How Do I Sharpen Lawn Mower Blades?

Updated/Fact-Chacked on August 14, 2021 by John

The general rule with lawn mower blade sharpening is that it should be done around twice a year, according to the weather, the grass type, and how often you mow it. 

In all cases, knowing how to sharpen lawn mower blades is bound to be helpful, and it’s one of our top tips for improving your lawn.

1. Preparation

• Remove your mower’s plug from its electricity source. If it’s battery-powered, take out the battery so that there’s no chance of the blade rotating while you’re working on it.
• Drain the gas tank to avoid having it dripping whenever you move the mower.
• Tip the mower onto its side so that the carburettor and the air filter are both facing up to give you the best access to the blade and its clamp.
• Mark the blade to lead you back to its original position.

2. Blade Removal

• Using a long-handled wrench, start loosening the bolt. Before you do that, force a piece of wood between the blade and the mower to prevent the blade from turning while you’re removing it.
• If there’s too much rust on the bolts and parts of the mower, apply some penetrating oil, leave it on for a few minutes, and return to your trials.
• After removing the blade, start cleaning it, and the mower’s inside with your safety gloves on to remove any accumulated mud or grass using a putty knife.

3. Blade Sharpening

According to the size of your blade and the mower type, choose the most efficient tool to use to sharpen your blade. 

• Hand File: The most basic tool. Clamp the blade using a tight vice and use the file on the blade perpendicularly down each of its two cutting edges. Try not to overdo it. 
• Bench Grinder: Requiring more safety procedures, such as goggles and overall protective gear. Take the blade and run it across the bench grinder’s spinning wheel again in the same direction as the cutting edges.
• Drill Fitted With a Sharpening Stone: Faster than hand filing and less messy than the bench grinder, and you won’t need more than 4-6 strokes with the drill running at full speed.

4. Blade Balance

The blade’s balance mirrors whether or not you’ve overdone filing one of the sides of the cutting edges.

• Hang the blade from its centre on a nail. Hold it, then leave it. If it stays straight, then it’s balanced. If it tilts to one side, that side needs to be filed to equal the other.
• Another method is to place it over a lawnmower blade balancer. Yet, this method isn’t as available for homeowners. 

5. Reinstall The Blade

Once you’re satisfied with the results, reinstall the blade in its previous position using your carefully placed markings. Then, tighten the bolt as much as possible.

Final Thoughts 

“How do I sharpen lawn mower blades” is a question that’s paramount to all homeowners who have gardens, and we hope we’ve helped. Using a blunt-edged blade in your lawnmower can seriously damage the prospect of your grass. So, follow these steps, and you’re all set!

Mary

Mary shares a passion for gardening with her husband John, though she is more focused on growing veg on their allotment at St. Margaret’s Allotments, Durham. Mary also works in the lawn care industry and manages the lawns for the Durham University campus.