To grind off or grow old a wooden part, remove paintwork, remove rust, drill burrs, wipe off putty, process plastic, polish stone – all this and much more are within the power of modern grinding machines. So, we offer the slogan: “Choose a grinder with us, choose like us, choose us better!”
Grinding: this process in many causes unpleasant sensations, even at one mention of it. What can I say, grinding – the operation is monotonous, time-consuming, laborious, dusty, sometimes noisy, a little harmful, but, unfortunately, inevitable. Modern requirements for finishing work have reached unprecedented heights, no one doubts the fact that the planes should be perfectly smooth and smooth. Finishing high-tech coatings tend to tend to thin layers and only emphasize the disadvantages of the base. Even enlarged, with the finished decorative coating sheet building materials have to be joined, followed by sealing / puttying or seam sealing followed by grinding. Domestic builders-finishers and guilds (furniture manufacturers, carpenters, stone products, bulk polymers, metals) slowly but surely get used to new standards, unknown before.
A highly specialized, relatively inexpensive tool, almighty grinding machines, helps us to cope with the task posed to working people, without which we can not do without. In the past, there was a painfully familiar emery, fixed on a wooden bar, or clamped in his hands. The foremost workers of capitalist production have given out a lot, a lot of wonderful professional grinding machines designed for any occasion, without depriving the attention of home craftsmen – amateurs to create something with their own hands. Understand the variety of grinders and make the right choice is really easy, the main thing is to know what the specific tool is for, and also clearly understand what tasks you will be setting before the grinder.
It is accepted to distinguish three main types of grinding machines: belt, eccentric (orbital), surface grinding (vibrating). All of them have their specialization and form a kind of cascade of possibilities, directed from quick rough processing to delicate finish grinding. Many of those who “on duty” are closely connected with grinding, have in their arsenal a complete set of tools of this class. Belt grinders are heavy artillery to remove large layers from large planes. The flat grinding machine is focused on finishing. A Eccentric grinder can produce even better results bordering on polishing, but, compared to vibrating machines, they have a different operating principle and other stuffing.
Above we carelessly called a belt grinder heavy artillery, in fact, it would be more appropriate to say “tank”. The working element of this well recognizable tool is an abrasive belt glued together in the form of an endless ring that moves along the two end rollers and clearly resembles the track of a tracked machine. Such units are relatively powerful, they have a relatively simple reliable design (angular gearbox plus V-belt transmission), low center of gravity, solid speed of the abrasive material. With the belt sander it is easy to remove a layer of material in a few millimeters, make an edge or rounding on the workpiece, remove the old paint and rust. This tool work with: wood, metal, polymers, mineral building materials … Clear the floor paint – yes, correct the planed timber – please align the putty wall with the marriage – no problem. However, it is worthwhile to understand that high performance is not the best friend of quality, there will always be scratches and shells.
It’s no secret that the performance of an electric tool is directly proportional to the power consumption of its motor – the higher it is, the more we can squeeze out of a particular unit. In the case of a belt sanding machine, the user can choose from models with an engine from 0.5 to 1.2 kW (Skil Masters 7660MA – 1200 W).
Please note that the tool of Chinese trademarks is often claimed with overestimated engine power, or if there are really sounded watts there, they are not balanced with other characteristics of the device. The record capacity is boasted by those manufacturers who have nothing more to show, except perhaps the heavy weight and bulkiness of the “unique” product.
The next important characteristic for a belt sander is the speed. Obviously, it must also be taken into account to determine the capabilities of the instrument. A fast machine will do more, but you will not be able to pin it down if the outstanding speed is not backed up by additional power. The whole fault is the notorious torque, which says that the more speed a tool has, the less power it has. The responsible manufacturer carefully balances these characteristics, makes them mutually variable, for which sometimes intelligent electronics answer. The speed of the belt in these grinders can be in the range of 150-550 meters per minute.
There may be a question, but why produce glistening, but relatively low-power belt sanders? Simply super-productive (fast and powerful at the same time) the tool is more difficult to control, it is heavier, larger, more expensive. It, with excessive pressure, it is easy to spoil the workpiece. In turn, maneuverable high-speed lightweights are convenient in a short time, often “in place”, to process the surface of a large area. If you still do not know what loads are waiting for the sander – choose a slower model, which can be slightly pressed, so it will be more versatile. Even more multifaceted are belt sanders with the possibility of pre-setting the high-speed mode (Sparky MBS 976, DeWalt DW433). Among them there are variants with smooth or step-by-step adjustments.
It’s time to say and about electronic systems that help in the work of belt sanders. These tools are not rich in electronic stuffing, compared to other types of electrical tools. Everything is usually limited by adjusting the speed of the tape. The switch responsible for this function is executed in the form of a slider or a scroll wheel. There are models with protection against overheating (Metabo BAE 75). With some stretch here can be attributed the function of fixing the start button in the on position.
Much more interesting is the situation with mechanical “gadgets”. A stand or special clamps intended for stationary fixation of the tool (it is very convenient for processing of small details) can come in the complete set. The grinding frame serves as a sort of limiter, which helps to avoid damage to the workpiece. A parallel or angled stop is useful for obtaining an accurate bevel or even parallel surface. The thin front roller in some models (Black & Decker KA88) has a small diameter, which allows to minimize the dead zone in the inner corners. Automatic tape alignment (a cunning barrel shape of one of the rollers) does not allow the latter to trail off treacherously at the most inopportune moment. Additional handle with a variable inclination or removable will significantly increase the functionality of the tool in the “clamped” places – sometimes palpable.
Special attention should be paid to the dimensions of the working plane – the sole, respectively, the length and width of the tape. Wide soles (100 mm) are characteristic for powerful professional models, due to what they become more stable and productive. Class “hobby” is usually limited to 75 millimeters. The long and wide outsole of expensive belt sanders has a complex construction consisting of a substrate and an elastic plate, which makes it possible to have a constant, uniform contact of the emery with the workpiece, such a tool “holds the plane” well. It should be mentioned “ribbons” with a narrow snap-in – these are so-called “electronic records”, which do not differ in their power and versatility, but the specialists value them for their unprecedented compactness (for example, Makita 9032 with a ribbon 9 mm wide).
The dust extraction system is in all tape machines, but not all of them work equally effectively. The dust control is carried out either by means of a vacuum cleaner connected through a branch pipe, or by collecting it in a bag, built-in filter. Of course, the vacuum cleaner is preferable, especially when grinding mineral bases. In super-cheap models, the impeller responsible for air intake can not cope with its function, the channels are rapidly clogged, and much harmful “flour” remains in the air.
If you take into account the cleanliness of the machining of parts, the surface grinders occupy an intermediate position between the belt and orbital. With their help carry out final grinding of flat surfaces made of a wide variety of materials – plastic, wood, stone, metal … Due to the relatively large working plane, the flat grinding machines are suitable for working with a serious quadrature. The secret of popularity of vibrating sanders lies in their moderate cost, accessibility of rigging elements, and also in the absence of dead processing zones (flat outsole outsole easily processes corners).
The main working member of the sheet sander is a plate, which with a small amplitude performs frequent reciprocating movements. The motor in such tools is placed vertically, which makes it possible to translate the rotational movements of the shaft into translational motion of the platform using the tandem “eccentric-counterweight”.
Most of the sheet sanders traditionally boast a motor power of 150-300 watts, they are quite maneuverable, moderately light and compact. A similar level of the power plant is almost always enough. However, such unanimity of manufacturers would be, at least, strange – there are models up to 600 W (Makita 9046). They, of course, are heavier and larger, but they can work for a long time without overheating at low speeds.
The most important indicator is the amplitude of the soles stroke. In different models, it can vary, although it is invariably a relatively small value. On average, the platform moves by 1-3 mm on the class, in more moving models figures of 5-6 mm (Festool RS 100) can appear. A large amplitude helps to grind the surface faster, but such processing will also be more rough.
Another nuance is the frequency of the soles. At high speed, the machine quickly removes a relatively thicker layer, and at a lower frequency it is easier to achieve precise finish grinding. Some manufacturers make the platform movement frequency variable, exceeding the mark of 20,000 strokes per minute (Bosch GSS 280 AE L-BOXX), which allows you to adjust to the processing of different types of materials, specific features of specific surfaces.
When choosing a sheet sander, special attention should be paid to the platform. With its dimensions, everything is quite simple, there are two options: a kind of “standard” and “mini” models – a plate area of about 100 mm2 (Makita BO4557, Sparky MP 250). Kids are well suited for narrow, jammed seats. Obviously, the sole should be of high quality, ideally flat, with clear geometric shapes. Budget tools are equipped with a platform of steel or high-strength plastic, and more expensive analogues – cast platforms from alloys with aluminum or magnesium content (Festool RS 100). A good outsole is characterized by precise balancing, which is easily determined by a low degree of vibration when working without load (idling). No less important, of what the lining is made, the most suitable option is a porous polymer, it “holds” the plane better than rubber.
In a separate class, sheet sanders with a delta-shaped platform are distinguished (Hitachi SV12SH, Makita BO4565). Because of the miniature size and good “patency” they are used to handle items with small parts and complex surfaces, such as furniture, carpentry, staircase elements, car body. Their triangular platforms are pivotal – you can continue to work unevenly “eaten” petals of the emery (Festool Deltex DX 93E) or removable (with a quick installation of another type of site – for concave / convex surfaces, for structuring, polishing, rubbing).
Emery in various ways can be attached to the site. It is more convenient when the paper is fixed on the Velcro, but special equipment is relatively expensive. The variant with spring-loaded clips is somewhat more complicated, but you can use inexpensive grinding paper cut by your own hand (it is only necessary to make holes for the dust separator in the right places).
The struggle with fine dust, which inevitably occurs when working with a sander, puts a lot of problems before the developers. They have to work hard to protect all mechanisms. In this case, a special sealing of the motor, protected bearings and switches, an impermeable housing, a system of channels with forced vacuuming are used. To remove dust from the working area and not saturate the air, it is sent to a sack-collector or filter, in most cases a vacuum cleaner can be connected to the nozzle – this is the most effective method of protection.
This type of sanders is designed for high-quality processing. Delicate grinding and even polishing – these are their elements, although the performance of such devices can be no less impressive than that of sheet sanders. They will cope with any material, most often such an instrument you will find in the wooden cases of masters, car painters. In the work with profile, volume, curvilinear objects, eccentric grinders are not equal, and they do not have any problems with the planes. The only thing where such a machine will save, it’s in the corners and small depressions – the “plate” there simply will not get.
As well as surface sanders, have an eccentric and counterweight, by means of which a circular grinding plate performs not only movement around its axis, but also on an “orbit” with a small amplitude. Interestingly, the axial motion is usually due to inertia, and in some models, is forced (via gear transmission – Kress 900 MPS). Such a complex movement of the working cloth, coupled with the highest speed of rotation, just allows you to get a surface of excellent quality, without depressions, waves and scratches.
From 200 to 900 watts – the engines of modern instruments of this type consume so much. Those that are more powerful, naturally, will be more productive, they will easily pull the sole larger, up to 150 mm in diameter (for example, a 400-watt Bosch GEX 125-150 AVE).
On the speed of translational motion orbital sanders also have differences. Speaking of rotation, this figure can be from 4 to 14 thousand eccentric revolutions per minute for models with regulation (Metabo SXE 425), and about 12,000 for models without one. If we talk about the concept of “oscillation” – then these figures will be half as much. In fact, everything is simple, the higher the speed, the rougher the processing, but the faster you can do the work.
The eccentric of the orbital sanders may not have the same “swing” – from 2 to 7 mm (Festool WTS 150/7 E-Plus). This is called the amplitude of the oscillation. The smaller it is, the less vibration the tool generates, the more compact the plate goes, the smaller the area we process, but the cleaner will be the grinding. In some models, the operator can set a certain amplitude, affecting the performance and fineness of grinding.
Compared with their fellow “orbit” is usually well napigovany electronics. We already talked about setting speed and amplitude, in addition to this, a professional tool is equipped with an automatic frequency control system (Bosch GEX 150 Turbo), so that it does not fall under the load – it’s constant electronics. In some models, there is an electrodynamic brake (AEG EX150ED K), which, after disabling the start button, immediately stops the work plate, preventing damage to the workpiece and reducing the possibility of injury. For powerful professional tools, a starting current limiter (Makita BO6040) can be provided, which smoothly accelerates the tool, preventing the starting jerk and protecting the network from short-term, but increased in times of load.
To very pleasant options we attribute a removable network cable, adjustable or detachable front handle, fixing the start key, functional dust extraction.
It is necessary to pay attention to the type of grinding sole. First, if you need a particularly delicate treatment, do not chase after a large plate, it, by the way, has a dead zone and the amplitude is about 5-7 mm. The plate, made of metal, has stability, high strength and excellent heat dissipation. Elastic plate well cope with convex surfaces. They all have Velcro for fixing the emery and dust extraction holes. These openings for individual manufacturers can be different in size, quantity and location, this feature should be selected suitable tooling.
If the financial issue is not the last value, then for the home workshop you can buy a model from the category of “hobby”. Good examples are offered by Black & Decker, Skil, Sparky, Bosch.
Pay attention to the mass and dimensions of the product of interest, especially if a lot of work is planned “in place”, in weight, on outstretched arms. Give preference to not too powerful car, but more speedy, it will be easier, more compact and cheaper. But for regular operations on the workbench, the large weight of the apparatus will become a plus rather than a minus.
Be sure to thoroughly “feel” the sander, find the most suitable for you in ergonomics. Determine the type of the main and additional handle, most likely you will have to choose between the “mushroom” and “staple”. See if the switches are convenient, and how they work, how easily the equipment changes, and whether the power cord is not interfering.
Check the moving parts of the product for any play. Look at the accuracy of fitting the body parts. Turn on the machine in the shop, at least at idle speed, estimate the level of noise and vibration. Take an interest in the cost, assortment and the possibility of interchangeability of consumables.
Weigh all the pros and cons, do not rush into the choice, then all repairs will go smoothly.