The main components of angle grinders are three in total: the armature, the stator and the gearbox. In this case, the armature is a rotating element, it contains windings and is required precisely to create the torque transmitted to the gearbox. The stator also includes windings divided into two parts. Electricity is applied to one of them, through a brush (carbon bar) enters the part of the armature that is currently touching it, then from the other part of this unit the current flows through the second brush to the next sector of the stator.
If the chain is good, the armature rotates and spins the disc through the gears. The speed reducer is needed to keep the speed within certain limits. As you can see, the repair of bolsters with their own hands can be quite simple, but you need to get to the nodes, so first unscrew the screw in the back of the housing (there is often a speed regulator).
The screw is usually held in place by a small plastic plate, without which the shroud will easily shift. You will see all of the above parts except the gearbox, which is hidden under the metal cover that takes most of the heat of the mechanism. You can remove the gearbox, unscrewing 4 screws, and now you get to the mechanical part of the angle grinder.
Even without electrical skills, you do not have to worry about how to repair the angle grinder, if you know exactly what does not work. There are relatively few alternatives. Specifically, if you see sparks in the armature area, if you get a distinctive smell when running, if the sheath gets hot and if you hear popping noises, the collector. the armature main assembly. is most likely the cause. It looks like the plates located around the rod, it is to them all the ends of the winding are reduced, and their main purpose. contact with the brushes.
Since we already know how to get to the armature, we remove the brushes from the special grooves where they are held by spiral springs (you can see these in the clockwork). This is to be done with the gearbox removed. Next, take the anchor by the rotary gear and pull it toward you. Try not to tear off the roller bearing which is mounted on the other end of the axle and is recessed in a special recess inside the housing. Clean the collector, if it is dirty, if it is burned, you will have to install a new armature.
If all the electrical nodes of the angle grinder are serviceable, but burned speed control unit, usually copiously covered with epoxy, replace it with an ordinary dimmer of sufficient power, connecting it in series with the angle grinder.
If when switching on the disc starts to gain speed and accelerates too much, there is definitely a short circuit in the stator winding. Repair of the angle grinder stator begins with cutting off the frontal parts of the coil, the remains of which are removed. Next, we make a new winding using a template clamped between two large plates on an axis that can be inserted into an electric drill. The main thing is to achieve an identical number of turns, made with the proper density and to maintain the thickness of the wire. We insert two coils into the stator body, we make conclusions from the same winding wire, insulating them with flexible tubes of appropriate diameter.
Remember unscrewing the 4 screws of the gearbox? You won’t find anything special underneath, just a sea of grease, rolling bearings and gears. In models with power up to 1100 W are usually used spur gears, mounted on the armature, but angle grinders with higher power, for example, 1500 W, require helical gears. Both versions have a conical shape, since the axis of the gear rod intersects with the armature shaft, and transmission is possible only by angular meshing of the teeth.
The speed of rotation of the disc is adjusted by the gearbox, thanks to a certain number of teeth on the pinion. For example, if armature gearwheel has 10 teeth and geared one has 41, then if armature rotation speed is 32800 rpm, disk will give only 8000 rpm for the same time. As a rule, the repair of the angle grinder gearbox is only to replace the gears. If the disc gear is broken, then remove it to replace it will be very difficult, in the gearbox is the node is best fixed.
However, if you have among the tools a universal puller with sufficiently thin legs, there should be no problem. It should be even easier to remove the pinion gear of the anchor shaft, it is always kept on the right thread, but do not hurry to unscrew it, first wrap the rag around it to prevent damaging the teeth with an adjustable wrench. And don’t be sorry for the grease inside the gearbox, sometimes it jams precisely because the grease is partly dried out and partly smeared on the surface of the metal housing.
How to Remove
In the following video on the Interskol model angle grinder has a large backlash on the spindle. The author describes in detail how to remove the sleeve of the slide bearing. For which electric screwdriver is fitted with a tapping tap for tapping into the inner sleeve. Next, the tap is performed mechanically to cut the thread, and after meeting it with the stop on the gearbox housing, the sleeve will be lifted by the cutting part of the tap until it is completely out of the landing hole.
The variant with pressing out parts seated with a great tension is not recommended by the author to make pullers in order to preserve their integrity. It would be better to use press machines for this kind of operation.
The plain bearing can easily be replaced by a needle bearing. The main thing is to match it to the outer and inner diameter of the bushing. The following describes the conduct of repair work with an angle grinder, in the design of which a needle bearing is used.
How to change gears on a Makita 9558HN
The repair of the rotor involves its replacement with a new or reconditioned one. Option to repair the rotor without help of others, but you need not only patience, equipment, material. This is the kind of work of the highest class.
In addition to electronic parts in the angle grinder goes and mechanical part, the main unit which is engaged in is the gearbox.
The gearbox consists of a housing, pinion and idler gears. The drive pinion is mounted on the rotor shaft. The driven gear is attached to the spindle pos.50.
On the Makita 9565 angle grinder driven gear is pressed on the spindle. In the Makita 9558HN angle grinder, idler pinion is mounted on the shaft with keyway.
Gearbox failures are related to gear teeth failure. Gears are slipping or some of the teeth are chipped.
Repair of the gearbox of a Makita angle grinder consists of replacing a pair of helical gears. Gear change is done only in pairs.
To remove the idler is not necessary without the press or a special puller. There is no need to use a hammer because the gear housing is made of a fragile material.
Checking the Motor
In addition to control circuits, the electric circuit of angle grinder includes rotor and stator. These are complex units and it is recommended to have them repaired in specialized centers. But nothing is impossible for Russian craftsmen. We recommend your own ways to repair the stator or rotor with your hands.
How to repair the stator of a Makita angle grinder
At failure of stator pos.24 of the angle grinder is indicated by the smell of burning, overheating of the angle grinder body, spontaneous revolution of the angle grinder. In the housing of the angle grinder pos.33 The stator is fastened with four 4×70 self-tapping screws pos.21. To prevent damage the stator is covered by protection pos.20.
Repair of the stator of a Makita angle grinder is to identify a short circuit or breakage of the windings. The best way to diagnose the stator is to use a special tool called the IR-2. The stator is declared defective if traces of darkened winding are visible, and a breakage or short circuit of the winding turns is detected.
The stator can be repaired easily. rewind the winding.
How to repair the rotor of a Makita angle grinder
If the angle grinder overheats, if there is a smell of burning, an increase in sparking near the collector, you need to pay attention to the integrity of the rotor pos.13.
Diagram of a Makita angle grinder
Disassembling the stator requires disassembly in series. To remove the rotor, release it from the gearbox pos.3. To do this, unscrew the hex nut M6 pos.4. To unscrew the nut, clamp the rotor with one hand. With the other hand, using a spanner wrench, unscrew the nut counterclockwise.
Remove the nut, pull out the flat washer pos.5, remove conical spiral pinion pos.6, remove retaining spring pos.7. Swinging the rotor sideways gently pull it out of the gear housing pos.3. After removing the retaining ring pos.8, use a puller to remove the bearing pos.9.
The Makita 9565 angle grinder uses a 6001LLB bearing.
It remains to remove the flat washer pos.10 and the gearbox cover pos.11.
Here is an external view of the rotor of a Makita 9565 angle grinder with the insulating washer put on, pos.14, a flat washer 7 pos.15, bearing pos.16 and the rubber dust cap 22 pos.17. The angle grinder has a 627zz bearing on the manifold side. Russian equivalent 80027.
The rotor is repaired by replacing it with a new or refurbished. It is possible to repair the rotor yourself, but you need not only patience, equipment, material. This is a high class type of work.
Tools required for repair
Repair with your own hands Makita angle grinders, requires the use of certain tools. Do not do without a screwdriver set. Preferably, they should be equipped with a ratchet mechanism. The best option, 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. And also prepare a spanner, bearing extractors, a hammer, soft metal. Well, you can’t do without the right lubricants, wiping materials, and liquids to wash off the old grease.
Start repair angle grinder with your own hands should be with the preparation of the workplace, install the correct lighting. You need a diagram of the angle grinder of the required model and the proposed instruction.
Any malfunctions of power tools are divided into two types: electrical and mechanical.
Consider the repair of nodes Makita angle grinder will be on the example of the scheme of Makita 9565 angle grinder.
Mechanical malfunctions of the Interskol angle grinder
From mechanical faults of Interskol bolsters, the weak point is the gearbox. The gears used in the gearbox will eventually wear out, the teeth are destroyed, and backlash occurs in the joints.
Repair of gearbox of Interskol angle grinder 125
In order to repair the gearbox of an Interskol angle grinder, it is necessary to determine the nature of the fault. Most mechanical problems of the gearbox can be determined visually or by ear. High run-out of the spindle shaft, jamming or rotation of gear wheels are determined by simple inspection of the spindle shaft condition. If you hear excessive noise, unusual noises, or overheating, you can tell by hearing or by touching the housing with your hand.
To disassemble the gearbox unscrew (4) four screws M4×14 pos.11, remove the lock washers DU-1000ER pos.12, pull out the gearbox cover pos.13. There will be a spindle mounted pos.10. Spindle is mounted in bearing pos.14. Bearing size 6201-2RZ. Russian analogue 180201.
Use a press to press the spindle out of the bearing housing. But you can also tap it out gently with a hammer. The main thing is not to damage the gear cover.
Bevel gear pos.16 is held in place by a keyway and secured by a retaining ring pos.17. As a key in the Interskol angle grinder 125/900 angle grinder uses a ball with a diameter of 3 mm. If you remove the circlip, it is very easy to remove the pinion. Other Interskol angle grinder 125 models use a key.
Remove the gears and inspect them for gapping, breaking or jamming, backlash in the keyway.
Repair the gearbox of the Interskol angle grinder 230
To disassemble the gearbox angular grinder 230 you need to remove the cover pos.6 by removing the four (4) screws. Spindle pos.8 is supported in the bearing pos.9, pressed into the cover housing pos.6. Bearing size 6203zz. Russian equivalent 180203.
Remove the gears and look at them for gear grinding, breaking.
Repair angle grinder Interskol angle grinder 230
Reassembling the tool with the new parts
After disassembling the tool, replacing any broken parts as necessary, reassemble. Make sure you have all the tools, lubricants and clean rags on hand to put the finishing touches.
All previous grease must be removed and replaced with fresh grease. Use lubricants from reputable manufacturers, buy them from specialised dealers.
Assemble the rotor first. You need to press the bearings, mount the impeller. Before doing so, carefully lubricate the bearings. Using a wood preloader, press them on top of the shaft.
Cover the collector bearing with the rubber guard. This is the same diagram of how to assemble the rotor shaft.
Then reassemble the gearbox. Begin this process by placing 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 together with the shaft inside the stator housing. It is necessary to press both housings together after the collector bearing is already in the housing. Next check to see if the rotor rotates easily on the bearings.
The final step is to place the cover back where it was. Check how the spindle shaft rotates. If you find that the rotation is light, even with the movement of your hands, you can proceed to screw the screws on. They do the fixing of the lid to the body. Before you do this, lubricate all the screws, using sealant.
Angle grinder repair costs
Experienced specialists of our workshop will carry out warranty and post-warranty repair of Makita bolsters. Note that the price in which it costs depends on the category of its complexity, which, in turn, is determined by the power of the tool, the nature of the fault, as well as the cost of spare parts. We use only original spare parts from the main supplier. By the way, we can also repair a Makita baker, and of any complexity.
If you have any questions about tool repair call us at ext. 120