Homemade from an angle grinder with a burnt anchor with your own hands
You can make excellent tools for working in a home workshop from the engine and gearbox of an angle grinder. But what to do if the engine of the angle grinder is completely out of order.
For example, I had one case when, after purchasing an angle grinder, a few days later the armature winding was damaged. I don’t know what they did there, but since then I haven’t bought cheap angle grinders.
In general, while cutting metal, an unpleasant smell of burnt plastic came from the body of the angle grinder. Then sparks and the characteristic sound of the anchor jamming. Having disassembled the angle grinder, I found out that the armature winding was badly damaged; probably, the wire began to cling to the body during operation.
That's it, buy cheap low-quality grinders. They won’t mention the manufacturer of the angle grinder, but I’ll just say that it’s ours, domestic. In general, without thinking twice, I decided where I could use the angle grinder with a burnt out engine. See what happened below.
Where can you use an angle grinder with a burnt out engine?
An angle grinder's anchor, if it cannot be restored, for example, when the lamellas or windings on it are damaged, can be used to make an adapter attachment for a screwdriver, drill, etc.
In principle, for this the anchor has everything we need, namely:
- Smooth surface and round shape;
- A rod that could be caught on;
- Slots for installing sanding belt.
The principle of operation of such a drill attachment is very simple.
You take it and install it in the chuck, after which you begin to process various workpieces with the nozzle. They can be made from materials such as wood, plastics, metal and even glass and ceramics.
Design, principle of operation and purpose of an angle grinder
The source of torque for grinder tools is a commutator electric motor . The final working value of the torque on the working attachment is achieved using a gearbox, the design of which is compact to ensure the minimum dimensions of the entire power tool, which is an important parameter for manual use of the device.
Scheme of operation of the grinder. Source
From the technical name of an angle grinder, its main purpose follows - grinding the surfaces of processed materials. However, the versatility and versatility of grinders allows, with the help of replaceable attachments, to perform such technological operations as cutting, stripping, polishing and some others.
How the gearbox works, sectional view, photos and drawings
The minimum dimensions of the gearbox are ensured by the use of bevel gears . The small bevel gear meshes with the large one, and the direction of rotation of the electric motor rotor shaft changes by 90°, thereby reducing the size of the angle grinder in length. The driven gear, narrow in thickness, allows the design of the gearbox housing to be made as flat as possible, which ensures the operation of the grinder in hard-to-reach places .
Grinder gearbox in section. Photo source
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The supporting units of the rotor and spindle shafts are made using ball bearings, needle bearings and bushings made of antifriction materials, depending on the model of the angle grinder, capable of withstanding large axial loads. The housing in which the shafts of the driven and driving gears are assembled and the bearing units are reliably protected from dust that is generated when working with an angle grinder. An example of a gearbox design is shown in the image. How to disassemble for the purpose of diagnostics and repairs can be found in a separate article.
Adjustment
The angle grinder's bevel gear will work without problems with shafts rotating freely in bearings that have no backlash. This is achieved by installing additional metal spacers on the drive and driven shafts to eliminate gaps formed during the assembly process.
A feature of the bevel gear is the adjustment of the gear itself . It is necessary to ensure alignment of the initial cones of the gears. Here you should also take into account the presence of a thermal gap , which prevents the transmission from jamming when heated during operation. metal gaskets are installed between the housing and the gearbox cover . The correct adjustment is monitored by the contact patch. In practice, this is done by applying a coloring substance, for example, blue, on the surface of the teeth and after running in the operating mode, the area of the working surface of the tooth on which there is no blue is visually determined. The correct location and size of the contact patch is shown in the image below.
Depending on the degree of transmission accuracy there should be:
a = (0.4 – 0.8)b;
hav. = (0.6 – 0.9)h.
In grinders, metal spacers are installed between the cover and the gear housing, the number of which corresponds to the correct initial adjustment of the gearing. As the teeth wear out, to maintain the gap and normal operation of the transmission, some of the gaskets are removed, thereby ensuring the life of the grinder gearbox.
Gear ratio (ratio)
Angle grinder (grinder) MAKITA GA9010C. Photo 220Volt
In the classical sense, the gear ratio of an angle grinder gearbox, like any other mechanical gearbox, is the ratio of the revolutions of the drive shaft to the revolutions of the driven shaft . For most angle grinders it ranges from 2.5 to 4 . The gearbox is a reduction gearbox in order to provide speeds at which rapid overheating of the treated surface does not occur and the torque required for operation is achieved.
To a greater extent, the gear ratio of grinder gearboxes depends not on the manufacturer’s model, but on the power of the grinder. Less powerful angle grinders have higher spindle speeds and, accordingly, a lower gear ratio. For powerful professional angle grinders, high torque is important and high spindle speeds are not used when working with large diameter nozzles to ensure safety. Here the gear ratios are closer to the maximum values.
Nozzle manufacturing process
First of all, let’s take and cut off the rod where the bearing is located from the burnt anchor of the angle grinder. We don't need all this in the future. It is best to cut the anchor using the same angle grinder, but you need to secure it firmly in a vice so that it does not fly out.
Then you will need to get rid of the gear and burn out all the wire on the anchor. We also don't need wire. To burn out the wire, and not have to worry about unwinding it manually, we will use a small gas burner.
As a result of all the above manipulations, we should have a clean armature blank in front of us, without wire, bearings and gears. It will be necessary to work a little more and sand the surface of the anchor with fine-grained sandpaper.
Design and principle of operation
The gearbox is a complete transmission unit through which the axis of the motor-power unit transmits torque to the cartridge.
Two or three transmission stages are installed in the gearbox
The design of the “household” dual-mode screwdriver assembly includes:
I'm shocked!!! What can an inverted gearbox from an angle grinder do?!!
- The plastic body is a small drum that is mounted on a cartridge. The body itself is fixed motionless, and the chuck shaft is inserted into a clamp on one of the transfer plates;
- 2 or 3 transfer plates (carrier) - a round metal plate, on one side of each there are 3 protrusions for small gears. On the other hand, one of them has a clamp for the chuck shaft, and the other (or 2 others) has another so-called. a “planetary” gear that turns three small gears;
- 6 or 9 small gears (three each: they can be of the same or different thicknesses) - these are the so-called “satellite” gears, which are installed and rotate freely on the protrusions of the transfer plates. With their teeth they interact with the sun gear located between them and with the ring gear, which is located on the inner surface of the housing;
- ring gear - an iron ring with teeth on the inside and small protrusions on one of the outer rings. It is placed on these protrusions and ball bearings on the inner surface of the housing.
The parts are lubricated, assembled one by one and installed inside the ring gear, which lies inside the housing drum (it has a seal with grooves for ball bearings and gear lugs). After which the surface of the open satellites is locked with an iron washer, in the center of which there is a hole into which the engine shaft with the next gear attached to it enters.
While the screwdriver is operating, the gear wheel on the motor shaft rotates the upper satellites, and they, spinning around their own axis and along the ring gear, respectively, transmit movement to the subsequent carrier. Depending on the number of plates and small gears, the rotation speed will decrease proportionally.
READ Which disc to cut slate with a grinder
As can be seen from the design of the gear unit, they are divided depending on the number of transfer plates into:
- two-stage.
- three-stage. In this case, another plate with a “planetary” gear and 3 satellites is added to the design.
Reference. The number of high-speed modes of the device depends on the presence of stages, and this, in turn, will affect its price.
Another indicator by which gearboxes are divided is the material from which their parts are made.
In the production of satellite gears the following is used:
- plastic. Such structures are relatively lighter, but at the same time their reliability is lower than that of their iron counterpart;
- metal. They are durable and with proper care and lubrication they will work like a clock.
Fundamentally. The disadvantages of iron parts are a continuation of their advantages - they are heavier than plastic ones and cost more. With all this, if a screwdriver is used without violating the operating rules 2-3 times a year, the master most likely will not feel any difference in the material from which the gearbox parts are made.
Installing the Sanding Belt
To do the following work you will need a piece of sanding belt. It will need to be cut into strips corresponding to the width of the anchor, then bend the edges and insert them into the slots. This must be done with each groove on the anchor.
The result of the work done will be a flap attachment for grinding a wide variety of products. Well, if you need a regular, round grinding attachment, then an anchor from a burnt grinder will come to the rescue.
Just wrap the armature shaft with sanding paper, cut off a piece and insert its ends into one of the grooves. By installing the armature rod into the chuck of a drill or screwdriver, you can make good use of a homemade product made from a burnt-out grinder engine.
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Operating principle of a two-stage screwdriver gearbox
This is a diagram of a two-stage gearbox. The design of the screwdriver gearbox is identical, only the number of satellites differs. For example, for a 3-speed gearbox, another mechanism is added.
On a chainsaw, how to use an angle grinder as an attachment and other options
The various abilities of angle grinder attachments to perform technological operations (cutting, stripping, grinding, polishing and others) are reduced to zero in the absence of power supply. The grinder performs its functions only in the presence of electricity. But, in street conditions, there is a device in the form of a chainsaw, on which angle grinder attachments can be installed. Why should you perform the following actions with a chainsaw:
- remove the standard chains and tires from it;
- install a pulley instead of the sprocket;
- put the belt on the pulley and press it with the lid;
- tension the belt using a special device.
READ Tool for cutting angle grinder
The following video shows the installation of an angle grinder attachment with a cutting disc and the tools used for this.
How to remove a needle bearing or a damaged journal bearing race
Grinder gearboxes use various bearings. They are subjected to heavy loads and do not cause malfunctions.
Bearing failure is determined by an increase in spindle shaft play. Having disassembled the gearbox housing without dismantling the large gear shaft, the needle bearing is visible.
The needle bearing is not used in many angle grinders. In the same grinders in which it is installed, its dismantling is carried out in several ways.
Having removed the destroyed part of the bearing, there is an option to remove the inner race using a machine tap. Clamp a machine tap of a suitable diameter into the screwdriver chuck and do not try to screw it into the bearing race until the tap rests on the bottom of the housing. Continue to slowly screw the tap into the cage. It will lift the clip along the threads.
The second method is that the remaining race of the destroyed needle bearing can be removed using a special bolt not a retaining ring.
How to repair a gearbox on an angle grinder with your own hands
What a gearbox on an angle grinder is is a pair of helical gears, which are also called a gear or bevel pair. Almost all grinders have gears with oblique teeth, but there are also models with straight teeth, for example, Bosch.
Due to the gears, torque is transmitted from the motor shaft or armature to the spindle - the executive body. The small cone-shaped gear is attached to the shaft, and the large one is connected to the tool spindle. Due to the fact that the second gear has a large number of teeth compared to the small one, the rotation speed decreases. This means that the spindle speed is less than the motor armature speed. However, the lower the speed, the greater the torque, which has a positive effect on the performance of the unit.
Let's return to our gears. They are made of steel, but the quality of this material may vary. Regardless of the quality of the gears, there comes a time when the teeth wear out (especially if the lubricant is not changed) or even break off. If the gear pair is worn out or damaged, they must be replaced, as they cannot be repaired. Moreover, it is necessary to change a pair of gears, and not one at a time. They are also sold in pairs, as they have a distinctive number of teeth. How to replace the gear pair on an angle grinder is described in detail in the video.
https://youtube.com/watch?v=CpwYXu81ACs%3F
Instructions on how to remove the gear pair (gearbox) on an angle grinder:
- First, unscrew the nut from the gearbox side
- Remove the rotor along with the bevel gear attached to the shaft. If the rotor does not disengage from the part of the housing in which the spindle is located, then you need to unscrew the two screws that are located behind the cooling fan
- Knock the gear out of the shaft and install a new one in its seat.
- Remove the second gear from the spindle shaft and install the new gear by pressing it onto the shaft.
Few people know how to repair a gearbox on an angle grinder with their own hands, but if this happens, then you need to arm yourself with the necessary tools and get started. There is nothing difficult in dismantling the gearbox; the main thing is to follow the sequence of actions.
Angular gearbox from an angle grinder or a hammer drill, please tell me.
Probably not quite on topic. but it’s necessary I’m thinking of a bicycle drive for a kayak
A person does not develop much power (for a long time on average 300-400 watts, although the torque is quite decent). And I thought that a gearbox from an angle grinder or a rotary hammer (where the motor is vertically located) would be quite suitable for transmitting thrust from the chain sprocket to the shaft at an angle of 90 degrees.
In general, tell me where I can buy a gearbox separately (and which one is better suited for such jesuitical purposes, the gear ratio is closer to 1:1, the better
). Or even better, maybe you can actually get hold of a gearbox where the thread is in a warranty workshop from a dead device, for free or for a nominal fee?
Help good people with homemade products
))
2 Vlad.t Probably everyone has an angle grinder gearbox with a gear ratio of 1/3.
Well, it's not scary, you can pick up the leading star.
PS There are not enough answers here
Or maybe someone can tell me a forum where they can answer me? Although I googled it yesterday and this forum seems to be the busiest on this topic. Is this where service people hang out? Or is it better for me to call warranty companies from different companies?
Buying a new gearbox will not be cheap. Even for Chinese grinders, a pair of gears costs at least 300 rubles. And the entire gearbox in the housing will be significantly more expensive. It makes sense to contact any large service center, and one that repairs various brands, including domestic ones. Second option. Go to some construction market, to tents where they repair tools and/or sell spare parts. You'll probably find something suitable there. You can also look for sellers who sell all kinds of iron (usually pulled from factories) - drills, cutters, machine parts. The gearbox or gears will, of course, no longer be from an angle grinder. Option three, look at motorcycle and auto parts. In cars and motorcycles, angular gears are also used, only here, most likely, there will only be gears, and not a gearbox. Finally, the fourth option. Take two bicycle sprockets and place them on perpendicular axes, so that the sprockets engage with their teeth. Why not angular gear?
Cutting machine / grinder stand
Cutting disc machines are very often used in the field of metal processing, mechanical engineering, furniture production, and in the woodworking sector. This equipment is also suitable for household use - it is used as a very successful tool for doing various jobs in the garage and workshop.
READ The nut on the grinder does not unscrew
It is convenient to do a wide variety of tasks on a cutting machine: dividing a metal profile into segments of suitable length; cut sheet metal; make blanks of the same type in large quantities in a short time; cut clay tiles; cut parts at any angle, obtain cuts of suitable length and depth.
