How to choose a grass trimmer

Recommendation points

• Petrol VS electric
• Choosing a price range
• Features of the drive design
• Boom, transmission and rigging

In a country house, a trimmer is indispensable. This is especially true for technology that can solve many problems from mowing the grass to cutting bushes and pruning trees. You will learn how to find the most suitable and reliable device in the review, where we will look at the key differences between modern trimmers..

Petrol VS electric

We will not focus on the obvious nuances, such as mobility at work or the cost of a unit of power. Instead, we will consider more practical issues: maintainability, resource, ergonomics, behavior of the power unit under various operating modes, and most importantly, the purpose of trimmers with different types of drive.

For a person who does not know how or does not want to do the maintenance of equipment himself, there is no fundamental difference between a gasoline or electric engine. Both of them have approximately the same cost of maintenance and repair, and the high cost of components grows in proportion to the cost of the trimmer: original quality consumables are always more expensive. The category of exceptions includes small-run models that have been discontinued. Finding spare parts for such equipment is even more difficult, so the unification of functional units is also important..

The advantage of a gasoline engine is that it has a massive flywheel, thanks to which the engine copes well with a sharp increase in loads. The run-out of the electric machine is much less: if the trimmer encounters a serious obstacle, the motor will almost instantly reduce its rotation speed and begin to warm up. From this point of view, gasoline units have one more advantage: they are not so sensitive to heating, while at 80–100 ° C the insulation of the windings begins to deteriorate in the budget electric braid.

The choice between electric and petrol drive is a compromise between comfort and power. Electric braids are lighter in weight and in terms of handling, they are much less noisy and do not generate exhaust emissions. However, for cutting lush vegetation or processing an area over 3-5 acres, it is better to give preference to gasoline units. In addition, only gasoline trimmers can work with steel circular knives, and the vast majority of electric trimmers are designed only for quickly wearing plastic knives or a small cross-section fishing line..

Choosing a price range

Before considering the technical features, it is worth talking about the cost of the trimmer. Today it is rare to find a model, the price of which is unreasonably high. There are small fluctuations, but they are formed by changes in demand within a certain price range:

Up to 3,500 rubles – cheap Chinese products that cannot cope with a large volume of tasks. They have almost zero maintainability, however, can be used for irregular mowing of small lawns or edging after a lawn mower.

From 3,500 to 7,000 rubles – the most interesting cars for an ordinary buyer, made in China. Repairs are usually carried out by replacing individual units; components are inexpensive and available on the wide market. This trimmer will effortlessly cope with the removal of dense weeds and thick stems, but it is better to limit the time of continuous work to avoid accelerated wear..

From 7,000 to 15,000 rubles – this category includes braids from well-known European and East Asian brands. Although the products are manufactured in Chinese factories, they are subject to stricter technical supervision and quality control requirements, which is why the percentage of service calls is extremely low. These are reliable “workhorses” that, in domestic use, are unlikely to require serious maintenance during operation..

Over 15,000 rubles – professional braids for commercial use. Distinctive features: the ability to work without interruption in a wide range of capacities, a well-thought-out repair and maintenance scheme by replacing inexpensive consumable items. Many representatives of this class are not a trimmer in the usual sense, but are combined systems. They are based on a multi-motor, to which a number of attachments are attached: for shearing hedges, pruning tree branches, cleaning sidewalk seams, blowing off cut greenery and even for shallow soil cultivation or snow removal.

Features of the drive design

When choosing a trimmer with an electric motor, there are few nuances. Plug-in electric scythes are equipped with universal collector motors, which are standard on all power tools. The main problems with these machines are poor quality bearings, poor rotor balancing and an imperfect air cooling circuit. In general, the quality and reliability of the electric motor increase in proportion to the cost of the tool, there are no exceptions or unique technical solutions in this regard..

The key difference between mains trimmers lies in the location of the motor:

• Lower – more comfortable in terms of weight distribution, but at the same time the engine is vulnerable to moisture and dirt getting into it along with the air flow.
• Upper – the motor is reliably protected from the ingress of foreign objects, but it is less convenient during operation and the presence of a transmission, which reduces reliability and leads to the appearance of parasitic power losses in friction units.

The main drawback of collector motors is a faulty control system. For such a tool as a trimmer, it is important to have a soft start and a responsive power control system, which in practice is usually implemented by resistive elements that have low reliability and accuracy, as well as a short service life..

Cordless models have a commutator motor with a gearbox that increases the spindle speed, and the most modern ones have a brushless or brushless DC motor. The advantage of the latter is the absence of a brush assembly, efficiency and good controllability, the ability to implement the most advanced electronic control schemes. With all the advantages, the other pan of the scale is quite expensive. Optimal Battery Trim Arrangement – Top Battery and Bottom Motor.

Standard repair kit for petrol trimmer or chainsaw

The petrol trimmer engine is available in two or four strokes. The latter type is more difficult to repair and maintain, but at the same time it is more reliable and stable under variable load. Four-stroke motors are heavier, which makes it advisable to use them only in professional-grade equipment designed for long-term operation without stopping. Most household models have a two-stroke engine, which is quite justified: fewer requirements for fuel quality, repair by simple and quick replacement of the cylinder-piston group, acceptable power dynamics.

With regard to power, for electric drives the minimum value can be considered 600-800 W, for gasoline two-stroke – 0.6-0.8 hp with a working volume of 30-35 cm3, for four-stroke – 1.2-1.5 liters. from. with a volume of up to 40 cm3. Excess power for a manual brushcutter is undesirable: the technique must be chosen for the tasks at hand, because with an increase in productivity, the weight of the power unit also increases, which reduces the convenience of operation and maneuverability.

Boom, transmission and rigging

It remains to figure out how the power transfer from the engine to the working tool is realized in various trimmers and what are the limitations of various technical solutions. The type of transmission can be judged by the shape of the rod: in a straight line, a rigid metal shaft is used, in a curved one – flexible on the basis of a steel or polymer cable.

The straight shaft features less parasitic losses and more reliability. A flexible bar, on the other hand, allows you to achieve a more rational distribution of weight, but this unit cannot be called reliable. However, in expensive trimmers, rather interesting solutions are used, in which polymer and composite materials are used, which reduce friction losses and increase resistance to stress..

The type of transmission determines the types of equipment that can be used with the trimmer. So, steel discs and high-speed cutting tools require the most rigid drive coupling, which means that only trimmers with a rigid shaft are suitable for cutting dry stems and branches of bushes. The rejection of the gear transmission in favor of cardan or CV joints helps to increase resistance to loads.

In turn, trimmers designed for delicate work, for example, cutting the edges of the lawn or narrow areas between the beds, can have a different scheme of transmission of rotation, selected for the sake of increased ergonomics or maneuverability. The same applies to the shape of the handles: the bike pattern is optimal for long-term work with heavy and powerful trimmer, while the D-shaped or J-shaped handle in combination with the curved bar makes it easy to use a wide range of combination systems and work with small landscape forms.