Some malfunctions that may occur with a power tool. Chipping of the cutting elements of the tool or its breakage Factory defects: a few words about the guarantee

One of the main tools used in construction and repair is an electric drill. Even children know what it is, but few owners of this instrument know how to repair it. Breakdowns happen with all tools, and if a drill breaks, you can repair it yourself with your own hands. Step by step description not only repairs, but also diagnostics of the drill are described in the material.

Electric drill - remember the design of the tool

An electric drill is a type of tool that is designed for drilling different types materials, including concrete and reinforced concrete. Only for this you will need to use a tool with an impact drilling function or an impact drill. You can find out how the tool works if you take it apart. A brief description of the design of Soviet and foreign-made electric drills is described below.

It should be noted that the design of modern drills of domestic and foreign production differs from the design of Soviet tools. Only these are minor differences, which consist in the absence of reverse on an electric drill, as well as impact drilling. So, structurally, an electric drill consists of two main parts - electrical and mechanical. The mechanical part is based on the following: structural elements:

1. Gearbox - a set of gears, due to which the speed decreases and the torque from the electric motor shaft increases
2. The cartridge is an executive body that is designed to secure working attachments
3. Bearings are supporting mechanisms for shafts and axes that ensure their rotation.
4. Impact mechanism - in electric impact drills this device is part of the gearbox

The electrical component of any corded electric drill consists of the following elements:

• A commutator type motor consisting of a stator (fixed part), rotor or armature (moving part) and a collector (copper plates or lamellas through which current is supplied to the armature winding)
• Graphite or carbon brushes are a transmission device through which current is transmitted to the rotor winding. Brushes are consumables, and when, this indicates their wear
• Start button - depending on model electric drill, switches are standard and with built-in speed controller
• Reverse button - Soviet drills do not have such devices. This is a polarity reversal mechanism through which the direction of rotation of the tool chuck changes. Installed separately or integrated into the start button
• A ferrite ring is an element (filter) through which noise in the network is smoothed out
• A capacitor is a filter element that prevents interference from entering the network
• The network cable is the connecting link between electrical outlet and tool

The photo above shows the design of the drill with the main components. Sooner or later, it becomes necessary to repair the drill due to the failure of its individual components and mechanisms. To do this, you first need to inspect the tool, identify the cause of the malfunction, and eliminate it. More details about what types of drill breakdowns there are, how to identify and fix them, are described in the material.

This is interesting! Old Soviet drills do not have a reverse mechanism or an electronic speed controller. Instead of an electronic regulator, a mechanical one is used, consisting of gears of different diameters and numbers of teeth. This method of adjustment is more reliable, since reducing the speed does not affect the power. However, this method of speed control is expensive, as it requires the additional use of a pair of gears. If one pair of gears wears out, you can continue to use the tool. Below are photos showing the design of the mechanical speed controller of an old Soviet drill.

What you need to diagnose electric drill breakdowns

Where should you start troubleshooting an electric drill? Of course, from the first signs, by which it becomes clear where the breakdown is hidden and which part needs repair. It is easy to identify mechanical problems with a drill, but with the electrical part everything is much more complicated. Here you will need appropriate tools from which you can draw conclusions about the malfunction of certain components, parts and mechanisms of the tool. To identify breakdowns in the electrical part of the electric drill, you will need to prepare the following tools:

• Voltmeter or multimeter. Preference should be given to the second option, as it is more effective and multifunctional
• Device for measuring interturn short circuit in an armature

To diagnose the mechanical part, you will need to perform the following manipulations:

1. See what specific function the drill does not perform
2. Inspect the integrity of the gearbox by first disassembling the tool body
3. Inspect the serviceability of the bearings, as these devices often fail in the absence of lubricant
4. Determine if the mode switch is working properly. If the device jams or fails, the tool will only work in one mode

In a drill, like any other type of power tool, various parts and mechanisms fail. The entire drill cannot break down completely, but in any case, even when the mode switch is faulty, the operator will not be able to use the tool to its full potential. That is why you need to learn how to repair a drill yourself. This is not at all difficult to do, even if you have no experience. Therefore, you should not buy at the first malfunction new tool, since the malfunction is sometimes easy to fix even without the need to replace parts. What types of breakdowns occur, how to fix them and what needs to be done for this are described in detail in the publication.

Where to look for a breakdown in the electrical part, the most common faults and their elimination

Electrical faults are the most difficult not only to identify, but also to eliminate. This is due to the fact that to see the principle of flow electric current impossible, but you can understand how a drill works. Based on the operating principle of the electrical part, appropriate conclusions can be drawn about possible malfunctions. The operating principle of the electric part of the drill is as follows:

• When the plug is plugged into a socket, voltage is supplied to the electric motor.
• The presence of a button in the design eliminates automatic start when the plug is connected to an outlet
• For the tool to start working, you must press the start button
• At the same time, the contact closes and current is supplied to the stator and rotor windings. The wires are connected to the stator directly, and to the rotor through brushes and a commutator assembly
• If we describe the principle of operation of a commutator motor alternating current, then it lies in the fact that the stator winding acts as a permanent electromagnet, due to which the armature is repelled. The armature will not rotate just like that, so it is also necessary to apply biased current to its winding

The rotor begins to rotate at a certain speed. This speed depends on the voltage. To reduce speed, regulators are used that work on the principle of increasing resistance. The greater the resistance, the lower the voltage, and accordingly the lower the rotation speed. Knowing the principle of operation of the electrical part of the drill, we will consider the main types of breakdowns and their elimination.

The drill does not turn on, what should I do?

When connected to the network, there are no signs of life of the instrument. Experienced craftsmen have had to deal with this phenomenon more than once, but what to do if such a phenomenon happens for the first time? Disassemble, diagnose and repair the drill. Troubleshooting when the drill does not turn on begins with identifying the presence of voltage in the network. It’s trite, but true - often the reason for a tool’s inoperability is the lack of voltage in the network. The reasons for this may be scheduled repairs at the transformer substation, tripping circuit breakers or the power cord of the outlet is damaged. Take a multimeter and measure the voltage in the network.

If the socket is working, then the next suspect for a malfunction is network cable. Yes, it also does not last forever, and can be damaged during the use of the tool. Do not try to find a breakdown visually, as this will be a waste of time. Take the tester and turn on the dialing mode, check the integrity of both wires. To do this, you need to disassemble the case and alternately touch one probe to the contact on the plug, and the second to the wire connected to the button. The cores are in good working order when the device “beeps”.

How to perform a simple repair of a drill button with a speed controller

If a preliminary check shows that the power cord is in good condition, then it is necessary to continue searching for the fault along the current flow circuit. The next element in the queue for troubleshooting is the button. On Soviet drills, such buttons are a simple mechanism through which contacts are closed. On modern tools, the trigger design includes a round regulator in the form of a washer with resistors, with the help of which the speed of rotation of the cartridge is regulated.

If the drill button does not have a regulator, then identifying and eliminating malfunctions is quite simple. To do this, you should disassemble it, inspect the integrity of the contacts and clean it with fine-grained paper sandpaper.

If an additional reverse switch is connected to the button, it must also be checked by testing. If it is determined that the breakdown is related to a malfunction of the button, then it is easier to replace it than to look for the malfunction and try to fix it.

Drill button why a capacitor is needed and how to check its serviceability

If you disassemble the button, you will find that in addition to this part a capacitor is connected (a yellow or black block). Could this unit cause the power tool to malfunction or not work? No, the capacitor is used to smooth out noise that occurs in the network. It serves as a filter element. If you disconnect it, the drill and other types of power tools will work as before. However, it is not recommended to operate the tool without a capacitor, since its absence (or malfunction) leads to the failure of semiconductor elements.

There is an opinion that the capacitor is designed to create a phase-shifting effect. This is an erroneous opinion, since this element does not affect the operation of the tool in any way, but only prevents radio interference from getting back into the network.

How to connect the drill button

Experience shows that drill malfunction in 60% of cases is associated with a malfunction of the shutdown button. Often, an attempt to replace this element leads to all the wires getting tangled, and the question arises - what should be connected where in order to connect everything correctly. This is exactly what is worth understanding so that wires connected at random do not lead to a short circuit.

It should be noted right away that the buttons on drills can have different designs, however, there are three types of their devices:

• Conventional ones without a regulator - when you press the trigger, the electric motor starts at full power. Typically, such buttons were used on old Soviet drills
• Button with speed control - there is a washer on the trigger, the movement of which increases or decreases resistance. The greater the resistance, the lower the rotation speed of the cartridge
• Buttons with speed control and reverse - the device is additionally equipped with a plate with a lever for switching the direction of rotation of the cartridge. Reversal is realized by changing the polarity of the voltage supply to the rotor and stator windings

One of the most difficult connection schemes is the last option. However, if you look at it, there is nothing difficult about connecting all types of buttons. The following diagrams for connecting the buttons of different drills - Bosch, Interskol and others will help you figure this out.

This scheme is also found in another design, as shown in the photo below.

The difference between these circuits is in the connection of wires from the reverse to the rotor and stator. Both options are correct and will work. It all depends on the model of the tool. By following the sequence of connecting the drill buttons, it will not be difficult to restore the functionality of the tool. Below is a diagram in the form of an illustration of connecting a drill button to an AC brushed motor.

It is worth noting that the drill button fails not only due to burnt-out contacts, but also due to wear of the expansion spring. With a large output, the spring breaks, which ultimately leads to jamming of the device.

How to identify a faulty brush assembly

Drill brushes, which are a consumable item, fail. The brushes are made of graphite, and with their help, current is transferred to the rotor through the commutator unit. During operation, brushes wear out, burn out, wear out and require replacement. The service life of brushes depends on various factors:

• Quality
• Collector serviceability

A brush malfunction can be identified by signs such as excessive sparking. If, before the drill stopped starting, there was excessive sparking with signs of carbon deposits, then it is highly likely that the carbon brushes need to be replaced. To replace, you need to remove the elements from the brush holders, remove the worn parts and install new ones in their place.

In addition to the malfunction of the brushes, it is necessary to pay attention to the condition of the copper lamellas of the commutator. If there are signs of soot on the copper base, as well as chips and other defects, then all this should be eliminated. If you cannot fix it yourself, then you should replace the anchor. The cause of carbon deposits on copper plates is excessive sparking of the power tool. In addition, when the collector is severely worn, a connection (short circuit) between the plates occurs, which is also unacceptable.

If the electric motor is faulty, when should it be replaced?

The commutator-type electric motor on a drill and any other tool is the heart of the equipment, which costs 60% of the total cost of the device. If the malfunction is related to the electric motor, then there are two ways to repair the drill malfunction - replace the entire motor or carry out diagnostics, identify the malfunction and eliminate it. It should be noted right away that you can do the diagnostics yourself, but you won’t be able to fix the faults yourself. Here you will need to take the faulty unit to a specialized workshop, but practice shows that it is easier to buy a new rotor or stator than to repair them.

Let's consider the principle of checking the serviceability of the stator and rotor of an electric drill motor with your own hands:

1. Using a multimeter in resistance measurement mode, the value between the armature windings and the metal core is measured. The presence of resistance indicates a violation of the integrity of the insulation
2. We use a marker to indicate the plate from which the check begins. Use the probes of the tool to touch the plates one by one and record the resistance value. In this case, the value between the plates should be approximately the same. A resistance difference of more than 10% is unacceptable and indicates the presence of a break
3. Checking interturn short circuit. A special device can be used to measure the presence of an interturn short circuit. It makes no sense to buy such a device specifically, since if there is no breakdown of the insulation on the body or a short circuit between the plates, then with a high degree of probability it can be assumed that the armature is working
4. After this, you should check the serviceability of the rotor. Similarly, the absence of resistance between the winding and the core is checked
5. Check the resistance between the windings. The absence of resistance indicates complete damage to the winding, and if it great importance it can be assumed that there is a breakdown. The video description below explains in detail how it is carried out. step by step check serviceability of the commutator motor

Malfunctions of the stator are less common than the rotor, but in any case, if the drill has recently been operating under high load, then the motor will fail. If it is determined that the motor on a drill is faulty, then it is easier to replace it than to repair it, and sometimes it is better to buy a new drill. The video below describes in detail how to find and fix electrical faults drills.

Failure of the mechanical part of the instrument

If electrical faults are difficult to identify, then dealing with mechanical breakdowns is much easier and cheaper. Mechanical defects can be identified even without the need to disassemble the instrument. If the drill cracks or the chuck does not rotate, but the characteristic sound of the engine is heard, it means there is a breakdown in the gearbox. When the attachment does not hold in the drill, there is a malfunction in the clamping jaws. Bearings may also fail and cannot be repaired and require comprehensive replacement..

Let's consider each type of malfunction, and the features of their identification and subsequent elimination.

1. The bearings have failed. Typically bearings last quite a long time and main reason Their rapid failure is the lack of lubrication or its depletion. There are two types of failures in bearings - complete destruction of the balls or wear. If completely destroyed, the part must be replaced. There are no difficulties when replacing bearings, so be sure to check their serviceability
2. Jamming of the gear unit - here breakdowns are associated with licking of the driven or driving gear. Even during operation, a tooth may break off, which will ultimately lead not only to a decrease in productivity, but also to a complete jamming of the transmission mechanism. If the gearbox malfunctions, the gears must be replaced. It should be taken into account that on household tools the gearbox can be made of plastic gears. They must be replaced with similar ones, otherwise installing metal gears will lead to accelerated engine wear.
3. Repair of the impact mechanism of a drill - unlike a hammer drill, this mechanism on a drill has a primitive design. The design consists of two parts, reminiscent of a friction clutch. Impacts are created by the movement of a toothed gear. The notches on the rotating gear mesh with teeth of a similar design on the housing, and as if jumping, clicks are created - they are also impacts. Malfunctions of the impact mechanism of a drill include the following: licking of jagged edges, which ultimately leads to a decrease in productivity. More often, the notches are licked off on the moving gear, which needs to be replaced. Another breakdown can occur when the shock mode of the limiter is not turned off. The reason is the wear of the metal ball, which, when the switch is moved, goes into the end of the shaft, thereby limiting the possibility of the gear teeth coming into contact with the protrusions on the body. To eliminate the malfunction, you should replace the ball in the design of the impact mechanism

4. Malfunction of the actuator - cartridge. Drills use key type chucks, which are characterized by increased reliability and efficiency. The clamping jaw on this part may fail and should be replaced. detailed instructions on how to remove, repair and

Bearings and cartridges are considered minor mechanical failures, and failure requires an appropriate approach. Even if diagnostics have shown that the gearbox does not need repair or replacement of parts, it must be dismantled, washed in gasoline and new lubricant applied. Such manipulations must be performed regularly, depending on the frequency of use of the power tool. Detailed description how to repair impact mechanism drill, described in the video report.

Learning to extend the life of a power tool from the moment of purchase

In order for the purchased power tool to serve for a long time and not fail at the most inopportune moment, it is necessary to ensure proper care from the very first day of purchase. This care includes doing the following:

• Store the tool exclusively in a dry and warm room. Exposure to moisture and low temperatures will lead to the formation of condensation and failure of the electrical parts of the tool
• Do not use the tool for a long time under heavy loads, as this will lead to overheating of the windings and failure of the electric motor.
• The presence of an impact mode does not mean that you can drill holes in concrete and reinforced concrete with a drill every day. The impact drilling function is auxiliary and is intended for infrequent use. For such purposes it is necessary to use
• If the brushes spark strongly, it is necessary to replace them without waiting until the tool stops turning on altogether.

When purchasing, keep in mind that drills are available for household and professional purposes. If you choose a cheap one household option, then you need to understand that such a tool is intended only for infrequent home use. Any home renovation using household drill will cause tool failure. If you need a drill to make repairs in your home, then you need to choose only professional options.

A drill is one of the popular power tools that are popular not only during construction and finishing works. Depending on the nature of use of the tool and its quality, such problems may occur. Negative consequences like a drill breaking down. To correct the situation, there is no need to buy a new tool, since you can repair the drill yourself. What you need to know for this, as well as what breakdowns can occur on the drill, we will find out further.

An electric drill consists of a plastic body (sometimes metal), as well as a work area, presented in the form of a chuck for attaching the corresponding attachments for performing various jobs. The body of an electric drill contains both electrical and mechanical parts.

The electrical part includes the following components:

• The AC motor is two-phase.
• Contact brushes located in the brush holder.
• Power tool start button.
• Power cable.
• Speed ​​regulator.
• Mechanism for switching the direction of rotation of the cartridge.
• Start capacitor.

The mechanical part is presented in the form of a gearbox and a bearing system. Main function The gearbox (set of gears) consists of transmitting torque from the electric motor shaft to the tool chuck. In impact drills and rotary hammers, the mechanical part is additionally represented by two pistons, as well as a ram and a striker. These elements allow you to turn on the impact mode, that is, the jackhammer function. The design of the tool is not at all complicated, so even an inexperienced specialist can fix any breakdowns that occur. Before you begin to repair the breakdown, you must find the cause, and for this you need to disassemble the tool.

Required tools and materials

To repair a drill yourself, you will need to use the following tools:

• screwdrivers to disassemble the tool;
• multimeter to determine electrical faults;
• sandpaper to clean oxidized contacts.

Depending on the cause of the breakdown, some materials will also be required. These include:

• gears;
• brushes;
• bearings;
• button.

In addition, if the tool has not been disassembled for a long time, then it is advisable to change the lubricant in the gearbox during disassembly. This will reduce the load on the electric motor and will also extend the life of the tool. Bearings also need lubrication, so regardless of the reasons for the malfunction of the tool, after eliminating them, you must definitely devote time to diagnostics.

Mechanical problems

Do-it-yourself drill repair begins with determining the causes of the tool malfunction. First you need to identify which part of the tool has failed: electrical or mechanical. As a rule, this is not difficult to do. The main mechanical problems include:

• Bearing failure.
• Gearbox failure.
• Gearbox failure.

Mechanical problems can be identified quite easily, since the sound of a running electric motor will be heard. If the gearbox or bearing is faulty, a characteristic sound will occur. If the cartridge is faulty, the master will not be able to clamp the working element in it.

1. The bearings are faulty. Bearings can fail only if dust gets into the lubricant, or from excessive loads. If the bearing has not crumbled, then eliminating the damage will not be difficult. To do this, you need to disassemble the tool, wash the bearing with kerosene, and then fill it lubricant. After this, do not forget to replace the seals, since, most likely, it was because of them that dust got inside the tool. It is better to lubricate bearings with special lubricants for high-speed devices.
2. Problems with the gearbox can only be eliminated by replacing the gears. As a rule, the entire mechanism is replaced, since it is almost impossible to find any spare part separately. You can purchase the gearbox for the drill itself if your drill has famous name. If the drill is unknown or made in China, then it is almost impossible to find any spare parts for it.
3. Cartridge failure. If a key chuck is installed on the tool, then such products rarely fail. But if this happens, then it is necessary to replace the entire device. In some cases, one jaw may become jammed in the chuck, so to eliminate the problem, the product must be disassembled and cleaned. Keyless chucks fail more often, so they should be replaced with a new one after they break or when the clamp becomes loose.

Often, in the mechanical part, the bearings or gearbox system, or less often the cartridge, fail. To eliminate a chuck malfunction, there is no need to disassemble the tool. In any case, repairing the mechanics of a drill is much cheaper than resorting to purchasing a new tool.

The most common electrical faults

Electrical malfunctions are determined quite simply, since when you press the start button, the tool will not emit characteristic features life. To repair a drill with electrical faults, you must first find the specific cause of the breakdown. Common electrical faults include:

A drill belongs to the category of those tools that are quite easy to self-repair. After identifying the cause of the malfunction, it will not be difficult to fix the breakdown or replace the failed unit. Be sure to remember that the tool may still be under warranty, so do not rush to disassemble it.

7.1. Manual locksmith tool and devices for everyday use must be assigned to workers for individual or team use.
7.2. Hand tools located in the tool room must be inspected at least once every ten days, as well as immediately before use. The faulty instrument must be removed.
7.3. Bench hammers must be made in accordance with GOST 2310 from steel grades 50, 40X or U7. The working ends of the hammers must have a hardness of 50.5-57 HRC at 1/5 of the length at both ends.
The heads of hammers and sledgehammers must have smooth surface, without chips and potholes, cracks and burrs.
7.4. The handles of hammers, sledgehammers and other impact tools must be made of dry hardwood or synthetic materials that ensure the strength and reliability of the attachment when performing work.
7.5. The handles (handles) of shovels must be smooth and firmly fixed in the holders.
7.6. The use of files, scrapers, screwdrivers without handles and bandage rings on them or with poorly secured handles is not allowed.
7.7. The crowbars and mountings used during work must be smooth, without burrs, cracks or hardening.
7.8. Chisels, cross-cutters, punches, bits must be made in accordance with GOST 7211, GOST 7212, GOST 7213, GOST 7214 from steel grades U7, U7A, U8 or U8A. Chisels, crosscuts and bits should not have cracks, caps, hairs, knocked down or beveled ends. Cutting edge chisels and crosspieces are hardened to 0.3-0.5 of the total length and tempered to a hardness of 53-58 HRC. The working part of the cutting beards, cores, etc. hardened to a length of 15-25 mm to a hardness of 46.5-53 HRC. The back of the instruments must be smooth, without cracks, burrs or hardening. The hardness for a length of 15-25 mm should be in the range of 33.5-41.5 HRC. There should be no damage to the working end.
Working with a chisel, cross-cutting tool and other similar tools should be done with glasses.
The work area must be fenced.
7.9. Hand scissors for cutting metal must comply with GOST 7210.
Manual lever shears must be securely mounted on special racks, workbenches and equipped with clamps on the upper movable knife, a shock absorber to soften the impact of the knife holder and a counterweight that holds the upper movable knife in a safe position.
7.10. The shape and dimensions of the wrenches must comply with the requirements of GOST 6424, GOST 2838 and GOST 2839.
Single-sided wrenches must comply with the requirements of GOST 2841.
Keys are made of steel not lower than grade 40X, and shortened ones - not lower than grade 40. The hardness of the working surfaces of the keys should be: with jaw sizes up to 36 mm - 41.5-46.5 HRC, more than 41 mm - within 39.5- 46.5 HRC.
The jaws of the keys must be strictly parallel and not rolled up. The dimensions of the wrench mouth must correspond to the dimensions of the nuts and bolt heads. The dimensions of the wrench mouth should not exceed the dimensions of the nuts and bolts by more than 5%.
Unscrewing nuts and bolts with wrenches is not allowed. large sizes using metal spacers, as well as extending keys using pipes and other objects (use wrenches with extended handles).
7.11. The handles of pliers and hand scissors should be smooth, without dents, nicks or burrs. WITH inside there must be a stop to prevent pinching of the fingers.
7.12. The vice must be manufactured in accordance with GOST 4045, firmly attached to the workbench so that its jaws are at the level of the worker’s elbow. If necessary, wooden ladders should be installed along the entire length working area. The distance between the axes of the vice must be at least 1 m.
The jaws of the vice must be parallel, have a notch and provide reliable clamping of the workpiece.
7.13. The condition of the jacks used in operation (screw, rack, hydraulic) must comply with the requirements of the factory instructions. It is prohibited to load jacks in excess of their rated load capacity. Each jack must indicate: inventory number, load capacity and belonging to the workshop (area).
7.14. Hand power tool must comply with the requirements of GOST 12.2.013.0.
7.15. Hand-held power tools and portable lamps must be connected to a voltage of no more than 42 V. If it is impossible to connect the tool to a voltage of up to 42 V, it is allowed to use a power tool with a voltage of up to 220 V inclusive, if there are protective shutdown devices or external grounding of the body of the power tool with mandatory use protective equipment(mats, dielectric gloves, etc.)
An electrified tool switched on for voltages above 42 V must be supplied complete with equipment personal protection. Connection to the electrical network must be made using plug connections with a grounding contact.
7.16. To protect against breakage or abrasion of the sheaths, cables and electrical wires must be inserted into power tools and portable lamps through an elastic tube fixed in the body part and protruding outward to a length of at least five diameters.
7.17. Removal of parts intended to protect against contact with moving and live parts must be impossible without the use of a tool, if the standards or technical conditions on this type equipment there are no other instructions.
7.18. Portable lamps must have a protective mesh attached to the handle and a hook for hanging. Live parts of the lamp socket and base must be inaccessible to touch.
7.19. Working parts of hand tools (circular electric saws, electric shapers, electric grinding machines etc.) must have protective covers.
7.20. When the power supply is interrupted or during a break in operation, the power tool must be disconnected from the electrical outlet.
7.21. If a malfunction is detected with the power tool, work with it must be stopped.
7.22. Disassembly and repair of power tools, plug connections, and wires are permitted only to electrical personnel. The power tool must not be transferred to another person.
7.23. Pneumatic tools (drilling machines, vibration chisels, impact wrenches, etc.) must comply with GOST 12.2.010 and be equipped with vibration-damping devices. Starting devices must be easily and quickly activated and in closed position do not allow air to pass through.
7.24. Hand-held pneumatic tools must be equipped with air exhaust silencers; in addition, exhaust compressed air should not fall on the employee and contaminate his breathing zone.
7.25. Pneumatic hammers must be equipped with devices that prevent the striker from flying out.
7.26. Before connecting the hose to the air tool, it must be purged. In this case, it should be directed in a direction where there are no people.
The hose must be connected to the pneumatic tool using a fitting with good edges and threads, nipples and clamps. The hose sections should be connected to each other using a metal tube, squeezing it over the hose with clamps. Fastening the hose with wire is prohibited.
Hoses to compressed air pipelines must be connected through valves. It is not allowed to connect hoses directly to the air line. When disconnecting the hose from the tool, you must first close the valve on the air line.
7.27. To check a pneumatic tool before work, you should turn it on for a short time at idle before installing a replacement tool.
7.28. A pneumatic tool can be put into operation only when the replacement tool (drill, chisel) is tightly pressed to the workpiece.
7.29. Care and handling of pneumatic tools must comply with the instructions and operating rules developed by the manufacturer for each type of pneumatic tool.
Repairing pneumatic tools at the workplace is not permitted. Repair of pneumatic tools must be carried out centrally and in accordance with technical instructions manufacturer.
After repair, a vibration level check must be carried out hand tools with subsequent entry in the passport.
7.30. Electric and pneumatic tools must only be issued to persons who have been instructed and knowledgeable about the rules handling him.
7.31. It is not allowed to work with faulty or worn tools.
7.32. It is not allowed to install on manual grinding machines circles intended for cutting material.
7.32. When working with hand-held electric and pneumatic tools weighing more than 10 kg, it is necessary to use balance pendants or other devices.

Looking into any tool store, you can be amazed not only by their cost, but also by their wide range - from dubious low prices, to incredibly expensive. It should be noted that a low cost does not always indicate a low quality product, and the high price of a device will not provide a guarantee long work tool.

The most common cause of power tool failure is the “human factor”, or more precisely, the illiterate use of the tool. Moreover, any employee of the service center will say that every second case of contacting service center may be considered a non-warranty case. And the surprising thing is that clients often use the device for its intended purpose, and the problem of breakdown is their lack of skill in working with the tool.

Examples of the most common breakdowns and their causes

• Damage to the device or rapid wear of parts occurs as a result of improper operation of the device. This often happens due to careless use, during which the user begins to overload the device. It is prohibited to press your body weight on the device. The blows the device delivers will not become stronger, but the mechanisms of the device will wear out much faster.
• Rapid wear of bearings in the grinding device. This is a common case that has nothing to do with the cost of the device and its brand. The reason for such wear in most cases is not manufacturing defects, but intensive use.
• Permanent armature burnout electric chain saw. It should be noted that customers systematically address the same problem and assure that they have operated correctly, in accordance with all regulations. During the verification process, trivial errors are identified that led to tool failure, which could have been avoided.

There are a huge number of such examples and can be considered either a warranty or non-warranty case, depending on various subjective reasons. However, in practice it has been shown that in most cases, it is not the manufacturer, but the user, who is to blame for device failure, which is confirmed by an independent examination.
We extend the service life of the device.

• Before purchasing this or that product, you should carefully read technical characteristics device, its description and reviews.
• Before using the tool, you should carefully read the instructions and the conditions under which the device can be removed from warranty. In cases where the listed items or at least one seems strange and raises doubts in you, then from purchasing of this device should be refused.
• It is necessary to correctly correlate the technical capabilities of the device and the amount of work.
• When purchasing, you should check the presence of the seal of the selling company, the authenticity of the warranty card, the presence and accuracy of the date of sale, as well as the indication of the addresses of the ASC.
• No matter how trivial it may sound, in order to extend the service life of any device, you must follow the instructions prescribed in the instructions. Taking good care of your tool will allow you to extend its service life for a long time.

Chipping of the cutting elements of the tool or its breakage

The reasons leading to chipping and tool breakage are often the same and can therefore be considered together.

1. One of the main reasons for these problems is the increased fragility of the tool material. In relation to mineral ceramics and hard alloys, this feature has already been noted more than once. High-speed steels have sufficient strength, but in practice one often has to deal with increased fragility of high-speed tools, which is caused by poor quality of the material (presence of foreign inclusions, large carbide heterogeneity, etc.), improper forging of workpieces or improper heat treatment; in the latter case, the tool’s hardness is often found to be excessively high. It must be remembered that the hardness of a tool that has protruding areas of small thickness on the cutting blade that are prone to chipping should be somewhat lower than the hardness of simple-shaped roughing tools.

Finally, it should be taken into account that cyanidation, which helps to increase the durability of the tool, is associated with a slight increase in its fragility. Therefore, as already indicated in Chap. I, cyanidation of instruments with a small cross-section often has to be abandoned.

2. Overload cutting tool when the shear cross-section is too large, when the strength of the part material is increased, or when the tool is excessively dull, i.e., working in conditions where the magnitude of the cutting forces expended exceeds those for which the tool design is designed. When milling, tool overload often occurs due to excessive runout of the cutter teeth, abrupt approach of the part to the cutter (before turning on the automatic feed), and large unevenness of milling due to an insufficient number of cutter teeth.

3. Weakening of the cutting part of the tool as a result of improper sharpening (with too large front or back angles).

4. Turning a tool with a rotary working motion (cutters, drills, countersinks) due to poor fit between the cones of the tool shank (or mandrel) and the hole in the machine spindle causes breakdowns, as it leads to a sharp increase in the load on the cutting blades (if the automatic feed does not stop) .

5. Chip pinching and poor chip removal are one of the most common reasons breakdowns of multi-blade tools.

When working with simple through cutters, the chips flow freely. When working with cutters, broaches, taps, drill bits for drilling deep holes all the chips being removed must be placed in the grooves between the teeth of the tool, and if the volume of these grooves is insufficient (which especially often happens when processing very viscous metals, such as mild steel, aluminum, which produce drain chips that occupy a large volume), then they become clogged with chips and the tool breaks.

A typical example is the frequent breakage of small taps. Often taps, regardless of their diameter, have four grooves. With a small tap diameter (4-6 mm), this results in a very small groove volume, and the tap core, in turn, is also weakened. Therefore, for small taps the number of grooves should be reduced, taking two grooves for a thread diameter up to 8 mm, three grooves from 8 to 14 mm, and four or more grooves above 14 mm.

Mills that remove large chips from steel parts must have a sufficient volume of cavities between the teeth; If regrinding of cutters is carried out only on the rear surfaces, then it is necessary to deepen the grooves from time to time.

The length of the working part of the drill, on which there are helical grooves, must exceed the drilling depth. If the walls of the hole cover the grooves and do not provide an outlet for chips, then breakage of the drill is inevitable.

6. Unsatisfactory quality of the cooling lubricant in terms of lubrication of the working surfaces of the tool can lead to chipping. With high lubricating and “cutting” properties of the liquid, cutting forces are significantly reduced; if the liquid does not get on the cutting surfaces, then the tool jams, chips and breaks.

7. Tool chipping and breakage may be caused by causes beyond the control of the tools themselves and may be due to faulty machine tools or fixtures.

Examples include: large slack in the feed mechanism drilling machine, as a result of which the drill is fed unevenly, jerkily and is heavily overloaded (especially when exiting the hole); development of guides or lead screw nuts milling machine; distortions of the part in the device for reaming, as a result of which the reamer does not fall into the preliminary drilled hole; strong vibrations of tools and parts, etc.

Especially often, instruments equipped with plates made of hard alloys or alkali ceramics, which are characterized by increased fragility and require great care in operation, chip and break.

In addition to the reasons discussed above, the following circumstances may also lead to chipping and breakage of such instruments.

8. The presence of small cracks on the plates (sometimes in the form of a barely noticeable “mesh”), which appear as a result of sudden cooling of the tool after soldering the plates or incorrect sharpening technology (use of abrasives with inappropriate characteristics; excessive rotation speed grinding wheel or its movements along the surface being sharpened; sharp cooling of the carbide during sharpening; using a “greasy” grinding wheel; too large contact surface of the grinding wheel with the plate being sharpened), and also due to unsatisfactory quality of manufacture of the hard alloy itself. It is characteristic that cracks caused by sudden cooling or improper sharpening usually have the appearance of straight or broken lines or a broken mesh, while defects in the carbide can lead to the appearance of cracks in the form of smooth curved lines of considerable width.

Interruptions in the supply of coolant lead to cracking and subsequent chipping of the plates, since in this case the heated hard alloy is subjected to sudden cooling. It is necessary to ensure that the coolant flows in sufficient quantities and that the falling chips do not block the carbide plate. If it is not possible to meet these requirements, then it is better to work without cooling at all.

When high-speed milling, coolant should not be used, since alternation of heating and sudden cooling is inevitable.

Measures to prevent cracking of carbide plates are described in the chapters above.

9. Chipping of plates made of hard alloy and mineral ceramics can be caused by non-compliance with those special requirements to the geometry of the tool, which contribute to increasing the strength of the cutting blade: the absence of chamfers with a negative rake angle or their insignificant width, insufficient angle of inclination of the main cutting blade (especially when working with impacts), too large rear angles, lack of transition cutting blades (for cutters) .

10. If the size of the chip-curling threshold is incorrect - its width is too small and its depth is too large - steel chips get stuck in it and this causes chipping of the cutting blades.

11. Chipping and breakage of carbide and mineral-ceramic plates are often caused by non-compliance with the basic rules of operating tools - careless handling of cutters, stopping spindle rotation when the automatic feed is turned on, etc. It is unacceptable to move a non-rotating cutter along an already machined surface when retracting after a working pass.

When working with cutters with mineral-ceramic plates, chipping often occurs due to impacts during cutting. Therefore, you should first trim the end of the workpiece or chamfer it, and also perform plunging with manual feed. For processing short parts with big amount It is not advisable to use such cutters for radial cutting in and out.

Carbide and mineral-ceramic instruments should be stored and transported in conditions that prevent impacts on the blades.

12. Mineral-ceramic and carbide plates are especially likely to chip when working with vibrations. The causes of vibrations and ways to eliminate them will be discussed below.

13. If chipping and breakage of plates cannot be eliminated by any means, then you should try to use a more durable hard alloy; in some cases, it turns out to be advisable to replace the carbide with high-speed steel.