How to put the disc on the trimmer correctly

Trimmer disc

disc, trimmer, correctly

The trimmer is a fairly common garden tool purchased for cutting grass. Models with line are suitable for soft grass, but disc trimmer is indispensable for tackling coarse undergrowth and shrubs.

Varieties of trimmer discs

The trimmer disc is available in different materials. And in order to decide which trimmer disc is better. metal or plastic, you need to decide what you will mow. So, a plastic disc is designed for short and thin grass, while a metal disc can easily cope with very dense and tall grass, shrubs, dry grass.

The shape of the cutter disc for the trimmer can be with 2, 3 or 4 cutting edges. Typically, these accessories are included in the basic set of tools for low and medium power. With it you can fight dense grass and small shrubs.

On powerful and professional equipment, saw blades are installed, which have up to 80 teeth, and sometimes also carbide (victorious) soldering on the teeth. Such a victorious trimmer disc is rarely used in private households, it is mainly used on professional lawn mowers. It has a very long service life and versatility for both fresh grass and dry, impenetrable weeds.

The discs also differ in blade thickness, which can be from 1.3 to 4 mm. Thin discs cut grass cleanly, quickly and accurately, but they become dull faster. The thickest knives do not wear out for quite a long time, but are more suitable for coarse growth and weeds.

As practice shows, the most common shape of a trimmer knife is round with teeth around the circumference. A variety with 4 large teeth and a row of small teeth between them is also becoming a frequent choice. They most effectively help in cleaning the area, can be easily installed on any trimmer model.

Benefits of disc trimmers

When mowing tall grass, it often gets tangled on the line and trimmer reel, which requires you to stop work and pick up these balls of grass with your hands. In addition, over time, the trimmer coil may break from this. As for the cutting disc, it can handle tall grass with ease.

The disc is also more effective when you need to cut dry grass, burdocks, hogweed, bushes and undergrowth. The only thing that a knife is afraid of is stones. For haymaking, the trimmer disc is the ideal solution.

over, metal discs do not wear out, so they do not need to be changed, unlike fishing line, which eventually becomes unusable.

Fitting the disc to the trimmer and observing safety measures

After you have decided which disc to take for the trimmer, you need to learn how to install it correctly. Initially, make sure that the bore on the disc is the correct hole, otherwise the disc will simply not fit your trimmer. And if you do succeed in securing it to the instrument, the disc may jump off during operation and seriously injure you.

Usually, each manufacturer for each model of the manufactured equipment also produces the corresponding equipment, so the choice of a knife should not become something very difficult. When you have installed the disc, check how securely it is attached.

If the disc is metal, it can only be installed on a trimmer with a straight boom, as this is due to the design of the unit. When mowing grass, bushes and thin trees, the disc, bumping into an obstacle (for example, a stone), bounces back, that is, in your direction. And when the bar is straight, the distance from the head to the feet is sufficient for your safety.

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 as well as 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 lawn mowers, 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.

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, and 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 homogeneous 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 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 lawn mowers.


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

Species overview

For lawn mowers, 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.

Each species has its own characteristics.

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

  • Species overview
  • Manufacturers overview
  • How to choose?
  • How to sharpen and deliver?
  • How to properly mow the grass?

Lawn mower knives are irreplaceable. It is enough to choose a suitable one, and you can use them to mow huge areas of grass. 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.

How to sharpen and deliver?

a lawn mower 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 just install new knives.

  • First of all, the knife is removed from the device. Sharpening directly on the mower 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.
  • You can sharpen your knives with a file, sharpener or 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.
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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.

  • Once sharpening is complete, the blade can be reattached to the trimmer and checked how efficiently 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 the trimmer is a snap. This procedure takes no more than 5 minutes, 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 lawn mower.
  • 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, the mowing head must be unscrewed from the lawn mowers.
  • 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.

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 lawnmower’s work.

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

Manufacturers overview

There are a lot of manufacturers of lawn mower discs. It is worth familiarizing yourself with the most popular among them. For example, the Bosch brand is known for its knives with two and three blades. The peculiarity of the knives of this company is that each of the blades can be replaced separately from the others.

Another company known for its bladed 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 their low weight.

Husqvarna is also known for its multi-tooth knives, especially the hay knives. Ideal for dense and dense grass. Of the minuses, it is worth noting the large weight of the discs and the fact that you cannot turn the knife over if one side of it 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, victorious soldering is erased very quickly.

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

Rezer discs are excellent at mowing grass, weeds, branches. The teeth can withstand well even cutting down trees with a thickness of 6 centimeters or more. However, they have a drawback in the form of winding grass on a shaft.

Patriot produces quality knives. Users note that if you choose the right disk for a specific job, then it will serve for a long time and amaze with its performance. Knives from this manufacturer are very easy to sharpen yourself.

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 lawn mowers. They fit perfectly with the curved shaft of this tool, which does not 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 knives are only suitable for the petrol trimmer. This is due to the flat bar that moves the disc away from the feet to a safe distance. Specially 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 put the disc on the trimmer correctly

How to mow with a trimmer (with a metal knife)

Walk around the site first.
a) to determine:
– the boundaries of the area where you will mow with the trimmer;
– where are the plants in the grass that cannot be cut (flowers, bushes, seedlings);
b) to determine the starting point (you need to start mowing with the trimmer from the lightest area in order to create an open space so that when moving into larger grass it is better to see the mowing area);
c) to determine the direction of mowing with the trimmer (depending on the presence of ditches, slopes and slopes of the grass);
d) to determine how to cut with the trimmer:
– in folds. if the area is flat with flat grass (so that there are fewer transitions);
– with the transition back to a clean place, when mowing lodged grass (its slope should be directed forward);
– mowing across a large slope (it is much easier to cut across a slope with a trimmer than going up and down a slope).

We put a metal knife: weed or hay. Protection, i.e. knife guard, obligatory (without additional protection for the trimmer head)
– to mow with a trimmer, it is necessary to assemble in order: a driver chuck, a metal knife (it must be put without skewing), a support cup, a fastening flange and screw on a nut (left-hand thread);
– insert the locking pin and turn the metal knife to lock the output shaft of the Husqvarna gearbox;
– tighten the nut with a wrench with a force of 3. 5 kg / m;

When mowing with a trimmer with a metal knife, you need to set:
– the speed of the knife, depending on the irregularities (to mow with the trimmer cleaner and faster);
– working grip of the disc: between 8 and 12 o’clock (when the knife moves to the left);
– reverse (can be working, cleaning up or idle);
– gas (by load);
– on an even level: the angle of inclination of the knife and the width of the mow (more);
– cutting height (to make it easier to mow with a trimmer or to make it cleaner);
– where to move (along the ditch, along the slope of the grass, on the site);

11 o’clock) and to the right with an inclination of the handles to the right (sector

1 hour), and take your time. to mow with a trimmer neatly and not to “dig” the ground;
– during work (and turns) do not forget to look around !:
1.To notice the gestures of others, turn off the engine and remove the headphones,
2. so that children, animals, spectators and assistants do not come closer than 15 m. when a metal knife collides with a stationary object in the grass, the trimmer or lawn mower (lawn mower) can be strongly thrown to the side or turned back, and the maximum speed of the metal knife is 10,500 rpm. and he is able to cut off an arm or a leg,
and also, when cutting with a trimmer, various objects (rubble, glass, debris) can fly out and ricochet out from under the metal knife.

How to mow with a trimmer correctly (more about mowing technique).

Engine speed when mowing with a trimmer is set depending on the load on the engine. the thicker the grass and, naturally, the heavier the engine, the bolder you need to open the hole (throttle valve in the carburetor diffuser).
Try to keep the engine operating speed constant while cutting with the trimmer (slightly above average). or less gas. only depending on the total load on the engine. There is no need to completely dump the throttle (and immediately accelerate again) with each sweep of the streamer. So it does not take long to burn the clutch, and it can overtake the edges on the drive shaft. and the overall wear of the trimmer (lawn mowers) increases dramatically.

remove the disc from the angle grinder

This method involves the use of the famous VD-40 grease.

It is probably like electrical tape, applicable in all cases of life.

You need to spray the flange, wait about 5 minutes and try to unscrew it with a wrench.

remove the disc from the angle grinder

First, figure out which way to unscrew the nut.

The flange must always be folded in the direction in which the disc rotates.

For this kind of work, you will need either two gas keys or two clamps.

Here’s what you need to do: destroy the remnants of the disc, fix the washer located behind the disc with one key, unscrew the flange with the second.

Cut-off wheels for an angle grinder, in turn, have their own subspecies, such as:

  • Cut-off wheels for metal work;
  • Abrasive wheels for working with stone;
  • Wheels for woodwork;
  • Diamond discs (mentioned above).

The purpose of each type of disc usually corresponds to its name.

Among the grinding discs, there are four main subtypes. flap, wire, diamond and bakelite-based grinding discs (straight, T41 profile and disc-shaped, T27 profile).

  • The flap disc is made from sandpaper. Its main purpose. it is the elimination of an existing coating such as old paint, primer or paint coat. Also, with disks of this type, wood products are polished.
  • Wire discs are used by artisans to remove rust. They can also remove other types of stubborn dirt.
  • Diamond discs are used for polishing stone.
  • Disc discs are made of plastic or rubber and are used to polish metal surfaces.
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Please note: in the process of working with most discs, a special paste or lubricant is used, which contains abrasives of the finest grinding. They are mainly used for sanding surfaces such as, for example, car body parts.

remove the disc from the angle grinder

This method is used in extreme cases.

How to Place a Disc on an Angle Grinder Correctly?

In order to correctly place the disc on the angle grinder, it should first be noted that the disc is mounted on the spindle of the angle grinder using a special clamping flange with M14 thread. Let’s take a closer look at how to remove a disc from an angle grinder. In order to unscrew the disc from the angle grinder, you first need to dismantle the flange. Especially for such purposes, manufacturers complete the angle grinder with a special open-end wrench. It has a specific shape. The pins located on the horns of this key are inserted into specially provided holes on the flange.

To unscrew the flange, we fix the spindle. To do this, we clamp the latch, which is usually a button on the top of the case. When pressed, the cotter pin is placed in the hole in the driven disc of the gearbox, and this in turn prevents it from rotating. Next, we insert the pins of the key into the specially provided holes on the flange, pressing the lock, you must simultaneously turn it counterclockwise and move the flange from its place. If the manipulations were successful and the flange succumbed, you can unscrew it by hand and put it aside.

Now let’s dismantle the disk. Often, in the process of intensive work with the tool, a kind of plaque from small particles of metal and abrasive material forms on the inside of the protective casing. For optimal, stable and durable operation of the angle grinder, remove the bottom of the flange and clean the casing with a steel brush.

How to remove, change a jammed disc from an angle grinder?

How to remove a disc from an angle grinder. an angle grinder (hereinafter referred to as an angle grinder), popularly referred to as an angle grinder, is probably the most demanded inventory that is present in the arsenal of almost every master, regardless of his qualifications.

This tool is actively used in abrasive processing: cutting, grinding, cleaning workpieces from stone, metal and many others. It is widely used in areas such as construction, woodworking and other similar types of work. Like any other tool, the angle grinder is also divided into several classes.

This refers to the following: household, semi-professional and pro-class instrument. This classification is determined by the power resource of the tool, its performance, the presence of certain additional options, material and workmanship, etc.

Consumables for an angle grinder, in addition to various types of cleaning brushes, are cut-off wheels and a variety of grinding discs. Types of Angle Grinder Accessories: How to Make the Right Choice?

The main question: How to choose the right disc for your angle grinder?

When choosing accessories for an angle grinder, first of all, you should decide on the type of proposed work. The choice of the type of disc will depend on this. We also want to mention that when choosing a consumable, be sure to take into account the power characteristics of each specific model. Examine the labeling. Often, it is printed on the disc itself and includes a set of symbols by which you can determine the relevance of this consumable to perform the intended work.

Also, focus your attention on such a parameter as the diameter of the disc. In no case should it exceed the size of the protective cover on the particular tool model. The size range of discs is usually represented by the following diameters: 115, 125, 150, 180 and 230 mm. The most common diameters are 125 mm. and 230 mm. They are optimal for most types of work and the capabilities of the tool itself.

Among the grinding discs based on bakelite, the most popular discs with a thickness of 6.00 mm. This parameter depends on the total diameter of the disc. The relationship is as follows: the larger the diameter of the disc, the greater its thickness and vice versa.

Angle grinder discs differ in the following main features:

  • Outside diameter;
  • Disc thickness;
  • The material from which the disc itself is made;
  • The characteristic of the maximum rotation speed;
  • And, of course, the area of ​​the proposed work.

For the best understanding, let’s take a look at the main types of angle grinder discs and define their application:

  • Cut-off wheels. It is the most widely used angle grinder consumable. Their main purpose is to work with metal, stone and wood. A variety of cutting wheels for an angle grinder are diamond discs. This is a heavy-duty tooling for the processing of materials with increased strength, such as reinforced concrete, tiles, porcelain stoneware, marble.
  • Grinding and roughing discs. As the name implies, this type of disc is used for grinding various materials, for example, polishing products made of stone, or for removing (roughing) the top layer, for example, removing a layer of rust or old paint coating.

Trouble with a leading star

Sometimes chain slack is due to drive sprocket problems. The most common situation is when it is poorly secured. Step-by-step algorithm to twist the asterisk:

  • Remove the engine cover.
  • Remove the air filter and unscrew the candle, putting in its place a special stopper to fix the piston in an immovable position.
  • Using the angle grinder wrench, turn the clutch disc clockwise to the highest position. Check the tightness of the sprocket, adjust its position. Figure 3. the driving star on the chainsaw

After tightening, reassemble the chainsaw, be sure to put on the protective cover. When assembling, check that the chain fits snugly on the bar.

Why did the chain fly off?

There are several reasons why the chain can fly off during operation. This may be due to improper tire operation or insufficient tire tension. The problem sometimes appears even with an insufficiently secured drive and driven sprocket. Determination of the cause allows you to accurately select the required repair, tools.

How to install a bar with a chain on a chainsaw?

Often, problems in the operation of a chainsaw arise when the tire is incorrectly installed. This can be determined by the characteristic rattling, vibration and low performance of the saw during operation. The tire is fastened to the body between the outer plate, fixing is carried out with a special bolt.

Popularly referred to as the “engine assembly”, this part consists of a drive sprocket and locking bolts. It is not difficult to install the tire together with the saw. you need to remove all protective covers, unscrew the fixing bolts by a third of the length and put the headset. Then tighten all the nuts tightly, turn the tensioner with a special lever.

How to properly put a chain on a chainsaw?

In most chainsaw models, the chain is easy to put on the tire by unscrewing the main screw, then the links must be placed on the drive sprocket. Before starting work, the general condition of all cutting surfaces and the guide groove and setting wheel should be inspected. Often, dirt and small chips accumulate in it, which will subsequently lead to planned repairs, deterioration of sliding. Step-by-step algorithm of work:

  • Loosen the screws securing the sprocket protection cover, usually it is tightened with a wing nut.
  • Turn the tensioning sprocket to the right until it stops.
  • Place links on the headset starting at the top. Drink so that they fall into the corresponding grooves.
  • Fasten back the chain sprocket mount, tighten the nut. The guides must fall into a special chute.
  • Release the chain brake, pull the chain along the mowing line to check the tension. Tighten the tensioner lever if necessary. Figure 4. Installing the chain on the chainsaw

How I align & tune Wahl clippers

The setting wheel should turn freely after installing the chainsaw chain. At the end of the work, it is imperative to lubricate all moving parts of the tool to avoid rapid wear.

Important! Installation of the headset should only be carried out with heavy protective gloves. This will protect you from injury and cuts from the sharp edges of the cutting edge of the teeth.

How to put a chain on a chainsaw correctly: instructions, recommendations, basic methods

The chain is an important element in the construction of a chainsaw. It is she who has the greatest load during work, so high-quality and systemic care is required. When using any model, it is important to know how to put on the chain correctly, to monitor its tension. If it is not secured correctly, there is a risk of stretching and coming out of the grooves. Reduced saw performance and increased risk of injury at high power.

  • Why did the chain fly off?
  • Loose tire
  • The chain is stretched
  • Trouble with a leading star
  • How to properly put a chain on a chainsaw?
  • How to install a bar with a chain on a chainsaw?
  • Fitting the tire on Stihl and Husqvarna
  • Chain tension

Loose tire

When the chain tension is reduced, the problem is often accompanied by a weakening of the tire itself. To check its condition, you need to inspect the place between the top plate on the headset casing and the inner surface on the case. When the locking bolts are loosened, the bar begins to move, which can be seen by the characteristic vibration during sawing. For frequent use, it is recommended to tighten the bolts regularly.

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Figure 1. Loose tire

If you decide to tighten the tire yourself, then you need to find and lower the chain brake. Turn the tension screw so that the chain fits snugly into the grooves. After that, pull back the chain in the direction of travel, if it is too tight, loosen the screw.

Important! Tire loosening is observed in both professional and household chainsaws. If the tool is used intensively, check the tension before each start.

Fitting the tire on Stihl and Husqvarna

Chainsaw models from the manufacturer Stihl may differ during the assembly process. Step by step guide:

  • Open the wing nut, remove the chain sprocket cover. Turn it on the tire all the way to the right.
  • Place the chain on the bar, starting from the top, the cutting tooth on the top side must point straight ahead.
  • Attach the assembled tire to the chainsaw, pull the structure over the sprocket. Slide the guide onto the shoulder bolt. Close the cover by placing the pins in the holes provided by the manufacturer.
  • Turn wing nut until sprocket cover contacts motor housing.
  • Turn the clamping bolt forward, the drive links should fit into the grooves in the bar. Tighten the wing nut completely.

At the end of work, check the tension, if the headset does not move well, adjust the tension with a nut. Engage the chain brake before starting.

The Husqvarna saw chain installation algorithm is almost identical. The main difference is that in most models, the tension and adjustment of the position of the headset to the body is controlled not by one, but by two wing nuts. There is rarely a separate adjustment lever on the outer sprocket guard, so the tension should be adjusted using bolts only.

Important! Before starting to work with the chainsaw, you should carefully study the owner’s manual. It describes in detail all the stages of setting up and assembling the instrument.

The chain is stretched

Any functional changes in the chain lead to a decrease in the productivity of the tool, injuries during operation.

It should be regularly monitored so that there is no deformation of the metal and stretching of more than 1 cm.

If this problem still occurs, you need to purchase a new chain or correct the old one.

Disconnect the chain links on the machine or fix it in a vice, file off the rivets and knock them out with a bit (it is not recommended to use an angle grinder).

Remove 1-2 links depending on the chain stretch. After that, put all the elements in place, insert the rivet and beat it off with a hammer, use a special rivet tool. For reliability, it is recommended to use a welding machine. At the end of the work, grind off excess and burrs with a thin file.

DIY trimmer attachment

For many summer residents, the trimmer has long become a familiar and almost irreplaceable technique. But it is not always possible to purchase a model that meets all needs. It happens that the trimmer copes with fresh young vegetation easily, but there is a desire to clear a place behind the fence or along the access road, and the tall ripe grass turns out to be too tough for the technique.

DIY trimmer attachment

We offer the option of self-production of the trimmer head from simple (almost improvised) tools.


  • metal perforated plate (100 mm x 240 mm)
  • 2 hacksaw blades for metal
  • 4 screws and 4 nuts M5
  • 4 washers and 4 oversized washers

From a safety point of view, hacksaw blades should not be completely hardened.

Everything you need to make a nozzle

The most difficult thing in making a nozzle is to symmetrically mark and make holes for the knives and the trimmer shaft. That is why a ready-made perforated plate is chosen.


First you need to make the base of the nozzle. To do this, cut a square with a side of 100 mm from a metal plate of an angle grinder. You need to mark it in such a way that there is a hole exactly in the center (at the intersection of the diagonals). To do this, measure a distance of 50 mm from the center of the selected hole perpendicular to the short side of the plate and outline the cutting line for cutting.

We mark the base of the nozzle

Cut off the excess and get a square of 100 mm x 100 mm. Now you need to round off the corners a little and drill out the central hole for the trimmer shaft.

Round off the corners and drill the center hole for the trimmer shaft

Cut the canvases for metal, measuring 8 cm from each end.We get 4 blanks with ready-made holes.

We cut canvases for metal

These blanks need to be shaped like knives. To do this, we outline the cut line by eye (special accuracy is not required), fasten all 4 blanks together and grind off the excess.

Cut out knives from blanks

As a result, we get knives of the same weight and size, they can be sharpened a little on one side. Now all parts of the homemade trimmer attachment are prepared, you can start assembling.

Everything is ready for assembly

Put a small washer on the screw and insert it into the corner hole. We put on the knife from above, placing the sharpened side in the direction of rotation of the trimmer shaft. This is followed by a large washer and a nut that is not tightened so that the knife rotates freely. We attach the other 3 knives in the same way.

Fixing the knives

The end of the screw must be riveted so that the nut does not fly off.

The end of the screw must be riveted

The attachment is ready. It is installed with nuts to the ground and fixed in the same way as the three-blade knife that comes with the trimmer. When colliding with a stone, the knives fold and go inside a little.

This idea was suggested by our regular video author Tatiana (Tula region). You can see in more detail the whole process of making such a trimmer attachment and find out some of the nuances by watching the video that she prepared.

When working with a trimmer, it is important not to forget about safety, using any attachments, especially homemade ones.

We suggest discussing this idea in the comments to the publication. Share your thoughts with us, and also tell us about your good solutions.

Without accepting any of the sides of this sharp (literally and figuratively) discussion, let me show you one of the latest models of lawn mowers from the German company Robert Bosch. It provides for both a deflecting knife and an arcuate bracket, which excludes the “striking” of the knife on objects not foreseen by mowing. I show the general view of the lawn mowers and the knife itself, in two positions. General view of lawn mowers

Knife in a deflected state

Folded knife

Good evening everyone!
Exactly three years have passed since the discussion of the “acute” problem for the trimmer. Over the past 1000 days, a clear picture has emerged: “Glory to the author. the craftsman who conducts an experiment on himself to reach the yield point of the metal from which these knives are made. He has every right to risk his own health. ” Nowadays in stunt films you can often see a frvza. “Do not try to repeat the movie stunts that were performed by professional stuntmen.” The very first article was supposed to end with approximately the same phrase: “Dear summer residents. This is my personal experiment. If you are not sure of your locksmith’s abilities, please do not repeat it. AND MOST IMPORTANT. I am not responsible for the operation of the tool, made in the footsteps of my articles.”
And the last thing. Do I see errors, judging by the photographs, of the execution of this tool. Yes, I see, and a rude one. Look closely at the plate, which is the carrier for the four knives. Look carefully at the FAR RIGHT HOLE in the photo.

Alas, the author of this device does not even suspect how the hole for the shaft should be made.

I inform you that the distance from the point of the hole closest to the edge of the plate to the very edge should be NOT LESS than the diameter of the hole itself. Students of mechanics will learn this truth no later than the second year of the institute. What do we see here? A thin isthmus resembling a narrow PEREKOP, making a peninsula out of the Crimea. This is a priori the place that is weak in this design. it experiences the same loads as other knives, but the “digging” there is very thin.
Where it is thin, there and.
I would like to hope, and quite sincerely, that over these three years this isthmus has not undergone loads comparable to the yield strength of this metal, but rather the alloy from which the perforated plate is stamped.