With a lawn mower blade, like with any blade, a sharp one is a safe one. If you want to give your grass a clean and healthy cut, a dull blade covered in chips and dings just wont do.
A less-than-sharp blade will rip grass blades and put extra strain on the motor, while a sharp one will neatly slice through grass like it’s not there. This is the case for all lawn mowers, not just the ones in our guide to the best lawn mowers.
The good thing about sharpening your mower blade is that you don’t need any specialist tools. There are plenty of gadgets available, but a steady hand and a flat file will clean up a well-worn blade in no time at all.
Just remember that once a blade gets significantly damaged, replacing it with a new one is better. An unbalanced and heavily chipped blade can hurt your mower or even become a danger to the operator. Follow these simple steps to return a keen edge to most mower blades. To free the blade, see our guide on how to remove a lawn mower blade.
What you’ll need
- Gloves
- Eye protection
- Wire brush
- Cloth
- Lubricating oil
- Workbench or table
- Clamp or vica
- Flat file or rotary tool with sharpening bit
The short version
- Inspect the blade
- Make sure you have all of the tools you need
- Clean the blade
- Work out which tool to use
- Sharpen the blade
- Examine the blade
With the blade removed, you can inspect it for damage. Look for chips, cracks, and any bends in the blade that might make it lose its balance.
Wear sturdy gloves and eye protection when working on any blade, and particularly with sharp or rusty blades. You’ll need a wire brush, a cloth, some lubricating oil, a workbench or table, a clamp or vice, and a flat file or rotary tool like a Dremel with a sharpening bit.
Give the blade a thorough clean with a wire brush and an old cloth to remove any dirt or dried grass and rust spots. Lubricating oil will help get off stubborn debris.
To safely sharpen a lawnmower blade, you should clamp it into a vice or onto a stable workbench or table. Using a clamp will keep your hands free and away from the edge.
You don’t need special tools to put an edge back on a mower blade. A simple flat file will do a good job, but if you have a Dremel with a sharpening bit, it’ll take less time and effort.
With the blade clamped firmly, pass the flat file across the whole cutting edge as smoothly and evenly as you can. If using a rotary tool, run it across the blade. Try to maintain the factory grind angle, which is usually 30° from flat.
Look for shiny new metal after you’ve passed the file across the edge. This shows where you’ve filed off the old metal. Try to keep the new edge as even as you can across the length of the blade. A few nicks on the blade are OK to leave, but if it’s really bad, you should replace the blade with a fresh one. If necessary, repeat the filing to get a smooth edge.
