How to remove the bearing from the grinder gearbox
The following recommendations will help you to successfully complete repair work on bearing assemblies.
- It is necessary to know the design of the operated angle grinder. You should study the technical documentation attached to the grinder. Knowledge of the location of units and parts will help to correctly disassemble and assemble the grinder during repair.
- The availability of the necessary tools for this will help to perform work on replacing bearings. This tool is not complicated and is almost always available in the arsenal of home craftsmen: screwdrivers, wrenches, hammers, a set of pullers or other manual devices (vise, extensions, drifts of various designs) for fixing and removing bearings.
- When repairing grinders, there is a certain order of work. You should adhere to it, taking into account some differences associated with the features of a particular model.
- Replace bearings if there is even a slight runout of the shaft, since a destroyed bearing can completely destroy the entire power tool.
- Make sure that the power tool is unplugged before carrying out repair work.
The bearing open for the Hammer grinder. Photo 220V
The tool used must be in good condition:
- the structural elements of the pullers (legs, rods, stops, screw devices) comply with the technical documentation;
- screwdrivers have smooth side edges, a straight rod is securely fixed in the handle;
- the jaws of the wrenches are parallel, do not have cracks or nicks;
- the hammers are securely mounted on the handles.
Compliance with these recommendations will allow you to correctly and safely disassemble the angle grinder, replace defective bearings, re-lubricate all parts and assemble the grinder for its further operation.
Interskol
Some designs of bearing assemblies are made without the use of interference fits. So, for example, in the next video, the ball bearing of the Interskol model gearbox housing cover is assembled into a support structure using a washer fastened with threaded connections. For better adhesion to the plane of the body, the surface of the washer is covered with an adhesive.
Hitachi
At first glance, some designs of bearing assemblies exclude the replacement of the bearing itself, which is included in such an assembly. However, the author of the following video found a way to do this in one of the Hitachi models and thereby save a decent amount of money in the proposed way.
To fix the bearing assembly, a wood crown was inserted into the drill, into the inner surface of which one of its outer diameters tightly sits. When the drill is running, using a sharp object, the plastic material is removed to the size of the outer ring of the bearing. Thus, nothing prevents you from removing the bearing with a hammer and an extension.
Further, when assembling a new bearing, a ring is inserted instead of the worn-out plastic (in the video it is most likely made of caprolon or other similar material). Since the ring in the video has a wall thickness that does not allow assembling the gear according to technical requirements, using a chisel, its inner diameter is finalized to the required dimensions.
Replacing the bearing of the LBM gearbox
The bearing units of the grinders take on heavy loads when performing work. This is due to the rather frequent failure of the grinders due to wear or destruction of bearings. You can remove the defective one and replace it with a new one, if you have the appropriate knowledge and a suitable tool.
- Recommendations
- How to remove
- How to remove / remove the needle bearing in the grinder
- How to change
- Bosch
- Makita
- Interskol
- Hitachi
- Sparky
How to change
Regardless of the models of the grinders, the method of replacing bearings is not much different from each other. Adjustment of the repair technology is associated with the design features that each brand has.
How to remove / remove the needle bearing in the grinder
It is not difficult to press in 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 action.
The stripper is an expanding collet with beads at the ends of the movable petals. The collet dimensions are made on a lathe, and the central hole is drilled for a rod that spreads the petals. The stripper is inserted inside the bearing and the collars, after the rod moves along the hole, rise up and abut with the lateral surface against the end of the ring. With the help of not very impressive, but reliable levers from the reinforcement with sharpened edges, resting on an inserted washer, the bearing can be removed from the housing.
Important: a needle bearing has a significantly longer service life than a sleeve bearing. However, during operation, the spindle shaft wears out, which also needs to be replaced. In the video described, the author found a replacement option. However, in most cases this can create additional problems.
How to remove
In the next video, there is a large spindle play on the Interskol grinder. The author describes in detail how to remove the sleeve bearing sleeve. For this, a tap with a diameter for threading in the inner sleeve is installed in the screwdriver. Next, the tap performs a mechanical operation to cut the thread and after meeting it with an emphasis on the gearbox housing, the bushing will rise along the cutting part of the tap until it is completely out of the bore.
The author does not recommend making the option with pressing out parts fitted with a large interference with pullers in order to preserve their integrity. It is advisable to perform such an operation on pressing equipment.
Simple malfunctions of the electrical part of the Bosch grinder
If you turned on the grinder, and it refuses to work, start looking for a malfunction with a break in the power supply wire. Most often, a wire break occurs at the point of entry into the grinder or into the plug. Do not twist, this will cause a short circuit in the tool.
To determine such a malfunction, it is necessary to open the grinder handle covers. In Bosch grinders up to 1000 W, the cover is fastened with one screw at the end. For Bosch grinders over 1000 W, the handle cover is fastened with several screws.
Using a tester, ring the power circuit from the input plug, pos. 5, to the switch. With a complete circuit, proceed to test the operation of the switch. Bosch grinders use simple switches controlled by the on-off lever.
But the electrical contacts of the switch burn out and cause the grinder to fail. It is impractical to restore the contacts of the plastic switch, it is necessary to change to a new one.
If the switch is intact, use a tester to check the presence of a circuit from each pin of the plug to each carbon brush. With whole circuits, the grinder should turn on. If it does not rotate, then there is a mechanical problem. Gears jamming or bearing destruction possible.
DeWALT Polisher Repair – Replacing the Spindle and Gear (DeWALT Part # N107430)
How to remove the bearing from the grinder anchor
How to remove the driven gear
By removing the gear cover, you can get the helical gear assembly, pos. 26.
To remove the gear, you need to use a press or a puller. But using a puller is difficult, since it requires the use of special thin jaws.
Before removing the helical gear, check the backlash of the gear connection, the integrity of the teeth, the contact patch.
On the shaft of the spindle, pos. 26, a bearing, pos. 50, is pressed. If the bearing has a large play, makes noises when rotating, the lubricant has dried out, it is preferable to replace it.
To remove the bearing, it is necessary to remove the gear, circlip and dismantle the bearing. If, when removing the rotor shaft assembly, the bearing remains in the gear housing, the bearing is removed using a hammer and a soft tip.
How to remove bearings from a Bosch grinder rotor
To dismantle the bearings from the rotor pos. 803 of the Bosch grinder, it is recommended to use pullers.
The bearing pos. 15 near the collector can be easily removed, but to remove the bearing pos. 14 from the impeller side, it is complicated by the fact that a number of preparatory operations must be performed.
Bearing pos. 15 is closed with a soft rubber seat. A similar rubber protection pos. 33 also covers the bearing pos. 14.
To dismantle the bearing, pos. 14, unscrew the nut, pos. 45, remove the spur gear, pos. 17, and the plastic protection, pos. 33. Using a puller, you can easily dismantle the bearing from the rotor shaft.
And if there is no puller? A vise, two metal strips and a hammer with a soft metal guide will come to the rescue.
Dismantling the Bosch grinder
Checking the electric motor
If your Bosch grinder is gaining momentum regardless of you, it starts to get very hot, sparks, you need to pay attention to the integrity of the rotor and stator windings.
An involuntary set of revolutions of the LBM indicates a malfunction of the stator windings. The integrity of the windings is checked with a tester, and the short circuit between the turns is checked with a special device.
Stator repair
The repair of a bosch angle grinder also includes the restoration of the stator. The main symptom of a stator failure is a spontaneous increase in the speed of a working grinder, which cannot be reduced by adjustments. A burnt-out stator winding changes color and becomes darker. The stator core also darkens from high temperatures.
It is easier to rewind the stator, although here you must follow certain rules and sequence.
If you removed the stator housing cover, carefully inspect the condition of the carbon brushes and rotor collector fins.
The length of the carbon brushes should not be less than 8 mm. By the way, Bosch grinders use carbon brushes with a “shot”, a device that stops the grinder operation at the minimum length of the carbon brush.
The collector lamellas must be free of carbon deposits or wear. Carbon deposits are easily removed with cotton wool dipped in alcohol.
Rotor assembly
The assembly of the rotor consists in pressing the bearings onto it, installing the impeller. The lubricated bearings are pressed onto the shaft using a wooden adapter. The bearing near the manifold is covered with a rubber protection. This is the general algorithm for assembling the rotor shaft.
Certain models of Bosch grinders have their own characteristics.
Mechanical damage
Bosch angle grinder is designed for cutting, grinding, polishing work. The operation of the tool in dust under heavy loads has a particularly detrimental effect on the durability of the gearbox, namely its gears.
In addition to wear and tear of the gear teeth, mechanical failures include the destruction of bearings and housing. Repair of a Bosch grinder in terms of replacing failed bearings, restoring the housing is easy to perform if there is a desire and need.
How to remove the bearing from the grinder anchor?
Today, home and professional craftsmen use several methods to solve this problem. If it becomes necessary to remove the bearing from the anchor of a grinder or other tool, this can be done using the following devices:
- Strippers. These are special devices that allow you to easily and safely remove bearings of different sizes from the anchor of the grinder. The use of pullers practically does not require the use of physical force, even if the bearing is tightly seated. The centering mechanism ensures the simultaneous installation of the device’s grippers. It can be used in any position. Before removing the bearing, you need to clean the grinder’s armature shaft from old grease, shavings, sand so that nothing interferes with removing the part. The centering mechanism allows the puller to position itself precisely. If the bearing is intact, and the dismantling process is carried out for inspection, it should be pulled out by the inner ring so as not to damage it. For large anchor shafts, grinders use a massive puller with three or four gripping paws, and for small ones, devices with replaceable plates or strips are suitable.
- Hammers, chisels, wrenches and other tools at hand. In this case, in order to remove the bearing from the anchor of the grinder, it is heated with gas, squeezed in a vice, grinded, chopped and many other operations are performed. These methods, of course, can be effective, but there is a great risk that the part’s seat will be mechanically damaged. And often the bearing itself after such manipulations without a puller will be unsuitable for further use. In addition, the performer may be injured due to pieces of clip hitting the face, eyes or head, which fly apart after impacts.
As practice shows, pullers are more effective in this situation. They allow you to quickly, easily and without much risk remove the bearing from the armature of the power tool and inspect parts or replace them. If you have to periodically carry out such operations, you should acquire such a useful device. The use of improvised devices is permissible only if you have experience in repairing power tools and an urgent replacement of a part is required.
How to remove a bearing from an armature of a power tool: a few practical tips
Today, many DIYers and professional craftsmen have a whole arsenal of power tools that help them cope with domestic and repair and construction tasks. Perforators, jigsaws, grinders, drills. all of them greatly simplify and speed up work. However, it happens that the power tool breaks down. Do not rush and send it to the trash because of this. Due to intensive use, the parts wear out, and therefore the equipment cannot work in normal mode. If you know how to remove the bearing from the anchor of the power tool, you can extend the life of your “helper”. Timely replacement and lubrication of parts allows you to operate the device for a longer time.
The main task of the motor of the power tool. it is rotation. The anchor is that important part of the device that makes the working mechanism rotate. The service life of the part depends on the power and speed, as well as the activity of the equipment use. Bearings are needed to reduce friction while moving parts. They provide smooth rotation and improve the running mechanism of the power tool. If the bearings are monitored and lubricated in a timely manner, their service life increases several times.
How to remove a bearing from the armature in order to check its performance?
The condition of the bearing on the motor of the power tool must be given due attention. When it wears out above the permissible limit, overheating occurs, and the motor starts to run noisily. If the bearing is not removed from the armature in time, then the stationary and moving parts will begin to touch each other when it rotates when it is running. And this, in turn, threatens with serious damage to the electric motor. This will require replacement of the rotor or armature. Checking the bearings is pretty straightforward. To do this, you need to install the motor on a solid surface, put your hand on top of it and rotate the shaft. The rotor must move freely and not jam. If you hear scratching noises or feel uneven rotation, this will be the first call to the fact that it is necessary to remove the bearing from the anchor and fix the malfunction.
Any bearing has backlash, that is, clearances. Their presence is quite acceptable, however, it is important that the indicators do not go beyond the permissible limits. Check for backlash:
- radial, or longitudinal. To do this, put the engine on a solid surface and try to tilt the shaft in different directions with your hand. The amount of offset depends on the size of the part. For household power tools, deviations should be barely noticeable;
- axial. The check in this case is simpler. It is necessary to take the shaft with your hand and pull or push the rotor in the opposite direction. In household appliance motors, deviations should not exceed 3 mm. The closer this figure is to zero, the better.
If during the disassembly of the electric motor you notice traces of friction of parts, it means that the bearings have worn out. It is necessary to immediately remove the bearing from the armature and replace the spare parts. This will allow you to avoid negative consequences in the form of engine breakdown or complete failure of the tool.
Features of pressing the bearing onto the engine armature
After you have successfully removed the bearing from the anchor, it is necessary to carry out a number of necessary manipulations before assembling the equipment. If you are installing new parts, it is necessary that they match exactly in width, as well as inner and outer diameters, with the old bearings. It is important that no dirt or dust gets inside the product during installation, because this can lead to corrosion, chips and all kinds of damage. The bearing is mounted on the anchor using a metal pipe, which must first be lubricated. During the pressing process, it is important to ensure that there are no distortions. You should also observe the following nuances:
- lubricate the bearings with a special thick substance. It can be moisture resistant;
- only ½ (for equipment with rotation up to 300 rpm) or 1/3 (for faster tools) of the bearing chamber is filled with grease. You should not put more substance, because all the excess will still be squeezed out during rotation.
Sometimes the process of fitting the bearing onto the armature is simplified if it is preheated in boiling oil. However, you need to be very careful in this case and make sure that the part does not heat up above 100 ° C.
How to remove the anchor from the grinder?
Often, during operation, the power tool becomes clogged with fine mechanical debris. This is fraught with overheating and failure of the device. To prevent such situations, it is recommended to periodically disassemble the tool to assess wear and clean it from contamination.
The grinder also needs regular preventive examination. When sawing or grinding various hard materials with it, fine mechanical dust scatters in different directions. It often falls directly into the instrument. To clean the device, you will have to disassemble it, while you need to navigate the question of how to remove the anchor from the grinder. Similar manipulations are also performed during the repair or replacement of any part of the tool.
In the grinder, it is the anchor that is most susceptible to natural wear and tear. Due to overheating or regular operation, a short circuit may occur in its contacts. You can also remove the anchor from the grinder to check its serviceability. In most cases, a failed part is not suitable for further use. It is replaced with a new one. But how to disassemble the tool without breaking it, and how to remove the grinder’s anchor? In this article, we will try to provide you with detailed information that will help you understand all the intricacies of the process.
Mandatory manipulations while removing the anchor from the grinder
Damage may not be seen on contaminated parts. When performing manipulations to remove the anchor from the grinder, as well as other components of the tool, do not forget to thoroughly clean them and wipe them with a dry cloth. If all parts are intact and working, removing dirt from their surfaces will still be an excellent prophylaxis to increase the service life of the device. Perform this step periodically to reduce stress on tool parts when working in challenging environments.
When removing the anchor from the grinder and its general disassembly for cleaning or repair, check the need to replace the lubricant of the metal parts of the tool. Litol-24 lubricant is usually used. By replacing the lubricant in time and removing internal mechanical debris, you can significantly extend the life of the electric angle grinder. This simple process will help prevent premature wear of component parts and the tool as a whole, as well as improve its performance.
How to remove the anchor from the grinder. preparation for work
Disassembly of the instrument, as a rule, does not require special training. It is enough to be attentive and careful, and you can properly remove the anchor from the grinder. The surface on which the power tool is disassembled must be level, dry and clean. Ensure sufficient lighting to clearly show all parts and fasteners.
How to remove anchor from a grinder. step by step guide
The process is carried out in several stages:
Grinder Repair – How to Replace the Gear Bearing
- In order to remove the anchor on the grinder, you must first unscrew the bolt that holds the casing. You can easily perform this manipulation, since there are no tight joints here. To carry out the work, you will need a universal multifunctional ratchet screwdriver.
- After loosening the bolt, the outer cover slides towards the cable. Individual models of grinders are created using a variety of components. A detail that is present in all power tools. this is the engine. It consists of a stator, armature, collector and brushes. After removing the case, you must remove these same brushes. To remove, you must first move the springs, after which they can be easily removed.
- After you take out the brushes, you can start removing the rotor. To do this, unscrew the four outer bolts. You can unscrew them with a screwdriver. Then the rotor head is removed. It is quite easy to remove it. manually by pulling it up. It remains to remove the rotor. It is removed along with the plastic cushion. This action can also be performed manually.
- Having removed the anchor from the grinder, it is necessary to remove the rubber seals on its axis. Next, it remains to free the part from the plastic pillow with a bearing and a gear. The upper nut is clamped with a gas wrench and unscrewed. This action does not require much effort. The plastic pad, gear and bearing are then removed. The anchor is removed from the grinder. Hence, the process is complete.
To collect the power tool, all steps must be repeated in reverse order.
The main difficulties that may arise in the process of removing the anchor from the grinder
Remember the sequence of actions when disassembling the tool and the position of all parts in the body. Sometimes, when removing the anchor from the grinder, certain difficulties may arise:
- it happens that the bolts and connections rust or the threads break during the disassembly process;
- as a result of a short circuit, the plastic parts of the device may melt;
- deformed plastic elements stick to metal parts, making it much more difficult to disassemble the tool.
If you are unsure of your abilities, it is best not to open your angle grinder at home. In this case, you will need the help of a specialist to properly remove the anchor from the instrument. If, when analyzing the state of the systems, tool parts and removing the anchor from the grinder, you find a breakdown that you cannot fix on your own, stop all further actions to restore the device to work. Contact a service center or workshop for help. A qualified specialist will conduct a detailed diagnosis of all parts and mechanisms of the tool, will be able to properly remove the anchor from the grinder, find and fix the breakdown. Your appliance will be ready for use again.
The process of removing the anchor from the grinder
Every serious job requires close attention. When disassembling the tool and removing the anchor from the grinder, you must try to remember the location of the components inside the case in order to successfully complete the subsequent assembly. Leave a separate place for the bolts so as not to lose parts. When disassembling the device, you may find the following tools useful:
- screwdrivers;
- pliers;
- hammer;
- vice;
- gas wrench.
You may also need grease and rags. All parts of the equipment are in close contact with each other. This is necessary so that under loads they do not vibrate and do not break, hitting each other. Sometimes such tight placement can cause difficulty in disassembly, including removing the anchor from the grinder. But it is enough to be extremely careful and attentive, and you will succeed. The analysis of the elements, assemblies and systems of the device implies the analysis of the gearbox, since they constitute a single whole.