How to attach a blade to a grass trimmer. Algorithm for installing a blade on a grass trimmer

Grass trimmer disc selection criteria and instructions for disc replacement

Grass trimmers mowing occurs at the expense of the mowing head with a line and metal discs. Each type of cutting equipment has its own fundamental features. The use of fishing line is limited to the type of vegetation, so where the head with cord can not cope with the task, a metal disc is used. How to choose a cutting disc for a grass trimmer, what they are, and how they are sharpened, find out the details before buying the appropriate equipment.

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

There are models of trimmers with flexible shafts, in which gearbox design is represented by a steel cable. These tend to be low-powered electric lawn mowers that are not designed for heavy use, as well as household lawn mowers. Use of metal discs on trimmers with a flexible shaft is impossible (only plastic discs can be used), since this will lead to rapid failure of the gearbox. Before you buy metal trimmer blades, you will need to figure out the type of transmission mechanism of your tool. rigid or flexible.

What type of transmission mechanism is used on the trimmer is specified in the technical description for the tool. If the grass trimmer has a curved boom, a flexible shaft is used in its design. Tools with a straight shaft can be equipped with rigid and flexible gearboxes, which depends on the power of the grass trimmer.

Trimmer blades are classified according to these characteristics:

  • Material of manufacture. they come in plastic and metal. Plastic blades are less efficient than metal ones, but they do not put more strain on the shaft and drive mechanism of the tool. Plastic discs are used on electric trimmers and domestic gasoline mowers
  • Design of cutting equipment. Steel discs are available in two types. bladed and toothed (milled). Plastic blades are produced in the form of blades. Toothed devices have a similar design to circular discs, while paddle blades have large, flat blades
  • Number of cutting edges. Number of teeth and blades on discs differs, which affects cutting performance. Toothed discs have up to 80 teeth, paddle discs have one to four
  • Additional coating. steel toothed discs have additional pobedite tips, which allows to use the tool for mowing grass on hilly terrain. In case of contact of steel blade with obstacles like stones and earth the teeth are not deformed and blunted due to pobedite tips. Experts state that devices with carbide tips do not last long. The brazing quickly wears out and the cutter is then used without the pobedite

Plastic blades for trimmers not only cost less than metal blades, but they also do not place high loads on the engine and transmission mechanism. This is especially true when the blade bumps into obstacles. The higher the elasticity of the cutting blade, the less likely the plastic discs will deform.

This is interesting! Toothed discs with a large number of links are used for cutting various types of grass. dead grass, green lawn grass and thick-stemmed grass. Cutting with a plastic blade is straight, clean, and level. In addition, a large number of teeth prevents their rapid blunting, and the presence of additional holes on the surface of the circle (peoration) is designed not only to cool, but also to reduce weight and increase inertia.

How to install the blade on a grass trimmer

The grass trimmer blade is easy to install. Use a full wrench to do this, disconnecting the cutting equipment and locking pin Procedure yes.

  • First of all, you should unplug the electric grass trimmer from the mains, gasoline. just a muffler. Remove and remove the protective cover on one side.
  • Then you need to connect the holes in the gearbox and the shaft to insert the pin and lock the drive.
  • If a hair spool was used, it should be turned clockwise.
  • Then you need to find the nut to tighten the knife.
  • The next step is to install the blades. Grass trimmers often wonder which side to put the disc on. This should be done so that the numbers and letters are at the top.
  • Then you need to put the cover on top and over it. The mounting nut, which must be tightened tight with a wrench.
  • The last step. Install the protective cover.

As you can see, the procedure is very simple and the same for many brands, be it STIHL or Husqvarna equipment.

Old Circular Saw Modified to Grass Cutter Blade | Tagalog

Note! If the owner of the device wants to replace the disc back cable, you can install the spool in the same way.

Disc selection criteria

You need to choose a plastic or metal blade, taking into account the area to be treated and the type of grass trimmer. electric or gasoline-powered. The number of blades will depend on what growth to remove with the tool. You can choose the desired disc shape, number of blades, and material of manufacture using the unit’s instruction manual. It usually determines which cutters are recommended for certain problems.


It is not recommended to attach metal blades to electric scythes, as the design features make them dangerous for the user This is due to the curved shape of the rod, the lack of locks on the handles and the high speed of rotation.

Important! The straight arrow allows safe use of the grass trimmer at times when the disc is rotating against an obstacle. In this situation, it bounces back to the person, so the curved design can cause injury.

On flexible bar trimmers For safety reasons, plastic blades should be used. Their purpose is to mow soft grass, dry grass. While metal discs are great for tall, dense, tough shoots, shrubs, and tree shoots.


The number of blades is important for different tasks. Thus, two or three pieces are enough to shred the grass. For mowing, you need four to eight blades on the disc. To destroy small shoots of trees and shrubs, there should be a large number of small teeth instead of discs.

Sharpening the disc

Regardless of the quality of the disc, over time it becomes dull and begins to mow poorly. If the blades are still relatively new and not practical, you can sharpen them yourself.

Important! Sharpening is only suitable for discs that do not have brazed hard material. Such parts are discarded and replaced with new ones.

  • Disassemble the grass trimmer, remove the blades;
  • Inspect the disc carefully. if cracks are found, it is better to replace the part with a new one, as further work is dangerous;
  • curved blades can be carefully bent with a hammer;
  • Considering the size of the disc, you need to choose the right file for the metal, this will ensure a more comfortable work;
  • at an angle of 30 ° equally sharpen all the upper cutting edges of the discs;
  • Reassemble the grass trimmer in reverse order.

You can use a low-speed grinder to sharpen the disc, installing a medium grit grinding wheel. With this tool, the process will move much faster. For safety you should wear gloves and face mask or goggles.

Thus, for mowing grass on gasoline and electric trimmers use plastic and metal discs of different shapes and with different sets of blades. They are selected according to the type of work performed and the size of the area to be treated. If the mower blades are dull, they can easily be sharpened or replaced on their own. Despite the simplicity of the procedure, you must exercise caution and take precautions to avoid injury due to negligence or damage to the equipment. A more detailed description of replacing a blade for a particular model of grass trimmer can be found in the instruction manual or on the official website of the manufacturer. For clarity, the general scheme of the process is shown in the video.

How to Properly Install a Disc for grass trimmer

Disks for lawn mowers: what are they, how to choose and install?

Blades for brushcutters. an indispensable thing. Enough to elect the appropriate, and you can mow large areas of grass with them. Naturally, the abundance of blades somewhat complicates the task of their selection. In order to understand which cutting attachment is best for you, you need to familiarize yourself with the most important of them. You should also learn in advance about the proper sharpening and operation of knives.

An overview of types

For brushcutters the preference should be given to special cutters. They allow you to mow higher and tougher grass than a line for a trimmer. Also the trimmer blade is good even for cutting back young bushes.

How to install the Brush Knife to the STIHL Weed Eater

How to choose?

There are many things to consider when choosing a mower blade. Metal toothed discs, for example, are often circular in shape. Teeth can vary in shape, appearance, size. For small trees and dense grass, it is better to give preference to discs with a huge number of teeth.

It is necessary to note such an advantage of milling discs for brushcutters as a sharp set of revolutions. But a high moment of inertia does not have the best effect on the drive unit. For dense mowing, for tall and small rough grass and bushes it is better to choose discs with 40 or more tines and peoria. They can not grind vegetation, and with all this, it will not actually wind up on the circle. If the number of tines is more than 60, you can safely mow grass and trees with a trunk width of up to seven cm.

Blades with solid blade and without holes are heavy, so it’s worth to choose them for large trimmers (more than 40 cm3). With all this, they are comfortable to mow the rarest grass, dead wood, and they are also suitable for mowing with different density.

Pobedite discs are the right choice for mowing near obstacles. If you need to mow grass in hay, preference should be given to iron knives with a huge number of teeth with even sharpening. Solid blades with a number of teeth from sixteen to 30 two are excellent for cutting plants with thick trunks.

In low-power trimmers, paddle discs with a lower moment of inertia are better. The fewer blades, the more force the tool has to shred the grass. So, discs with 2 blades are mostly used for cutting homogeneous grass. The main advantage of this type is that it throws cuttings to the side.

The thickness of the blades is also important in the choice. Disks can be stamped or forged. The first have a low price, but all this can be very damaged, encountering an obstacle. As for forged disks, they are not chipped and sheared when colliding with hard objects.

Only plastic blades should be chosen for electronic trimmers. Their low weight will not create unnecessary load on the engine. The soft plastic allows blades when hitting an obstacle not to break, but just a little bend or deform. Use these cutting elements is recommended for mowing dense, soft grass.

Manufacturer’s Review

There are an unlimited number of manufacturers of brushcutter blades. It is worth to familiarize with the most popular among them. For example, the Bosch brand is known for its blades with 2 and 3 blades. The peculiarity of the knives of this company is that each of the blades can be changed separately from the others.

Another company that is popular with its paddle blades is “Shark”. The advantage of this design is that the blades are mounted to each other at an angle of 100 to 20 degrees. Finally it is easy to adjust each of the blades, which is comfortable for different vegetation. Another feature of blades from this manufacturer. the low weight.

Installing the cutting disc

How to properly install a disc on a gasoline grass trimmer. In the video we.

On powerful and professional equipment are installed saw blades that have up to 80 teeth, and sometimes even hard-alloy (pobedite) on the teeth. Such a pobedite disk for grass trimmer is rarely used in private households, it is mainly put on professional brushcuts. It has a very long service life and versatility of use for both fresh grass and dry impassable weeds.

Discs also vary in blade thickness, which can vary from 1.3 to 4 mm. Thin blades cut the grass cleanly, quickly and neatly, but they dull more quickly. the thickest blades do not wear out for a long time, but are better suited for thorns and weeds.

As practice shows, the most common form of a blade for grass trimmer. round with teeth on the circumference. Its variety with 4 large teeth and a row of small tines between them is also a frequent choice. They most effectively help in cleaning the area, they are easily installed on any models of trimmers.

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What is the best knife

Modern manufacturers offer the consumer a wide choice of disc varieties. Cutting parts are classified according to the following criteria:


Material for the blades is plastic or metal, which defines their purpose. the question naturally arises as to which disc is better to use: plastic or metal? The choice is determined by factors such as:

Three-blade plastic blade for an electric grass trimmer

In terms of safety, steel cutters are not recommended on electric mowers. they are almost always equipped with plastic blades. The peculiarities of the design of the electric tool itself, its technical characteristics make the installation of metal cutting parts dangerous:

According to the rules of safe use, plastic blades are only used on mowers with a flexible shaft. Plastic blades are designed for mowing soft grass (e.g. burdock, nettles) and dead wood. Metal disc-cutter is used for mowing thick, tall, rough grass, bushes and shoots of various trees, because its cutting properties and wear resistance are higher than that of its plastic counterparts.

Grass trimmer cutter with 40-tooth carbide tips

The device, as well as the technical characteristics of chain saws determine the use of metal nozzles when working with them:

  • the presence of a straight boom increases the distance to the mower’s legs;
  • comfortable handles with stops;
  • Infinitely variable speed increase.

Gasoline-driven power units with metal discs are good for mowing large areas with grass or bushes.

Number of blades

The shape of disc blades almost does not affect the quality and speed of work, it is their number that counts. disc mowers are recommended for haymaking; for example, with 8 or 4 main and 4 auxiliary blades. If they are few (2, 3), such blades shred the grass very strongly. Cutters with more fine tines are used for mowing young shoots of trees and bushes.

Patriot PT453 lawn mower with a metal disc for shrub mowing

Metal blades for lawnmowers are sharpened in different ways: on one side and on both sides. Dull or badly sharpened cutters’ cutting edges reduce productivity and lower the quality of work. This increases the load on the tool and fuel consumption.

When the blades hit a stone and the tool bounces off, it is very dangerous and can injure the brushcutter.

Select the cutting element for the grass trimmer by material, size, design should be based on the type of tool and its engine power, the amount of work to be done and the type of plants to be mowed. Partly in this will help the manufacturer’s instructions to the model used. there are written the recommended parameters of cutters.

What blades should be installed on electric and lawn mowers?

Before you buy a brushcutter blade, let’s find out what kind of blade and when it is used. Today manufacturers offer the consumer a large number of types of these consumables. In general, all cutting tools designed for mowing the grass can be classified:

Main material for trimmer blades can be plastic or metal. The use of such expendable elements depends largely on two parameters:

For safety reasons, manufacturers do not recommend putting steel blades on electric grass trimmers. Virtually all battery- and cordless lawn trimmers are equipped with plastic blades. Depending on the manufacturer, they can be solid disc-shaped design, with several blades, or in the form of a special mowing head that provides for installation of removable blades of plastic.

Straight boom at the gasoline grass trimmer and curved at the electric

Putting a metal blade on the electric grass trimmer does not allow its design features.

  • The curved boom of the unit reduces the distance from its working part to the legs of the mower. In the event of a collision between blades and a stone or other hard object, the grasshopper is thrown to your feet.
  • The high torque mentioned above, when a metal blade hits a hard object, transmits a high load to the flexible shaft of the grass trimmer and its motor. What causes their premature failure.
  • The handle of an electric brush cutter most often does not have a limiting strip that serves as a stop. Which does not rule out leg injuries.

Exactly these features allow using plastic knives only on trimmers with electric motors. When hitting an obstacle the blades break enabling the mower’s legs to be safe from possible injury.

The use of metal knives only on gasoline trimmers is also conditioned by design features.

  • Straight boom design increases distance to the legs for complete safety.
  • Comfortable U-shaped and J-shaped handles give a firm grip. The D-handles of the brushcutter are equipped with a stop that rests against the mower’s leg, preventing the head from coming to your feet when the cutting disc encounters a hard obstacle.
  • The clutch of the gasoline engine allows a smooth acceleration to the optimum speed. And when the blade hits a hard surface, it is able to absorb some of the impact.

So gasoline grass trimmers with metal blade attachment are best used on larger areas. They can successfully cope not only with high rough grass, weeds, burdocks and nettles, but also bushes and young trees.

The shape of the blades of the disc placed on the grass trimmer does not affect the quality of work performed. The speed does not depend on them either. Triangular, trapezoidal, rectangular forms are all a marketing ploy by manufacturers.

How to sharpen and set?

Sooner or later the lawnmower will need regular maintenance, if constantly used. One of the important points is the timely sharpening of blades. A metal disc can certainly work in a blunt state, but it should not be used. This leads to a decrease in performance, motor overheating, gearbox wear. To sharpen the teeth or blades is not difficult at all, but if desired, you can simply install new blades.

  • First of all the blade is removed from the device. Sharpening directly on the brushcutter is not recommended because it is unsafe.
  • Next you need to inspect the cutting assembly for chips, cracks or damage. If they are present, a new blade will need to be installed.
  • To sharpen the blades, you may use a file, sharpener or angle grinder. The safest tool is considered to be a file, with which even a beginner can cope. To sharpen the knife, it is placed in a vise, and then processed manually at an angle of 30 degrees. This method is regarded as the highest quality.

When using an angle grinder, it is important not to overheat the metal, otherwise the disk will quickly become unusable. Angle grinder with a thin abrasive wheel is suitable for sharpening discs that have many teeth. Once sharpening is complete, the blade can be inserted in the grass trimmer again and checked to see how well the tool is working

Do not touch the sharp parts of the blade to avoid injury

When the sharpening process is complete, the blade can be inserted in the grass trimmer again and checked to see how effectively it performs. Do not touch the sharp parts of the blade to avoid injury.

The blade will wear out over time and must be replaced. Install the new disc on the grass trimmer is not difficult. This procedure takes no more than 5 minutes, if you follow the simple instructions.

To start with, the blade guard has to be removed, but on some models it may stay on. The metal blade guard, for example, is not removable from the brushcutter. Then you need to take a wrench with six sides (hexagon) and use it to lock the gearbox. The hole for locking should be looked for on the side or on the end. After that, it is necessary to twist the mowing head from the brushcutter. Then the disc will be installed in its place

It is worth to pay attention to the fact that the inside diameter of the blade must be fully located in the groove allotted for this purpose. The front side of the nozzle should be facing upward

Now you have to fix the disc with the special washer and tighten the fixing nut counterclockwise

Before doing this, the gearbox shaft must be locked. The last step is the installation of the protective cover of plastic.

According to cutting edge design

  • with two tines. for young soft grass, lawns;
  • with three teeth. for young grass, dead wood, weeds;
  • with four tines. for hard grass and young tree shoots
  • with eight teeth mow the grass without a strong chopping;
  • with 24 tines. for hard and dry grass, bushes, thin trees
  • with 40 and more teeth. for cutting any grass, bushes, trees;
  • With 80 or more for professional brushcutters.
  • with two. for a soft and low grass trimmer;
  • With three. for mowing weeds;
  • With four or more blades for mowing grass into hay.

By material

The disc for the lawnmower can be made of metal or plastic. It should be specified that for an electric brushcutter, plastic blades should be preferred. They fit perfectly with the curved boom of this tool, which does not separate the working area and the legs of the mower too much. Plastic knives are good for mowing overgrown dry grass, for example, nettles or burdock trunks.

Metal blades are only suitable for the gasoline grass trimmer. This is due to the flat bar, which moves the disc away from your feet at a safe distance. Specially shaped handles also contribute to safety. When hitting a hard object, part of the shock is absorbed by the clutch of the engine. Iron knives are suitable for mowing grass from large areas, weeds, bushes, young trees.

Cultivator on a brushcutter. an effective replacement for shovel and hoe

You can use a shovel or a grass trimmer cultivator attachment to loosen the soil. The first tool has only one advantage. the ability to always maintain physical form. Now about the advantages of the lawn mower cultivator:

  • High plot cultivation speed.
  • Efficiency. the cultivator not only loosens the soil but also breaks it up. Immediately after cultivation, the ground is ready for planting different crops.
  • Does not reduce the amount of black soil. Shallow cultivation helps to preserve the fertile soil layer.
  • No physical fatigue. The process of trimmer cultivation is similar to mowing grass.

Cultivator from gasoline trimmer is used to till the soil between the rows. fluffing and weed control, so the device is also called a power tiller. When choosing a grass trimmer cultivator attachment, it is important to consider the following recommendations:

  • The quality of the cutting elements. by choosing cheap devices, you are likely to face the fact that when processing compacted soil will deform the blades;
  • the presence of a protective cover. a mandatory attribute, the absence of which is unsafe for the operator, as small stones and dust will fly in the operator’s face;
  • Sufficient weight of the device. the nozzle should have the weight not less than 5 kg, otherwise it will be thrown upwards from vibrations.

Such a device is used by gardeners for weeding potatoes, while simultaneously fluffing up the soil and removing weeds. Justifies itself the device in the presence of large amounts of work, so it is recommended to evaluate the trimmer attachment for grass cultivator on its merits. A significant disadvantage of equipment is a significant load on the shaft and engine, so it is very important to take breaks as often as possible, and to use powerful units.

Grinding trimmer discs properly, what you need to know about it

When using a lawnmower with metal cutting blades, they become dull. This is a normal phenomenon, but you can not continue to use such an attachment. Blunt blades have a poor cutting performance so besides unsatisfactory mowing results you will overheat the engine and wear out the gearbox. If the blades or teeth of the cutting discs on the trimmer are blunt, it is necessary to sharpen them. Some people prefer to buy new cutting wheels, which is not rational at all.

attach, blade, grass, trimmer

This is interesting!All types of cutting blades and blades with pobedite tips must be sharpened. To sharpen a wheel with a pobedite, you need a special diamond wheel. How to sharpen a tipped disc is described in detail in this article. A step by step description of how to sharpen the disc of the grass trimmer:

  • First, you need to remove the cutting element from the tool. It is not safe to sharpen the tool
  • Inspect the element for suitability. Cracks, chips, and other deformations are not allowed. If you have any of these, you need to replace the device
  • For sharpening the disk are used tools and materials such as a sharpener, file, angle grinder. What is better to choose, depends on the skill of the operator. The easiest and safest way is to use a file. To do this, the cutting tool is clamped in the jaws of the vice and the sharpening process is carried out manually at an angle of 30 degrees
  • If a grinder or angle grinder is used, it is necessary to grind carefully. When sharpening, the metal must not be allowed to redden (metal release will occur), otherwise it will lead to rapid wear and abrasion of the cutting part
  • Optimal option, which is recommended for beginners (it is also used by masters with experience) is the use of a file. The file can be used to sharpen the cutting edge of the tool as precisely and accurately as possible at an angle, which has a positive effect on the performance of the tool
  • If you have to grind a milling disc with a large number of teeth, it is recommended to use an angle grinder with a fine abrasive wheel for such cases

The video below shows you how to correctly sharpen milling disks with many teeth.

After sharpening the grass trimmer disc, all that remains is to install it in place, and make a test of the tool’s effectiveness. After sharpening, make sure you do not touch the sharp parts because you might get injured.

To summarize, it should be noted that the efficiency of grass mowing depends on the right choice of trimmer disc. For mowing grass on the roadsides and paths, the line for the trimmer is used, but to control weeds in the country, as well as for the purpose of making hay in the fields and in woodlands, lawn mowers with metal discs are used. If your budget allows, it is advisable to buy 3 types of metal discs and try them out for yourself to experience the difference.