Bearing units of the grinders take over heavy workloads. This is due to a fairly frequent failure of grinders due to wear or damage to bearings. You can remove the defective one and replace it with a new one if you have the appropriate knowledge and a suitable tool.
Successfully complete the repair of bearing assemblies will help compliance with the following recommendations.
- Necessary know the design of the operated angle grinder. You should study the technical documentation that came with the angle grinder. Knowing the location of components and parts will help to correctly disassemble and assemble the angle grinder during repair.
- Perform replacement work bearings will help quality availability of required tools. 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 hand tools (vice, extensions, drifts of various designs) for fixing and removing bearings.
- When repairing grinders There is a certain order of work. It should adhere to it, given some differences associated with the features of a particular model.
- Replace bearings in the presence of even a slight runout of the shaft, since a destroyed bearing can completely damage the entire power tool.
- Before carrying out repairs, make sure that power tool unplugged power supply.
Open bearing for Hammer angle grinder. Photo 220V
The tool used must be in good condition:
- structural elements of pullers (paws, rods, stops, screw devices) correspond to technical documentation;
- screwdrivers have straight side faces, a straight shaft is firmly fixed in the handle;
- sponges of wrenches are parallel, have no cracks and nicks;
- hammers are firmly mounted on the handles.
Compliance with these recommendations will allow you to correctly and safely disassemble angle grinders, replace defective bearings, re-lubricate all parts and assemble the angle grinder for its further operation.
How to take off
The following video on the Interskol model angle grinder has large spindle play. The author describes in detail A method of removing a sleeve of a plain bearing. For this, a tap diameter is installed in the screwdriver for threading in the inner sleeve. Next, the tap performs mechanical thread cutting operation and after meeting it with an emphasis on the gear case, the sleeve will rise along the cutting part of the tap until it completely leaves the landing hole.
Option with parts extrusion, planted with a tight fit, the author does not recommend producing pullers in order to preserve their integrity. Such an operation is preferably performed on press equipment.
Plain bearing can be easily replace with needle bearing. The main thing is to choose it in accordance with the outer and inner diameter of the sleeve. The following describes the repair work with an angle grinder, the design of which uses a needle bearing.
Video: Bosch Angle Grinder Bearing Replacement
How to remove / remove the needle bearing in an angle grinder
Pressing a new needle bearing is not difficult, but removal requires the use of an original puller. In the next video, the author describes the manufacture of such a device and its practical action is shown.
Puller is a collar with collar at the ends of moving petals. The dimensions of the collet are made on a lathe, and the central hole is drilled under the rod extending the petals. The puller is inserted into the bearing and the beads after the movement of the rod through the hole rise up and abut the side surface against the end of the ring. With the help of not very effective looking, but reliable levers from the reinforcement with sharpened edges resting on the inserted washer, the bearing can be removed from the housing.
Important: The needle bearing has a significantly longer service life than a plain bearing. However, during operation, the spindle shaft wears out, which also needs to be changed. In the described video, the author found a replacement option. However, in most cases this can create additional problems.
How to change
Regardless of the models of grinders, the method of replacing bearings is not much different from each other. Correction repair technology related with design features, that each brand has.
The following video describes gearbox bearings replacement for one of the Bosch models, which has a large backlash on the spindle. Here, the main executive body creating the efforts of extrusion / extrusion are ordinary bench vise. The use of various extensions in the form of appropriate-sized pipes and other similar parts allows you to transfer forces to the desired location using the jaw jaws. Some operations are in progress. using extensions and light hammer blows.
The design feature is plastic flange. To extrude / press in the flange bearing, the author removed the plastic interfering with this process using a knife and a torch. Perhaps, if you have the skills of a turner, just cut this material on the machine.
One Makita model describes the process of replacing bearings without the use of special tools, any available means at hand. As base surfaces used wooden blocks from hard rocks that take on the load when performing various technological operations using force.
As snap applied suitable thickness metal sheets and socket heads (suitable pipes may be used) when knocking out bearings. The centering holes of the shaft serve as the basis for the pointed rod (in the video this is the modified old screwdriver), with the help of which the shaft itself is released. The only tool for industrial production is snap ring puller, although without it you can figure out how to remove them using improvised means.
Some designs of bearing units are made without interference fit. So, for example, in the next video, the ball bearing of the gear housing cover of the Interskol model assembled in a supporting structure with a washer, fastened by threaded connections. For a better fit to the plane of the body, the surface of the washer is coated with an adhesive.
Some designs of bearing assemblies at first glance, it excludes the replacement of the bearing itself, entering into such a node. 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 with the proposed method.
To fix the bearing unit, a crown on a tree came into the drill, one of its outer diameters fits tightly into the inner surface of which. With a working drill plastic material is removed with a sharp object to the size of the outer ring of the bearing. Thus, nothing prevents the bearing from being removed with a hammer and extension.
Next, when assembling a new bearing instead of wasted plastic, a ring is inserted (in the video, it is most likely from caprolon or other similar material). Since the ring in the video has a wall thickness that does not allow assembly of the gear according to the technical requirements, with the help of a chisel, its inner diameter is finalized to the desired size.
In the next video, one of the models of the Sparky brand angle grinder failed. To determine the cause of the malfunction, the author made a complete disassembly of the angle grinder with washing and cleaning of all parts. Details on the disassembly process in this video did not stop. This technological operation can be viewed in the article under the link "How to disassemble the gearbox."
After analyzing the condition of components and parts, it turned out that the cause of the malfunction of the angle grinder was the front rotor bearing. It was easily replaced with a new one, which inserted into the gear housing without interference and fixed with a washer using threaded screws. The life of the Sparky angle grinder from the video is 15 years, so the appearance of other defects is not ruled out and the author correctly concludes that a new angle grinder is purchased.