How to sharpen lawn mower blades?

After one year of use of your mower, you may notice that it no longer cuts like the first day and that it has lost efficiency and performance. Do not worry. This is something normal. The most likely thing is that the edge of your mower is a little worn and shows notches or notes it is blunt. Let’s know how to sharpen lawn mower blades.

It’s time to sharpen the blades of your lawnmower! In the past article, we talked about the turn off the lawn mower. For this, we will give you all the tips so you get a perfect result.

How to sharpen lawn mower blades?

How to sharpen lawn mower blades

Before carrying out any work in which you have to use tools and may pose a danger, we recommend that you use all necessary means of protection, such as gloves, goggles.

First, you must take into account if your lawn mower is gasoline or electric, because if it is gasoline the first thing you should do is empty the tank, since to disassemble the blades you must knock the mower to one side, and if you forget this simple step, you can spill gasoline on the ground.

Now that you have emptied the deposit of your lawnmower, we are going to disassemble the blades step by step:

To avoid accidents and to start the machine, we will disconnect the power if the cutter is electric or disconnect the spark plug in case you have a gas lawnmower.

Now tilt the mower to one side and place a block of wood blocking the blades so they can not turn freely.

Then loosen the blade bolt by turning it counterclockwise and do not forget to put a piece of tape or some spray to mark the bottom part of the blades (it is a very typical mistake to place them inside out mounting them again).

Finally, clean the blades to remove the remains of grass or mud that may remain using a rag and a little water and soap if necessary. Dry them well if you use water to clean them.

Sharpening the blades

We already have the blades off the machine! Now the most important thing is sharpening. For this task, we recommend that if you are not very handy, take them to a professional who sharpens them, but for the most launched we will give you all the advice to make them perfect.

Sharpen blades by hand

Sharpen blades by hand

First, you must fix the blades well to a vice or sergeants or something similar. The objective is to keep them fixed and not move while we work.

Then use a metal file to sharpen the blades. Move the file at an angle of 40-45º until the bright edge remains and the notches that had been produced disappear.

It is very important that you do not sharpen the blades too much (it is not a question of leaving it like a ham knife), with which you notice the sharp edge is enough, as the blades when turning quickly, will cut the lawn without any problem.

Sharpening knives by machine

Sharpening the blades to machines is a process similar to sharpening by hand, but obviously with some type of electric tool. We are going to give you 3 options so that you can choose the one you like the most.

First of all wear glasses and gloves to avoid any accidents, since the filings of the blades can jump and enter the eyes or cause a wound.

Fix the blades well to your work table using a is well secured.

Now we can use these 3 machines: a grinder with the metal disc, a belt sander or a Dremel with a special tool for sharpening mower blades (675), which gives the perfect sharpening angle.

If you use the grinder or belt sander, you should sharpen at an angle of 40-45º until the edge is bright and without notches (remember not to sharpen too much).

If you prefer to use a Dremel, it is not necessary to look at the cutting angle, since there is a special tool for sharpening gardening tools (675) (available on Amazon) that gives the optimum angle of sharpening so you do not have to worry if you are doing it or not correct.

Final assembly

Final assembly

Once sharpening the blades of our mower, it is time to assemble them again. First place the blades in their correct position. You will not have problems if you marked them with tape or spray as we indicated in the disassembly step.

Lubricate the area of the main bolt with a little lubricant type WD 40 or 3 in 1 to avoid that it can oxidize in the future and to be able to loosen the bolt without problems the next time.

Finally, tighten the bolt clockwise with the tightening torque indicated by the manufacturer. It is usually 70 Nm. Use a torque wrench for this. If you do not have this type of key, make a firm tightening and make sure that the blades can turn freely.

Tricks and tips

You already have the blades of your lawn mower sharp! You only have to know a couple of things.

The blades should be sharpened once a year and a maximum of 3 or 4 times throughout its useful life, after this it is better to change them and put new ones, since their effectiveness may be affected.

When using electric tools for sharpening, the blades can become very hot and can become weak, be careful, and cool the area with a little water if necessary.

Now you just have to enjoy your lawn mower and maintain a garden in perfect condition with much less work than with a badly sharpened blades.

News Reporter

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