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Believe it or not, you can easily sharpen lawn mower blades in the comfort of your own home with some common tools found in most households!
After learning about how to do it at home, continue reading our full general article on how to sharpen lawn mower blades.
Image credit: My Ocean studio/Adobe Stock
Tools Needed
- Bench vise
- File
- Socket/ratchet set
- Wire brush
- Spark plug wrench
Materials Needed
- Gloves
- Marker
- Lubricant
- Safety goggles
Step-by-step Guide (9)
1. Safety
Firstly, always disconnect the spark plug, using a spark plug wrench, before you start working on your lawn mower. This simple step can prevent accidental startups, thereby keeping those fingers safe and intact.
Wear thick gloves while handling the blade. Even a dull blade has potential to cause harm when handled improperly, so imagine what a sharpened one can do!
Safety goggles is another non-negotiable during this kind of project. When sharpening lawn mower blades with an angle grinder or any tool for that matter, flying debris is almost inevitable.
A secured blade limits potential accidents caused by unexpected movement mid-sharpening. Remember: stability is key when dealing with sharp objects!
2. Tip the lawn mower and mark the blade
First and foremost, you have to tip your lawnmower into position. Your goal here is to make the blade accessible for maintenance.
Pro tip – always tilt your mower so that the carburetor and air filter face upwards; this prevents oil or gas from leaking out.
The next thing in your lawn care maintenance journey is marking the blade. Just grab a marker or paint pen and make a mark on the bottom end of it. This way, whether you’re working with a rotary mower or reel type, you’ll know which side should face out.
3. Remove the blade of the lawn mower
You’ll need a wrench or a socket that fits the nut on your particular mower model in order to remove the blade. Use this to loosen and then remove the bolt holding the blade in place. To make it come of a bit easier, try spraying some lubricant on the bolt.
With rotary mowers, you’ll find just one blade attached under the deck that requires removing, whereas reel mowers have multiple blades on a cylindrical reel which can be more complex to disassemble.
4. Inspect the blade for any damage
Look for obvious signs such as large chips or dents in the cutting edge. These are clear indicators that your blade might require more than just sharpening.
Now, how to tell if your lawn mower blade needs sharpening? Well, watch out for is whether the grass cut by your mower appears uneven or torn.
Take note if there are any hairline cracks forming near the center hole or along the length of the blade. Such minuscule fissures could eventually deepen over time and eventually cause a catastrophic failure during operation.
5. Sharpen the blade using a file
Fasten the blade with a bench vise and hold one end of the file against the cutting edge of the blade. Use moderate pressure and slide along with an even stroke at an angle towards yourself. This action is known as draw filing. You’ll want to continue this process until you notice a shiny fresh metal edge appearing along with the length of the sharp part.
And that’s how you can sharpen lawn mower blades at home!
6. Clean the blade
Use a wire brush, scrub off any lingering debris on the cutting edge of your blade. A bit of soap and warm water usually does the trick quite well for most rotary mowers or reel mowers alike.
7. Balance the blade
To balance the blade, you can use a nail lodged in a wall. Place the center hole of the blade onto the balancer or nail and see which way it tilts. If one side dips more than the other, that means there’s still more metal and therefore is heavier on that side.
If you notice an imbalance at this point, Don’t panic! Simply file off some more from heavier side until it hangs evenly. It might take several times of sharpening and balancing before achieving perfect balance, but when working on routine maintenance tasks like these for our reel mowers or rotary mowers, patience is key!
8. Reinstall the blade on the lawn mower
Remember the markings you made earlier? It’ll come in handy now.
- Begin by positioning yourself comfortably next to the mower where you can see the blade mount clearly.
- Hold up your newly honed blade and align it with the mount using the holes on either end of the blade. Make sure the marked side of the blade is facing out. Once aligned, carefully insert the bolts back into the holes.
- Tighten them slightly with your fingers before switching over to a wrench or ratchet for a more secure fit. While doing so, make sure not to overtighten these bolts as it could potentially lead to unnecessary wear and tear of both the bolt threads and mount holes.
- Don’t forget to replace the spark plug and spark plug wire.
9. Test the lawn mower
Press the start button or pull the cord gently until you feel a slight resistance. As soon as it’s running, watch out for unusual vibrations. If there are any, turn off your mower immediately. An unbalanced blade may be causing this issue and can damage your lawnmower’s engine over time. The blade should operate smoothly and effectively; if not, you may need to re-do balancing it correctly.
It’s also crucial to assess how well your newly sharpened lawn mower blades handle the grass cutting task. Try mowing a small patch of grass and inspect how evenly cut they are from their roots.
