How to install a wheel on a grass trimmer.

Rules for replacing blades on the grass trimmer

If the disc on the trimmer is used regularly, it needs to be removed and sharpened or replaced with a new one from time to time. This part can be made of metal or plastic, have a different number of blades, but the replacement process remains the same. over, this procedure is similar for equipment from different manufacturers, whether Carver or Huter, but there may be slight differences. Changing the blade on the trimmer is simple enough if you follow the safety precautions and know the correct procedure, a description of which can be found in the user manual. The whole process of replacement step by step, as well as the method of self-sharpening blades, will be described in this material.

A line is the most popular attachment for trimmers when using brushcutters in country houses. It is inexpensive, suitable for various trimmer heads, and safe to use. The disadvantage of using a fishing line is that it is only useful for mowing low growth. In other situations, the string is immediately clogged, regardless of whether a gasoline or electric grass trimmer model is used. It is also very economical to tangle vegetation with the spindle, which causes considerable resistance to the shaft and can lead to shaft breakage. It can also cause the piston system in chain saws to fail or the motor in electric trimmers to burn out.

Therefore, to mow high or stiff vegetation, different nozzles are used. So, for cleaning tall and rough grass, thin shoots of trees and shrubs, it is better to install and use a disc. This mowing head is much less likely to get clogged, which makes the machine more resistant to wear and tear.

For your information! Due to the fact that the engine of electric and battery-powered trimmers is less powerful than that of gasoline-powered models, the use of discs is more relevant for gasoline-powered mowers.

How to install a saw blade on a grass trimmer

The main working bodies of any grass trimmer are the spool with a fishing line or a special disk (plastic or metal). Just like a line, a plastic blade can be used to mow green grass, and a metal blade for dry grass, reeds, and even bushes. Is it possible to increase the functionality of grass trimmer by installing the saw blade on it??

Installation of diamond disc

This operation does not differ in appearance from the attachment of a typical disc, except that even more attention, care and diligence are required. Remove the spool with the fishing line, blocking the gear shaft with a special pin or a suitable diameter screwdriver, turning the container for the fishing line counterclockwise. We try on the diamond disc to the lower washer and make sure that its seating hole is larger than the diameter of the seating ring on the washer. At high revolutions the saw blade may shift and unbalance will occur, which will inevitably lead to the breakage of the tool and even to the injury of the operator or people in the vicinity. Let’s try on compensating washers one by one and choose the one that suits the width and the gap between saw blade seating place and centering shoulder of lower saw blade completely. Put the lower washer with the wear ring, the diamond disc, the upper washer and the cover plate on the gearbox shaft one after the other to redistribute the clamping force over a larger area. Tighten the complete set on the gearbox shaft using the left-hand threaded nut, first by hand and then with a socket wrench while locking the gearbox shaft from below with a suitable screwdriver. Remove the plastic tube from the teeth and check again that the saw blade is firmly fixed to the gearbox shaft. If it turned out to be reliable, the grass trimmer, with a diamond disc installed, is fully prepared, both for traditional and not intended for this tool, to work.

Craftsman 22″ Walk Behind Trimmer

Putting it to the test

For safety you should wear a safety helmet with a clear face shield and gloves on your hands. Start with small dry branches, work our way up to larger ones, and finish by sawing off 7-8 cm dried and half-dry tree trunks. We make sure that the grass trimmer with diamond disc works quite effectively, reliably and safely. Both cross cuts and bevels are very smooth. No crumpled or torn wood fibers are visible. Mowing with the diamond disc is also quite comfortable, efficient and productive regardless of its height, density and degree of dryness. So, the grass trimmer with circular saw blade not only perfectly performs its direct function (mowing the grass), but also expands its range of application (removing knots and branches from trees, and sawing thick trunks). Attention! You should not be keen on installing large diameter and thickness saw blades on the grass trimmer, as this will cause an increased load on the gearbox and engine, and possible premature breakdown. It will also reduce the safety of working with such tools, which should not be allowed in any case.

Features of brushcutter discs

Blade discs are available in plastic and metal, and in various shapes for different applications.

  • Two-, three- and four-blade blades with distinctive blades are used for mowing grass and woody growth. However, they are not suitable for making hay, because they shred the shoots by cutting them several times.

Plastic blades are used as an alternative to metal discs. They do not need to be firmly seated in the head and rotate due to centrifugal force. The durability of plastic blades is high, so the service life is long enough.

For your information! The advantage of plastic discs is that after hitting an insurmountable obstacle, they bounce back and there is no renewed contact.

Installing the cutting disc

How to install the right disc on your petrol grass trimmer. Here in the video we show.

High-power and professional machines have saw blades that have up to 80 teeth and sometimes even hard-alloy (tooth biting) inserts on the teeth. This kind of pobedite blade for grass trimmer is rarely used in private households, it is mainly put on professional brushcutters. 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 be 1.3 to 4mm. Thin discs cut the grass cleanly, quickly and accurately, but they blunt faster. The thickest blades do not wear out for quite a long time, but are better suited for thorns and weeds.

Practice shows that the most common blade shape for grass trimmers is round with teeth around the circumference. The variant with 4 big teeth and a number of small ones between them is also a frequent choice. They are the most effective in cleaning the area, easy to install on all models of trimmers.

Which cutter is better?

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


The material for the blades is plastic or metal, which determines their purpose. It is logical to ask what kind of disc is better to use: plastic or metal? The choice is determined by such factors:

Three-blade plastic blade for electric grass trimmer

Steel cutters are not recommended for electric lawn mowers in terms of safety. they are almost always equipped with plastic blades. The design features of the power tool itself, its technical characteristics make the installation of metal cutting parts dangerous:

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

Grass trimmer cutter with 40 tungsten carbide tips

The design as well as the technical features of chain saws determine the use of metal implements:

  • straight boom for extra legroom
  • comfortable handles with stops;
  • Infinitely variable speed increase.

Gasoline-powered machines with metal discs are well suited to mowing large areas of varying grass or shrubs.

install, wheel, grass, trimmer

Number of blades

The shape of the disc blades has practically no influence on the quality and speed of work, it is the number of blades that counts. rotary cutters are recommended for haymaking, e.g. with 8 or 4 flail blades and 4 additional flail blades. If they are few (2, 3), such blades shred the grass very strongly. Highly tine steeply wound rotary cutters are used when mowing young growth of trees and bushes.

Patriot PT453 lawnmower with metal disc for mowing shrubs

Metal blades for lawnmowers are sharpened in different ways: on one side and on both sides. Dull or badly sharpened cutter blades reduce productivity and the quality of work. Higher tool loads and fuel consumption.

Danger of the blades colliding with rocks, causing the tool to bounce, which can injure the mower.

Choose a cutting element for 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 the manufacturer’s manual for the model you’re using can help you with this. there are the recommended settings for the blades.

What blades to put on the electric and lawnmower

Before buying and putting a knife on a brushcutter, let’s find out what they are and in what cases they are 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:

The basic material for trimmer knives can be plastic or metal. The use of such consumable elements largely depends on two parameters:

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

Straight shaft in a gasoline grass trimmer and curved shaft in an electric one

To put a metal blade on the electric trimmer for grass does not allow its design features.

  • The curved boom of the machine reduces the distance from the working part of the machine to the mower’s legs. In the event of a collision between blades and a stone or other solid object, the grass trimmer swings back to its feet.
  • High torque, which we mentioned above, in case of collision of metal blade with a solid object, transmits a large load on the flexible shaft of grass trimmer and its engine. What causes their premature failure.
  • Handle of an electric mower most often does not have a limiting strip that serves as a stopper. That does not prevent feet injuries.

These are the special features that make it possible to use plastic blades only on electric-powered trimmers. When hitting an obstacle, the blades collapse, thereby protecting the mower’s legs from possible injury.

Use of metal blades on gasoline trimmers is also conditioned by design features.

  • Straight boom design gives better leg clearance for best safety.
  • Comfortable U-shaped and J-shaped handles let you hold the tool firmly. D-handles of brushcutters are equipped with a limiter that rests against the leg of the mower that does not let the head to the legs when the cutting disc meets a solid obstacle.
  • The clutch of the gasoline engine allows you to smoothly gain speed to the optimum level. And when the blade hits a hard surface, it can absorb part of the impact.

Thus, gasoline grass trimmers with a metal blade installed are best used on large areas. They can successfully handle not only tall rough grass, weeds, burdocks and nettles, but also bushes and young trees.

The shape of the blade disc put on the trimmer for the grass has no effect on the quality of work performed. Speed does not depend on them either. Triangular, trapezoidal, rectangular shapes are all a marketing ploy by manufacturers.

How to sharpen and set?

The lawnmower with constant use will sooner or later start needing regular maintenance. Timely sharpening of blades is one of the important points. The metal disk, of course, can work in a blunt state, but you can not use it. This leads to lower performance, overheating of the motor, and wear of the gearbox. Sharpening the teeth or blades is not difficult at all, but if desired, you can simply install new blades.

  • First of all, the knife is removed from the device. Sharpening directly on the brushcutter is not recommended because it is unsafe.
  • Then it is necessary to inspect the cutting element for chips, cracks, and damage. If you have them, you will need a new disc.
  • A file, sharpener, or angle grinder can be used to sharpen the blades. The file is considered to be the safest tool, even a beginner can cope with it. 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 disc will quickly become unusable. an angle grinder with a fine abrasive wheel is suitable for sharpening discs that have many teeth. After sharpening, the disc can be installed on the grass trimmer again and check how effectively the tool works

To reduce the risk of injury, do not touch the sharp parts of the blade

Once sharpening is complete, the blade may be inserted in the trimmer and checked to determine how well the tool performs. Do not touch the sharp parts of the blade to avoid injury.

The blade will wear out over time and must be replaced. The new disc for the grass trimmer is easy to install. This sharpening procedure takes no more than 5 minutes if you follow the simple instructions.

You must remove the blade guard to begin with, but some models may leave it on. The metal guards on brushcutters, for example, are not removable. Next, you should take a wrench with six facets (hexagon) and use it to lock the gearbox. To find the locking hole, look for it on the side or end. After that, the brushcutter head should be unscrewed. The disc will then be installed in its place

Note that the inside diameter of the blade must be fully seated in the slot provided for this purpose. The front side of the mowing head should be with the letters upwards

Now you need to fix the disc with the special washer and screw the fixing nut counterclockwise

Before doing this, the gear shaft must be blocked. The last step is to install the plastic guard.

By execution of cutting edges

  • with two tines. for young soft grass, lawns
  • with three teeth. for young grass, dry grass, weeds
  • with four tines. for tough grass and young tree shoots;
  • with eight tines mow grass without heavy chopping;
  • with 24 tines. for hard and dry grass, bushes, thin trees
  • with 40 or more teeth. for cutting any kind of grass, bushes, trees
  • 80 teeth and more. for professional brushcutters.
  • with two tines. for soft and low grass mowing;
  • with three. for mowing weeds;
  • with four or more tines. for mowing grass for hay.

By material

The disc for the lawnmower can be made of metal or plastic. It should be clarified that for an electric brushcutter, plastic blades should be preferred. They fit well on the curved bar of this tool, which doesn’t separate the working area and the mower’s legs too much. Plastic blades are good for cutting overgrown, dry grass such as nettles or burdock trunks.

Metal blades are only compatible with petrol grass trimmers. This is due to the flat bar, which removes the disc from the feet at a safe distance. The specially shaped handles also contribute to safety. When hitting a hard object, part of the impact is damped by the engine clutch. Iron knives are suitable for mowing grass from large areas, weeds, bushes, young trees.

Difficulty choosing between a fishing line and a knife

The trimmer line is used for low and soft grass, for taller grass, with obviously stiff and old stems it is better to use a knife. In the set of brand models of trimmers, these two cutting tools are usually included in advance. Depending on the frequency of use of this or that element, branded models, as a rule, serve at least 5 seasons.

VKRP Line Trimmer Wheel Set

Competent choice of line

A line for a trimmer is not considered a very reliable cutting tool, because it can easily get caught on a glass, a stone, a thick branch and break. Therefore, before choosing a line for a trimmer, you need to decide on its thickness. Usually, the thickness is prescribed in the instruction, which also set out its functional features. Standard line for a trimmer has a diameter of 1-1,4 millimeters, but its competent selection will always depend on the power of the mower itself. As a rule, a normal package contains 15 meters of fishing line. It will suffice for 5-10 applications. At the same time, there are also larger coils, in which the wire length is about 200 meters.

IMPORTANT! It is necessary to pay close attention to the date of manufacture of the filament, because the older it is, the faster it will break!

Forms of line section

This parameter will depend on the type of grass. A round line for the trimmer is very strong and is suitable for almost all types of vegetation. But it is quite noisy when working, so to work with it in relative comfort, you need to use earplugs or construction headphones.

Line material can be both shaped and made by section in the form of a star, square or polyhedron. Such thread should be used during cleaning of ground cover from thick and stiff stems, especially since the noise from it is rather low. At the same time, it is worth mentioning that its increased efficiency lies in the fact that it has sharp corners, hence the ability to qualitatively cut parched grass. However, this kind of thread tears much more often.

Choosing the right diameter of fishing line

For soft/fresh grass you need special line diameter. However, this does not mean that thick cord (trimmer line) can be installed on any mower, regardless of its power limits. Before such installation, be sure to read the recommended specifications, which are listed in the instructions. As an example, we can denote the following situation: an attempt to wind a 2-millimeter cord on the machine, which is designed to work with no more than 1.2 millimeters of thread. will invariably lead to a breakdown of the entire equipment, t.к. Overheating of the engine will inevitably occur.

According to the thickness of the diameter of the cord can be divided into the following sizes:

  • 1,2 to 1,6 millimeters. thin. Perfect for lawn care, including infrequent mowing. Mowing equipment capacity can be from 0,5 to 0,7 kW.
  • 2-2.4 millimeters is the most popular version of the material. Used in medium-powered equipment, which is extremely common among avid gardeners. Capable of cutting both dead grass and young growth.
  • 3-3,2 millimeters. considered the choice of professionals, it is usually installed on powerful gasoline grass mowers, without problems copes with rough deadwood and weeds.
  • 4 mm is the thickest available and even has some aluminum added to make it stronger. has a very clear motor power limit, which is why it is rarely used, and only against weeds with a strong root system.

IMPORTANT! As a rule, the manufacturer colors the trimmer line in certain colors (from softer to more aggressive, for example, from green to red) to make it easier for the potential buyer to visually understand the thickness of the cord.

Line construction material

The standard material for the cord is nylon, which is especially flexible and robust and can withstand extremes of temperature and volume. Also, there are threads with metal core. they are stronger than nylon by about 30 percent and less prone to wear. Great for tall grass. Regarding the variability of prices: nylon will cost about 100, and the material with metallic inclusions. from 800.

Sharpening the trimmer blades correctly. what you need to know about it

During the operation of the lawnmower with metal cutting blades there is a dulling of the blades. It is a normal phenomenon, but such an attachment must not be used any longer. Blunt blades have low performance, so in addition to unsatisfactory mowing results, you also get overheating of the tool’s engine and wear on the gearbox. If the blades or teeth of the cutting discs on the trimmer are blunt, they must be sharpened. Some people prefer to buy new sharpening blades, which is not at all sensible.

install, wheel, grass, trimmer

This is interesting!All types of cutting discs must be sharpened, including those with pobedite tips. To sharpen a wheel with a pobedite, you need a special diamond wheel. What is the process of sharpening a disc with Pobedite tips on the teeth is described in detail in this material. A step-by-step description of how to sharpen a grass trimmer disc:

  • To begin with you need to remove the cutting element from the tool. Sharpening with a tool is not safe
  • Inspect the tool for suitability. Cracks, chips and other deformations are unacceptable. In the presence of such, it is necessary to carry out the replacement of the device
  • To sharpen the disc, you use 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 performed manually at an angle of 30 degrees
  • If you use a grinder or angle grinder you will need 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
  • The optimal option, which is recommended for beginners (it is also used by masters with experience) is to use a file. The file can be used to sharpen the cutting edge in the best possible way at an angle that will have a positive impact on the cutting performance of the tool
  • If you have to sharpen a milling disc with a large number of teeth, then an angle grinder with a fine abrasive wheel is recommended for such cases
install, wheel, grass, trimmer

The video below shows how to properly sharpen large toothed milling discs.

After sharpening the blade of the grass trimmer it is only necessary to reinsert it and check how well it works. After sharpening, keep in mind that it is better not to touch the sharp parts, because you can be injured.

To summarize, it should be noted that the effectiveness of grass mowing depends on the right choice of trimmer disc. For mowing the grass on the roadsides and paths, a line for the trimmer is used, but for controlling weeds in the countryside, as well as for making hay in the fields and in wooded areas, lawn mowers with metal discs are used. If your budget allows, it is advisable to buy 3 types of metal blades and try them out for yourself to see the difference.

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