About the speed regulator angle grinder
Some angle grinders are equipped with a speed regulator. It can be useful when cutting relatively soft materials such as stone, tiles or wood. When cutting metal, it is set to maximum. It is good if the regulator cannot be moved accidentally (for example, it is sunk into the body and turns tightly). True, there is a fly in the ointment in this barrel of honey.
Firstly, with a decrease in speed, the engine cooling impeller also rotates more slowly, which leads to an increased heating of the tool.
Secondly, when the speed regulator fails, it burns out not to break, but to short circuit. This means that by setting a low speed, you can get an abrupt increase in speed right during work, without being ready for this. Of course, it is also possible that the regulator burns out when the instrument is idle, but this is no better: a burned-out regulator, set to low speed, misleads the master, and again there is a wild jerk of the instrument for which the master is not ready. If at this moment there is a low-speed disc on the spindle, it can simply burst from excess speed. In other words, for all the usefulness of the speed regulator, its damage can lead to very sad consequences.
In general, it is better not to cut soft materials with a grinder, but to cut hard materials with great care and only with an abrasive disc. LBM is a grinding machine, and the ability to cut by rubbing is secondary
It's like cutting with a router or milling with a drill: there is a technical possibility, but such a solution cannot be called optimal. Therefore, when going to buy angle grinders, think about what you are going to do with it and ask yourself, is it not better to buy a jigsaw or circular for these purposes?
However, suppose you know exactly why you need angle grinders. Manufacturers offer many options for angle grinders, classifying them in different classes, completing them in different ways and assigning different prices. Which car to choose?
DIY making
For manufacturing, many are trying to install a dimmer from lighting lamps or a vacuum cleaner rotation regulator. Nothing will come of this because of the high loads in the first case and the difference in the number of revolutions in the second.
To make a device for adjusting the speed of rotation yourself, you need to be able to read and develop electronic circuits and translate them into a finished product. Otherwise, you just need to buy a ready-made regulator or a grinder with it.
For the manufacture of an elementary thyristor controller, you need to purchase five necessary parts on the radio market, and the device itself of a small size of the device will fit into the case without problems. But angle grinder with such a device will lose momentum when used. It is only enough for polishing and working with soft materials.
If serious work with large-diameter disks is planned, a regulator on the KR1182PM1 microcircuit, or a similar imported one, is suitable. Such a scheme will provide a minimum drop in power and maintain rpm, and also does not wear out the electric motor.
The issue of adjusting the speed during manufacture is especially important. on the basis of various stationary grinders machines like a circular saw. Then the regulator can be connected in a separate starting machine.
Any method of correcting the rotation of the device expands the range of its application and work with it becomes more convenient and safe.
Tips for choosing a grinder with a smooth start
For work away from sources of energy, choose a tool that runs on a battery. This increases the cost and limits the operating time, but allows the use of angle grinders even in the field.
There are also gasoline and pneumatic grinders, which are used mainly in industrial enterprises. Devices with internal combustion engines do an excellent job of cutting large-sized workpieces with a diameter of up to 400 mm. Compressed air models require a compressor with a capacity of 200–400 l / min.
Consider other parameters that affect the choice of a grinder.
The size of the applied disks
All discs for grinders, including devices with a speed control function, are divided into two types: cutting and stripping. The diameter of the circles varies from 100 to 500 mm. The most common sizes are:
- 125 mm;
- 180 mm;
- 230 mm;
- 360 mm.
On overall models, it is allowed to install discs of a smaller diameter, provided that the bore is correct.
It should be remembered: the larger the disk size, the more massive the device will be. This will affect the cycle time.
Engine power
The power of household models does not exceed 1 kW. For professional devices, this parameter can reach 5 kW.
The depth of cut directly depends on the value of this parameter.
Manual and electronic protection
Biting the disc while in use is the biggest nuisance. The grinder can break out of your hands and cause serious damage. Possible reasons:
- contact of the circle with a foreign object;
- working with an object that is too strong;
- poor tightening of the spindle nut;
- exceeding the maximum number of revolutions of the nozzle;
- operation of a disc, the material of which does not correspond to the processed surface.
All this leads to the fact that the working nozzle breaks or scatters into parts. In the latter case, the fragments flying at high speed pose a danger to human health.
To reduce the risk of injury, manufacturers equip the tool with anti-jam mechanisms.
All inexpensive models have a special casing to protect against disc fragments in case of jamming. These are international safety requirements.
Protection systems can be divided into two types:
- Mechanical. On professional models with a speed control function, special couplings are installed. In the event of an overload or seizure of the disc during the transmission of torque, it begins to slip, preventing damage to the nozzle.
- Electronic. In this case, a special safety unit is responsible for an emergency stop. Its principle of operation is based on reading electrical parameters during operation. An abrupt cessation of rotation is accompanied by a surge in current, to which the sensors instantly react, de-energizing the tool.
Other functions
- Protection against accidental activation. Two start buttons are installed on the angle grinder. Switching on occurs only when pressed simultaneously.
- Load stabilizer. When cutting extremely dense materials, the electronic system automatically maintains the set number of revolutions. The function is useful for craftsmen who work with dimensional workpieces made of stone, marble or concrete.
What is the angle grinder intended for?
The angle grinder was invented specifically for grinding, therefore, unlike a sawing tool, it works at a very high speed. Cutting the material is carried out by grinding it. When cutting wood or plywood with a metal blade, high-speed friction causes the workpiece to smolder or even catch fire. Plastic or soft metal under such a disc will simply melt. It is possible to process soft materials with a "grinder" only when using special discs.
Cutting corrugated angle grinder using an abrasive cut-off wheel
To cut stone, brick and tile, use diamond-coated discs with several cooling slots along the edge.The use of circular saw blades, as well as Chinese saw blades with a "Bulgarian" fit, is a gross violation of safety rules and therefore is strictly prohibited.
Contrary to popular belief, angle grinder is not a universal tool, and trying to do all the work with it is wishful thinking. Seeing the desire of the craftsmen to cut various materials with a "grinder", BOSH has developed a universal carbide disc Multi Wheell 2608623013. This is an abrasive disc with slots for cooling, thanks to which it does not burn the material being cut. Note that neither BOSH nor other reputable companies produce saw blades for angle grinders.
BOCH Multi Wheell Carbide
When buying any disc, it is important to make sure that the speed (rpm) indicated on the label is not less than the spindle speed of your angle grinder. A disc rated at 8,000 rpm may shatter when operated at 10,000 rpm
This is especially important if the angle grinder does not have a speed control function.
How to maintain angle grinders
The rules will allow you to maximize the life of the grinder.
Before use you need:
Inspect the instrument for damage to the cable and housing. Bare wires will cause electric shocks or short circuits in the network. Due to cracks in the housing, the grinder can collapse during operation. Defects can often be eliminated by means of repair adhesives, "cold welding".
Install the disk before connecting to the network. After that, rotate it by hand, making sure that it is installed correctly. Installation should be carried out using special keys that are supplied with the angle grinder. Do not overtighten the nut. It is recommended to place cardboard spacers between the disc and the clamping nut to facilitate removal after work.
Connect the angle grinder plug to the network and try to start it
It is important to make sure that no extraneous noise is heard and no sparks appear from the ventilation holes.
During work, it is strongly not recommended to put the working tool on a workbench or floor. This can cause both injury and damage to the angle grinder. If the geometry of the circle is badly disturbed, it is better to replace it. Excessive vibration has a bad effect on the condition of the gearbox parts.
Have you ever worked with an angle grinder?
There was a case!
After work you need:
- Disconnect the instrument from the mains.
- Carefully remove the circle using the original key.
- Blow out dust and chips from ventilation openings with compressed air. At home, you can use a vacuum cleaner.
It is recommended to disassemble the case and thoroughly blow through the internal elements about once every six months (with intensive use - once a month). A brush is also used to remove accumulated dust.
LBM with smooth start-up and speed control is an indispensable tool for repair, production and construction. It became not so difficult to choose a quality tool - high competition allows you to purchase relatively inexpensive and reliable grinders.
The main thing to pay attention to:
It is important to carefully operate the purchased power tool and service it in a timely manner.
- Selection of cordless grass shears. Pros and cons, model overview
- Cordless grass trimmer
- Which trimmer is better: electric or petrol?
- Best cordless scythe models
Optional accessories
Manufacturers often complete their products with additional accessories that greatly facilitate the workflow. These accessories include a quick-release nut like the SDS-Click superflange from BOSH or its counterpart from Makita.
BOSH SDS-Click quick-release nut
The additional handle, which the cheapest angle grinders are equipped with, has the simplest design, while the more expensive tools are equipped with a handle with an anti-vibration shock absorber.Such a handle can be bought separately, while the main thing is that the thread fits to the socket of your angle grinder (the sockets for the handles of different "grinders" may differ).
Bosch: Model GWS 850 CE
"Bosch" grinders with speed control and a power of 850 watts are ideal for grinding natural and artificial stone with diamond cups. This angle grinder is one of the most demanded electronic tools in the work of professional stonecutter engravers, who every day face the need to polish in places where granite or marble is cut. This grinder is lightweight, which greatly facilitates operation: the master can hold it with one hand.
The Bosch GWS 850 CE variable speed grinders are warranted for one year of professional use.
The grinding speed can be adjusted using six positions. The range of speeds of rotation of grinding attachments and discs is from 2 800 to 11 000 revolutions.
The quality of polishing directly depends on the speed of rotation of the attachments. The smaller it is, the higher the quality of work. This requirement applies to granite, marble, glass and other surfaces that can be handled with a grinding tool equipped with an adjustment function. For working with marble surfaces, experts recommend choosing the speed at which the sander produces 2800 revolutions. Wooden surfaces can be processed with special attachments at the highest speeds. The maximum speed for this grinder is 11,000 rpm.
The Bosch GWS 850 CE comes with a wrench, handle and two fastening washers for discs and nozzles.