How A Hedge Trimmer Works And How It Is Cleaned

Not only must this tool be used in the correct way but you must also know all the steps necessary for proper maintenance.


After planting the hedges, the time has come to cut them, perhaps giving them a particular shape, personalize and beautify your garden. To do this you need a suitable tool; choose from the best selling hedge trimmers.

 First we need to understand what a hedge trimmer is, then we will analyze its operation and finally explain how to do maintenance. 

By reading our article carefully you will avoid incurring very common mistakes among those with little experience in this regard and will guarantee your tool a long life as well as perfect functioning.

What it is

The hedge trimmer is used for maintenance cutting or pruning hedges. To avoid confusion, we explain the difference. The maintenance cut concerns new shoots and the hedge is shortened by 10 or 15 cm. 

This cut should be done when the shoots are ripe. Pruning is distinguished in light and strong. When light pruning is carried out, the shoots are shortened to about ⅔ of their length, while competing shoots are eliminated. For arboreal hedges, strong pruning is carried out once a year.

How does it work

The hedge trimmer can be electric (battery or cable) or with an internal combustion engine. Regardless of the type of maintenance, the operation, or if you prefer, the movement of the blade is always the same. 

Once the engine is started, the rotation of the double-toothed blade is activated. The blades go back and forth; in making this movement the branch which is in the middle of two teeth placed in sequence is cut off.

The hedge trimmer should be chosen based on the power, the length of the blade and the cutting thickness. Generally power and cutting thickness are directly proportional. 

In other words, the greater the cutting thickness and the greater the power precisely because it is assumed that large branches must be severed and therefore require more force. As for the length of the blade, it must be chosen taking into account not only the height of the hedge but also the user in order not to be forced to use a ladder.


The maintenance

The hedge trimmer ( the best models ) requires correct and careful maintenance. Lymph, bark fragments, dust, earth etc. thicken on the blade. All these things are not good for the blade that needs cleaning. The attachment of the blade must be found. 

This information is available in the instruction booklet. Unscrew the screws and immerse the cover (only if made of metal) of the attachment in the white oil and clean. Remove the blade; this too must be cleaned with great care using white oil.

Once the blade has been cleaned, it is necessary to sharpen its teeth, let’s see how. You can use a flat grain file or a sharpening stone. In both cases the sharpening angle is 45 °. Grasp the file with two hands, one on each end.

 The file must perform one-way movement. Once this is done, you can reassemble the blade, taking care to grease it with molybdenum disulphide or lithium grease. 

Consider the following things: not all blades can be dismantled, tempered blades cannot be sharpened; the only solution is to replace them.




In the case of a hedge trimmer with internal combustion engine, maintenance requires more effort. In addition to what has been seen for the blade, other aspects must be taken care of.

 Check the spark plug at least once a year, in particular you need to check the distance between the electrodes which in general must be 0.5 mm, however always check the instruction booklet. 

To disassemble the spark plug it is necessary to remove the cap and cable, then using the special key, unscrew the spark plug. Measure the distance of the electrodes with a feeler gauge and possibly reduce it manually. The gear mechanism of the gearbox must be lubricated with grease every 20 working hours. Filters should also be cleaned every 20 hours.

The ventilation grille must be kept clean in order to ensure the necessary cooling of the engine. 

This is an operation to be done after every 10 hours of work; dirt must be removed with compressed air. After each use, give the hedge trimmer a good clean, starting from the motor body and with a cloth remove all the residues that obstruct the ventilation grille.

Always check the oil level but above all, do not start the hedge trimmer without being sure that there is oil. This is a mistake that many commit the first time they use the petrol engine hedge trimmer, perhaps taken by the heat of trying “the new toy”, they allow themselves a distraction that could be fatal.

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