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How to sharpen lawn mower blades by hand. Step by step.

When you notice that your lawnmower is giving a clean-cut, it can be time to clean and sharpen the blades. Even when you do not notice a problem, you should sharpen the blades from your machine at least once a year. Dull blades make the engine working harder and increasing the wear and tear. Dull blades can also tear the grass, giving you brown, damaged, and pale looking grass. This article will show a step-by-step method of sharpening your blades easily.

How to sharpen lawn mower blades by hand. Step by step:

  1. Gather the necessary tools.
  2. Remove the blades.
  3. Clean the blades initially using a file.
  4. Use a sharpening stone as an additional step.
  5. Use a sharpening rod to smoothen the cutting edge.
  6. Balance both sides of the blade and fix them back.
(CC BY 2.0) by Tony Webster

Sharpening your lawnmower’s blades once or twice a year if you use it more often will help work more efficiently and make your lawn look beautiful. Collect the needed tools, and remove the blades from the mower. You have different methods to sharpen the blade; you can bring it to a mechanic, use a sharpening machine, or just do it by hand. Doing it by hand is what we will explain in this blog, and it is not that difficult. After sharpening, you can put it back on the mower, but it is essential that you always have to check the blades’ balance. If the balance of the blades is not ok, it can be bad for your machine.

How to Sharpen the lawnmower blades by hand:

1. Gather the necessary tools:

All sorts of works need a lot less effort if you use the right tools for the job, and sharpening the blades of your lawnmower is no exception. Sharpening is a technical process, but with the right directions and guidance, you can get through it easily. It would be best if you have the following tools:

  • A pair of safety gloves.
  • A sharp file.
  • A deep burring rod.
  • A sharpening stone.
  • A sharp knife to remove any burs or dirt.
  • A bench vise to clamp the blades.

2. Remove the blades:

Before removing the lawnmower blades, it is essential to know the prerequisites. This includes ensuring that the spark plus is disengaged before starting. Empty the mower’s fuel tank so that it may prevent any spilling of fuel if you need to tip the mower. You should take the opportunity to clean the body, under the hood, and other visible parts before removing the blades. On the off chance that you put your machine absent for the season without cleaning it, your springtime cleanup is attending to be distant more difficult.

Next, remove the blades of the lawnmower as explained. Incline the lawnmower against its side to loosen the retaining nuts and bolts, which helps the lawnmower’s blade work and keep the blade from spinning. While removing the blades, keep in mind or note down the order, location, and orientation of blades so that each blade may be fixed back to its original location. It can be a good idea to take some pictures or a video with your phone, so reattach it later is easier.

3. Clean the blades using a file:

To sharpen the blades, clamp them on the bench vise. Remember that there is a flat and a chiseled side of each blade. Using the flat file, you have to sharpen only the chiseled side. Following the actual blade’s contours, sharpen the edges with the file (usually 10 inches), keeping the attack angle around 45°. Sharpen the blade’s top edge with regular forward strokes as a flat-file only cuts in the forward stroke. Give regular thrusts to the file and make sure that the original contour is made. When you see metal chipping off from the top surface and notice a silverfish shine at the edge of the blades, it means that the blade is getting sharper.

After starting from the initial medium angle of attack, lower the angle so that the file and blade almost parallel. This helps to ensure a sharp exposed edge of the blades. Also, take care of any curves that the blade might have by rotating the file and adjusting to them. In doing all this, ensure that you have your safety gloves on. This will help to secure your hands from any injury. Moreover, it is recommended to sharpen the lawnmower’s blades at the start of the mowing season. In case that the lawnmower is used very frequently, then sharpen the blades twice a season of mowing grass.


4. Use a sharpening stone:

The next step is very similar in function to the previous step. Take a sharpening stone. These are commonly available in the market and mostly used to sharpen knives. The only difference between a file’s and a sharpening stone’s operation is the stone’s direction. A sharpening stone can be used in both forward and reverse strokes. It does some sharpening but is more effective in smoothening and polishing the blade surface. It gives the chipped off metal and cuts a fine finish so that the cutting edge geometry remains significantly homogenous.

5. Use a sharpening rod.

The diamond-impregnated sharpening rod can be used as an additional sharpening step. Take the rod (most common and esteemed is the Smith’s sharpening rod) and give it regular thrusts on the top surface of the blade edge. It helps in 2 ways. It removes any irregularities or burs present on the sharp or flat side and makes the whole cutting edge regular. Second, if you have made the cutting edge razor sharp using the file and sharpening stone, the rod can help flatten the sharp, brittle edge a bit. This prevents the blade edge from breaking abruptly if it may come in contact with a twig or branch.

6. Balance both sides of the blades and fix them back:

The final step and the most important one is to check the balance of both blades. Check that both the long blade’s edges are equally chipped off, showing a similarly exposed polish surface. Sometimes, depending on the nature of grass, it may stick to the blade edge. After you have removed this debris and grass, note that the blade should be balanced weight wise and that both sides have been polished.

After this, the blade has to be fixed back in the original orientation and location to work smoothly as per the initial plan. Tighten all the nuts and join all the connections. Before cutting any grass, you turn on the mower, let it run freely to notice any noise or imbalance that previously didn’t exist. In case of any issues, tighten the screws.

Frequently Asked Questions:

1. Is it necessary to sharpen the blades of the lawnmower?

Sharpening the lawnmower blades will help it work more efficiently and effectively. Depending on the type of grass and environment, the lawnmower blades become damp and dull over time. Sharpening them will prevent damage to the engine and damage the grass because the dull blades destroy the grass more than they mow it.

2. Is it safe to sharpen the lawnmower’s blade by hand at home?

Yes, one can clean the lawnmower’s blade with hands at home. All you need is to wear gloves on your hands and then carefully take out the blade from the lawnmower. Clean them with a bristle brush, and before taking out the blades from the lawnmower, one should first dislodge it from the electricity (if it is an electrical mower). As compared to removing, more caution is to be taken when the blades are to be fixed back because then, they have been recently sharpened.

3. How many times should one sharpen the blades of a lawnmower?

It is not necessary to sharpen the blades of a lawnmower every time you use it but yes, sharpen the mower’s blades in the season of mowing. For places where the mowers have to be used in excess, sharpening should be done twice a season to ensure your mower’s better and longer life.

Final Remarks:

Lawnmowers, like all devices, have to be maintained and looked after. For a mower, its blades are the prime functionary units that get dull over repeated use. Also, grass and debris may get stuck to the blades that reduce the engine life, and disrupt the cutting process. However, this is nothing to panic about, as this issue is not difficult to do. Sharpening the lawnmower blades by hand is the most straightforward procedure, and anyone can do it.  The steps mentioned above can be done using basic tools like a file or a sharpening stone. Sharper blades last longer.