Over the mowing and encountering obstacles such as small stones or pieces of wood, the blade of the lawn mower wears and is damaged. Either the machine will no longer succeed in mowing the lawn correctly or it will, but the result will be doubtful. Indeed, the lawn will be shredded with the passage of the blade. That means it’s time to sharpen the mower blade and change it if necessary. How to sharpen a lawn mower blade? Follow the guide.
Types of cutting blades for lawn mowers
There are several types of blades that promise different renderings and that are suitable for specific jobs. Whether you have a manual, electric or ride-on lawn mower, what is certain is that it is imperative to maintain it regularly and to sharpen their blades so that they remain efficient.
Each type of lawn mower has specific blades:
The manual lawn mower is equipped with helical blades.
The thermal lawn mower is equipped with grinding devices.
The ride-on lawn mower is equipped with rotating blades.
The rotating blade
We often find the rotary blade on freestanding models. It is a horizontal blade fixed to a vertical axis and which, when it rotates, creates a movement of air in the housing. This has the effect of sucking in the air and straightening the grass, making it easier to mow. The blades of grass are then expelled to the grass catcher. If the lawnmower is equipped with the mulching option then the severed grass will again be chopped into fine particles. Thus transformed, the herbs can be used as fertilizer to nourish the lawn.
It is interesting to remember that the speed of rotation of the rotary blade is 3000 revolutions per minute. The blade does precise and fast work even when the grass is wet.
The helical blade
We generally find the helical blade on manual mowers. These are several units assembled to form a horizontal cylinder. More concretely, the system consists of a helical blade and a counter blade. By turning on itself, the cylinder cuts the grass and cuts it continuously as if it had been sheared.
The helical blade ensures precise mowing and provides a short cut. However, to achieve this result, it is imperative that the ground is flat and that the mowing is carried out at least twice a week.
The grinding devices are especially noticed on the thermal mowers. It is an assembly of articulated blades which, when they are activated, crush the grass. The movement is driven by centrifugal force and this type of blade can easily overcome large grasses and brush.
The result is not as aesthetic as with the rotary blade, but its main advantage is that where others lose performance, it ensures efficient work. Indeed, it can be used on bushy terrain and the blade does not break when meeting the first obstacle (stones, roots, etc.).
Maintaining the blades of lawn mowers
The maintenance of the different blades is not done in the same way. If for some it is necessary to sharpen, the blade of the lawn mower regularly, for others, once a month is more than enough. As a reminder, it is necessary to sharpen the blade of the lawn mower to ensure a good quality of lawn cut.
The rotary blade must in particular be sharpened regularly, as soon as it is noted that the cuts are no longer done correctly and that instead of being sheared, the blades of grass appear broken. The helical blade does not need to be sharpened because the friction movement on the counter blade is sufficient to sharpen it. For grinding devices, even if the blade is solid, it will still be necessary to count with a sharpening in good standing at least once a month.
A sharp blade ensures a well-kept garden lawn. If the blade is dull, it will break the grass instead of cutting it. Crushed grass cells will cause yellowing of the lawn and the blade may even die without specific maintenance.
Sharpening the blade of a lawn mower: the steps to follow
First of all, it’s good to take a few precautions, to avoid any risk of accident.
On a lawn mower and a ride-on mower, start by putting on gloves and goggles before stopping the engine. It is necessary on some models to disconnect the spark plug cable, in order to ensure that the engine does not start unexpectedly.
On an electric mower, simply unplug the mower before you begin sharpening the blades. In all cases and even if the model is equipped with the immobilizer option, it always make sure to remove the keys from the ignition.
Cleaning the casing of the lawn mower
Once the mower is placed on one of its sides, we will start by cleaning the casing with a brush to remove the dirt and plant waste that has accumulated there.
Disassembly of the lawn mower blade
To disassemble the blade, you will first block the blade with one hand before unscrewing the screws with the other using an Allen key or a wrench depending on the type of screw. The washers should then be removed before checking the general condition of the blade. Small chippings may be noticed on the cutting surface or the cutting angle is no longer straight. In either case, it means it’s time to sharpen the blade.
Sharpening the blade of the lawn mower
For quick and efficient sharpening, use of an angle grinder is preferred. Before attacking, do not forget to coat the protections since the tool rotates at high speed.
Before plugging in the device, we should also think about equipping the grinder with a thick disc, then just hold the blade of the lawn mower on a workbench in a vice or with a clamp.
To begin with, we will grind one side of the blade axis flat to remove the chips and then tilt the blade to restore the cutting angle. Then grind along the blade, taking care not to overheat it. We then repeat the operation with the other side. Note that the edges of the blade should never be ground or it will lose its effectiveness.
You can also invest in a sharpening and blade balancing kit.
Balancing the lawn mower blade
We put a screwdriver in the hole of the axis of the blade before keeping it balanced on a screwdriver. If it is horizontal, it means that the blade is well balanced. If this is not the case, you will have to think about grinding one side of the blade again.
The blade is again sharp, we end the operation by removing residues and other dirt that would have stuck on the blade with a wire brush. We take this opportunity to also brush with the blade and mower attachments before putting the screws and washers in their place and voila, the lawn mower is ready to use again!