How to properly attach the disc to the grass trimmer

Lawn mower discs: what are they, how to choose and install?

Brushcutter knives are an irreplaceable thing. It is enough to choose the right one, and you can mow huge areas of grass with them. Of course, the variety of knives complicates the task of selecting them somewhat. 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.

By material

The lawn mower disc can be made of metal or plastic. It should be clarified that plastic blades should be preferred for electric brushcutters. They fit perfectly with the curved shaft of this tool, which doesn’t separate too much between the work area and the mower’s legs. Plastic knives are good at mowing overgrown dry grass, for example, nettle or burdock trunks.

The metal blades are only suitable for the petrol grass trimmer. This is due to the flat bar that moves the disc away from the feet to a safe distance. Special shaped handles also contribute to safety. When hitting a hard object, part of the impact is absorbed by the engine clutch. Iron knives are suitable for mowing grass from large areas, weeds, bushes, young trees.

How to sharpen and deliver?

a lawnmower with constant use will sooner or later begin to need regular maintenance. One of the important points is the timely sharpening of knives. The metal disc can, of course, work in a dull state, but it cannot be used. This leads to a decrease in performance, overheating of the engine, and wear of the gearbox. Sharpening the teeth or blades is a snap, but if you want, you can simply install new knives.

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• First of all, the knife is removed from the device. It is not recommended to sharpen directly on the brushcutter, 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.
• You can use a file, sharpener or angle grinder to sharpen knives. 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 disc will quickly become unusable. an angle grinder with a fine abrasive wheel is suitable for sharpening discs with many teeth.

• When finished sharpening, the blade can be put back on the grass trimmer to see how well the tool is performing. Do not handle the sharp parts of the knife to avoid injury.

Over time, the knife will wear out and should be replaced. Fitting a new disc to your grass trimmer is a snap. This procedure takes no more than 5 minutes of time, if you follow simple instructions.

• First you need to remove the protective cover, but on some models it may remain. For example, metal covers cannot be removed from the brushcutter.
• Next, you should take a key with six faces (hexagon) and use it to block the gearbox. The hole for blocking must be sought from the side or from the end.
• After that, it is necessary to unscrew the mowing head from the brushcutter.
• Then a disc will be installed in its place. It should be noted that the inner diameter of the knife must be completely located in the groove reserved for this. The face of the nozzle should be with the letters facing up.
• Now you need to fix the disc with a special washer and screw the fastening nut counterclockwise. Before doing this, it is necessary to block the gearbox shaft.
• The last step is to install a protective plastic casing.

Species overview

For brushcutters, preference should be given to special knives. They allow you to cut taller, tougher grass than line. In addition, the knife is suitable even for pruning young bushes.

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

How to choose?

When choosing a knife for a mower, there are many points to pay attention to. For example, metal toothed discs are most often circular in shape. Teeth can differ in shape, appearance, size. For small trees and dense grass, it is better to give preference to discs with a large number of teeth.

It is worth noting such an advantage of milling discs for brushcutters, as a quick set of revolutions. However, a high moment of inertia does not have the best effect on the drive of the machine. For dense mowing, for high, as well as for small coarse grass and bushes, it is better to choose circles with 40 or more teeth and perforation. They are able not to chop up vegetation, and at the same time it will practically not wrap 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.

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Solid discs and discs without holes are very heavy, so they should be chosen for powerful trimmers (over 40 cm3). At the same time, they are convenient for mowing rare grass, dead wood, they are also suitable for mowing with different densities.

Victory-tipped discs should be chosen for mowing plants near obstacles. If you need to mow grass for hay, then steel knives with a large number of teeth with an even sharpening should be preferred. Solid discs with 16 to 32 teeth cut well plants with thick stems.

For low power trimmers, paddle discs with a minimum moment of inertia are better suited. The fewer the blades, the more the tool will chop the grass. Thus, discs with two blades are most often used for mowing uniform grass. The main advantage of this species is that it throws cut plants to the side.

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

The thickness of the blades is also important when choosing. Discs can be stamped or forged. The former are distinguished by a low price, but at the same time they can be severely damaged when faced with an obstacle. As for forged discs, they do not chip and cut when colliding with hard objects.

For electric trimmers, choose only plastic blades. Their low weight will not put unnecessary stress on the engine. Soft plastic allows the knives to not break when facing an obstacle, but simply bend or deform slightly. The use of such cutting elements is recommended for cutting thick soft grass.

By form

By shape, knives with disc blades and several blades are distinguished, which are at a certain distance from each other. The shape of the blades may also vary. It should be noted that this does not affect either the speed or the quality of the brushcutter’s work.

Currently, manufacturers began to offer, in addition to traditional shapes, also triangular, rectangular and trapezoidal.

By making cutting edges

• with two tines. for young soft grass, lawns;
• with three teeth. for young grass, dead wood, weeds;
• with four tines. for tough grass and young tree shoots;
• with eight teeth, mows grass without too much chopping;
• with 24 teeth. for hard and dry grass, shrubs, thin trees;
• with 40 or more teeth. for mowing any grass, bushes, trees;
• 80 and more. for professional brushcutters.
• with two. for soft and low braids for grass;
• with three. for mowing weeds;
• with four or more. for mowing grass for hay.

Disk selection criteria

You need to choose a plastic or metal knife, taking into account the area of ​​the site that you plan to process, as well as the type of grass trimmer. electric or gasoline. The number of blades will depend on which growth needs to be removed with the tool. You can choose the desired disk shape, the number of blades and the material of manufacture using the device’s operating instructions. Usually it prescribes which cutters are recommended to be used for solving certain tasks.

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Features of discs for brushcutters

Knife discs are available in plastic and metal, as well as in various shapes to perform diverse tasks.

• Two-, three- and four-bladed knives with pronounced blades are used for mowing grass and tree growth. However, they are not suitable for making hay, as they grind the shoots, chopping them several times.
• Massive four-blade discs are designed not only for clearing the ground from grass, but also for mowing hay. They prevent repeated cutting of the shoots, thus making them suitable for harvesting for the winter.
• Discs with cutting edges around the perimeter are relevant for beveling reeds and reeds. These knives are very heavy. a necessary quality to cut through thick stems.
• Professional saw blades for hedge trimmers and brushcutters for cutting small trees and bushes.

Plastic knives are used as an alternative to metal discs. They do not need to be firmly fixed in the head, but they rotate as a result of centrifugal force. The strength of plastic knives is high, so the service life is quite long.

On a note! The advantage of plastic discs is that, hitting an insurmountable obstacle, they bounce off, and repeated contact does not occur.

Blades

The number of blades is important when solving diverse tasks. So, for grinding grass, two or three pieces are enough. To harvest hay, it is necessary that there are four to eight blades on the disc. To destroy small shoots of trees and shrubs, instead of blades on the disks, there should be a large number of small teeth.

Rules for replacing knives on the grass trimmer

If the trimmer disc is used regularly, it will need to be removed from time to time and sharpened or replaced with a new one. 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, be it Carver or Huter, but slight differences are possible. It is quite simple to change the knife on the trimmer if you follow the safety precautions and know the correct procedure, the description of which can be found in the user manual. The entire replacement process step by step, as well as the method of self-sharpening knives, will be described in this material.

Sharpening the disc

Regardless of the quality of the disc, over time it becomes dull and begins to chop grass poorly. If the knives are still relatively new, and replacement is impractical, you can sharpen them yourself.

Important! For sharpening, only those discs that are not soldered from hard materials are suitable. Such parts are thrown away, and new ones are acquired instead.

• disassemble the grass trimmer, remove the knives;
• carefully inspect the disc. if cracks are found, it is better to replace the part with a new one, since its further operation is unsafe;
• bent blades can be gently bent with a hammer;
• given the size of the disc, you need to choose the right file for metal, this will ensure more convenient work;
• sharpen all upper cutting edges of the discs at an angle of 30 °;
• reassemble the grass trimmer in reverse order.

To sharpen the disc, you can use a low speed emery machine with a medium grit grinding wheel. With such a tool, the process will move much faster. For safety, you need to wear gloves on your hands, and a protective mask or goggles on your face.

So, for mowing grass on gasoline and electric trimmers, plastic and metal discs of various shapes and with a different set of blades are used. They are selected in accordance with the type of work performed and the size of the cultivated area. If the blades on the mower are dull, it is easy to sharpen them or change them yourself. Despite the simplicity of the procedure, you need to be careful and remember about safety, so as not to injure yourself through negligence or damage the equipment. A more detailed description of replacing the knives in relation to a specific grass trimmer model can be found in the operating instructions or on the manufacturer’s official website. For clarity, the general scheme of the process is shown in the video.

How to Fit the Disc to the Grass Trimmer

Attaching the blade to the grass trimmer is very simple. For this, a complete wrench is used that disconnects the cutting attachment and a pin that blocks the gearbox. The procedure is as follows.

• First of all, the electric grass trimmer should be disconnected from the mains, the gasoline trimmer should be simply turned off. Disconnect the protective cover and move to the side.
• Next, you need to align the holes on the gearbox and the shaft in order to insert a pin into them and block the drive.
• If a spool with line was used, it must be unscrewed clockwise.
• Then you need to find a nut to twist the knife.
• The next step is to install the knives. Trimmer owners often wonder which side to put the disc on. This must be done so that the marking with numbers and letters is on top.
• Then you need to put a boot on top, and above it. a fixing nut, which must be tightened tightly with a wrench.
• The last step is to 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.

On a note! If the owner of the device wants to replace the disc back on the line, you can install the reel with it in the same way.

When is the use of knives relevant?

When using brushcutters in summer cottages, the most popular attachment is the fishing line. It has a low price, is suitable for different trim heads, and is safe to use. The disadvantage of using a fishing line is that it is convenient only for mowing low growth. In other situations, the string will kick in immediately, regardless of whether a gasoline or electric grass trimmer is used. In addition, vegetation is wound around the spindle, which creates significant resistance on the shaft and leads to its breakage. It can also provoke failure of the piston system in petrol cutters or engine burnout in electric trimmers.

Therefore, for mowing tall or hard vegetation, various attachments are used. So, for harvesting high and coarse grass, thin shoots of trees and shrubs, it is better to install and use a disc. This nozzle clogs up much less frequently, which contributes to greater wear resistance of the equipment.

On a note! Due to the fact that the engine of electric trimmers and battery models is less powerful than on petrol cutters, therefore the use of discs is more relevant for petrol mowers.

Material

It is not recommended to put metal knives on electric scythes, since the design features make their use dangerous for the user. This is due to the curved shape of the rod, the absence of stops on the handles, as well as the high rotation speed.

Important! The straight bar ensures safe use of the grass trimmer when the disc hits an obstacle while spinning. In this situation, it bounces back towards the person, so the curved structure can cause injury.

Plastic knives should be used on gooseneck trimmers for safety reasons. Their purpose is mowing soft grasses, dead wood. Whereas metal discs do an excellent job with tall, dense, hard undergrowth, shrubs, as well as tree shoots.