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How to Sharpen Lawn Mower Blades (3 Popular Methods)

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If you own a lawn mower, at some point you're going to need to sharpen the blades. Your lawn mower takes a beating, and the blades are getting the worst of the assault.

This article will show you how to sharpen your lawn mower blades and provide you with three different methods. Sharpening lawn mower blades isn't a difficult task and you'll be pleasantly surprised at how much nicer your lawn looks. 

When to Sharpen Lawn Mower Blades

You should thoroughly inspect your mower blades for damage and dullness at least once a year, but checking them on a regular basis is always best.

If you notice damage, you should replace them before your next mowing. However, if they're dull, a good sharpening will significantly improve your mowers performance.

Mowing your lawn with dull blades can cause a ragged cut. In addition, your grass will turn brown and be susceptible to disease.

Your mower requires sharp blades in order to deliver a great looking and healthy lawn. 

Visual Signs of Dull Blades

Visually inspecting your blades regularly is always a good idea, but also pay attention to how your grass looks after mowing.

Here are a few signs that indicate it might be time for a sharpen:

  • After mowing the height of the grass is uneven
  • The grass blade tips look frayed, and a short time later, they turn brown
  • The grass blades look tattered and torn, instead of a clean and even cut
  • When inspecting the mower blades, you notice the blades have nicks, dents, or they've been damaged by a rock or concrete
Tools to sharpen blades

How to Remove your Lawn Mower Blades

Before sharpening your lawn mower blades, you'll first need to remove them from the mower. We highly recommend wearing gloves and protective eye gear.

Here's how to remove the blades from your mower:

  • Disconnect the power source. If your mower is gas, remove the spark plug wire; if its electric, disconnect the power cord or remove the battery.
  • For gas mowers, you'll need to drain the gas tank
  • Turn the mower on its side (the air filter and carburetor should face upwards for a gas mower)
  • Use a wrench to loosen and remove the nut that attaches the mower blade to the deck. Pay attention to how the blade is positioned to prevent putting it upside down when you're reattaching it later. Be careful not to let the blade fall to the ground
  • Clean the blades with a microfiber cloth or a dry rag. In some cases, it may necessary to use a brush or penetrating oil to clean the blade

Preparing the Blade for Sharpening

After you've removed and cleaned your lawn mower blades, it's time to get ready to sharpen them. On opposite sides of the blade is a 3 to 4-inch long cutting edge. 

Clamp the blade onto a worktable or into a vise so that one of the cutting edges (chiseled side) is facing up. Take a close look at the blade and check for cracks or dents. If you see any, you'll need to replace the mower blade with a new one.

Unfortunately, a damaged blade can not be sharpened.

Cutting Grass with a pair of scissors

3 Methods to Sharpen Lawn Mower Blades

Some people like to sharpen their lawn mower blades to a razor sharp edge, but we recommend only making them butter knife sharp.

When blades are sharpened to a razor edge, they tend to develop nicks when they come in contact with sticks, which will shortens the service life of the blade.

There are several methods to sharpen lawn mower blades. It can be done by hand, punches and chisels, or with a drill or a bench grinder. Here are three of our favorite methods

How to Sharpen Lawn Mower Blades by Hand

One popular method is to sharpen the lawn mower blade by hand. Hand sharpening gives you more control over the entire process.

Here's what to do:

  • Follow the contours of the blade with a flat file, in single downward strokes 
  • As you start to see the shiny new metal, try to balance the filing across the full cutting surface of the blade
  • Once the blade is sharpened, drag a sharpening stone over the edge to slightly dull it down. This will help protect your blade from nicking when it hits a stick
  • Turn the blade in your vice so you can sharpen the other side.
  • When sharpening the other side, you'll want to try to take the same amount of material off. This will keep your blades balanced.

A best practice is to "hang the blade" using the center hole from a nail or hook. This will allow you to check if the blade is properly balanced. If it leans to one side, you can take a little more metal from that side.

Watch the Video

How to Sharpen Lawn Mower Blades with a Drill Powered Sharpener

Another way to sharpen your lawn mower blades is to use a drill-powered sharpener. The one available from Arnold is specifically designed for sharpening mower blades and it'll give you the proper angle automatically. Plus it comes with a blade balancer!

Arnold BSK-1 Lawn Mower Blade Balancer & Lawn Mower Blade Sharpener Kit

Arnold BSK-1 Blade Sharpener

The Arnold BSK-1 Lawn Mower Blade Sharpener will help you properly sharpen and balance your blades.

When sharpening lawn mower blades, you should always wear gloves and protective eye gear. We highly recommend using a vice to secure your blades while sharpening.

Here's how to use the Arnold BSK-1 drill-powered sharpener:

  • Place the blade between the grinding stone and the plastic disk
  • Run your drill back and forth over the edge of the blade until sharp
  • Repeat with the other side
  • Check the blade balance with the enclosed kit

Watch the Video

How to Sharpen Lawn Mower Blades with an Angle Grinder

An angle grinder is another way to sharpen your lawn mower blades. When working with an angle grinder, you should always wear gloves and safety googles. We also highly recommend wearing long sleeves.

Here's what to do:

  • Secure your mower blades in a vice grip
  • With a 40-grit flap disk on your angle grinder, begin grinding by following the same angle as the blade 
  • Start at the center of the blade and move your grinder to the end
  • To keep the blade balanced, count the number of strokes, and then match it when you are working on the other blade
  • Hang the blade on a nail or hook to check for balance

Watch the Video

When to Purchase Replacement Lawn Mower Blades

It's a good practice to visually inspect your blades on a regular basis.

If you notice the blades have any nicks or dents, they should be replaced and not sharpened.

Also replace, if the blades are heavily damaged from an impact with a rock or concrete. In addition, check the thickness of the mower blade and look for blade erosion as this can happen with use over a period of time.

Regular sharpening of your blades will extend their service life, but if you're not interested in breaking out the file, then it's a good idea to replace the blades every year. As always, check your mower's owners manual for the manufacturers recommendation.

Buying New Blades

Lawn mower blades are relatively inexpensive.

Oregon lawn mower blades are among the most popular because they are high quality and are used by some of the top manufacturers. 

Oregon's Gator Blades are made for mulching with a riding mower, and create a high amount of air lift inside the cutting deck.

If you're looking for quality mulching blades, then you should take a look at Oregon's G5 Gator Blades, or their Oregon G3 Gator Blades.

If you need Husqvarna lawn mower blades, or blades for any other walk-behind mower, then you'll find no shortage of options on the market. This Husqvarna Premium Blade Replacement is suitable for 22" mowers. It's a standard straight edge blade for basic cuts.

If you need a mulching blade for a 22" lawn mower, then you might want to check out the Maxpower Universal Gold Metal Mulching Lawn Mower Blade. MaxPower is a trusted OEM manufacturer, and their blade quality easily meets, and frequently exceeds, factory installed mower blades on Craftsman, John Deere, and other top name mowers.

Last update on 2024-06-12 / Affiliate links / Images from Amazon Product Advertising API

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