Trimmer Cutting Disc

Trimmer Cutting Disc

Knives for lawn mowing. an indispensable thing. It is enough to choose the right one, and you can mow huge areas of grass with their help. Of course, the variety of knives somewhat complicates the task of selecting them. To understand which cutting element is needed, you need to familiarize yourself with the main ones. You should also find out in advance about the correct sharpening and operation of knives.

Species overview

For lawn mowing, preference should be given to special knives. They allow you to mow higher and tougher grass than fishing line. In addition, the knife is suitable even for trimming young bushes.

There are many types of discs that differ in cutting edge, shape and material of which they are made.

Each species has its own characteristics.

For cutting edges

  • with two teeth. for young soft grass, lawns;
  • with three teeth. for young grass, dead wood, weeds;
  • with four teeth. for hard grass and young shoots of trees;
  • with eight teeth mowing grass without strong chopping;
  • with 24 teeth. for hard and dry grass, shrubs, thin trees;
  • with 40 or more teeth. for mowing any grass, bushes, trees;
  • from the 80th and more. for professional lawn mowers.


  • with two. for soft and low braids;
  • with three. for mowing weeds;
  • with four or more. for mowing grass on hay.

In shape

The shape distinguishes knives with disk blades and several blades that are at a certain distance from each other. The shape of the blades may also vary. It is worth noting that this does not affect either the speed or the quality of the work of the lawn mowing.

Currently, manufacturers have begun to offer, in addition to traditional shapes, more triangular, rectangular and trapezoidal.

By material

The lawn mowing disk may be made of metal or plastic. It should be clarified that for electric lawn mowers, plastic blades should be preferred. They are great for the curved bar of this tool, which does not too separate the working area and the legs of the mowing. Plastic knives are able to mow well overgrown dry grass, for example, nettles or burdock trunks.

Metal knives are only suitable for gas trimmers. This is due to the even bar, which removes the disc from the legs to a safe distance. Handles of a special shape also contribute to safety. When hitting a solid object, part of the shock is extinguished by the engine clutch. Knives made of iron are suitable for mowing grass from large areas, weeds, shrubs, young trees.

Manufacturers Overview

There are a lot of manufacturers of lawn mowing wheels. It is worth getting acquainted with the most popular among them. For instance, Bosch brand is known for its two and three-blade knives. A feature of knives of this company is that each of the blades can be replaced separately from the others.

Another company known for its blade knives is Shark. The advantage of the design is that the blades are fixed relative to each other at an angle of 120 degrees. As a result, it is easy to adjust each of the blades, which is convenient for different vegetation. Another feature of knives from this manufacturer is low weight.

Husqvarna is also known for its multi-tooth knives., especially with hay knives. Ideal for thick and dense grass. Of the minuses, it is worth noting the large weight of the disks and the fact that you can’t turn the knife over if one of its sides is sharpened.

Inforce knives do a good job with undergrowth and branches. In practice, the metal from which the cutting elements are made shows itself to be very durable. The only thing is that in some models the victory taps erase very quickly.

Disks cope equally well with different types of grass, as well as shrubs and trees.

Rezer wheels perfectly mow grass, weeds, branches. The teeth withstand even cutting down trees 6 and more centimeters thick. However, they have a drawback in the form of winding grass on the shaft.

Patriot produces quality knives. Users note that if you select the right drive for a particular job, it will last a long time and amaze you with its performance. Knives from this manufacturer are very easy to grind on their own.

How to choose?

When choosing a knife for a mower, you should pay attention to many points. For example, discs with metal teeth are most often made in the shape of a circle. The teeth may vary in shape, appearance, size. For small trees, as well as thick grass, it is better to give preference to discs with a large number of teeth.

It is worth noting such an advantage of milling wheels for lawn mowing as a quick set of revolutions. However, a high moment of inertia does not affect the drive unit of the unit in the best way. For thick mowing, for tall, as well as for small rough grass and shrubs, it is better to choose circles with 40 or more teeth and perforation. They are able not to grind vegetation, and at the same time it will practically not be wound around a circle. If the number of teeth is more than 60, then you can safely mow grass and trees with a trunk thickness of up to 7 cm.

Disks with a solid blade and without holes have a large mass, so they should be selected for powerful trimmers (more than 40 cm3). At the same time, it is convenient to mow rare grass and dead wood, they are also suitable for mowing with different densities.

Discs with victorious soldering should be selected for mowing plants near obstacles. If you need to mow grass on hay, you should give preference to steel knives with a large number of teeth with smooth sharpening. Solid discs with a number of teeth from 16 to 32 cut plants with thick stems well.

For low-power trimmers, blade discs with a minimum moment of inertia are best suited. The smaller the blades, the stronger the tool will grind the grass. So, disks with two blades are most often used for mowing homogeneous grass. The main advantage of this species is that it throws the cut plants to the side.

When harvesting hay, it is recommended to choose knives with four blades so that the grass is not chopped.

The thickness of the blades is also important when choosing. Discs can be stamped or forged. The former are notable for their low price, but at the same time they can be severely damaged when faced with an obstacle. As for the forged discs, then they do not form chips and cuts in a collision with solid objects.

Video: Trimmer Cutting Disc

For electric trimmers, only plastic knives should be selected. Their low weight will not create an extra load on the engine. Soft plastic allows the knives not to break while being on an obstacle, but simply to bend or deform slightly. Use of such cutting elements is recommended for mowing thick soft grass.

How to sharpen and deliver?

When used continuously, the lawnmower will sooner or later begin to need regular maintenance. One of the important points is the timely sharpening of knives. A metal disk, of course, can work in a dull state, but you can not use it. This leads to reduced performance, overheating of the engine, wear of the gearbox. Sharpening teeth or blades is not difficult at all, but if you wish, you can simply install new knives.

  • First of all, the knife is removed from the device. Grinding directly on the lawn mowing is not recommended, as it is unsafe.
  • Next, you need to inspect the cutting element for chips, cracks, damage. If they are, then you will need to install a new disk.
  • For sharpening knives, you can use a file, a sharpener or an angle grinder. The safest tool is a file that even a beginner can handle. For sharpening, the knife is placed in a vice, and then manually processed at an angle of 30 degrees. This method is considered the highest quality.

When using an angle grinder, it is important not to overheat the metal, otherwise the disk will quickly become unusable. An angle grinder with a thin abrasive wheel is suitable for sharpening discs with many teeth.

  • At the end of sharpening, the disk can again be installed on the trimmer and check how effectively the tool works. The sharp parts of the knife cannot be taken to avoid injury.

Over time, the knife wears out and should be changed. Installing a new disc on a trimmer is a snap. This procedure takes no more than 5 minutes if you follow a simple instruction.

  • First you need to remove the protective cover, but on some models it may remain. For example, metal casings are not removed from the lawn mower.
  • Next, take the key with six faces (hexagon) and use it to lock the gearbox. The hole for blocking must be sought from the side or from the end.
  • After that, the mowing head must be twisted from the lawn mowers.
  • Then a disk will be installed in its place. It is worth paying attention that the inner diameter of the knife should be completely located in the groove reserved for this. The front side of the nozzle should be placed upside down.
  • Now you need to fix the disk with a special washer and screw the fixing nut counterclockwise. Before doing this, it is necessary to lock the gearbox shaft.
  • The last stage is the installation of a protective casing made of plastic.

How to mow grass?

Mowing grass begins with the launch of lawn mowers. This is best done on earth to make it safer. Also, before working with a lawn mowing, it is advisable to wear an unloading belt, which can be on couplers or a carbine. After starting the tool is attached to the belt and you can start work.

An important point before mowing is balancing the belt. It is correct if the load on the operator’s hands is minimal. The mower only moves the device with his hands, otherwise he will be too tired.

The main weight should rest on the shoulders of the worker.

The tool must be moved smoothly to the right and left. In this case, the trimmer should be located at the same distance from the ground. It is important that the operator moves slowly (“duck steps”).

It is not easy for beginners to maintain momentum at the same level. Depending on the density of the grass, the speed should change. For example, mowing young grass does not require much power at all.

It is important to feel the operation of the unit. After all, if the lawn mowing cannot cope with the grass, then it is necessary to increase the speed. However, constant operation at high speeds quickly wears out the tool.

When mowing with a benzotrimmer in one direction, experts recommend increasing revolutions, and moving to the other to dump gas and take a step forward. This method is especially good if you need to put the grass in the rolls.

For what are the wheels for lawn mowers, see the next video.

Grass mowing with trimmers occurs due to the use of a mowing head with fishing line and metal discs. Each type of cutting device has its own fundamental features. The use of fishing line is limited by the type of vegetation, therefore, where the head does not cope with the task, a metal disk is used. How to choose a cutting disc for the trimmer, what they are, and how to sharpen, we find out the details before buying the appropriate equipment.

What types of trimmer knives are

Initially, we note that metal discs can be used not only on gasoline, but also on electric trimmers. The main condition for the use of metal cutting knives on equipment is that the transmission mechanism (shaft or gear) must be of a rigid type in the design of the tool. A rigid type gearbox is a metal shaft that transmits torque from an electric or gasoline engine to a working body.

There are models of trimmers with flexible shafts, the design of the gearboxes in which is represented by a steel cable. These are, as a rule, low-power electric lawn mowers that are not designed for heavy loads, as well as domestic lawn mowers. Do not use metal discs on trimmers with a flexible shaft (you can only use plastic discs), as this will lead to a quick failure of the gearbox. Before buying metal cutting mills, you will need to find out the type of gear mechanism of your tool. rigid or flexible.

What type of gear is used on the trimmer is indicated in the datasheet for the tool. If the trimmer has a curved rod, then a flexible shaft is used in its design. Straight-bar tools can be equipped with rigid and flexible gearboxes, depending on the power of the trimmer.

Trimmer knives are classified according to the following criteria:

  • Material of manufacture. they are plastic and metal. Plastic knives are less effective than metal knives, however, they do not exert a large load on the shaft and tool drive mechanism. Plastic discs are used on household electric trimmers and lawn mowers.
  • Cutting device design. Steel disks come in two types. blade and gear (milling). Plastic knives are released in the form of blades. Toothed devices have a similar design with circular discs, and blade devices have large flat knives
  • Number of cutting edges. The number of teeth and knives on the discs is different, which affects the performance of cutting tools. On toothed discs, the number reaches 80 links, and on lobed discs. from one to four pieces
  • The presence of additional spraying. steel gear discs are additionally equipped with victorious soldering, which allows the use of tools for mowing grass on hilly surfaces. When the disk touches obstacles in the form of earth and stones, the teeth do not deform and do not blunt, which is achieved due to the presence of victorious solders. Specialists claim that carbide tipped devices do not last long. Soldering wears out quickly, and then the cutter is used without defeating

Plastic knives for trimmers not only cost less than metal knives, but also do not exert high loads on the engine and gear mechanism. This is especially true when the knife runs into obstacles. The higher the elasticity of the cutting knife, the less likely it is to deform the plastic discs.

Advantages of trimmer discs compared to fishing line

The trimmer disc, in comparison with the cord, has its advantages. You need to know these advantages in order to ultimately decide whether to buy and use metal cutting knives. Consider all the advantages of trim discs:

  1. The ability to cope with different vegetation, unlike fishing line. It can be dead wood, long and thick-stemmed grass, and even small vegetation. The fishing line can hardly cope with medium-sized grass, and it is not able to cut thick-stemmed grass. The cord will either get tangled up in the grass, or the fishing line will wear out quickly, which is not rational
  2. High speed of achieving results. Unlike fishing line, the disk cuts grass qualitatively in one pass (with good sharpening), without leaving “cocks”, so mowing with a metal circle trimmer is faster than when using the cord
  3. Disks do not wear out, unlike a cord. Cutting knives or parts of the wheel are dull, but the issue is resolved by sharpening. How to sharpen a trimmer metal wheel is described in the material below. With prolonged use, the cutting devices wear out, but they last for at least 3-5 years
  4. Long service life unlike fishing line, which is associated with the design of equipment

There are also disadvantages of the considered cutting devices for trimmers. The first drawback is that you cannot work with a tool when cutting grass is carried out next to obstacles in the form of trees, buildings, stones, benches, etc. When a disk collides with an obstacle, the drive brakes, which is reflected in the form of such minuses:

  • Engine overheats
  • Damaged blade parts that become dull
  • Transmission mechanisms fail. flexible and rigid shafts (gearbox)

If you plan to mow thick grass in the field, then it is impossible to do without a trimmer with a metal disc installed. The fishing line is used for mowing small grass in private areas near obstacles.

Choosing the best cutter for lawn mowing

Some manufacturers of trimmers with a rigid transmission shaft design complete their tools with not only fishing lines, but also steel disks. This is not always the case, and if this situation is appropriate, then if necessary, instead of a mowing head with fishing line, a metal disk is installed. However, this is not always the case. First you need to make sure that you can use a steel disc on the trimmer. Consider all types and designs of cutting knives manufactured for trimmers.

Disc gear knife in which cases is used

Metal gear discs have the shape of a circle, at the base of which are located the corresponding number of teeth. These teeth come in many forms, shapes and sizes. The more teeth, the more efficient the tool is to cope with thick grass and even small trees. Milling wheels for trimmers gain speed faster, which is their advantage. They also have a high moment of inertia, which is their disadvantage. This negatively affects the drive unit of the tool, as the starting power increases, and as a result the motor overheats with frequent stops. In addition, the equipment differs in the presence and absence of perforation.

  1. Perforated circles with holes and a large number of teeth up to 40 teeth. effectively cope with mowing thick, tall and small, coarsened grass and shrubs. The larger the number of teeth, the less grass is ground. Grass is not wound around circles with many teeth. Discs with teeth in the amount of 60-80 pieces are intended for mowing grass with small trees available on the territory, the thickness of the stems of which does not exceed 7 cm
  2. Solid. disks that do not have holes in the structure. They have a lot of weight, so putting them on lawn mowers with an engine capacity of up to 30 cm3 is strongly not recommended. The tool simply cannot pull out the heavy cutting element. Compared with perforated, they weigh 1.5-2 times more. Effectively cope with dense and rare grass. The smaller the number of knives, the more grass is crushed, and the load on the motor increases. The load on the gearbox also depends on the angle of grinding of the teeth.

If the operator is faced with the task of mowing thick grass and dead wood, it is recommended to choose discs with perforation and a large number of teeth. Solid discs are suitable for mowing green grass of different densities, but they are used exclusively on powerful lawn mowers with an engine capacity of more than 40 cm3.

Where are the blade knives suitable for trimmers?

Compared to gear or milling discs, blade blades are lightweight, therefore they are used on low-power trimmers. Bosch supplies its electric lawn mowers with just these types of cutting knives. Their advantage is in the minimum moment of inertia, which eliminates the negative impact on the drive mechanism.

The number of blades affects the grinding of grass. The smaller the blades, the more the mowed grass is crushed. For mowing homogeneous and homogeneous grass, two-bladed discs are used. Their dignity is that they throw away cut growths to the side. For mowing grass in the field when harvesting hay, it is recommended to use 4 or more blade nozzles. They do not crush the mowed grass, nor do they load the drive mechanism of the tool.

Plastic circles on the trimmer. when applied

If gas milling trimmers and metal blades are used, then it is recommended to use plastic circles for power tools. Their main advantage is low weight, so the load on the electric motor is completely excluded. Structurally, the nozzle is a plastic base on which knives are mounted around the perimeter. Knives are made of soft plastic, which, in contact with an obstacle, bends without deformation. The knives are mounted on a round base at an angle of 120 degrees.

They are designed to mow thick grass with electric trimmers when the line cannot cope. If the nozzle has a large moment of inertia, then it can be reduced by making symmetrical holes. When the teeth are blunted, they must be sharpened at an angle of 30 degrees using a grinding wheel with a low or medium roughness.