Every household has a lawn mower. When you pick up the lawn mower, you will find two blades that are meant to cut the grass. One of these blades is the knapper blade. The other is the bag blade. But what if you want to do something else with these inconvenient blades?
Possibly make a knife out of them. They are sharp and big enough. Here we will explain the tools and techniques you need to make your own sharp and colourful knives with your lawn mower’s blades.
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Do Lawn Mower Blades Make Good Knives?
Lawn mower blades are sharpened on a grinding wheel, like most industrial cutting tools, so they are evenly sharpened on both sides.
This makes them easier to grind and sharpen than a knife made from bar stock. Lawn mower blades are made of hardened steel, so they should resist corrosion.
The problem with lawn mower blades as a knife material is that they are unlikely to be straight.
Knives need to be straight, and lawn mower blades are usually bent at 15 degrees from the horizontal.
How to Make Knives with Lawn Mower Blade?
Step 1: Find Your Blade
- Find a lawn mower blade.
- Find a lawn mower blade that is not too rusty.
- Find a lawn mower blade that is not too thick.
- Find a lawn mower blade that is not too thin.
Step 2: Scrap off the Old Paint
Now it’s time to start scraping off the old paint. There are a few ways you can do this, but we’ll go over each in turn:
- Use a grinder or file:
If your blade is still sharp enough, you can use either of these tools to remove stubborn layers of paint from around the edge of your mower blade. Be careful not to damage any parts of the blade as well.
- Use sandpaper or wire brushes:
If neither option above works well enough for you, then try using some sandpaper on top of whatever else was used earlier. And scrubbing away at whatever’s left behind until nothing else will come off easily anymore. Without damaging anything else, which may take a while depending on how thickly coated everything was original. So don’t give up too soon if things aren’t going smoothly immediately.
Step 3: Cut Out Your Blade
Now that you have your blade, it’s time to cut it out. First, use a hacksaw or metal file to smooth out some of the rough edges around the circumference of your blade.
Then use a belt sander or drill press to finish off any remaining minor imperfections in your knife.
Step 4: Flatten the Metal
Now, it’s time to flatten and straighten out your metal. Use a hammer and anvil to do this, or if you have a grinder handy use that instead. Once you’ve flattened out each side of the blade with varying degrees of success, use files and sandpaper until everything is smooth.
Keep in mind that as soon as you file away material from your blade’s edge, there will be sharp edges left behind this could make cutting difficult at first, but they’ll eventually smooth out over time as well.
Step 5: Shape the Knife
Once the blade is shaped, it’s time to cut out the handle. To do this, use a hacksaw or file to remove any burrs from your blade and then drill holes at each end of your new handles so they can be bolted onto your knife.
Step 6: Design and cut out your handle
Now that you have your blade, it’s time to design a handle. Since this will be a one-of-a-kind project, it’s best to use wood as your material of choice. You can use whatever type of wood you like from cedar to oak and everything in between.
But for this process, we’ll be using an old lawn mower blade.
Once your chosen piece of wood is cut out and sanded down, apply a finish on both sides before attaching the handle onto the blade via screws or nails, depending on how much pressure you want from them during usage!
Step 7: Clean and polish your blade
Cleaning and polishing the blade is a must. You can use a grinder, wire brush, or wire wheel to clean it up, but make sure that you don’t damage your blade by using too much pressure.
When polishing the blade after cleaning it up, there are two ways, grind down its edges so that they become smooth again or buff them with an abrasive compound like diamond stones or even sandpaper.
If you want to do both at once, then I recommend using a buffer tool with an adjustable speed knob. This will enable you to control how fast your machine spins while grinding away at the blade edge until it is smooth enough for use in cutting tasks like chopping vegetables into pieces or slicing fruits into slices.
Related Read: How Can I Fix Plastic Gas Tank on Lawn Mower?
Are Lawnmower Blades Hardened Steel?
Yes, lawn mower blades are hardened steel. Cutting blades are hardened steel to make them harder and more durable. The difference between lawn mower blades and knives is that lawn mower blades are hardened to a much higher level.
Knives are hardened to around HRC 58-62, while lawn mower blades are around HRC 65-68.
This extremely high hardness level, combined with the toughness of the steel, means that lawn mower blades should be suitable for cutting but not be brittle.
What Grade of Steel are Lawn Mower Blades?
Lawnmower blades are high carbon steel. They are hardened and tempered to a high standard, making them suitable for cutting various materials. The high carbon content makes them harder and more resistant to wear and tear.
The carbon content also makes the blades easier to sharpen. Lawnmower blades are made from steel with a carbon content of 0.4% – 0.6%. This makes it low-carbon steel, which is why it is so cheap.
It is also much softer than high-carbon steel, which is why it becomes blunt quickly. This low-carbon steel is also more prone to corrosion.
Can You Heat treat Lawn Mower Blades?
Yes, you can heat treat lawn mower blades. They are high carbon steel and thus can be hardened by heating them to around 1600℉ and then cooling them slowly in an oil bath or an air or water quenching bath.
You can then temper the blades by heating them to around 900℉ in an oil bath and then quenching them in a water bath or air. The hardening and tempering will make the blades tougher, harder, and more resistant to damage. The blades will also resist corrosion better as they will have a harder and more even surface.
Final Takeaways:
Lawn mower blades are made of high-carbon steel and are hardened to a very high standard. This makes them suitable for cutting a wide variety of materials. The only problem is that they are not straight. You can heat treat them to make them tougher, harder, and more resistant to damage.
Lawn mower blades are not suitable for making bushcraft or survival knives, but they could be used to make kitchen knives. Knives are generally made from bar stock, but it would be interesting to see what happens if you try to make a knife out of lawn mower blades.
