How to change the bearing on a Makita angle grinder

Maintenance angle grinder (grinders) with their own hands. Tips for repair and prevention

Dana article offers ways to find faults in different models of arc grinders and repair angle grinder (angle grinder) with their own hands. Here you can find answers to questions about how to disassemble the gears of most popular models of lathes, how to replace gears and bearings, and how to repair them. Gears and bearings pressed in and out, repair methods and accessories.

Along with the general malfunctions of angular grinders of different brands, there are their own peculiarities. This comes not only from the differences in the design of bolt cutters, but also from the materials and components used.

It is also important who made the tool. Knowledge of the peculiarities in the design of grinders allows you to repair angle grinder with your own hands qualitatively and quickly. The following information will help to repair the angular grinding machine of any brand.

Along with the original tools, the construction market was flooded with cheap knockoffs. And do not think that fakes are made exclusively in China. Power tools of Chinese manufacturers are not inferior in quality to manufacturers from European countries or countries of Southeast Asia.

Quality tools from Chinese manufacturers for the European consumer go through several stages of incoming inspection. For third countries, Chinese manufacturers do not control the tool. But the tools are made on the same lines, in the same factories, by the same people. That’s why there is such a difference in price.

To make the repair of angle grinder with your own hands, you should have a scheme of this angle grinder and understand it. Bosch angle grinder repair is different from Interskol angle grinder repair. And then there are angle grinders by Makita, Hitachi, Metabo.

Some general useful tips for organizing the repair of the angle grinder

Before we start repairing the angle grinder, let’s look at some useful tips:

  • Before you start disassembling the angle grinder, carefully read its description, the scheme of assembly and the order of work.
  • Always follow the sequence of operations.
  • Strictly obey the safety instructions.

The most common cause of angle grinder failure is wire breakage near the handle. First you need to check for voltage on the button, this is done with an ordinary voltage tester. Then check the button itself for operability.

Learn more about diagnosing and repairing the electrical section of an angle grinder.

How to remove a needle bearing or broken plain bearing cage

Different bearings are used in the gears of angle grinders. They are subjected to heavy loads and cause malfunctions.

Bearing failure is determined by an increase in play of the spindle shaft. When you disassemble the gear housing and remove the big gear shaft, you will see the needle bearing.

The needle bearing is not used in all grinders. In the same grinders in which it is installed, its removal can be done in several ways.

After taking out the destroyed part of the bearing, the inner ring can be removed using a machine tap. Engage a machine tap of suitable diameter in the chuck of an electric screwdriver and try to screw it into the bearing cage until the tap hits the bottom of the housing. Continue slowly screwing the tap into the cage. It will lift the cage along the thread.

The second method is that the remaining rim of the destroyed needle roller bearing can be removed with a special bolt and retaining ring.

How to remove the helical gears on an angle grinder

Repair of the angle grinder gearbox begins with the dismantling of the helical gears. It is the gears that become the main cause of malfunctions of the angle grinder gearbox. The small pinion gear, attached to the rotor shaft, most often needs to be replaced in boltcutters.

The helical gear can be attached to the rotor shaft in two ways:

  • Gear is fixed with a keyed connection and clamped with a nut.
  • The pinion is attached by means of a threaded joint. Both right and left-hand threads are used.

The large helical idler pinion is also attached to the spindle shaft in two ways:

In addition to replacing the gears in the bolsters often need to replace one or the other bearing. And there are at least three of them in the construction of the angle grinder.

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Materials and tools

The first question a home handyman faces when constructing a stand for an angle grinder. what to make it from? The answer to this question is elementary: let’s make something out of it. If you have water pipes, they can be useful for making joints and guides. If there is a metal corner. let’s assemble a frame out of it.

The main and most complex component of the pendulum cut-off saw is the hinge assembly. It has the highest load, and the swing arm should not be able to randomly deflect to the left or right. Take the greatest care in designing this assembly. It is ideal to use roller bearings. Find a pair of suitable sizes, and then build the rest of the construction around them.

Ball or roller bearings are best for mounting the swing arm. This gives the best possible precision and rigidity. But if you don’t have any suitable ready-made products, you can always look at pairs of self-made designs for this unit.

If there are no ready-made bearings, choose pairs of metal pipes and steel pins of suitable diameter. This will allow you to make not too high quality, but homemade bearings. Good pendulum arm hinges used for fixing doors and wicket doors are good enough for the “plywood” machine.

In any case, it is best to make the pendulum arm itself from metal angle or metal profile. But the holder, which will be attached to the angle grinder, will probably be made of a wooden bar.

For reliable and tight fixation of the angle grinder in the holder it is better to cover the bed with soft and durable material. For example, with leatherette. And it is more convenient to clamp the angle grinder to the holder with flexible metal ties with a screw knot. Such are widely used in plumbing and car service.

The base is best made of thick sheet metal. Compromises are possible, up to thick plywood mounted on a wooden beam frame. It is good to provide on the working table the possibility of fixing the thrust angles at some standard angles to the axis of the cut. In this way we get a “mitre saw”.

Do not forget that you can no longer control the angle grinder on the machine in the usual way. We can replace the operator’s hand on the control keys with the same screw clamps for pipes. But the keyboard control station (which we will fix on the bed), the socket for inclusion in the chain of a fixed angle grinder and wire with a plug long enough to include the whole machine into the network should be pripasti.

If we have metal workpieces, it is best to connect them by welding. If you do not have such an opportunity, it is better to turn to the familiar masters of the business. Bolted connections come loose over time and nullify all the advantages of the metal frame.

Of course, in the manufacture of the machine will come in handy and the angle grinder itself. Cutting blanks for the rack with it, you can feel like Munchausen, pulling himself out of the swamp by the pigtail.

Tools required for repair and replacement of unusable parts

For quality and effective repair of the angle grinder, you will need the simplest tools, which are available to almost every diligent owner.

The presence of an electric screwdriver will greatly facilitate the disassembly procedure of the angle grinder. But, in its absence, you can easily dispense with a variety of screwdrivers. Preferably they should have a ratchet mechanism.

To unscrew the nut that attaches the helical drive pinion, you will need a wrench, called a spanner.

No need for a special puller to disassemble the bearing.

Carry out diagnostics of the electrical component of the device to be repaired, using a tester. There is also a special device that determines the short circuit of coils. This device is very convenient because you can diagnose a fault in the stator or rotor without having to remove the unit.

Be sure to have a diagram of the structure of the grinder. Knowing the location of the main components will greatly facilitate the disassembly of the mechanism, repair, or replace bad parts.

How to disassemble the angle grinder and remove bearings. Step-by-step steps

Having disassembled the given device, you will be able to replace the broken bearings, to relubricate all details, to make dismantling of spoiled brushes and to mount the new ones.

In order to disconnect the rotor and stator housings, you must first remove the handle housing in the machine. This is to remove the carbon brushes. They hold the rotary manifold.

The second step is to remove the four screws that hold the two housings. rotor and stator.

Take out the gearbox with the starter motor and start disassembling it. On the gearbox are also screws, which need to be unscrewed. There are four of them in total. This procedure will require some effort on your part, as the factory assembly requires the use of sealant.

Angle grinders of different models have different kinds of gears. In models with low power. the use of spur gears. With power over one thousand watts. use helical gears.

When you remove the gear cover, it will be possible to remove the assembly that houses the helical gear. To remove it, use a press or a puller.

For this you have to use special thin tubes. For this reason, it would be inconvenient to use a puller.

Before removing the pinion, it is necessary to check the play in the gear connection. Also check if all the teeth are intact. And the contact patch is checked.

If you determine such signs in the bearing, which is on the spindle shaft:

If all of these signs are present, the old part must be replaced with a new one. To do this, the bearing must be disassembled. How to do this?

First remove the pinion along with the retaining ring. After that, you can easily remove the worn element. When you remove the rotor shaft assembly, the bearing may remain in the gearbox, inside the housing. In this case, use a hammer, with a soft pad on top.

To remove the drive gear in the angle grinder, do this:

After checking the appearance of the gear, determine whether this part needs to be replaced. Note that both gears must be replaced at the same time.

Angle grinders with low power have a needle bearing, it serves as a support bearing.

Remove that part only when it has completely collapsed. There is a proven way to pull out a ruined casing.

1.Choose a larger tap diameter than the inside diameter in the cage.

2.Insert and fit it into the chuck of an electric screwdriver. Gradually, at low speed, screw into the cage. When the tap hits the housing bottom in the gearbox, the cage will lift.

The rotor shaft has two bearings in addition to the needle bearings. To loosen them from the rotor I would recommend using an extractor.

The bearing attached to the manifold is easy enough to remove. The impeller also has a bearing, which will take a little more time and skill to remove. Both bearings are covered with special rubber covers for protection.

To remove and replace these parts, unscrew the nuts, remove the spur gear, as well as protection made of plastic. You are now free to remove the bearing from the rotor shaft with a puller.

If you do not have a puller in your tool kit, there is one method, take note of it. Remove the bearing with a vise along with two metal strips, and a hammer, which has a special metal pad.

How to change the bearing on the Makita angle grinder

During all time of operation of the power tool, for the first time I “burned” it. During prolonged work, my Makita 9555HN angle grinder got very smoky. It happened because of haste and inattention at the same time. In the combination of all my actions and events there was a very strong overheating of the tool. Timely overheating was not noticed due to the fact that the work was carried out in welding boots. Since they are leather, they are safer to work in, as they will not wind up unlike rag or knit ones. And since the mittens are designed to protect from the temperature, the work was carried out as if nothing had happened.

In addition to simply long work, which lasted about an hour and a half, there was another aggravating moment, the tool used a somewhat heavy tooling in the form of a thick, six-millimeter grinding wheel and a metal brush in the form of a cup.

The operating time of this copy of the angle grinder is small, so we will repair it.

Disassemble the tool. The process is simple enough: unscrew the screw that secures the black plastic cover and take it through the power cable. Then we lift the spring-loaded locks of brushes and remove the brushes (there are two on different sides).

We proceed to the disassembly of the front of the angle grinder. Unscrew the four screws that fasten the gearbox and remove it. Next, remove the rotor of the electric motor. For this you need to use a screwdriver. We set it in the technological groove and carefully turn, controlling the process. It is easy to pull out the rotor, without any excessive force (the main thing is not to forget to remove the brushes).

Blow the rotor with compressed air and inspect it. From the outside there is absolutely nothing to complain about. it’s perfect. The enamel on the visible part of the wires is not darkened and retains its integrity. Unfortunately, there is no way to check it for intercircuit failure. Let’s put it aside and take it apart.

Now we need to get to the stator. After we took out the rotor we got the access to the plastic fixing of the stator cover. Remove the two long screws and pull it out. Before you start removing the stator, you have to disconnect its windings and straighten out the wires. To remove the stator you can use a rubber hammer. The process is as follows: light hammer blows on the front end of the housing angle grinder, and because of the fairly large mass, the stator begins to emerge from the landing place. When removing the stator, you have to make sure that the wires run freely through the technological windows and don’t get caught on anything.

Inspection of the stator revealed the presence of burned-out conductors of its windings. The enamel on them had darkened considerably and some damage had occurred. Stator to be replaced.

We still have an open question with the rotor. I recall that some of the big stores that sell power tool parts can tell you and check some parts. We take the stator and the rotor and go in search of parts.

But before going to the store, the rotor will have to be disassembled a bit. We need to remove the plate and bearing from the front. If it is the other way round, it may be difficult to check it. To remove the plate need to unscrew the nut M6. The bevel helical pinion is mounted without a key, the fit is loose. Having removed the pinion carefully pull the bearing together with the plate.

As expected, it was not too difficult to check and buy the necessary parts for replacement. All you had to do was get to the right, specialty store for those very parts. Here we have checked the rotor which in its turn is also “fused” and bought new parts.

Let’s start assembling by preparing all parts and assemblies of the angle grinder. First of all it is necessary to blow out the dusty elements with compressed air. Next, wash the gear parts in gasoline. After that we will lay out all the components of the angle grinder and proceed to assembly.

Assemble the tool with new parts

After disassembling the tool, necessary replacement of all destroyed parts, we will reassemble. Make sure you have all the tools, lubricants, clean rags on hand to put the finishing touches.

All previous grease should be removed and replaced with fresh grease. Use lubricants from reputable manufacturers, buy them in specialized stores.

First of all it is necessary to assemble a rotor. It is necessary to press in bearings, to install the impeller. Lubricate bearings thoroughly beforehand. Using a wood shim, press them on top of the shaft.

Cover the collector bearing with the rubber shield. This is the same diagram of how to assemble the rotor shaft.

Next, reassemble the gearbox. Begin this process by installing the gearbox on the rotor shaft housing. When the shaft is already inside the housing, put the drive pinion on it, then the washer and the lock nut.

Now place the gear case, with the shaft inside it, inside the stator case. You need to press both housings together after the collector bearing is already in the socket. Next check whether the rotor turns easily on the bearings.

The final step is to put the cover back where it was. Check the rotation of the spindle shaft. If you find that the rotation is light, even with the movement of your hands, you can screw in the screws. They perform the fixing of the cover to the body. Lubricate all the screws beforehand, using sealant.

Disassembling the angle grinder for preventive maintenance

I would recommend disassembling your sander not only to repair and replace worn parts, but also for regular preventive maintenance. This will significantly extend the life of the electrical device. Every mechanism works longer and better if it is taken care of properly. The angle grinder is no exception.

Disassemble the tool as described in this article. Only now you are not doing it for repairs, but to thoroughly clean and lubricate such a necessary tool in the household.

The most ideal option for cleaning is to use compressed air and a blowing nozzle in compressors. You have to consider that the angle grinder is cooled through the distance in the middle of the armature and stator.

Excessive amounts of construction dust, various particles on the engine. It all needs to be cleaned from time to time.

And if you have disassembled the angle grinder for prevention, apply fresh grease to the parts, as told earlier.

As you can see, maintenance and repair of angle grinder is not such a difficult task!

Important nuances

When independently performing repair operations, most users have a question. how to remove the bearing from the armature of the angle grinder without a puller, which is used by professional craftsmen? In such a situation you will have to use available improvised means. vice, wooden hammer or soft metallic mandrel, steel bands, wrenches, etc.п.

Particular attention should also be paid to solving the problem. where to buy a quality bearing for the angle grinder

This is best done in specialized stores, in workshops with an established high reputation or on reputable online resources.

At an affordable price to buy a bearing on the angle grinder or to order repair equipment offer workshops “Udachnaya Technica Service. The quality and efficiency of our services will certainly make you happy!

A secret. everything in this blog is made of iron was cut with one single angle grinder, my favorite Hitachi G13SR3. Today I already have three of them, separately for cleaning and cutting, but I started with one:

Small, light, with quite enough power for my tasks she did not do anything else, that not only cut and in whose hands have not been but But nothing is eternal under the moon and recently the machine began to make some unnatural sounds, which tended to increase. Decided to open and defect before the gearbox finally jams and chews up, after all, a proper rebuild is always preferable to a replacement

I hollowed out and washed everything and got such a soup set:

An organoleptic analysis showed that the shaft bearing had gone to the eternal hunting world and urgently needed to be replaced. The rest of the gearbox nodes are in near-perfect condition and have no signs of wear. speaking of quality angle grinder for a thousand and a half (before the jump in the exchange rate).

To get to the bearing you need to remove the idler pinion from the shaft, which is fixed with a split locking ring for ostentation. Why for ostracism? Yes, because the pinion sits on the shaft on a press fit and you can not remove it with an extractor, not enough force. I used my favorite three-armed small Jonnesway, having fine-tuned its legs on an emery machine. the unit is tight and you can’t disassemble it with a stock puller. The bearing sits on the classic seating, there is nothing special waiting for anyone, all elementary pressed in a vice with a simple tooling.

Let me repeat: you can only disassemble the assembly without any losses by using a good rigid puller, don’t try to pound on the shaft. you will crack the pinion, unglue the shaft and end up throwing out the entire angle grinder. No tool. no work, in this case there is no other way!

After razrabanivanii reducer to molecules detalushki went into the ultrasonic bath bathed in Detalan and the result I got here is such a soup set:

Peculiarities of repair of different brands of angle grinders

Dana article suggests methods of finding defects in the grinders different models are not repair angle grinder (angle grinder) with their own hands. Here you can find answers to questions about the procedure for disassembling the gears of the most popular models of angle grinders, replacement of gears, bearings and their repair. There are recommendations on how to press and unpress the gears and bearings, repair methods and tools.

In addition to common malfunctions in angular grinders of different brands have their own peculiarities. It comes not only from the differences in the designs of grinders, but also from the materials and components used.

It is also important who made the tool. Knowledge of the peculiarities in the design of grinders allows you to repair angle grinder with their own hands qualitatively and quickly. The following information will help to repair any brand of angular grinding machine.

In addition to original tools, the construction market is flooded with cheap knockoffs. And don’t think that fakes are made exclusively in China. Power tools from Chinese manufacturers in quality are not inferior manufacturers of European countries or Southeast Asia.

Quality tools from Chinese manufacturers for the European consumer go through several stages of incoming inspection. For third countries Chinese manufacturers do not control tools. But the instruments are made on the same lines, in the same factories, by the same people. That’s why there is such a difference in price.

To repair the angle grinder with your own hands, you must have a diagram of the angle grinder and understand it. Repair of Bosch angle grinder is different from Interskol angle grinder. And then there are angle grinders by Makita, Hitachi, Metabo.

A few general tips on how to organize an angle grinder repair

Before proceeding to repair the angle grinder, consider a few useful tips:

  • Before you start disassembling the angle grinder, carefully read its description, the scheme of assembly and the order of work.
  • Be sure to follow the sequence of operations.
  • Strictly observe safety precautions.

The most common cause of angle grinder failure is a wire break near the handle. First you need to check the presence of voltage on the button, this is done with an ordinary voltage tester. Then check the button itself for proper operation.

change, bearing, makita, angle, grinder

How to remove the bearing from the Bulgarian anchor?

Today, home and professional craftsmen use several methods to solve this problem. If it is necessary to remove the bearing from the armature of a grinder or other tool, it can be done with the following devices:

  • Removers. These are special devices that allow you to easily and safely remove bearings of different sizes from the Bulgarian anchor. The use of pullers requires virtually no physical force, even if the bearing is tightly seated. Centering mechanism allows for simultaneous attachment of the unit’s handles. Can be used in any position. Before removing the bearing, the Bulgarian anchor shaft should be cleaned of old grease, chips, and sand so that nothing interferes with the removal of the part. Centering mechanism keeps puller in place with precision. If the bearing is intact and the disassembly process is performed for inspection, it must be removed from the inner ring to prevent damage. For large shafts, Bulgarian anchors use solid three or four grip legs, while devices with interchangeable plates or strips are suitable for smaller shafts.
  • Hammers, chisels, wrenches and other handy tools. In this case, to remove the bearing from the Bulgarian anchor, it is heated with gas, squeezed with a vise, grind, chop and perform many other operations. These methods can certainly be effective, but there is a high risk of mechanical damage to the part’s seat. And often the bearing after such manipulations without a puller will be unsuitable for further use. In addition, the contractor can be injured by contact with the clamps, which will disintegrate after hitting the face, eyes or head.

How to disassemble the gearbox correctly: Guidelines

When the gearbox completely refuses to work, a complete disassembly is required to replace parts and clean it thoroughly. In order to do this work, a bench vice must be prepared. All work must be carried out in a defined sequence:

  • Unscrew the bolt holding the gearbox housing with a wrench.
  • The rotor body is carefully clamped in a vise.
  • Use a hammer to gently tap the housing to remove it.
  • Finding a convenient position for the rotor to remove the bearing. The vise is clamped again.

Read also: Capacitor for starting the electric motor

Placing a block of wood to knock out the bearing. To remove the pinion from the gearbox axle requires:

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

Sliding bearing repair

The bearings are considered to be the main “vulnerability” of the angle grinder. And although there are only three of them in the entire structure, these elements are often the cause of mechanical failure. So, the bearings are negatively affected by:

  • Use at maximum capacity;
  • The rotation is too fast;
  • insufficient lubricant volume;
  • ingress of dirt and dust particles;
  • Untimely/incorrect replacement of carbon brushes or their deformation.

The design of any varieties of grinders provides for rapid replacement of bearings.

Faults relating to deformation or wear of this element suggest an extraneous noise.

To detect damage by checking backlash shaft, i.e. by rocking it sideways when the tool is installed. If there is play, the plain bearing must be replaced as a matter of urgency.

To repair the bearing, you must pull it out of the housing and remove it from the gearbox shaft.

Dismantle this part with a special puller. The bearing can be removed from the rotor using folk methods. To do this, metal strips or wrenches must be placed in a vice. The bearings should be placed on them and, using a massive hammer and an insert of metal, pounded out of the shaft axis.

A few words on grease

Reliable operation of the gearbox and its durability is largely dependent on timely lubricant change and its proper selection.

Russian market offers a wide range of lubricants. Among them are lubricants Russian width=”500″ height=”389″[/img]

Modern tool manufacturers strongly recommend using only their own lubricants. This is the manufacturer’s policy.

Among Russian-made lubricants, we recommend that you use those specifically designed for gearboxes.

But the quality of the angle grinder is affected not only by the properly selected grease, but to a greater extent by its timely replacement! Do not procrastinate with grease replacement, watch its condition.

Grandpa Ashot’s firm

Angle grinder got its nickname “angle grinder” at the time of the Soviet Union. Because, at the time this tool was made and delivered from Bulgaria. Angle grinder in the arsenal of household tools is the most versatile and multifunctional helper. The angle grinder in operation is subjected to strong and uneven loads and long periods of operation, so malfunctions occur more often than with other power tools.

My angle grinder has an unusual noise and increased vibration when it is turned on. Further operation of the tool with such signs is more expensive.

Repair of angle grinder begins with unscrewing four screws of gearbox cover.

By prying with a screwdriver, remove the gear cover, complete with a secondary shaft and pinion. The secondary shaft bearing turned out to be functional, without backlash and seizure.

But the front bearing of the armature. completely disintegrated. The bearing balls were in the gearbox grease and the small pinion retaining ring was worn on one side. To replace the front bearing you must first unscrew the armature brush covers and remove the brushes.

Then unscrew the four screws fastening the gearbox of the angle grinder to the stator and remove the anchor along with the gear housing.

To remove and install the armature pinion retaining ring, I had to make a rudimentary tool. For this purpose I used an old pair of scissors. The tips of the scissors were ground down on the emery as in the photo.

This is what my snap ring looked like. To install the circlip easier, the tips of the scissors were heated with a gas torch until red hot and bent at right angles to the plane of the scissors. Then heated and cooled again in machine oil.

After removing the armature gear I pulled the anchor from the gearbox housing. This is what the front armature bearing looks like.

After we bought new bearings and a retaining ring from a store and continued with our angle grinder repair.

The outer ring of the armature bearing is removed from the gear housing by lightly tapping on a metal screwdriver inserted into the groove of the ring on the inside of the gear housing. It is important not to allow the cage to be tilted when pressing it out.

And here’s the inner ring of the bearing sitting snugly on the armature shaft.

To remove it I used a standard threading mandrel.

The studs were unscrewed from it to rotate when threading. And the lumberjack itself is mounted on the bearing cage, so that the screws for fixing the lumber, get into the groove of the bearing cage. Then we screw in the screws evenly from each side and thus secure the latch-holder in the cage. Now grabbed with the legs of the extractor for the armature holder and remove the cage from the shaft.

This is how the front armature bearing of my angle grinder looked like.

The new bearings should be filled with grease. To do this we need a sharp awl, some Lithol 24 grease and a mandrel for mounting the bearing caps. To lubricate a closed bearing you need to remove the cap by prying it with an awl, as in the photo.

Now grease the bearing and put the bearing cap back on.

To put the cap in the bearing without damage you need to pick up a mandrel with a diameter a little bigger than the outer diameter of the bearing cap. I used a socket wrench head.