Do-it-yourself protective cover for a lawn mower. How to make an electric trimmer with your own hands from a vacuum cleaner or other power tool

Hand trimmers mow vegetation either with a fishing line or with knives. At the beginning, the functionality of the trimmer is limited to mowing soft grass with normal and low height, since plant debris is wound onto a flexible shaft, or in other words, sticks to the spool. By installing a trimmer blade, it becomes possible to cut off tougher trunks and trim young bushes.

Types and uses of trimmer knives

The systematization you will like is carried out according to the following characteristics:

Based on the material of the knife: iron and plastic knives are known. The choice is often limited not so much by the user’s desire as by the power of the drive - iron blades are heavier, and the trimmer shaft equipped with them develops more slowly, which adversely affects the durability of the motor. But the cutting ability and durability of iron knives is much higher than that of plastic ones.
For making cutting edges. They are distinguished by significant diversity, and as a rule they come with 4 or more teeth, single or different heights, and also solid or with technological holes.
According to the shape of the knife itself, which has a solid disc blade, or made in the form of several blades with a similar distance.

The choice of the size and design of the trimmer blade depends on the intended purposes, the type of rod and the power of the motor. If the trimmer rod is bent in the shape of a letter J, then there is no need to use a metal knife, since if it comes into contact with a powerful obstacle, nettle, stone, trimmer will be sharply thrown back, towards the mower. Then even the highest restrictive casing will not save the worker from a leg injury. On trimmers with a straight shaft, the rebound distance will increase.

Plastic trimmer blades, although less durable, are quite capable of cutting most types of grass. In addition, their increased elasticity does not create additional loads on flexible shafts electric trimmers.

The configuration of the cutting edges determines the quality of the cut. For hard grass, dead wood, woody shoots, disc blades with the largest number of teeth are better: then, regardless of the speed of rotation flexible shaft, the cut will be clean and even. The inertia of perforated knives is significantly less than solid ones, and this does not particularly affect the durability of the tool, taking into account the fact that the tool is made of high-quality tool steel. The exception is cheap Chinese-made products: knives there are made from any steel.

Where and which knife is better?

When the fishing line’s capabilities are not enough, you should think about replacing it with a metal or plastic knife. If a replacement knife is included with the trimmer, there are no problems: replacing the cutting equipment is done in accordance with the instruction manual for the trimmer. However, this does not happen every time.

Motokosa. How to replace a damaged shield.

Motokosa. How to replace a damaged shield. The shield was damaged for several days. Maybe I was unlucky. B high

Metal disc knives

Usually, several of these knives are included in the trimmer kit, but you can also purchase them separately by measuring the outer diameter of the knife and the configuration of the mounting hole. Nettle, circular cutters from Stihl and Husquarna are interchangeable with each other. Circular knives differ in the number of teeth, height (some have different heights), and also the continuity of the blade. In most cases, such knives are installed on trimmers from Stihl, Huter, AL-KO, equipped with a straight bar, and are more rigid. They cope well with old growth and long trunks, however, when working with young grass, sticking of the mowed mass is often observed on inner surface protective casing.

A trimmer with a perforated blade, compared to a solid one, picks up speed faster. The disadvantage of circular knives is the increased moment of inertia, so the starting power of the drive increases.

On cheap designs and with frequent stoppages in work, this leads to overheating of the motor and negatively affects its durability.

These are the knives that he uses to complete his electronic trimmers. trademark Bosch. Their moment of inertia is small and does not actually affect the performance of the drive. The ease of use of this design lies in the fact that separate replacement of all blades is possible. For trimmers of this type, the rod is bent in the shape of a J-shaped blade. Two-bladed knives work stably on a homogeneous mowed mass. They perfectly throw the cut shoots to the side and do not allow residues to stick or wrap around the rod shaft.

Three-blade and two-blade knives are quite competitive with disk knives in their capabilities, but the thickness of the blade should not be less than 2 mm. At the same time, forged knives are more durable than stamped ones (found on Chinese-made trimmers).

It is easy to distinguish them - on stamped blades, traces from the cutting punch are clearly visible with the presence of corresponding chipping and shear zones, which is not present on forged ones.

Shark knives “Shark” is essentially an attachment of three bladed knives, with each blade fixed relative to the other at an angle of 120°. The advantage of this design is that each blade can be customized individually. And therefore, when mowing an area with various types vegetation (grass, weeds, dead wood), the quality of mowing will be approximately the same. Today, since the interval between mowing the grass with each blade is reduced, the discarding of the grass occurs more actively. The “Shark” head is compatible with many standard sizes of electric trimmers and has a small own weight

, but requires periodic adjustment of the blades, which are attached to the base with conventional screws. There is an option to reduce the moment of inertia of the circular knife by independently perforating its surface, nettle, on a punching press. The perforation holes are made to be placed strictly symmetrically relative to the center of mass of the knife. The tool becomes lighter, but its cutting capabilities do not change. Beneficial effect The correct sharpening of the blades of the replaceable knife also ensures proper sharpening. It is produced at low speed grinding wheel

with normal grain size. The teeth are sharpened at an angle of 30°. You should not use a trimmer knife tipped with carbide - the quality of the cut remains virtually the same, but the weight of the tool will increase.

DIY trimmer knife

A piece of pipe (copper is better than metal) of a suitable diameter for the production of an adapter sleeve for the outlet part flexible shaft.
A sheet of steel less than 1 mm wide for the washer.
An ordinary cotter pin in accordance with GOST 397-66, for attaching the base to the trimmer shaft.
Steel strips 1...1.2.4 mm wide for the production of knife blades.
Fasteners (it is better to use rivets rather than screws or a nut for a knife, even if it is included in the original kit).

A view of a homemade trimmer knife is shown in the figure.

Manufacturing equipment is created in this order. First, the general dimensions of the device are marked so as not to go beyond the boundaries of the protective casing. Then a sleeve is made from a piece of pipe. To improve the fit, the bushing is made split and seated along the outer surface of the output part of the trimmer shaft. Since the diameter of the washer is determined only by the dimensions of the available space, it can also be selected from the nearest standard sizes. The washer is welded to the bushing in such a way that the formed seam leg is the smallest.

Abstract on maintenance petrol trimmers and brush cutters

Fuel mixture

Oil– high-quality two-stroke oil for high-speed equipment (10-15 thousand rpm, about 200 rpm). Do not use motorcycle oils (low engine speeds) or for aquatic equipment (other cooling systems) - their use does not provide the necessary lubrication of the piston group and parts of the entire engine! Petrol- at least some untainted high-octane gasoline (with a number of 92 and higher, with a density within the range of 750-770 kg/m3). Fuel mixture proportion– 1:50 (2%) or 20 ml/cm3 of oil per 1 liter of gasoline. For example, in transparent plastic bottle(1 l) pour in half a measure of gasoline, then add oil with a honey syringe (20 ml/cm3) and mix, add gasoline and mix thoroughly. If the quality of gasoline is unclear or the working conditions are difficult, then the amount of oil should be increased to 22-25 ml/cm3. Shake the mixture before each filling. Having made a protective casing (how to install it on the protective casing and on the trimmer. Replacing the fishing line on the trimmer, how to install the mowing head and blade on the trimmer. Store the purchased fuel for less than 2 weeks. If the color of the consistency has changed (from sea green to, for example, brown ), then its use is not recommended.

Run-in.

Run at least one tank of fuel with the engine (without load!) with frequent changes in speed ( idling– highest speed). The next 5 hours of operation in gentle (50%) load mode. After running in, it is imperative to check the engine speed (using an electric tachometer in service center) and, if necessary, their adjustment by a specialist.

Maintenance.

Engine. The air filter must always be clean (no dirt or sawdust); The foam filter must be moistened with oil. The fuel filter should be inspected once a week (changed as needed). Check the tightness of nuts and screws before work. Cleaning the muffler (or its mesh) and spark plugs from carbon deposits – as necessary. Install the coil with cover 14 and remove the coil 17 as when closing the protective casing. Angular reducer. Once a day, clean off dirt (such a “fur coat” does not allow the gearbox to cool properly) and apply grease to the gearbox pair.

Assembly protective casing trimmer Huter

Manufacturing protective casing For trimmer.

Protective cover for trimmer

Manufacturing instructions protective cover for gas trimmer.

Line and trimmer heads. Use only special cutting line – do not use wire or metal cables! Install fishing line only with the diameter recommended by the manufacturer. Wind the bobbin tightly, but do not cross the threads. Clean the mowing head from dirt and lubricate it if necessary. Remove the protective casing with the fishing line must be correctly installed on the shaft. Initially, they are installed in the trimmer on how to properly put on the protective cover. A deformed or worn head can damage the gearbox and/or shaft of the brush cutter.

Cutting discs. The cutting parts must be well and correctly sharpened using the necessary templates and files and observing the angles of the cutting parts depending on the brand of the disc. Double-sided discs should be regularly turned 180° and worn evenly. A dull disc or a disc with poor or incorrect sharpening does not cut well, and thereby overloads the engine, which leads to a rapid reduction in its service life. Protective covers. The motor on the electric trimmer is on them, since there is no protective cover with. It is forbidden to work without protective casing– this is dangerous for the life of the operator and can overload the motor of the brush cutter. Each type of cutting equipment should only use its own protective cover.

A haircut. Hold the trimmer head directly above the ground at an angle. The work is done by the end of the string. Allow the string to operate at its own speed. How to wind the fishing line on a thicker cord and install it without them touching the protective casing. Do not press the string against the area to be mowed! This overloads the engine and mowing head - they can break down or melt!

Trimming with a knife. Mow with a pendulum motion from side to side, the movement from right to left will be working, and from left to right will be return. The blade should cut the grass with its left edge (on the clock dial - between 8 and 12). Compliance with the recommendations listed above will extend the service life of gasoline-powered vehicles many times over.

In the summer, in order for the dacha plot to look neat, you have to mow the grass often. A trimmer, a lightweight hand-held lawn mower in the shape of a cane, helps to cope with this speed of an ordinary scythe.

A sort of electric scythe, but instead of a blade it has a fishing line.

A recognizable drawback of trimmers is that you cannot work with them without special protection (mask and glasses): the grass scatters at high speed in different directions, getting into your face and eyes.

The reason for this is the small shield above the rotating line.

To solve this problem, I trimmed the “original” plastic shield, leaving only the third part attached to the rod.

Then I made a new one from a duralumin sheet 0.2.4 mm wide and 250x250 mm in size, and attached it with 2 screws from above to the remaining part of the former shield.

Instead of aluminum, they use a plate made of rubber or linoleum, but then the shields made of these materials will have to be secured with metal wire so that the edges do not accidentally get under the spinning fishing line.

While using any electronic trimmer One big drawback appears: the resulting grass juice and haylage scatter far to the sides and up, covering the mower with greenery from head to toe. You have to use special clothing and a mask to protect your face and eyes; unfortunately, the dust gets into your boots and settles on your headdress. After just an hour of work, the mower turns out to be “all covered with greenery, completely covered”! We have to waste extra time on the next “sanitation”.

Increasing protection on your trimmer at home. Additional protection for trimmer/Protection trimmer

The reason for this cut is that trimmers have an extremely small shield over the rotating line. In mine, for example, the shield occupies only the sector that on the watch dial corresponds to the numbers from 4 to 8, which is obviously not enough.

To eliminate this defect, I cut off the plastic shield in my own trimmer, leaving only the third (central) part attached to the rod. Then I made an enlarged shield from a duralumin sheet with a width of 0.3.2 mm and a size of 250x250 mm, which I attached with 2 screws from above to the remaining part of the former shield (see figure).

In the process, the resulting new shield began to cover the entire semicircle of rotation of the line facing the mower, protecting him from flying greenery. The effect of such modernization was excellent! Nowadays even boots don’t get dirty above half the tops.

If there is no duralumin sheet, use a rubber plate, or linoleum. To prevent the edges of such material from drooping, they will have to be reinforced on top along the perimeter with metal wire. At the same time, the peripheral parts of the material must be held in a raised state by the wire. The shield material is attached to the wire specifically in these places that are inaccessible to a rotating fishing line.

From Bulgarian

Every master has a grinder. This is the most suitable tool for creating a trimmer. Unlike store-bought devices, it is stronger in power and has good speed. Let's look at how to make a trimmer from an angle grinder with your own hands, the order of work:

First, prepare the bracket. It is designed to fit around the body of the angle grinder. metal plate applied to the body and bent.
On both sides of the case there are threaded holes in which the reversible handle is attached. The trimmer bracket is attached to them.
Holes are drilled in the bracket on both sides so that they correspond to the openings located on the tool body. For accuracy, marks are made on the part with a marker, clamped in a vice and drilled.
Then a guide is attached to the bracket. Its size should match the length of the body or be slightly shorter. The guide is attached welding machine, the remaining scale is knocked off. The part is polished with a metal brush.
From metal pipe make a handle (bar). To secure the handle at a slope, the tip of the pipe is cut off at a bevel. The finished handle is welded to the structure, the scale is knocked off and the part is cleaned with a brush.
To attach the tool, you need to unscrew the protective disk of the angle grinder.
Then the homemade product is installed on wheels. To do this, you can borrow wheels from a cart or baby stroller with brackets.
First, install the grinder, then the wheel with bracket. Everything is secured with a bolt. On the other side they make the same fasteners.
The cutting unit is made of steel cable. Nylon wire intended for trimmers is suitable. It is threaded through the clamping nut and the key hole using the criss-cross method. Then the nut is tightened together with the cables.
The wire is fixed with electrical tape.

A neatly trimmed lawn is not only beautiful in itself, but also in a certain way indicates the status of the owner of the house. Nowadays, it is not difficult to find a lawn mower that is suitable for its performance and design. But there is another option. If you have a medium-power electric motor lying around on the farm, then after spending a few evenings, you can easily turn it into a simple and convenient homemade lawn mower, saving not such a small amount of money that you would have to pay for a branded lawn mower - and even enjoying creativity.

General structure of the lawn mower

In its simplest form, a lawn mower consists of the following components and parts:

Engine.
The frame on which all mower components are attached.
Knives.
Protective casing.
Wheels.
Handles for control.
Control system parts: switch, RCD, power cable with plug.

The frame of the simplest design is a metal sheet 2-3 mm thick with a hole in the middle for the passage of the motor shaft. The sheet is reinforced with a frame made of metal corners. The engine is attached to the sheet at the top, a protective casing at the bottom, an axle for the wheels on the sides, and handles for control.

If the motor is flanged, it can be attached directly to the sheet by drilling holes in the latter that coincide with the holes in the flange. If the engine is of a conventional design, two perpendicular corner posts must be welded or screwed to the sheet so that they coincide with the engine feet.

Homemade lawn mower. Fastening the electric motor to the corners.

Holes are drilled in the corners for mounting the engine. If the holes are made in the form of grooves, this will allow the engine to be shifted relative to the frame when mounting, thus changing the distance from the knives to the ground. This design feature will be useful when selecting optimal height cutting grass. But it’s easier to make holes for different engine height positions.

The central place of the lawn mower is the cutting unit, consisting of a mandrel with two short (or one long) knives attached to it.

Engine

A good option is asynchronous electric motor power 500-600 W and above, with a speed of about 3000 rpm. A big plus of an asynchronous motor is its low noise level. The higher the engine speed, the better and smoother the haircut. In fact, the quality of mowing is determined not by the speed of rotation of the blades, but by the linear speed of movement of the cutting edge relative to the grass. At the same engine speed, the higher the linear speed of the cutters, the larger the grip (the diameter of the circle along which the cutting edge rotates). Therefore, with a large grip (more than 40 cm), the engine speed may be lower. However, in this case, the motor power must be greater in order to overcome the increasing resistance. Practice shows that this option is quite workable: grip - 50 cm, engine power - 1 kW, speed - 1500 rpm. But in principle, a 500 W motor with a frequency of 1500 rpm will mow the grass, although worse. Only with low engine power, you need to sharpen the knives regularly.

To connect a three-phase motor to a single-phase network, it is necessary to use a circuit with working and starting capacitors. Connection information three-phase motors There is plenty of access to a single-phase network on the Internet. It is not difficult to find formulas for calculating the required capacitance of capacitors. In practice, they take approximately 200 uF for a motor with a power of about 2 kW. For a power of 500-600 W, 60-80 uF is sufficient.

When making a casing for the engine, you need to provide holes for cooling the engine.

You can make a lawn mower with your own hands using a conventional electric drill with a speed of up to 3000 rpm. Coming up with a way to attach a drill to a frame is not that difficult. However, you need to understand that in terms of reliability and duration of continuous operation, the drill cannot be compared with an asynchronous motor, so if you have to mow a relatively large area, preference should be given to the latter.

A drill is more suitable for making a homemade trimmer.

In the case of a drill, it is very simple to mount the knife. The knife with the hole in the center is clamped with a nut on the bolt, and the bolt is clamped in the drill chuck.

Mandrel

Most simple design The mandrel is a disk or strip with a flange in which there is a hole equal to the diameter of the motor shaft. The flange is put on the shaft and locked on it, knives are attached to the disk or strip. The diameter of the disk or the length of the strip depends on the planned working width and the length of the knives. As a finished mandrel, you can use a pulley with a landing diameter suitable for the shaft of the existing engine. This will solve two problems at once - centering the mandrel and its fastening. But the pulley must be reliable enough.

The mandrel must be securely fastened to the motor shaft. This is usually done using bolts screwed into the flange perpendicular to the shaft axis.

You can use a stone holder for a sharpener as a mandrel.

To prevent grass from wrapping around the shaft, you can cover it with a tin can.

If a suitable pulley or other suitable parts are not found, you will have to order the manufacture of a mandrel from a turner or make it yourself from a pipe of a suitable diameter and a strip or circle welded to it. There are three problems here: finding a pipe of suitable diameter, ensuring the perpendicularity of the welded strip or circle with respect to the pipe, and centering the mandrel after its manufacture. With some effort, all these problems can be solved.

Knives

Flat tool steel with a thickness of 2-3 mm and a width of 20 to 50 mm is used as knives. The thinner the knife, the better it cuts. However, a thick knife is stronger, which, given the obstacles encountered in its path in the form of bumps, various foreign objects and even stones, which is very important.

The design of knives has two main options. The first is a knife in the form of a long strip, which is attached to the mandrel symmetrically relative to its axis. The length of the knife in this case is equal to the width of the grip - usually 30-50 cm. The sharpened ends of the strip act as cutters. In this case, the knife and the mandrel can be one integral part in the form of a plate, to which a flange with a mounting hole is welded or riveted.

The second option is two short knives 50-80 mm long, which are attached to the edges of the mandrel at an angle of 180° to each other. They can be positioned straight or with a slight slope. The knives can be secured with two or one bolt. The first method is more reliable, however, fastening with one bolt allows the knife to fold (without breaking or deforming) when it hits an obstacle - a stone or a bump. The fastening of folding knives must be inspected regularly, because... Over time, the screws may wear out.

The steel for knives must be sufficiently hard, but not brittle, otherwise the knives may break, which will not only require their replacement, but also create the risk of injury from a flying piece. The experience of amateur craftsmen shows that wood hacksaw blades 2 mm thick are very suitable as a material for lawn mower blades. The technology for making a knife from them is simple. Two strip-shaped blanks are marked on the canvas (or one long knife is made from the canvas with sharpening at the ends and holes for fastening in the middle), which are then cut out with a grinder. Holes for fastening are drilled in the workpieces. After this, all that remains is to sharpen the knives, attach them to the frame and center them.

If drilling holes is problematic, then you can place the blade on a metal surface with a hole slightly larger in diameter than the hole in the blade should be and hit it with a punch. The protrusion formed after the impact is removed with a file (if the metal is soft enough) or with a sharpener. If the hole does not meet the required diameter, the process is repeated.

In essence, there are many options for making functional knives, as well as materials for making them. The main thing is to sharpen them well, center them (so that there is no vibration) and securely fasten them. When attaching knives to the mandrel, you need to use lock washers and locknuts. Without this, the mounting bolts will unscrew due to vibration.

If possible, it is better to make the cutting edges slightly curved down, like on branded lawn mowers. This will reduce the grass from wrapping around the motor shaft. Or you can make a disk that covers the shaft. Also, if the engine power is close to the power of branded lawn mowers, you can buy a branded lawn mower blade ().

Wheels

The diameter and position of the wheels must be selected so that the knives are located at a distance of 5-6 cm from the ground. This mowing height is considered optimal - both from the point of view of the aesthetics of the lawn and the quality of the haircut. If the grass is cut at too high a height, it will bend, allowing the blades to pass above it and remain uncut. Cutting lower is difficult due to the unevenness of the ground.

There is no clear opinion about what number of wheels is optimal - 2, 3 or 4, among craftsmen operating homemade lawn mowers. 3 or 4 wheels are good because they set exact distance from knives to the ground. Two wheels make the lawn mower more maneuverable and allow you to cut grass in any hidden places. In addition, it is easier to find two identical wheels than three or four. However, you can make the wheels yourself, for example from plywood and bearings, so the last argument is not so convincing. Ultimately, the choice remains with the master himself.

If a two-wheeled lawn mower is selected, there must be protection against the rotating blade touching the ground.

If you choose a three-wheeled lawn mower, then two wheels should be on the handle side so that you can lift the front of the mower for a turn by pressing on the handle.

How larger diameter wheels, the better. A lawn mower with small wheels is more difficult to push through grass.

If the edge opposite the cutting edge of the knives is bent upward (or blades are riveted to them), they will work like a fan, lifting and rotating the cut grass with a flow of air. At the same time, if you make a cut in the casing (in the quadrant where the knives run) and pull a mesh bag or box over it, then the cut grass will be collected in it.

At the end of the article there is a video demonstrating the operation of the second lawn mower.

Without a bag, the grass will be laid in the direction specified by the cutout. Without a hole in the casing, the grass will be crushed, this will be mulching. But for all this you need enough powerful engine, and to avoid cutting grass from stuffing into the engine, the space between the engine and the knives must be covered with a disk.

Working with the mower will be safer if one of the handles is equipped with a lever that, when released, turns off the power supply to the engine.

Security measures

When starting to make a lawn mower with your own hands, you need to understand the dangers posed by operation similar devices. If we talk about the main threats, there are two of them: defeat electric shock and injury from rotating knives. Both are classified as very serious, so safety measures must be taken very carefully.

It is necessary to carefully insulate all electrical wire connection points - both on the engine itself and on the control parts. The insulation on the supply cable must not be damaged. To power an electric motor, you must have a double-insulated cable with at least 3 cores. The mower body is reliably grounded, for which one of the cable cores is used. Or they connect the lawn mower to the network using an RCD device. protective shutdown, designed to de-energize electrical devices when a person touches their parts that are energized due to insulation failure.

Do not operate the mower without a protective cover. When working, you need to make sure that there are no people nearby. Broken knives fly out at high speed. And if the operator himself is protected by a casing, then in some designs of homemade lawn mowers, the front area of the mower remains open. It is advisable to mow in rubber boots. This will protect you from the consequences of falling into various objects that are thrown away by the rotating knife.

Do not use the mower in wet weather or early in the morning when there is dew.

Below is an example of a homemade lawnmower gone wrong.

The engine is completely open, and there is no homemade casing, there is not even a protective disk on the side of the knives, although there is a huge hole there. There is no cover to protect the lawnmower from flying blades or thrown stones. The handles are welded and cannot be adjusted in angle; in addition, they cannot be removed when storing or transporting the lawn mower.

Video of DIY lawn mowers:

Homemade lawn mower from a basin

When using the content of this site, you need to put active links to this site, visible to users and search robots.