Learn how to remove and sharpen lawn mower blades to keep your lawn mower in tip top shape!
We are going to address a couple of basic questions concerning lawnmower blades within this post and they are:
- When should you sharpen you mower blades?
- How do you sharpen lawnmower blades?
When you think about a well-maintained lawn, rarely do you think about the mower blades and what they need to do their part. This might be due to all the advertisements draw our attention to killing weeds and insects along with feeding the lawn. These tasks are important pieces to a healthy and happy lawn, but if your blades aren’t up to snuff, you will fall short of creating that picturesque yard you have envisioned.
Sharp blades allow for a cleaner cut of each blade of grass. In addition, the clippings will be distributed more easily which leads to less grass buildup under the mower deck, so the deck chute will clog less often. At the end of the day, you will have healthier grass and that picturesque lawn you are working to achieve.
P.S. Is there an area of your lawn that’s difficult to mow? Consider if it would work to turn this area into a No Dig Garden Bed to avoid the trouble!
Tools needed to to complete this project:
- Course cut file OR Drill attached Blade sharpening kit OR Angle grinder OR Bench grinder
- Bench Vise
- Nail or Balancing Kit
- Gloves
- WD-40 or other type of penetrating solvent
- Safety glasses
- Scraper
- Wrench or socket set
- Wire brush or scrapper blade
How do I sharpen lawnmower blades?
Lawnmower blades are made of soft steel. This makes sharping blades much easier than you might expect. I use a file, but there is no reason that any of the five different tools listed in this post could be used for the task. Below is a step-by-step approach to getting your blades back in tip-top shape in a very small amount of time.
Removing the blade from the lawnmower
- Remove the spark plug wire from the spark plug. This will prevent accidental starting of the mower while removing the blade.
- Access the bottom of your mower by tipping the mower to its side, keeping the mower side with the fuel tank and air filter facing up. This will prevent a fuel spill and possible flooding of the carburetor.
- Secure the blade to prevent it from moving when you loosen the nut. I use a C clap and small block of wood attached to the inside of the mower deck to prevent the blade from moving past the block.
- Mark the side of the blade facing you to help identify which side of the blade should be facing you when you return the blade to the mower.
- Using your wrench or ratchet set, remove the nut that is holding the blade in place under the mower.
- Rethread the nut to the shaft; hand-tighten to prevent the nut from getting misplace while you a working on the blade.
- Now is also a good time to clean mower deck of any build up of grass clipping. A wire brush or scrapper will work well.
Sharpening the blades
- Secure the blade in the vice.
- Evaluate the cutting edge of the blade before you begin sharping to have a better understanding of what you need to do to each cutting edge, rough spots and nicks will develop differently on each end of the blade.
- Using a file will require you to work with long even strokes with the focus being on covering the entire cutting edge with each pass. Light pressure is the trick to being able to move the file just enough to accomplish a full pass. A full pass insures that the file is removing an even amount of steel across the entire cutting edge.
- Place the file on the blade at the original angle of the cutting edge and work across the cutting edge until you have developed a butter knife edge on the blade. Using any of the listed tools, work with the same goal in mind: maintain the original angle and work across the length of the cutting edge with each pass. Repeat until you have the butter knife edge on the bald
Balancing the mower blades.
- A balanced blade is a must to ensure an even cut of your lawn and no damage comes to the motor or shaft.
- A balancing kit can be used to check the blade is balance. Its a simple process. Place the center hole of the blade on the balancing kit. The blade should sit horizonal when the blade is balanced. If the blade is not horizonal, you will need to file or grind from the end of the blade that was lowest while on the balance kit. Remove matterial from the end of the blade not the cutting edge. Repeat until the blade is horizonal on the balancing kit.
- A stationary nail or rod can also be used to test the blades balance. Place the center hole on the nail or rod. If the blade is not horizonal across the nail or rod, grind or file on the heavy end of the blade and test for balance again.
Reinstalling the blade to the mower
- Access the bottom of your mower by tipping the mower to its side, keeping the mower side with the fuel tank and air filter facing up.
- If you haven’t already cleaned the mower deck now, this is a good time to remove any grass or other materials that have build up. A wire brush, wood chisel or paint scraper will work nicely. These wire brushes can be used with the drill to make fast work of this job.
- Locate the mark you made before removing the blade from the mower, with the marked side facing you remove the nut.
- Secure the blade to prevent it from moving when you tighten the nut. I use a C clamp and small block of wood attached to the inside of the mower deck to prevent the blade from moving past the block.
- Remove the C clamp and block of wood and return the mower to all four wheels.
- Secure the spark plug wire to the spark plug. Now you are ready to mow the lawn.