How to disassemble the gearbox of a Makita 9069 angle grinder

Electrical diagram of a Makita 9069 angle grinder. Repair of angle grinder. with their own hands

As you know, nothing is everlasting and even brand-name tools break, not to mention the so-called “mass-produced goods”. And angle grinder (angle grinder). is no exception. By the way, to call the angle grinder “angle grinder” were in the Soviet Union, because then this tool was produced in Bulgaria, and there were supplied the first models of. Angle grinder, as a tool, has become very popular due to its versatility and ease of use. There are also many varieties and models of angle grinders, but the principle of operation and design is not fundamentally different. Therefore, having considered the structure of the tool, possible faults and repair methods, they can be applied to any model of angle grinder.

The design of the angle grinder is relatively simple. The basis of the tool is its body, inside which there is an electric motor, starting device and gear transmission to the spindle, to which various attachments are mounted.

body is made of strong, impact-resistant plastic. Depending on the power, there are different sizes and shapes of tools. Some models have an angular speed regulator, which is designed for optimal speed selection for different types of work.Another component may be a gearbox. Gearboxes are designed to ensure optimum transfer of rotation from the rotor of the electric motor to the cutting or grinding wheel. The number of revolutions on the gearbox output shaft is reduced. Properly chosen speed and diameter of the wheel. is the key to the most efficient operation of the tool.

A disc change button, when pressed, locks the disc in a certain position, preventing it from spinning when it is removed.

safety clutch acts as a torque limiter in the event of suddenly occurring reactive torque. Otherwise, if the disc jams in the material, the angle grinder begins to rotate sharply, which can lead to injury. This clutch prevents such rotation.

The electric motor consists of a stator and a rotor as standard. The stator sits in the guide flanges of the plastic housing of the angle grinder. A special device called a brush mechanism is located on the back of the stator. It contains copper-graphite brushes. Brushes are necessary to transfer the voltage to the rotor through the collector assembly.

The rotor is inside the stator and is fastened in the housing in bearing units that are inserted directly into the body of the tool. The front bearing unit is usually made in a metal plate, or, this plate can be made of aluminum alloy.

The gear case of the angle grinder is almost always made of aluminum alloy and has several threaded holes for attaching an additional handle. By screwing the handle into different holes, you can change the planes when working.

Gearbox is two gears that change the direction of the output shaft by 90 degrees and reduce the speed of rotation. The ratio of the number of teeth of the primary gear to the number of teeth of the secondary gear is called the gear ratio.

Typical malfunctions of angle grinders and methods of diagnosis and repair

the angle grinder suddenly stops working.The first thing to do. physically unplug and turn the disc by hand. If the disk does not rotate or rotates very tightly. immediately disassemble the tool for visual inspection. If it rotates easily, the most probable thing is. Electricity is not getting to the motor brushes. So the problem is either in the power plug, or in the wire itself, or in the mechanism of the “Start” button. It is enough to disassemble the case and “probe” the cable with an ordinary tester, or by any other means, for the presence of a break. After repairing a wire break or replacing the wire, the angle grinder will work.

The wire and plug are guaranteed intact, but the tool still does not work. It is necessary to disassemble the starting mechanism, and it is desirable to mark the removed contacts. if subsequently they are connected incorrectly, it could burn out the winding or jam the armature. It is not often possible to repair the starter mechanism. It is easier and safer to replace the starter button with any similar one with suitable power parameters. Such a button is not expensive and you can buy it at any store of the corresponding profile.

Start button and power cord are in good working order, angle grinder does not work. Check brushes and brush holders. Brushes may be broken or completely worn out. The resource of these devices is usually limited to a few years, of course, it all depends on the intensity of use. Repair breakage or replace brushes.

Then go more serious faults, respectively, and repair requires certain knowledge and skills.

Breakage or slipping of gears gear teeth;. seizure of bearings;. failure of the armature or stator;. Failure of control electronics;. Manifold failure;. housing deformation;

When determining the mechanical defects of the angle grinder, you should pay more attention to the condition of the plonet (large gear), the shank (the gear on the shaft) and the bushings. Uneven wear of cogs or shafts wobbling indicates the immediate replacement of worn parts.

Breakage of spindle locking button. caused by only one careless movement, i.e. by pressing (intentionally or accidentally) the button while the disc is turning. Breakdowns sometimes result from trying to remove a jammed disk using a button. Many grinders have special slots on the spindle, where the disk is mounted specifically for the usual wrench, look at his angle grinder, most likely you have this. So, it is better to use them and a cog spanner than a disk detent button.

Chipped gears. Usually they are caused by jamming (in this situation, tool breakage is not the worst thing that can happen). A sign of malfunction is a rattling noise in the gearbox. If the gear has lost two or three teeth, the tool can not cut. In this case you need to replace the pinions in pairs and change the pinion and bevel wheel. When you go to the store for gears, do not forget to write down the name of your angle grinder and its power.

Failure of the electric motor. Often this happens with tools that work in the dust and are forced to rest in the sand or on the ground: the dust suction chips the winding. But it is possible to kill the motor without dust. through overloading, especially if the tool is low-powered. That’s why small angle grinders often burn out not only the armature, but also the stator. The electronic speed control unit of small lathes can also break down. If you use an angle grinder to cut very dusty materials, in particular slate, it helps to protect the tool by putting a stocking over the ventilation slots in the housing.

The device of an angle grinder

The angle grinder is indispensable in many cases. As with any other tool, it should be treated rather carefully. To qualitatively perform the repair of angle grinder with their own hands, you need to know how it is arranged.

It is located inside the electric motor and begins to rotate during operation. The higher is its rotation speed, the more power the angle grinder has.

Is a separate place for the armature, on which the control and power windings are located. The collector is used to send signals to the control unit and to the motor.

These elements are used to drive the current from the power cable to the collector.

Located in the front of the angle grinder. It transfers the mechanical energy from the armature to the disc as it rotates.

Is one part of the motor with the armature located inside. This part is the most complex by design. because all the windings are very precisely pressed into it.

The tool also includes its housing, cable with plug, and holding handles.

Before you start to repair the angle grinder with your own hands, it is best to have a layout and wiring diagram and detailed instructions, which corresponds to a particular model. The tool should be repaired with your own hands with certain knowledge.

How to properly perform the repair of angle grinder with their own hands

Angle grinders (angle grinder), popularly called grinders, are a popular and reliable tool. But everything breaks down at some time. Perform repair angle grinder with their own hands is not difficult, if the instruction in front of you, telling a step by step order of repair angle grinder. Below you will find answers to any questions about repair of gearbox, rotor, stator, carbon brushes of angle grinders.

Angle grinders among home masters are especially popular. The possibility of changing the working tools allows you to perform cutting, grinding, polishing operations.

Soft-start device makes the work of the tool safe and convenient. Angle grinder repair is simple and can be performed independently. For those who dare to carry out repairs to the angle grinder itself, you will need a diagram of the angle grinder of the right type, tools, lubricants and this manual.

Any repair of angle grinder with their own hands begins with the study of emerging failures. The design of angle grinders is simple enough. The rotating rotor transmits the torque via helical gears to the shaft (spindle) of the tool. The necessary working tool, whether it is a cutting stone, grinding or polishing disc, is installed on the spindle and the necessary technological operation is performed.

Speaking of the shape of the tooth. Low-powered angle grinders have spur gears. Helical gears are used in angle grinders with power over 1000 watts.

Angle grinders, like any tool, break down over time. The causes of failure of the angle grinder can be different. They do not only appear as a result of improper use, but also because carbon brushes and lubricants are not replaced on time.

Regardless of the model of angle grinder malfunctions in all appear in the same nodes. Troubleshooting grinders are conventionally divided into mechanical and electrical. For novice repairers, faults are divided into simple and complex.

Mechanical faults angle grinder

angle grinder is an angle grinder designed to perform cutting, grinding, polishing work. the angle grinder during work is exposed to high loads, works in a dusty environment.

Excessive loads when using the angle grinder in the cutting mode cause increased wear not only of the bearing, but also of the gear teeth.

The main fault of the angle grinder on the mechanical part, wear or destruction of the sliding bearing on the shaft of the large helical gear reducer.

Troubleshoot the angle grinder is not difficult, if you have at hand its scheme, description and recommendations for carrying out repair work.

Repair of sleeve bearings

The weak point of any angle grinder is the bearing. Although there are only three of these, they are the most common causes of mechanical breakdowns. Bearings are negatively affected by

  • high rotational speed;
  • operation under extreme conditions;
  • Insufficient lubrication;
  • ingress of dust or dirt;
  • untimely replacement or destruction of carbon brushes.

Every angle grinder is designed for quick and straightforward replacement of bearings.

Troubleshooting angle grinder associated with wear or destruction of the sliding bearing on the gearbox shaft is characterized by the appearance of unpleasant extraneous sound.

Failure of the sleeve bearing is detected by checking the backlash of the work tool shaft. Determined by swinging in different directions of the shaft when installing the working tool.

When reinstalling the working tool, check the play of the shaft by jiggling it in different directions. There should be no or minimal backlash.

If play appears, the plain bearing must be replaced.

Repair of bearing consists in its removal from the housing and remove from the shaft of the gearbox.

It is best to remove the bearing from the shaft with a puller. The inner ring of a damaged bearing is best recovered using a suitable size tap previously screwed into the cage.

Bearings are removed from the rotor with a puller or by popular method.

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Wrenches or metal strips are inserted into the vice, the bearings are placed on the keys and with the help of soft metal and a hammer weighing at least 400 grams are knocked out from the shaft.

Repair of angle grinder gearbox

Check the degree of wear of the angle grinder gear reducer gears for the contact patch. Beforehand the gearbox must be completely free of old grease. A special blue coating is applied to the small gear wheel and the gear wheel is turned. Next, you need to remove the driven large bevel pinion and look through a magnifying glass at the contact patch. It should occupy at least 50% of the tooth surface in total.

Otherwise the gears need to be replaced or the tooth profile needs to be corrected. Correcting the tooth profile is repeatedly described on the pages of this site.

But this fault can only be repaired by an experienced craftsman. often than not, chamfered, sheared or broken gears are replaced as a whole, and in pairs.

How to disassemble the gearbox of an angle grinder correctly

When repairing the gearbox of any angle grinder, the most difficult task is to remove the gears and press out the bearing.

Disassembling the gearbox starts with removing the gearbox cover pos.1 and disconnecting the stator case and releasing the rotor pos.2. The freed rotor is clamped in a vice and the fixing nut is unscrewed pos.3 of the small drive pinion.

The spindle bearing is pressed into the gearbox cover. To remove the bearing, in some angle grinders, you must remove the retaining ring that secures the support bearing, and remove the bearing.

Broken bearing pos.1 in the gearbox housing pos.2 is the easiest to get. By prying it off with a screwdriver.

On other models, the pinion is locked in the spindle by a retaining ring.

There are several ways to attach the large idler pin to the spindle:

Small pinion is either screwed on the shaft by the left thread (in some Sparky models, the thread is right-hand), or it is fixed by the keyed joint and clamped by the nut.

How to Remove Gears

Grinders up to 1000 W use spur gears and angle grinders use helical gears.

How to disassemble the angle grinder yourself

Disassembly of the angle grinder does not require special locksmith skills, it does not cause serious difficulties. But the work must be done very carefully and with utmost care. How to disassemble the angle grinder, you can read on the pages of the Internet. Many sites show videos with a detailed technological process. To disassemble the angle grinder is necessary, not only when it broke down and needed to replace any part, it should also be done to clean the tool from dirt.

In case of a breakdown of the angle grinder, the first thing to do is to disassemble it and clean it well, in most cases the tool starts to work.

That is why the actions that are necessary to disassemble the angle grinder, everyone who owns such a tool and wants it to work long and qualitatively. In stores there is a wide range of this mechanism, manufactured by a variety of companies. They differ:

However, all models of any manufacturer have the same technological assembly. All angle grinders come with the same set of parts.

Main modules used

  • Body, usually made of special impact-resistant plastic.
  • Powerful electric motor.
  • Quality gearbox.
  • Smooth start.
  • Motor switch.
  • SJS system. The system enables the tool to work smoothly without jolting. It also stops the angle grinder in case of disc jamming, reduces vibration as much as possible. Saves the operator from serious injury.
  • Protective guard.
  • Auxiliary handle. It can be used to hold the angle grinder during the work. This handle can be mounted in a variety of positions, which gives the tool versatility.

The process of disassembling the angle grinder requires several tools:

The difficulty of disassembling the angle grinder is due to the fact that the parts have a very tight contact. This allows you to cope with the highest loads. Parts do not move during work and no oscillating movements occur. Of course, disassembly is best done by a master, but you can try to do everything yourself with the utmost care.

Tools required for work: round pliers, ruler, caliper, pliers, power drill, steel brush, megohmmeter.

Before you start to disassemble the angle grinder, you need to prepare the workplace, removing all unnecessary parts from the workbench. Clean table will make it possible not to accidentally lose any small detail.

The first step is to unscrew the bolt that holds the jacket. It is very easy to remove it, there are no particularly tight connections. Then you need to unscrew the screw, remove the plastic plate. The outer hood must be moved in the direction of the cord.

Basically, all models of lathes have a variety of devices. However, the common part is an electric motor, which includes:

Another indispensable part of the angle grinder is the gearbox, designed to regulate the power and speed. The electric motor together with the gearbox is secured in the housing.

It’s held by four bolts. They must be unscrewed and the gearbox must be removed with extreme care from the angle grinder housing. Disassembly of the reducer is necessary for its cleaning and replacement of worn parts. This is one of the most important components of the angle grinder and is under great strain during operation.

To remove the rotor from the gearbox housing, unscrew the nut that holds the rotor. Use a special puller to remove the rotor. Such an operation is associated with some difficulties, so if you do not have special skills, it is better to leave such work to professionals. A puller is indispensable here.

I must say that for the simple removal of dirt, such a detailed disassembly is not required. It is only needed to replace a worn bearing or worn rotor.

To remove the anchor, you must first remove the brushes and gearbox, gently pull out the anchor, holding it by the gear.

Some effort is required for this operation. Removal of the anchor from the body should be carried out very carefully, as it is easy to break.

When during the work there is a strong sparking, great heating of the body, you just need to take out the armature to clean the collector. The device will be ready to use again.

When the gearbox doesn’t work at all, you must disassemble it completely to change parts and clean it thoroughly. To carry out the work, you need to prepare a locksmith’s vise. All works are made in a certain sequence of operations:

  • Loosen the screw that holds the gearbox housing with a wrench.
  • Clamp the rotor body in a vise with great care.
  • Making light blows with a hammer, the body is extracted.
  • Finding a convenient rotor position to remove the bearing. The vise is clamped again.

Using a block of wood, the bearing is knocked out. To remove the pinion from the gearbox axle it is necessary to:

  • Wrap a cloth around the rotor and secure it in the jaws of the vice.
  • The pinion is also wrapped with rags, using a gas wrench, turn it counterclockwise.

The spindle axle works in conjunction with the main pinion, which has in its composition:

To disassemble the spindle housing, you must first remove the main pinion, which are used special tools.

After removing the pinion, place the housing in a vise. Laying a block of wood and hitting it with a hammer, carefully remove the spindle with the bearing on it. The bearing is removed in the same way as above.

Disassembling the gearbox should be done routinely, particularly if the tool has been subjected to intensive use. Having disassembled the gearbox, replace the lubricant. The most common lubricant used is Lithol-24. It should be said that the grease should be changed continuously after a certain period. This increases the life of the gearbox for many years, thanks to the reduced wear of its constituent parts.

Pressing the planetary gear

To begin the process logically, let’s look at the reasons why the pressing of the assembly is necessary:

Any competent repair, involves replacing only the damaged parts, having conducted a preliminary defectoscopy of the tool as a whole. With a high probability, preliminarily exclude unprofitable actions. A non-professional approach, pressing the assembly, can put the spindle shaft and the gearbox housing flange at risk (as practice shows, not an uncommon occurrence)

    The preliminary step is “soaking” seating deep penetrating grease (WD-40 ideally / or any analogue) for about 10 minutes, at least, it will not make worse.

Features of designs of foreign manufacturers angle grinder

In this chapter we will consider the design features of lathes manufactured under the brands Bosch, Hitachi and Makita, as well as repair angle grinder with their own hands.

Bosch angle grinder repair

Bosch angle grinders are reliable tools that do not bother the user. But not every user treats the tool correctly. Repairing a Bosch angle grinder most often involves replacing bearings.

Structurally, all Bosch angle grinders are made according to the same scheme. Spindle shaft pos.25 is pressed into the helical sprocket wheel pos.26 and rests in the gearbox housing pos.821 on needle bearing pos.51.

If the bearing fails, the bearing rim is left inside the housing and is not easy to remove. We recommend two ways to remove the needle bearing cage. These are described in the section “How to remove the needle bearing.

In case of wear or galling of teeth of the gear pair they should be replaced both of them and only in pairs. When disassembling the gears, remember that the drive pinion is mounted on the rotor shaft on the threads, and the left one is fixed by the nut. driven large helical gear pos.26 is pressed on the spindle shaft pos.25.

Repair Hitachi angle grinder

Hitachi angle grinders are especially popular with Russian consumers. And this is logical. There are practically no homemade knockoffs of Hitachi bolt cutters on the market. Simple design allows you to easily perform repairs of any complexity.

Hitachi angle grinders have a high reliability and not often come across the table of repairmen. The main reason to get to the table angular grinder Hinachi for repair. gearbox failure, namely, loss of teeth gears.

Disassembles the gearbox of angle grinder easy. To disassemble the gear housing pos.3 from the stator housing pos.37, you need to release the carbon brushes.

Remove the four screws pos.1 securing the gear housing and stator housing. Separate gear housing and stator housing. The gear case will detach along with the rotor pos.8.

To remove the gear cover, pos.23, you have to unscrew the four screws pos.24. Drive helical gear pos.33 is fixed to the spindle shaft pos.26 by means of a key pos.25 and remove with a puller. Bearing pos.21 can be removed with a wire puller.

Repair Makita angle grinder

A special feature of the Makita family of angle grinders is the quick-release safety cover pos.19.

the Makita angle grinder more often than other grinders get repaired. But the reason is the high percentage of fakes, flooded the Russian market.

A real Makita is a reliable, durable tool. But, like all angle grinders, suffers from gearbox failure, its gears.

Gearwheels are replaced if they get stuck or cracked.

To repair a Makita 9069 or Makita 9558 HN angle grinder, it is necessary to disassemble the angle grinder.

If the gearbox is defective, which can be determined by play of the spindle shaft, gear jamming, slipping of the idler gear, then disconnect the gearbox from the stator housing. Release carbon brushes pos.35, unscrew the four screws pos.10 and disconnect the gear housing from the stator housing pos.37.

In the next step unscrew the four screws pos.18 holding the rotor cover pos.15. Drive pinion pos.14 is removed with the help of the Persian. Drive pinion pos.43 is secured by a keyway and secured by a nut pos.42. Rotor shaft bearings pos.3 removed with pullers.

How to disassemble the angle grinder for diagnostics

In order to diagnose the electrical parts of the angle grinder and to repair any mechanical damage it is necessary to disassemble the machine. Disassembly is carried out according to the following algorithm.

Diagnose the electrical part of the angle grinder

As mentioned above, most often the angle grinder fails to work because of damage to the electrical part of the machine. To properly diagnose the electrical circuits of the tool, electrician repairmen use a special device. a tester.

If you pressed the button to start the machine, and it does not work, then in 90% of cases the cause of the breakdown is not so serious that you can not repair the angle grinder with your own hands.

Experts advise to adhere to the basic rule of power tool repair: move from simple to complex.

The first thing you will need to check the electrical cable and the plug at its end. If it is collapsible, then unscrew it and check the reliability of the contacts. Otherwise, you will have to disassemble the angle grinder (remove the hood of the machine) and “test” the cable with a tester, and make sure that the current approaches the contacts of the “Start” button. If the device will show a breakage, the cable should be replaced with a new one.

The situation when the current comes to the button, but does not pass further (with the switch on), indicates a faulty switch. Button cannot be repaired. It should be replaced with a new one, but first mark the contacts to be removed so that you can connect them correctly. Incorrect connection of the contacts can burn out the motor winding.

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If this check shows that both the cable and the start button are serviceable but the brushes are not energized, the brushes should be stripped of their brush-holder pads. If this procedure is ineffective, it is recommended to replace the brushes. Further, if the brushes are all right and are receiving current, then the rotor and stator should be checked for shorts and interruptions.

Checking the Motor Armature

The motor rotor can have the following problems: Inter-voltage short circuits and broken wires on the lamella contacts. Check the armature of the angle grinder can be multimeter: the device is transferred to the mode of changing resistance, set the value of 200 ohms, and using the probes measured resistance between the two adjacent blades. You need to check all pairs of blades in this way. If the resistance values are the same, then the rotor winding has no damage. Detecting other resistance values while “probing”, as well as detecting a broken circuit, indicates a fault in this coil. Repair of the angle grinder armature will then be necessary.

Usually the breakage of conductors occurs at the connection to the winding. Look at the points where the coils attach to the blades and make sure that the contacts are securely soldered.

If you do not have a measuring device, then you can check the rotor, using a 12 V light bulb and a battery for this purpose. The power should be between 30 and 40 watts. Check as follows: apply 12 V voltage from the battery to the plug of the angle grinder, connect a light bulb in the gap of one wire, start rotating the spindle of the angle grinder. If the winding is working properly, the light bulb will burn evenly, without blinking. If there is an intercircuit, the degree of incandescence of the bulb’s coil will change. In this case, the repair of the angle grinder armature with your own hands will be difficult, since the winding circuit of the armature is quite complicated, and the process itself requires special equipment and knowledge. That is why it is recommended to entrust this operation to professionals. But the best way out of the situation will be to replace the armature on the angle grinder with a new one.

If the lamp does not light up when testing the rotor, it indicates the presence of a breakage in the stator or a short circuit in its windings, as well as problems with the electric brushes.

Checking the motor stator

To check the stator of an angle grinder, use a multimeter as in the previous case. The values should be set to 20-200 ohms and do the following. Touch the stator winding contact with one probe and the housing with the other probe. If the instrument shows resistance, it means that there is a breakdown on the ground. Touch the probe to the contacts of one winding and then to the contacts of the other winding. If the resistance is the same, then the coils are fine. If one winding the device shows an open circuit on one winding, then you will need to rewind the stator or replace the part with a new one.

Rewinding stator at home without special knowledge, skills and equipment will be problematic. It is best to contact a professional motor rewinder.

Diagnose the electrical part of the angle grinder

As mentioned above, most often the angle grinder refuses to work because of damage to the electrical part of the machine. For proper diagnosis of electrical circuits of the tool, masters of repair of electrical equipment use a special device. a tester.

If you pressed the button to start the machine, and it does not work, then in 90% of cases the cause of failure is not so serious that you can not repair the angle grinder with your own hands.

Specialists advise to follow the basic rule for repairing power tools: start from the simple to the complex.

The first thing to do is to check the electric cable and the plug at the end of it. If it is demountable, then unscrew it and check the reliability of the contacts. Otherwise, you will have to disassemble the angle grinder (remove the hood of the machine) and “test” the cable with a tester, and make sure that the current approaches the contacts of the “Start” button. If the instrument shows a breakage, the cable must be replaced with a new one.

The situation when the current comes to the button, but does not go further (when the position is on), indicates a faulty switch. The button cannot be repaired. It must be replaced by a new one, but first mark the removed contacts in order to connect them correctly in the future. Improperly wired contacts can burn out the motor winding.

If the check shows that both the cable and the start button are intact, but there is no current flow to the brushes, it is necessary to clean the contact plates of the brush holders. If this procedure is ineffective, replacement of the brushes is recommended. Next, if the brushes are OK and are receiving current, check the rotor and stator for shorts or interruptions.

Checking the motor armature

The rotor of the electric motor can have the following faults: inter-turn short circuits and broken wires on the lamellar contacts. You can check the armature of the angle grinder with a multimeter: the device is set in the mode of changing resistance, set the value of 200 ohms, and using the feeler gauges measured resistance between the two adjacent blades. All pairs of blades must be checked in this way. If the resistivity is the same, the rotor winding has no damage. Detection of other resistance values during “testing”, as well as the identification of open circuit indicates a malfunction in this coil. If this is the case, you will need to repair the angle grinder armature.

Usually the breakage of conductors occurs at the connections to the winding. Inspect the places where the coils are connected to the lamellae, make sure that the contacts are soldered.

If you do not have a measuring device, you can check the rotor, using a 12 V light bulb and a battery for this purpose. Power should be within the range of 30-40W. Checking is done as follows: supply voltage of 12 V from the battery to the plug of the angle grinder, connect a light bulb in the gap of one wire, start rotating the spindle angle grinder. If the winding is functioning, the light bulb will burn evenly, without blinking. When there is an intertwist closure, the degree of incandescence of the bulb coil will change. In this case it will be difficult to repair the armature of the angle grinder with your own hands, because the winding diagram of the armature is quite complicated, and the process itself requires special equipment and knowledge. Therefore, it is recommended to entrust this operation to professionals. But the best way out of the situation will be to replace the anchor on the angle grinder with a new one.

If the light does not come on when testing the rotor, this indicates a break in the stator or a short in the stator windings or a problem with the electric brushes.

Checking a Motor Stator

To check the stator of an angle grinder, use a multimeter as in the previous case. You need to set the values to 20-200 ohms and do the following. Touch the contacts of the stator coil with one probe and the housing with the other probe. If the device shows a resistance, it means that a breakdown has occurred on the housing. Touch the contacts of one coil with the feeler probes and then touch the contacts of the other coil. If the resistance is the same, it means that the coils are serviceable. If one winding has an open circuit, then the stator needs to be rewound or the part needs to be replaced with a new one.

Rewinding the stator at home, without special knowledge, skills and equipment, will be problematic. It is better to turn to professionals who are experienced in rewinding engines.

Mechanical failure and troubleshooting

Mechanical breakdowns of the angle grinder, you can include the following.

  • Worn motor armature bearings. You can usually feel a strong vibration while the machine is running when the bearings are worn. In addition, you may hear grinding and other noises. Sooner or later the bearing will be destroyed, and the spilled balls will end up in the gearbox gears. If this happens, then in addition to the bearing, you will also have to change the gears. Of course, it is better not to wait for this trouble, and at the first signs of bearing failure replace it. How to get to this part of the angle grinder was explained above.
  • Wear of the ball bearing or sliding bearing of the gearbox. As in the previous case, when you turn on the machine will feel vibration and hear noise, unusual for normal operation of the angle grinder. To prevent further damage to the gearbox, it is necessary to replace the faulty part.
  • Worn gears in the gearbox. Gears wear out quickly due to insufficient lubrication. For the same reason and warms up the gearbox. Keep an eye on the lubrication inside the gearbox and change it if necessary. How to disassemble the gearbox, was described above. Lubricant should be used specifically designed for gearboxes angle grinder, and you can buy it in stores where this tool is sold. If for any reason the teeth of at least one pinion are broken, then the whole set of gears (pair) must be replaced.

Mechanical failure also includes breakage of the shaft retainer. To change the clamp it is necessary to disassemble the gearbox and remove the big gear.

Repair angle grinder Makita 9069 with their own hands to change the armature

In detail: Repair of angle grinder Makita 9069 with your own hands to change the anchor of the real wizard for the site olenord.com.

If circular sparks occur when the grinder is plugged in, it is an indication that the armature lamellas are burned out and must be replaced immediately. You will learn how to repair the tool with your own hands from our step-by-step tutorial on the example of Makita 9069 angle grinder.

It’s easy enough to replace the armature in an angle grinder. There is no need to send the tool to a workshop, you can do it yourself.

With a flat screwdriver unscrew the brush knot cover, remove the brush knot washer to remove the tool cover (the covers are on both sides of the angle grinder) and remove the brushes.

Unscrew the 4 screws that fix the gearbox to the housing.

Removing the gearbox together with the armature and the dust ring. Put aside the housing and the ring. we will not work with them.

Unscrew the 4 screws of the gear cover with an L-type wrench and remove it.

The small gear on the anchor is fixed with a retaining ring (the ring is black). Remove retaining ring with puller.

Unscrew the front and rear anchor locking bolts.

Remove the anchor with the bearing and small gear.

disassemble, gearbox, makita, 9069, angle

Remove the armature locking plate and wipe off dust and grease with a rag.

Take a new armature and install the lock disk on it.

Install the small gear and fix it with the snap ring.

Align the holes in the gearbox and the armature locking disk and screw in the front and back anchor locking bolts.

Put the gasket in place and install the gearbox cover.

Insert the gearbox with armature into the angle grinder housing.

Install the brushes and fix them with the covers.

If when you turn on the grinder in the mains there is a circular sparking. this is an indication that the armature lamellae burned out, and requires urgent replacement. How to make repairs with your own hands you will learn from our step-by-step master class on the example of the Makita 9069 angle grinder.

Replacing the anchor in the angle grinder is simple enough. It is not necessary to give the tool to a workshop, you can do it yourself.

Unscrew the brush unit cover with a flat screwdriver, remove the brush unit washer to remove the tool cover (the covers are on both sides of the angle grinder) and remove the brushes.

Remove 4 screws securing the gearbox to the housing.

Remove the gearbox with the armature and the dust ring. Put the body and the ring aside. you can’t work with them.

Unscrew 4 screws of the gearbox cover with hexagonal L-en key and take it out.

Lock the small pinion on the armature with the retaining ring (black ring). Remove the retaining ring with a puller.

Unscrew the front and rear anchor locking screws.

Remove the anchor with the bearing and the small gear.

Remove the armature locking plate and wipe off dust and grease with a rag.

Take the new armature and set the disk fixing on it.

Install the small gear and fix it with the retaining ring.

Align the holes in the gearbox and the anchor locking plate and screw the front and rear anchor locking bolts.

Read more:  How to put a diamond disc on an angle grinder

Putting back the gasket and installing the gear cover.

Insert the gearbox with the armature in the body of the angle grinder.

Install the brushes and fix them with covers.

Most tools used in the economy, is not immune to breakage. Angle grinder, which are available from almost every craftsman, eventually break down. Different models of angle grinders can be similar in type of failure. But each brand has its own characteristics in design and components. The well-known Makita brand is valued for its high quality. durability. However, the devices of this brand also tend to break.

Repair can be done at home. Spare parts for the machine can be easily purchased. Before repairing the device, you need to read the attached diagram.

Types of Makita brand angle grinders and their features

Based on the diameter of the working circle, the brand grinders are divided into classes:

  • Lightweight. have a wheel with a diameter of 115-125 mm. Are distinguished by their light steerability.
  • Average. the diameter of the circle is 150-180 mm. Professional models and domestic models with different motor power.
  • Heavy. disc diameter 230 mm. This class is represented by models for professional purposes when working with concrete, brick, etc.п. Characterized by the latest safety systems.

Amateur devices differ in power and price. Professional equipment is designed for prolonged heavy loads and has an increased power reserve. Models with power over 1000 watts are equipped with a comfortable back handle, which is covered with special pads that protect against vibration.

As for the design of this brand of bolt cutters, it is characterized by the presence of such additions:

  • The labyrinth device, used for protection against dirt and dust;
  • Armored coating of motor windings;
  • A special system for soft start and overload protection (Super-Joint-System).

Malfunctions with the Makita angle grinder can be divided into two types:

First you need to inspect the device. The mechanism of the angle grinder is the torque from the rotor through the gear to the spindle of the working body (wheel, cut-off stone).

There are components in the control circuit, the malfunction of which can be repaired by yourself. The weak point is the brushes. It is therefore essential to check the torque being applied to the spindle of the tool (wheel and cut-off stone) beforehand. Also check the continuity of the power supply from the plug to the breaker terminals.

Assembly of the Interskol angle grinder

The Interskol angle grinder is assembled exactly like other brands of angle grinders. Only use serviceable parts and assemblies that are free of old grease. There are several steps to assembly.

How to assemble the gearbox of the Interskol angle grinder

To assemble the gearbox assembly, assemble the spindle by putting bearings and bevel gears on it.

To the spindle pos.10 the gearbox housing cover pos.13, bearing pos.14, bearing cover pos.15, bevel gear pos.16. Gear wheel is fixed on the spindle by the keyway joint pos. The 125 angle grinder uses a 3 mm diameter ball as a key. To secure it on the spindle the pinion is locked by a circlip pos.17. Fit the assembled spindle into the needle bearing, pos.18. A needle bearing is pressed in the gearbox housing pos.21.

Assembly of the gearbox of the angle grinder 230 begins with the assembly of the spindle assembly pos.8 on which the bearing pos.9, retaining ring pos.10. Gear wheel pos.11 is pressed on the spindle. The spindle is inserted into roller bearing pos.12. Bearing size НК1210.

To facilitate press-in of idler pinion pos.11 On the spindle pos.8 heat the pinion and cool the spindle.

Drilling machine made of the engine from a washing machine and the gearbox from an angle grinder

Materials and tools used by the creator:

The list of materials:- Motor from a washing machine 650W / 1350 RPM;- Gear from the 180th angle grinder;- Angle;- Round pipes;- Sheet steel;- Bolts and nuts;- Spring;- Switch;- Cable with good insulation.

The process of making a drilling machine:

Step 1. Revamping of gearboxFor the machine tool it comes in handy gearbox

cable from the angle grinder to 180, it lowers the speed of the motor more than thegearbox 125 angle grinder, as a consequence, we get the highest torque, and the axle in this gearbox is thicker. The maker cuts off a piece of armature with an angle grinder and knocks the rest of the armature off the axle. It also comes in handy to cut a piece from the body of the angle grinder to screw this part with a bearing seat to the gearbox. If such a part is not available, it can be welded himself from a sheet of steel, using as a cage, a piece of pipe.

Step 3. BaseWe make a base for the drilling machine, it must be very strong, so that the whole structure will not fall off. You can use a piece of a channel that fits on the base. If you don’t have a channel it can be welded from thick steel. Bolt the machine to the base by welding on the lugs.

Also we welded to the base 4 studs, it can be pipes or iron bars. Insert the rods into the carriage first, and then bolt them to the base. Only in this way will you fit the uprights correctly.

Step seven. Finishing touches and testsInstall a drill chuck on the gear shaft, to screw a chuck, you can weld a nut to it for an angle grinder or cut the thread right in the chuck.

We paint the frame to prevent rusting, now the machine looks good. Set the breaker for easy disconnection of the machine if needed. The machine is ready, the creator has put in a chuck a large drill bit and drills his monster all in order, from timber beams, and ending with a thick sheet steel.

The machine is great, a machine for the real man. At this point the project is complete, I hope you liked the project and that you have found useful ideas. Good luck and creative inspiration, if you decide to repeat a similar. Don’t forget to share with us your ideas and do-it-yourself!

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Part diagram Makita 9069

On this page you can pick up and buy original parts for Makita 9069 angle grinder angle grinder parts. spindle, nut, flange, protective sleeve, gear case, motor housing, lock button, bevel gear, armature (rotor), stator, carbon graphite brushes, brush holder, bearing, shock absorber, button, link. Makita 9069 angle grinder parts have photos, price, description, reviews. To select, order and buy Makita 9069 parts. Choose the part that corresponds to the part number in the parts list next to the diagram and click on its name.

1 M5X2 screw, 3, 43 stop button4 Self-tapping screw 5×355 Safety ring S- 96 Drive pinion 9069Analogous ball bearing and tapered pair7 Ball bearing 6301DDW8 Bearing cage 579 Fan 8010 Yakir 9069 and Anchor analogous11 Insulating gasket12 Ball bearing 6200DDW13 Fairing14 Stator 9069 and stator analog15 Self-tapping screw 4×2516 Switch housing 906917 Self-tapping screw 5×6018 Makita label19 Motor housing 906920 Label21 Brush holder cap 7- 18 22 Carbon brushes and analog brushes23 Nameplate24 Miniature switch 9069, button with plate.Start button and push button analog25 Self-tapping screw 4×1826 Fixing plate for cable27 Power cable 1.0-2-2.528 Cable protection 9.3-9029 Switch housing 906930 Flange nut 14-45 and super nut31 Inner flange 42 and super nut32 Protective guard 906933 M8x2534 Hexagonal screw M5x1635 Spindle 906936 Bearing shield37 Ball bearing 6203DDW38 Protective ring R- 4039 Idler pinion 906940 Screw M5X41 Side handle 36 and handle with vibration42 Gear case 906943 see item 2 Special key 35 Noise suppressor Gear lubricant

Original Makita part. For Models: Makita 9027, 9027S, 9029, 9029S, 9037, 9039, 9047, 9047S, 9049, 9049S, 9057S, 9059, 9059S, 9067, 9067, 9067S, 9069, 9069S, 9069S, BJR240. Features: 5 mm thread diameter/ Thread length mm.

For models: 4112HS angle diamond saw; 9027; 9027S; 9029; 9029S; 9037; 9039; 9047; 9047S; 9049; 9049S; 9057; 9059; 9059S; 9067; 9067S; 9069; 9069S; 9077; 9077S; 9079; 9079S; GA7010C; GA7012C; GA7020; GA7020R; GA7020S; GA7030; GA7030R; GA7030S; GA7040R; GA7040S; GA7050R GA9010C; GA9012C; GA9020C; GA9020R; GA9020S; GA9030; GA9030R; GA9030S; GA9040R; GA9040S; GA9050; GA9050R; Maktec MT903 angle grinder; HM1303; HM1303B; HM1304; HM1304B; HM1500; HM1500B; HM1800; HM1801; HM1810; SA7000; SA7000C polishing machine. Parameters: WITHOUT self-switching. / Length of graphite 16 mm / Thickness of graphite 7 mm / Width of graphite 18 mm / Mounting. U-turn. heel/ With spring/ 2 pcs. included

A genuine Makita replacement part. For: All models of Makita angle grinders, etc. Dimensions: Outer diameter 50 mm/ Inner thread M14/ Height (dimension) 13,5 mm/ To minimise the “sticking” of accessories, fixation by hand.

For: Makita 9067; 9067S; 9069; 9069S angle grinder. Parameters: Motor power 2000 W/ Outer diameter 95 mm/ Inner diameter 55 mm/ Casting frame length 45 mm/ Center distance between mounting slots 83 mm/ Stator overall length 93 mm/ Number of leads 4.

Original Makita spare part. For models: 4112HS, 9027S, 9029S, 9047S, 9049S, 9057S, 9059S, 9067S, 9069S, 9077S, 9079S, GA7020S, GA7030S, GA7040S, GA9020S, GA9030S, GA9040S. Marking: MARQUARDT 1362.0113. Features: Voltage 250 V / AC current 13A / soft start unit / Size of the mounting plate on the body 31.5 x 127 mm / Dimensions of the key with the trigger 15.5 x 31.5 x 109.5 mm / Number of contacts 6 pcs.

Original Makita part. For: Makita GA9010, GA9020, GA9030, GA9040, GA7010, GA7020, GA7030, GA7040, GA5040, GA4540 angle grinder. Parameters: Distance between hole centers of the nut. 35 mm/ Overall length. 240 mm.

For models: angle grinder 180, 230 mm. Parameters: M14 thread/ Thread length 11 mm/ Overall length 167 mm/ With rubber pads.

Makita original spare part. For: Makita angle grinder: 9067; 9067S; 9069; 9069S. Parameters: Pin height 30.5 mm/ Pin diameter 10 mm/ Distance from edge to pin stop protrusion 3.5 mm/ Spring inner (outer) diameter 12 (14) mm/ Key diameter 3.5×20.5 mm.

Original Makita spare part. For models: 9047, 9047S, 9049, 9049S, 9057S, 9059, 9059S, 9067, 9067S, 9069, 9069S, 9227CB, BJR141, GA7030, GA7030R, GA7030S, GA7040R, GA7040S, GA9030, GA9030R, GA9030S, GA9040R, GA9040S, HR160D, HR4000C, HR4500C, JR140D, JR180D, RP0910, RP1110C, RP1800F, RP1801F, RP2300FC, RP2301FC, GA7020, GA7020R, GA7020S, GA7050R, GA9020, GA9020R, GA9020S, GA9050, GA9050R, JR3050T, JR3060T, JR3070CT, MT903 Features: Thread diameter 5 mm/ Thread length 25 mm/ Overall length 37 mm.

Makita original spare part. For models: Makita 6832; 9027; 9027S; 9029;9029S; 9037; 9039; 9047; 9047S; 9049; 9049S; 9057S; 9059; 9059S; 9067; 9067S; 9069; 9069S; AT3624; BBC231U; BBC300L; BC231UD; BGA450; BGA452; BGD800; BPJ140; BPJ180; DGA450; DGA452; DGD800; EB7650TH; EBH252U; EBH253U; EM2650UH; EM2651LH; EM2651UH; EN4950H; EN4951SH; EY2650H; GA4540; GA4540C; GA5040 GA5040C; GA5041; GA5041C; GA6040; GA6040C; GA6041C; ME2464; MS2454CE; MS2454U; MS2454UE; MS2464U; MS2464UE; SA5040C. Parameters: Diameter 9 mm / Thickness 1 mm.

A genuine Makita replacement part. For models: Makita 9069; 9069S angle grinder. Parameters: Height (dimension). 19mm/Inner diameter. 9mm/ Planting. slot 9.5 mm/ Number of teeth 12.

⚠ The following safety precautions must be followed ⚠

  • The main thing in the safe use of the angle grinder is to anticipate the behavior of the parts of the product to be cut at the moment of their separation;
  • When operating the machine, assume a stable operating posture and wear a face mask, as well as protective clothing, footwear, gloves and headwear to prevent injuries caused by fast-flying particles from the disc and the material being worked on, taking into account ricochets from nearby obstacles, clothing and hair;
  • Protect the cord of the machine from accidental damage and do not allow it to come into contact with hot surfaces, petroleum products or chemically active substances.
  • Unplug the angle grinder when replacing the blade;

⚠ It is forbidden ⚠

  • Do not use the angle grinder without the blade guard in place;
  • Working with sparks on oneself (when the disc breaks, splinters fly in the direction of the sparks jet)
  • Do not bend the power cord within 5 cm of the angle grinder housing or carry the tool by the cord;
  • Work on materials containing asbestos, cement, chalk and abrasives.
  • Allow children access to the car;
  • Operate the angle grinder in a dripping environment, in rooms with high humidity, or outdoors when it is raining or snowing;
  • Operate the angle grinder in rooms with explosive or chemically active atmospheres that are destructive to metals and insulation;
  • Use replacement wheels that have expired their warranty period without first testing them for mechanical strength;
  • Use circular saw blades;
  • Use the machine from a ladder;
  • Work with the angle grinder inside boilers, tanks and power supplies;
  • Leave the machine connected to the mains without supervision;
  • Pull or twist the cord and subject it to stress;
  • Do not operate the machine if there is at least one of the following faults: damaged plug, damaged wire or cable sheathing, indistinct operation of the switch, sparking under the brushes of the electric motor, smoke or smell of burning insulation, unusual noise, knocking or vibration level, damage or breakage of body or gear parts, destruction of the replaceable wheel (disc).

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