How to disassemble the gearbox of a Sparky angle grinder. Needed tools

Self-repairing a Sparky angle grinder

The Russian consumer gives preference to Sparky grinders not only because of the high operating convenience, but also because of the ease of repair of angle grinder Sparky, a favorable price-quality ratio, the availability of speed adjustment device, anti-vibration handle, the original protective casing.

Sparky angle grinders are available in three classes: small, medium and large. The class is determined by dimensions. In the small class produces 15 (fifteen) models, whose weight ranges from 1.2 kg to 2.4 kg. The middle class is represented by three models, whose weight is in the range of 2.5 3.3 kg. In the large class includes 10 (ten) models, which weigh up to 6.3 kg. Recognizability of Sparky grinders gives a bright appearance: purple body, bright red or silver color of the gear housing.

Design features of the angle grinder Sparky

The features of the angle grinder Sparky include:

  • Multifunction switch that has a function that locks the angle grinder in place;
  • The housing is made with double insulation;
  • There is a device for soft start, setting and maintaining a constant rotor speed;
  • The design of the brush holder prevents dust from being trapped and the carbon brushes from getting jammed;
  • The angle grinder uses automatically switching off carbon brushes;
  • It is completed with an anti-vibration handle;
  • The use of a protective cover with the possibility of quick installation and removal;
  • The gearbox housing is made of durable, lightweight magnesium alloy;
  • Intelligent venting system for improved cooling.

Sparky M750 / REVIEW

Gearbox disassembly must be performed frequently, especially when the tool has been subjected to intensive use. After disassembly, change of lubricant. In most cases “Lithol-24” is used. It should be said that the grease must be changed daily at regular intervals. It helps to prolong the reductor operation life for more than one year due to the reduced wear of its component parts.

Russian consumers prefer Sparky angle grinders not only because of their high operating convenience, but also because of ease of repair of angle grinder Sparky, good quality-price ratio, availability of speed regulation device, anti-vibration handle, original protective hood.

Angle grinder firm Sparky available in three classes: small, medium and large. Class is determined by dimensions. In the small class produced 15 (fifteen) models, whose weight ranges from 1.2 kg to 2.4 kg. The middle class is represented by three models, the weight of which lies in the range of 2.5 3.3 kg. The large class includes 10 (ten) models, which weigh up to 6.3 kg. Recognizability of Sparky grinders is given by their bright appearance: purple body, bright red or silver color of the gear housing.

Necessary tools for repair

Repair with their own hands Makita angle grinders, requires the use of certain tools. Can’t do without a screwdriver set. It is preferable that they were equipped with a ratchet mechanism. The best option is to use a cordless electric screwdriver. To repair the electrical part of a Makita angle grinder, you will need a tester, the IK-2 short-circuit detection device. Also prepare an open-jaw wrench, bearing extractors, a hammer, and a soft-metal. Well, you can not do without the right grease, wiping materials, liquids to wash off the old grease.

Start repair angle grinder with your own hands should be with the preparation of the workplace, the installation of proper lighting. You will need a diagram of the angle grinder needed model and the proposed instructions.

Any faults on power tools are divided into two types: electrical and mechanical.

Consider the repair of nodes of the Makita angle grinder will be on the example of the scheme of the Makita 9565 angle grinder.

How to remove / remove the needle bearing in the grinder

It is not difficult to press a new needle bearing, but Removal requires the use of an original puller. In the following video, the author describes the manufacture of such a device and shows its practical effect.

Puller has a collar with a collar on the ends of the moving blades. The barrel is sized on a lathe, and the center hole is drilled under the rod that expands the lobes. The puller is inserted into the bearing, and the shoulders, after moving the rod through the hole, are lifted up and adjacent to the side surface to the end of the ring. The bearing can be removed from the housing by means of not very effective looking, but reliable armature levers with pointed edges, leaning against the inserted washer.

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Important Note: A needle roller bearing has a much longer life than a conventional bearing. However, the spindle shaft wears out during operation, which must also be replaced. In the video described, the author found a replacement option. However, in most cases this can create additional problems.

How to Disassemble the Gearbox of an angle grinder

Disassembly angle grinder does not require special locksmith skills, it does not cause severe problems. But the work should be done very carefully and with the greatest vigilance. How to disassemble the angle grinder, we often see on the web pages.

Sites show videos with detailed workflow. Dismantle the angle grinder is necessary, not only when it broke down and some parts are useful substitute, it must be done, and the same for cleaning tools from dirt.

When a breakdown of the angle grinder, you should first disassemble it and clean it well, almost always the tool starts to work.

For this reason, the activities that are needed to disassemble the angle grinder, should know who has such tools and wants it to work long and well. In stores there is a wide range of this mechanism, made by various companies. They differ:

But our client is the model at least any manufacturer have a similar technological assembly. What is left for our customer to do Angle grinders are equipped with a similar set of parts.

Main modules used

  • Body, usually made of special impact-resistant plastic.
  • The most powerful electronic engine.
  • High quality gearbox.
  • Smooth start.
  • Motor switch.
  • SJS system. The system allows the tool to run smoothly without jumps.

What may be required for operation

The process of disassembling an angle grinder requires several tools:

The complexity of disassembling the angle grinder is due to the fact that the parts have a very tight contact. This allows it to handle the heaviest loads. No shifting of parts and no oscillating movements. Of course, disassembly is best done by a master, but you can try to do everything yourself with the utmost care.

Tools required for operation: pliers, ruler, caliper, pliers. steel brush, megohmmeter.

Angle grinder Fiolent MSHU2 9 125E at PromSegment

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

The first step is the unscrewing of the bolt holding the hood. It is very easy to remove, there are no tight joints. Then you need to unscrew the screw, remove the plastic plate. The outer casing should be moved in the direction of the cord.

Basically, all models of lathes have a variety of devices. However, the common part is the 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 mounted in the housing.


It is held by four bolts. They need to unscrew and with extreme care remove the gearbox from the body of the angle grinder. Disassembling the gearbox is necessary to clean it and replace worn parts. It is one of the most important components of the angle grinder and is under tremendous strain during operation.

To remove the rotor from the gearbox housing, it is necessary to unscrew the nut that holds the rotor. Use a special puller to remove the rotor. Such an operation is connected with some difficulties, so if you don’t have special skills, it’s better to leave such work to professionals. You can’t do without a puller.

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It must be said that no such detailed disassembly is required for the simple removal of dirt. It is only necessary to replace a worn bearing or a broken rotor.

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

Some force is required for this operation. Remove the armature from the housing with extreme care as it breaks easily.

When you notice a big spark during work, a big heating of the body, you should just take out the armature to clean the collector. The device is now ready for use again.

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How to disassemble the gearbox correctly: Notes

When the gearbox no longer operates at all, it must be completely disassembled to change parts and thoroughly clean it. To carry out the work, you need to prepare a locksmith’s vise. All work is performed in a specific process sequence:

  • Loosen the bolt holding the gearbox housing using a wrench.
  • Gently clamp the rotor body in the vise.
  • The body is extracted by hitting it lightly with a hammer.
  • Find a convenient position of the rotor to remove the bearing. Clamp the vise once again.

Use a block of wood to tap out the bearing. To remove the pinion from the gearbox axis is necessary:

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

BOSCH GWS 6-100 angle grinder gearbox repairing / how to open & fitting all gearbox spare 2022 //

How to remove the spindle: tips

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 cogwheel, which requires the use of special tools.

After removing the pinion, place the housing in a vise. Using a wooden block and hitting it with a hammer, carefully remove the spindle, which bears the bearing. Removal of the bearing is done in the manner described above.

disassembly of the gearbox should be carried out at regular intervals, particularly if the tool has been subjected to intensive use. After disassembly perform grease replacement. Lithol-24 is most often used. It should be noted that the grease should be changed permanently at intervals. This prolongs the life of the gearbox by many years, thanks to the reduced wear of its constituent parts.

The order of disassembly of the angle grinder Sparky

Regardless of the power of the Sparky family, the disassembly procedure is almost the same.

Disassembly begins with removing the carbon brushes. They are easy to reach when you remove the housing cover or the brush holder guard.

The thing is, to get the rotor out of the stator housing, the carbon brushes prevent the rotor from being removed by rubbing against the lamellae of the collector.

In the next step the gear case and stator housing are separated. You only need to remove the four screws that hold the gearbox housing and stator housing.

To disassemble the gearbox housing, remove the gearbox cover by removing the four screws. The idler shaft assembly is mounted in the gearbox cover. We’ve already looked at disassembling the idler shaft assembly.

The electrical section is even easier to disassemble, since it contains even fewer parts.

Carbon brushes are mounted in brush holders and fixed with special clamping springs. When taking out brushes for repairs, remember where and in which direction they are installed. The brushes wear unevenly. And the wear of the brushes is affected by the angle of rotation of the rotor.

Possible electrical problems

Electrical faults on a Bosch angle grinder can be divided into simple and complex faults.

Simple electrical faults on the Bosch angle grinder

If you have turned on your angle grinder and it refuses to work, start looking for the problem with a broken power cord. often than not, wire breaks occur at the entrance to the angle grinder or at the plug. Do not allow twisting, it will cause a short circuit in the tool.

To determine this malfunction it is necessary to open the handle covers on the angle grinder. In Bosch grinders up to 1000 watts, the cover is attached with one screw in the face. On Bosch angle grinders over 1000 W, the handle cover is secured with several screws.

Use a tester to test the power supply line from the input plug to the pos.5 up to the switch. If the circuit is intact, proceed to check the switch operation. Bosch power tools have simple switches that are controlled by the trigger.

But the electrical contacts of the switch burn out and cause the angle grinder to malfunction. It is not advisable to restore the contacts of the plastic switch, it is necessary to change it for a new one.

If the switch is intact, use a tester to check the circuit from each plug pin to each carbon brush.If the circuits are intact, the angle grinder should start. If it doesn’t rotate, the problem is in the mechanical part. The gears may be jammed or the bearings may have collapsed.

Checking the Electric Motor

If your Bosch angle grinder picks up speed regardless of you, begins to get very hot, sparks, you should pay attention to the integrity of the rotor windings, stator.

Unwanted speed of the angle grinder indicates a malfunction of the stator windings. Check the integrity of the windings with a tester, and the short circuit between the coils checked with a special tool.

How to determine the rotor malfunction

Rotor repair is a complex technological process available to craftsmen with straight hands.

A rotor malfunction is indicated by a drop in engine speed, or a long, sparkling trail on one of the brushes. This is the first sign of a short circuit of the armature winding turns.

It is preferable to have the rotor repaired in a specialist workshop. And you can rewind yourself, if you decide to do the repair of an angle grinder Bosch with your own hands.

Dark color of the rotor winding and burned manifold lamellae indicate short circuit in the rotor circuits. The fault can only be eliminated by replacement with a new rotor.

Stator repair

Repair of a Bosch angle grinder also includes restoration of the stator. The main sign of stator failure is the spontaneous increase in speed of the angle grinder, which can not be reduced by making adjustments.Burnt stator winding changes color, becomes darker. The stator core also darkens from heat.

The stator is easier to rewind, but even here you must follow certain rules and sequences.

If you have removed the stator case cover, carefully inspect the carbon brushes and rotor header lamellae.

Carbon brushes must be at least 8 mm long. By the way, Bosch angle grinders use carbon brushes with a “shot”, a device that stops the angle grinder at the minimum length of the carbon brush.

The collector lamellae should not show any signs of fouling or wear. You can easily remove the carbon deposits with absorbent cotton and alcohol. Stator overheating and rotor short circuit

Get Another Angle Grinder

Faults in the speed regulators

Bosch angle grinders, especially the low power ones, are equipped with speed controllers. The speed regulator can be accessed by opening the handle of the stator housing, which is held in place by one end screw.

The speed range can be adjusted with a potentiometer hidden in the handlebar.

A faulty regulator is quite easy to remove as it is only attached to the guide rail.

Repair of the speed regulator angle grinder is a complex process, the performance of which requires not only special knowledge, but also tools and equipment.

If the RPM regulator is out of order and there is no new one, disconnect the supply wires and install a jumper.

The jumper installed when the speed regulator fails is shown in red.

Angle grinder repair with your own hands. fix typical faults

The basic principle in the repair of any electrical equipment is “proceed from the simple to the complex”.

Whether it’s a domestic electric circuit breaker or a turbine at a hydroelectric power plant, the repair sequence should rule out elementary faults first. Electrics and electronics aren’t called “the two sciences of contacts” for nothing. Typical malfunctions of bolt cutters, together with the methods of troubleshooting, are as follows:

  • The tool suddenly stops showing signs of life. There is a 90% chance that the current from the outlet is not reaching the 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 for breaks. very often it is enough to replace the wire, and the angle grinder will work like new;
  • The wire and the plug are assured to be intact, and the tool is still immobilized? The starter needs to be disassembled and it is advisable to mark the removable contacts: if they are connected incorrectly afterwards, the winding could burn out or the armature could jam. The trigger can be replaced by any similar, working parameters are marked on it quite legibly;
  • The “start button” and the power cord are in working order, but the angle grinder does not want to work? It is time to take care of the brush holders. Very often it is enough to sand down the contact plates on the collector and you get a long-awaited spark and a steady humming of the mechanism. If it is not there, it is necessary to carry out replacement of brushes. The resource of these devices is usually limited to several years. A number of models are available with soldered brushes, and new brushes must be soldered out and installed as a complete set, and partial replacement is not allowed;
  • After replacing, carefully inspect the old electric brushes. if they have uneven wear, it is a clear sign of a shift in the center of gravity of the tool or its movable internal part. It is better to contact a specialized firm for repair of complex electrical equipment. independently adjust the balance without experience is unlikely to succeed.

Brush replacement is one of the “pinnacle of the first level” of troubleshooting in electric grinders. You can and further describe repair recommendations, how to disassemble the gearbox of the angle grinder, to rewind its winding or reconfigure the electronic stuffing. But serious breakdowns require a serious approach. If you’ve never seen the gearbox, how can you possibly repair it?? The chance of turning on the angle grinder depends on your common sense. saving on a professional repair will turn out to be the loss of the entire tool.