Build Daily


August 12, 2017 18:08

Repair manual angle grinding machines with their own hands


  • 1 Mechanical faults LBM
    • 1.1 Repair plain bearings
    • 1.2 gear Repair Bulgarian
  • 2 How to disassemble the gearbox Bulgarian
    • 2.1 How to remove geargear
    • 2.2 Repair spindle lock button
  • 3 Electrical faults Bulgarian
    • 3.1 Finding wire break power
    • 3.2 faults carbon brushes
    • 3.3 Repair speed switching and control buttons
    • 3.4 stator Repair
    • 3.5 rotor repair LBM
      • 3.5.1 Repair collector and rotor slats
  • 4 Video repair grinders
    • 4.1 Repair grinder with his own hands (start button)
    • 4.2 troubleshooting 125 th Bulgarian
    • 4.3 Repair Bosch PWS 720-115
    • 4.4 How to replace bearings on grinder Bosch

grinders (LBM), Bulgarians called in the people,They are popular and reliable tool.But when something breaks.Perform repair grinders with their own hands is not difficult, if before you instructions telling step by step procedure for repairs LBM.Below you will find answers to any questions about gear repair, rotor, stator, carbon brushes angle gr


Angle grinders among domestic masters are very popular.Possibility of turnover of working bodies allows for cutting, grinding, polishing operations.

presence of soft starter makes the tool work safe and convenient.Repair angle grinder simple and can be performed independently.For those who dare to carry out repairs on their own angle grinders, angle grinders scheme will need the right type of machine, tool lubricants and this instruction.

Repairs grinders with their hands begins with the study of emerging problems.Bulgarian device is quite simple.Rotating rotor through helical gear transmits the torque on the shaft (spindle) working body.On the spindle is set the desired working tool, whether it is a stone cutting, grinding or polishing a circle and performed the required processing step.

Speaking of tooth shape.In the low-power grinder mounted spur gear.Helical gears are used in the grinder with over 1000 watts.

Type grinders in the context of

Angle cars, like any tool break over time.Reasons Bulgarian faults can be different.They come not only from improper use tools, but also delayed the replacement of carbon brushes, lubricating fluids.

Regardless of the angle grinder model fault at all appear in the same units.Bulgarians Faults are divided into mechanical and electrical.Beginners repairers faults are divided into simple and complex.

Mechanical faults LBM

Bulgarka - angle grinder is designed to perform the cutting, grinding, polishing operations.The Bulgarian during operation is subjected to heavy loads, working in a dusty environment.

Excessive load when using grinders in "Cutting" mode causes increased wear of the bearing is not only, but also the gear teeth of the gears.

Home malfunction grinders for mechanical parts, wear or destruction of the sliding bearing on a shaft large spur gear reducer.

Bulgarian Repair the problem is simple, if the hand is its diagram, description and recommendations for repair work.

Repair plain bearings

weak point of any angle grinder is bearings.And although they are few in the construction of all three, they often lead to mechanical failure.On bearings have a negative impact:

  • high rotation speed;
  • work at extreme conditions;
  • insufficient lubrication;
  • dust or dirt;
  • untimely replacement or destruction of carbon brushes.

design of all Bulgarians provides fast and does not constitute any difficulty replacing the bearing.

Faults Bulgarian associated with deterioration or destruction of the sliding bearing shaft end are characterized by the appearance of unpleasant extraneous sound.

destruction plain bearing test detected backlash shaft Fitting the working tool.Determined by swinging in different directions during the installation of the shaft of the working tool.

In another installation check the working tool shaft backlash, shaking his end in different directions.Backlash should be absent or minimal.

appearance of backlash indicates the need to replace a plain bearing.

Check the spindle shaft backlash

Bearing Repair consists in the removal of the body and removal from the gearbox shaft.

To remove the bearing from the shaft using a puller better.Inner race of the bearing destroyed is best to get in using tap the desired diameter, pre-screwed into a holder.

Removing the bearing race

With rotor bearings are removed by using a stripper or a national way.

inserted in the grip of keys or metal strips, bearings are placed on the keys and using nastavki soft metal and a hammer weighing not less than 400g beaten out from the shaft axis.


gear grinders Repair

The wear pinion gear grinder is checked for contact patch.Pre-reducer is completely cleaned of old grease.On the small gear reducer is applied to a special blue, reducer rotates.Then it is necessary to remove the large helical gear driven and look through a magnifying glass at the contact patch.It should occupy a total of at least 50% of the tooth surface.

Determination of gear tooth contact spot

Otherwise gear must be replaced or corrected tooth profile.Tooth Profile Correction described many times in the pages of this site.

But this fault is corrected only experienced masterom.Chasche all licked, cut or broken gear change completely, and as a couple.

How to disassemble the gearbox Bulgarian

When repairing any gear grinders most difficult task is the removal of gears and Pulling out the support bearing.

gear Dismantling begins with removing the cover and disconnect the gear position 1 of the stator housing and the release of item 2 of the rotor.Freed rotor is clamped in a vice and twisting nut pos.3 driving pinion.

Untwisting securing the pinion nut

The cover is molded gear spindle bearing.In order to reach the bearing, remove the snap ring, thrust bearing locking in some Bulgarians, and remove the bearing.

Removing the cover of the bearing reducer

Destroyed bearing pos.1 pos.2 easiest to get in gear unit housing by prying with a screwdriver.

In other models, the gear spindle fixes the retaining ring.

The tool for removal of lock rings

Driven big gear on the spindle is mounted in several ways:

  1. Gear pressed onto the spindle.
  2. pinion is keyed.

leading a small gear on the shaft is screwed on the left-hand thread (in some models, Sparky, right-hand thread), or fixed keyed and clamped with a nut.

Mounting the pinion nut on the rotor shaft

How to remove the gear reducer

The grinder 1000 W apply spur gears, angle grinding and typewriters used helical gears.

Gears are mounted in different Bulgarian differently.The pinion gear is mounted on the rotor shaft keyed connection or set on the thread.The driven gear is attached to the spindle shaft interference fit or use the key connection.Details on how to remove the gear and bearing from the shaft.

repair gear is to replace them, and only in pairs.

Continuous and uninterrupted operation of the gearbox depends on the availability of sufficient lubrication and timely replacement.

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Repair spindle lock button

spindle lock button is used to quickly remove desktop instrumenta.Knopka breaks down when you click on it at the time of rotation of the disk.Repairs grinders is a complete replacement of a button.

button should be pressed only in a state of stopping the grinder.

Electrical faults Bulgarian

Schematic diagram main part of the Bulgarians is almost the same.The rotor transmits torque through the gearbox on a work tool.The rotor rotates in the stator field.Control circuits are made up of buttons, regulating speed and smooth start-performing tool, carbon brushes, providing the transmission of an alternating voltage to the commutator bars.Power to the instrument is supplied through the connecting cable.

The main faults on electrical grinders are:

  • break the power cable at the input to the tool;
  • destruction or wear of carbon brushes;
  • failure of the power button;
  • open or short-circuit of the stator;
  • open or short circuit rotor;
  • delamination or develop slat collector.

faults on electrical grinders best defined tester or other device.Suitable for these tselee and homemade device called the people «Arkashka» .

Bulgarian scheme is quite simple and requires no special knowledge.You just need to exercise caution and safety when performing repair work and know electrical engineering at secondary school.

Details grinders including electrical part

Finding wire break power

One common breakdowns grinders becomes impossible to turn on the instrument, or stalling during operation.The cause of the fault of this kind becomes the power cable break poz.27 in the entrance location.Troubleshoot replacement of the cable or by removing the failed plot.The fault can be easily found using the tester.

If no tester on hand, but there is a screwdriver with neon indicator light, the fault can be found, serially connecting the power cord to the phase.

Faults carbon brushes

Reliable operation of any power tool to a large extent depends on the integrity and proper operation of the carbon brushes.The qualitative fit of the carbon brushes, their correct position relative to the commutator bars affects the efficiency of the rotor collector.

Remember!The length of the electro coal can not be less than 8 mm.

Timely replacement of carbon brushes to avoid most of the problems.

degree of wear of carbon brushes is characterized by species at the site sparking collector.Sparks should be uniform across the contact patch of the coal brushes and lamellae and not exceed the length of more than 8 mm.The circular sparking talks about a fault in the rotor circuit.

Carbon brushes for grinders

The grinder is recommended to use carbon brushes only tool manufacturers.Homemade carbon brushes can be installed, but only for a short period and immediately replaced at the earliest opportunity.

repair start and speed control

Faults power button is most often manifested in a difficult and precarious when you turn on the Start button.This fault appears and disappears spontaneously.

unacceptable working grinder with a faulty power button.This fault leads to jamming cutting discs during operation, and their destruction with unpredictable consequences.

fault persists complete replacement of the buttons on the new one.

In modern models bolgarok integrated soft starter with a speed regulator.Repair is not subject to, and will require complete replacement.No advanced master left-handed, of course, and will be able to fix this unit.

Protsessed to : Alison filter ;

Stator Repair

On the failure of the stator indicates spontaneous promotion machine shaft, Bulgarian begins to gain maximum speed.This failure points to the emergence of inter-track circuit in the stator winding.

dismantled Bulgarian

Some faults only specialists can eliminate.Extending the smooth operation of the stator can only be timely cleaning, lubrication and replacement of carbon brushes and bearings.

Usually stator crashes are rare.By this frequent causes overheating of the tool when working.A problem occurs strong heating body grinders and odor of burning insulation.

The stator may be either open or short circuit.Without going into the stator failure data can be easily found using the IR-32 device.

Faults are eliminated by replacing the stator.For lovers of tinkering with his own hands can recommend to rewind the failed stator own hands.Nothing complicated about it.

stator Removed easily, but in different models of angle grinders in its own way.

Removal Procedure stator:

  • grinder to remove the gearbox;
  • remove the rotor after removing the bar attachment;
  • remove the plastic protection of the stator;
  • unscrew the screws in the stator housing;
  • remove the handle cover and disconnect the power cord to the stator;
  • remove the stator housing by tapping on a wooden mallet or a bar.

rotor repair LBM

The failure of the rotor in the grinder caused by misuse of the tool, frequent overheating, late replacement carbon brushes, hit on the lamella collector of the abrasive particles and dust.

beginning increases the length of the sparks on the collector, then there is a smell of burning, and in the last stage, the smoke.The work is accompanied by a faulty gearbox thump and rumble.

destruction of even a couple of teeth leads to a malfunction of the instrument.

prolong the lifespan of the rotor can prevent dust from entering the instrument and preventing overheating of the tool, a timely change of the carbon brushes and lubricants using only the working tools and of such diameter that the tool recommended by the manufacturer.

rotor is a complex assembly that requires repair service centers.But lovers of tinkering with his own hands can repair the rotor alone.

Repair collector and rotor slats

Dismantling the rotor is not particularly difficult.

procedure for removal from the rotor angle grinder:

  • remove the lid handle grinders;
  • Release and remove the carbon brush;
  • unleash mounting gear case screws to the main body;
  • remove the gear case;
  • extract rotor.

Filmed rotor is necessary to examine carefully.If lamellae rubbed big grooves, they should be removed, pierce the reservoir in a lathe.

With minor grooves of the defect is eliminated by grinding.The rotor is clamped in an electric socket and using needle files and sandpaper removed generation.The process is simple.

drill clamped in a vise or securely mounted on a level surface.The drill chuck inserts one end of the rotor, is hosting the lamella, and securely clamped.With the rotor bearings previously removed.

second end of the rotor must be supported set of wooden bars.Drill activated and exhibited a small number of turns.In the first stage, use sandpaper grit large №40..80, the final stage of a smaller №120..200.

After sanding is necessary milled slots between the lamellae.It is best to perform a hacksaw blade specially sharpened.