as popular taking out the blades for sharpening, it is still useful.

Should you push or pull angle grinder? ›

Allow the wheel to pull itself through the workpiece rather than trying to force it through. This minimizes friction and force, and helps extend the life of the cutting grains. Don't push too hard.

What is the hardest material to cut with a grinder? ›

Best Materials for Drilling, Cutting and Grinding. A natural diamond is the hardest material on the Knoop Hardness Scale, as is well known. It is considered a superabrasive, and has a long list of things it is regularly used to drill or otherwise shape.

What is the hardest metal to cut with grinder? ›

INOX means nothing more than stainless steel. Stainless steel is the hardest metal to cut due to the addition of nickel to the metal construction process. Anything made of stainless steel is harder to cut.


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