Construction characteristics
Pneumatic hand tools are inherently powered by air. During operation, air is supplied, compressed by the compressor. The higher the air pressure, the higher the rotational speed of the disc. This technique weighs on average from 600 g to several kg. The lightness allows you to reduce hand fatigue and better handle the required surfaces.
Pneumatic grinders consist of several key components: a housing, a rotary motor, a starter, a centrifugal regulator, and a protective cover. The basis of the product is a metal case. Due to its lightness and strength, it improves the convenience of the user, at the same time being the protection of working elements from accidental mechanical damage. An equally important element is the handle, on the convenience of which the distribution of the load on the hand and the efficiency of work depend.
The design includes an abrasive disc, which can differ in diameter, which directly affects the quality of processing and its execution time. The sole of pneumatic grinders is necessary for performing rotational movements. The noise level of the devices may vary depending on the type.
The eccentric versions feature low compressed air consumption, which contributes to cost savings. Such structures are quite strong and durable, due to which the costs of their maintenance are reduced. The availability of special options allows for continuous dust removal, minimizing finishing operations as well as reducing costs. The quality of the grinding and its pattern are ensured by the precise movement of the eccentric.
Products can be equipped with the option of braking the sanding pad, due to which it is possible to reduce the number of errors at the beginning of work. Some models are characterized by low vibration levels. This not only simplifies the workflow, but is also less harmful to the operator's health.
Views
The classification of belt sanders is made according to a number of characteristics. The main criterion is the scope of the models. According to this parameter, household and professional tools are distinguished. The former process mainly straight surfaces, while the latter are intended for the formation of complex arbitrary shapes and grinding curved and convex bases. Professional models are often equipped with a curved sole that can be pulled forward if necessary. In addition, the working life of the pro-units is much higher than that of inexpensive household appliances. Therefore, if regular use of the machine is expected, then it is preferable to choose a more functional device.
Among the professional models, there are highly specialized units designed for cleaning and grinding pipes, butt joints and any other rounded elements made of wood or metal. Such units differ from traditional models by the device of the tensioning mechanism and the absence of a sole. And one more type of professional equipment is represented by stationary machines. Such samples are characterized by increased power and are often equipped with a grinding disc.
The next criterion for classifying mechanisms is the tension of the sanding belt. On this basis, two types of devices are distinguished: with two and three rollers. The latter are equipped with a movable part with a third roller installed on it.Such a device allows the web to bend and capture a large area of the processed surface, thereby providing a more accurate and high-quality grinding. The first do not have such advantages, being traditional household models designed for simple processing of flat surfaces.
Another sign of the classification of machines is the type of motor power supply. Distinguish between electric, pneumatic and battery models... The former are completely volatile and require a 220 V power source in the immediate vicinity. The latter operate from an air compressor, are characterized by high power and performance, and can be used in the field. Battery-powered devices include pipe grinders with batteries with a capacity of more than 4 A. h and weighing about 3 kg.
Surface Grinders (Vibratory)
These machines have a mass of 1 to 3 kg, are equipped with a rectangular sole with a clamping mechanism along the edges, which fixes the sanding paper. There are models with the ability to fix the rig to the sole with Velcro.
The sole performs reciprocating movements in an annular orbit, due to this, grinding or polishing is carried out. The power of the electric motor of this tool is from 150 to 600 W. The sole is of two types: standard - 100 X 200 mm, and mini - miniature options with a base of about 100 X 100 mm.
The choice here is simple: mini surface grinders are suitable for narrow spaces, they are lighter and more maneuverable than standard ones.
Designed for delicate processing of large flat surfaces. They occupy an intermediate place in the cleanliness of processing parts between belt and eccentric ones. With the help of a surface grinder, they carry out finishing grinding of various surfaces: wood, plastic, stone.
Advantages: the ability to grind and polish inside corners, the availability of consumables and the reasonable cost of the grinder itself.
Disadvantages: high noise relative to orbital.
Varieties
Depending on the ability to move, belt grinders are divided into two types:
The first is a small electrical appliance with a handle for holding. You can work with it almost anywhere. During work, the technique is moved along the ground surface.
The second ones are installed on a special tabletop. Moving such equipment from place to place is very difficult. Therefore, the workpiece is moved, and not the device itself. Typically, this type of grinder is used to work with small parts. They are also widely used in jewelry making, as they are suitable for precise processing of small items.
Expert opinion
Dmitry Levin
Most mobile devices can be converted to stationary if necessary. This is done by securing them to a workbench with two or three metal clamps.
Depending on the type of power supply, the devices are:
The former are powered by a 220 V household electrical network, the latter are powered by a rechargeable battery. Both techniques have advantages and disadvantages. So, network grinders have more power and can function for any time, since the duration of their operation does not depend on the capacity of the battery.
However, they restrict the movement of the person using them by the length of the power cord. Battery equipment can be taken even where there is no power supply. However, it has a less powerful motor and battery life is limited by the battery charge.
Which belt sander do you use?
Networked Rechargeable
By functionality, grinders are divided into:
Standard tapes have tape only. Combined ones provide the ability to connect other attachments for grinding (for example, a disc).It is usually implemented using a transfer mechanism that transfers the rotation of an electric motor to an additional axle.
Angle grinder device, component parts
The design of angle grinders is distinguished by a relatively simple and technological design, which made it possible to establish their production at many enterprises.
The angle grinder consists of the following parts:
The body, which is made of reinforced polymers. Such materials are characterized by high strength, wear resistance and environmental impact. On the outer surface there is a button for turning on the tool with a lock. Some of the models have windows covered with hatches for replacing the drive brushes.
An electric motor powered by a household network or batteries. On angle grinders, drives are used that can provide high shaft speeds. To cool the windings and other parts, a fan is installed in the front part on the axle.
Single-stage bevel gear in a separate housing made mainly of magnesium or aluminum alloys. Consists of bevel gears, the shafts of which are mounted on ball or plain bearings. The interaction of parts with each other in the gearbox is ensured by the housing, which is filled with grease.
A spindle consisting of a shaft with a metric thread, a thick-walled washer and a nut for attaching a cut-off wheel or other equipment. On the gearbox housing, a button is usually provided on the opposite side, which fixes the shaft at rest. This is necessary for dismantling and installing new equipment.
The removable handle is threaded and can be screwed into the gear housing in one of the selected positions. This is done for the convenience of holding the power tool in the process of performing various types of work.
The cover is protective, covers part of the cutting wheel and does not allow the sheaf of sparks that is formed during operation to fly in all directions. The device protects the worker and the surrounding objects from wear and tear products of the tooling and material fragments formed during its processing.
The angle grinder is supplied to the consumer complete with a user's manual and a special wrench for attaching the equipment. The latter is a steel strip with two pins that match exactly with the holes in the fixing nut. In some cases, the manufacturer adds spare carbon brushes to the delivery set.
The principle of operation of angle grinders
The angle grinder is driven by an electric motor, which is turned on by pressing a latching button or switch. Power is supplied from the mains, as well as from a built-in or removable battery. Mostly the tool is equipped with collector motors, in which the stator winding has a large inductive resistance. This circumstance makes it possible to significantly reduce the operating currents.
While spinning, the shaft of the electric motor rotates the drive gear in the gearbox, which drives the driven gear, and thus transfers the force to the spindle. The body of the movement is made of magnesium or aluminum alloys to improve heat transfer. There are two types of gearing between gears: spur and helical (conical Glisson system). The second option is preferable because it provides greater reliability and helps to reduce noise.
On more expensive and more complex models, a trip clutch is used, which is installed between the motor and the gearbox. The main function of this unit is to prevent kickback when the disc suddenly stops due to jamming. This protects the operator from possible injury and the grinder components from damage. On such angle grinders, the spindle fixing button can be pressed until it stops completely.
The choice of a design scheme in which the plane of rotation of the cutting wheel or brush is parallel to the tool axis is explained quite simply. During the operation of the angle grinder, a significant torque arises, tending to divert the tool to the side. This effort is easily compensated by the operator, due to the optimal position of the arms along and perpendicular to the axis.
Selection Tips
Modern ESM are equipped with various functionalities.
It is important to choose the correct speed control - this function allows you to correct coarse and fine grinding, which should be done during most jobs.
Dust collectors are also important. Some models (for example, devices from the "Makita" company) may have 3 protective containers for the dust collector: PVC box, rag bag, paper bag
In some models, a small vacuum cleaner is also used, which is important if it is necessary to process large areas.
An additional handle (often screwed on) is often in demand, it allows you to distribute mechanical pressure, which greatly facilitates the work. The ESHM of DWT is very convenient in this respect - the models from this manufacturer are equipped with side handles that allow you to comfortably work with vertical planes.
It is also important to have a soft start of the device, which ensures the safety of the workpiece. After a sharp start of the ESM, excessive vibration is always observed, which can generate defects and chips
- The pressure indicator is also important, which makes it possible to smoothly launch the ESM. The bench force indicator makes it possible to more accurately handle equipment and workpieces.
- Abrasive retainers are important. The most popular of these is duct tape. There is also Quick-Fit, which provides block replacement.
It is important to decide on the abrasive before starting work. So, for example, there are universal abrasives that are prepared specifically for a specific workpiece: the larger the grain fraction, the more rough the processing will be.
Important: abrasive for metal is suitable for working with wooden blanks. One of the important points is perforation
The holes on the rig and platform, as well as on the backing plate, must be mated. This modification is not always found, so sometimes the easiest way is to buy a sheet and make holes manually
One of the important points is perforation. The holes on the rig and platform, as well as on the backing plate, must be mated. This modification is not always found, so sometimes the easiest way is to buy a sheet and make holes manually.
Rating
The first place was taken by grinding machines manufactured by Hammer LZK. Grinder models of this manufacturer have different power and low weight. Most buyers noted a whole list of positive qualities of this tool, among them: ease of use, high power, which is combined with low energy consumption, affordable price and durability.
On average, a tool of sufficient power from the manufacturer Hammer costs 2000-2500 rubles.
The second place was shared by manufacturers of grinders "Interskol" and Makita. Both brands of tools effectively cope with careful processing and cleaning of surfaces, they have sufficient power. At the same time, the domestic model "Interskol" is distinguished by its extremely low weight (less than a kilogram), which makes it very easy to use and allows it to work for a long time. Reviews from buyers of these brands of tools are generally good.
Among the minuses, a purely personal preference for convenience is noted, and both brands cope well with the main task.
But in third place are the grinding machines of the manufacturer Bosch. In general, the owners noted that the tool does a good job.Among the minuses, some users highlighted the weak quality of the nozzles for the grinder, as well as its tendency to overheat during long work. Moreover, the price of these foreign grinding machines is far from small, so they are not in great demand.
The fourth place is taken by the "Enkor" instrument. The big advantage of this grinder is its high power and low cost. It is for the affordability of the price that many users have forgiven the manufacturer for small disadvantages. Among them, it is worth noting a high level of noise during operation, perceptible vibration and a short cable for the mains.
So, analyzing the reviews of the owners of various grinding machines, it should be said that each of them has its own advantages and disadvantages. For some, some of the disadvantages will be completely insignificant, while others, because of them, will not be able to work with the tool. Therefore, the choice of a grinder should be carried out according to personal preferences, but the above indicators should still be studied.
In the next video, you will find an overview of the Bosch PSM 1400 VENT multifunctional grinder.
Features and Applications
The belt sander is an electromechanical tool that is used when sanding wood, concrete and metal substrates, while ensuring their absolute smoothness and uniformity. With the help of the device, you can effectively and quickly remove the old paintwork from metal and wood, as well as make rough processing of unplaned boards and beams. LSHM is capable of treating areas of any area, as well as performing primary and intermediate grinding on them with the removal of a thick layer of wood.
In addition, some models are equipped with clamps that allow you to fix the tool in an inverted position, that is, with the working surface up. This allows you to grind miniature parts, sharpen planes, knives and axes, as well as grind and refine the edges and edges of products. However, such work should be done with extreme care, moving in the direction of the belt abrasive and not touching it with your fingers. But also many machines are equipped with a bounding box that controls the grinding depth. This function is very convenient for beginners and does not allow to grind off thicker material.
Another important feature of the devices is their ability to grind and clean surfaces close to the wall. This is due to the design feature of the LShM, which consists in flat sidewalls, the absence of protruding elements and the presence of additional rollers that allow processing dead zones
For the high efficiency of processing, which consists in the alternate removal of layers, and the ability to work in hard-to-reach places, tape machines are often compared to planers. However, unlike the latter, tape units require a minimum of labor costs, since they cope with the task much faster. This is due to the displaced downward center of gravity, which makes working with LBM easy, not requiring the application of great physical effort.
Eccentric (orbital) devices
An orbital sander differs from other types of CMM in that it works like a conventional vibrating sander, only with circular motions of the sole.
Due to the rotation of the working platform, a certain layer of material is removed, and the vibration grinds and cleans the surface to be treated. The working depth is controlled by the force of pressing on the tool. The rig is attached to the bottom of the unit with Velcro.
The eccentric sander can be either electric or pneumatic. The pneumatic eccentric sander is mainly used in manufacturing and has its advantages over electric tools.
- Since this circular CMM does not have an electric drive, its weight is much less.
- Due to the low weight of the tool, it is used for leveling walls and ceilings.
- Due to the lack of an engine, the unit has a minimum number of parts that can fail.
- The grinder can be used in areas with increased explosion hazard, where the use of power tools is prohibited.
The eccentric sander is the number one machine for sanding materials thanks to its superior surface finish. Therefore, "orbitals" are mainly used for fine grinding and polishing. They are used to process plastic, metal surfaces, perform grinding and polishing work on wood, polish varnished surfaces. They are also often used in a car service for preparing car bodies for painting and for polishing a car after painting.