Sharpening Lawn Mower Blades


Last Updated August 2019

Lawn mowers are great devices to keep your lawns nice and trim. They can be used to cut the grass and even mulch the clippings to give back fertilizer to the lawn again.

However, the real success of the mower basically depends on the sharpness of the blade. A sharp mower blade can deliver a clear cut to the grass leaving your lawn looking nice and uniform – just like a carpet.

A blunt blade will shear the grass and leave an unevenly cut lawn which is not appealing to the eyes. Hence regular sharpening lawn mower blades is important task.

The lawn mower blade sharpening is something that any service center can do. They have the knowledge and the tools to carry out the task.

However, this would cost you quite a lot of money and also, if you do it during the growing season – which is when everyone with a problem would go to the service centre – you may have a longer waiting time too. In some cases this is inevitable, but not for sharpening your mower blades. This can be done at home with minimal fuss.

Step by Step Process on Sharpening Lawn Mower Blades

Here are the simple steps to sharpen your lawn mower blade to start getting that clean cuts in your lawn again.

You’ll be amazed how simple the process really is.

  • For safety reasons, before doing any maintenance, including sharpening lawn mower blades, you need to first disconnect the spark plug and keep it aside.
  • If your mower has a battery, disconnecting it is also a good idea.
  • Now tilt the mower to locate the central screw that holds the blades together.
  • Before removing the blade for sharpening, check if it is bent. Major damage can be seen with naked eye, else you need to hold one end of the blade and mark its level on the deck. Not turn it by 180 degrees and mark the level of the other blade, if they are close than 0.125 inch, they are good, if they are widely apart, then you need to replace the blade itself.
  • If you are certain that the blades are aligned, then using a wrench loosen the screw holding the blade to the axis. Remove the blades carefully.
  • Now you can either use grinding wheel to sharpen the blades or file to do so. Some mover kits come with the sharpening tools so you can use them too.
  • If you are not certain how to sharpen the blade or do not have the right tools, you can just carry the blade to the service center to have them sharpened. Since you are just sharpening the blade, you can get it done a lot faster than having them dismantle it.
  • Once sharpened, you need to balance the blades on a rod. For best cutting results the blades must be well balanced at the center.
  • If they are not balanced, you may have to file one side a bit more to distribute the weight evenly.
  • Once you have the sharpened and balanced blades, you need to fit them back in the mower and tighter the screw. Ensure that you place the blades properly and also tighten the screws well. If the replacement is not done properly the mower will vibrate when started.

There are some safety precautions that you must take while sharpening the lawn mower blades.

Always use good working gloves to protect your fingers.

Blades may be dull enough to cut the grass, but they are sharp enough to cause some serious injury to you.

Some times, the blades do not go dull completely; they just develop some aberrations along the rim due to the regular abuse they go through.

In such cases you can just file them without removing them from the mower assembly too. Just remember to file at the same spot on the other mower too, to retain the balance between the blades.

Thus you can see that sharpening lawn mower blades is not a tough job at all. So need not spend lot of money and time at the service center to get your mower back in shape, with a little self-drive and some hard work, you can sharpen your own lawn mower blades.