How to permanently install the grinder

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Grinding tool

Grinding machines are electric hand-held tools for grinding and polishing surfaces of various materials. They can be used for wood, metal, plastic and wood-based materials, removing from their surface dirt, nerves and other defects. There are several types of sanding tools which differ in their effect on the surface of the material to be sanded:

  • Stitching. The grinding wheel is pulled through the tool without interruption. The shape of the plate in such machines is rectangular and has a uniform plane.
  • Eccentric. The grinding wheel is glued to the pad by means of the sticky surface (Velcro) which gives orbital guidance. The pad also rotates about its axis.
  • Vibrations. The pad is intensively vibrating, buffing the material. It can be differently shaped, allowing the surface to be treated in places where it is inaccessible.

Schlifuvalni machines are used for rough and finish sanding surfaces of wood and other materials, poliruvannya cars, removing iron from metal parts, restoration of products, etc.

How to choose a grinder

To begin with, consider the list of criteria that should be followed when selecting a grinder for use at home or in your own small workshop.

Professional or household?

We have already hinted above that this review will deal with affordable machines, which automatically implies domestic or, at most, semi-professional models. Here we briefly explain why this is so.

Professional power tools are, in almost all technical respects, disproportionately superior to any domestic tool. These models are originally designed for continuous continuous operation in several shifts. It is not only the endurance of moving parts that is important here, but also the reliability of secondary components, blocks, parts. All this makes such high demands on professional power tools that, by definition, even a limited-function model cannot even be of average price.

That is why, if you are not planning to open a construction firm, and you need a grinder from time to time, it makes no sense to buy a professional unit. It is too expensive and impractical. And a good household grinder is quite capable of handling the needs of a small private workshop.

angle grinders (angle grinders)

The most common, almost “people’s” form factor of grinders are the well-known even to children “angle grinders”, that is, angle grinders. By the way, many people mistakenly believe that the word “angle” is meant purpose for processing angles, when in fact there is a design feature. the working shaft is at right angles to the plane of the motor.

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As it happens, these types of machines are overwhelmingly bought and used for cutting, not sanding. Also, it’s too big a niche to consider on par with other form factors. That’s why in this rating we will consider only those machines that are not used in any other way than for grinding, and the “angle grinder” will consider a separate topic.

Belt grinders

Belt grinders use, as it is easy to guess, an abrasive belt glued into a ring as the working surface. Depending on the model, belt widths between 65 and 110 mm are available. Two end rollers rotate the belt. Speed of movement. 150 to 400 metres per minute.

often than not, they are used for rough pre-treatment of even surfaces. They are extensively used in interior construction, where thick layers of material must be removed quickly and with little effort, or putty places sanded down. Also this form-factor can cope with the processing of parts of doors and windows during their manufacture. In some rare cases, they are used in the intermediate stages of the car painting process.

The great productivity of the draw frames has a downside: roughness of finish. They leave behind noticeable machining marks such as abrasions, scratches, indentations. Therefore, for the final finishing, it is necessary to use a machine of another type.

Vibratory grinders

Machines of this type are also called flat-grinding machines precisely because of the shape of the working surface and the nature of processing. The main working part is a soft rectangular soleplate. When you turn on the soleplate begins to make reciprocating movements with small amplitude, but with great speed, due to which the effect is achieved.

Here we observe a direct dependency of the surface treatment speed and its quality on the amplitude of the sole movement. The greater the amplitude, the higher the material removal rate, but also the lower the quality. So if you really want to do pre-finish and finish sanding with the same machine, look for models with variable speed and/or amplitude. If you want to sand hard to reach places, you will need a delta sander with an iron-like soleplate.

Flat grinders can use different ways to attach the abrasive sheet. with clamping clamps or on “velcro”. Machines with clamps are often cheaper and generally more versatile due to the simplified selection and availability of consumables. As for the “Velcro”. this mount is trivially more convenient. Many models support both types of attachment, and in our rating we will look at several such examples.

Eccentric sanders

Finally, eccentric machines are special grinders, in which to the reciprocating torque is added and circular rotation. This adds to the efficiency of the device and makes them almost indispensable for machining curved and profiled surfaces. These machines are most often used for superfine polishing.

The eccentric machines are differentiated by disc speed and oscillation amplitude. The dependency of machining speed and quality on the aplitude is exactly the same as in surface grinding machines. Changeable abrasive sheets are fastened by means of a clamp or the same “Velcro”.

Dust extraction

Whatever type of grinder you are looking to buy, you should always pay attention to the presence of a complete system of dust removal. Most often domestic machines are equipped with compact filter bags, dust collectors, but it is also desirable that the design of the unit was provided the possibility of connecting to an external vacuum cleaner. Under no circumstances should you neglect high-quality dust removal or, even more so, to save on this issue, as the “mist” that the grinder raises is most often detrimental to health.

If you are going to work on plastic surfaces, an eccentric or low-speed vibrating platform machine is the best choice. The same machines are suitable for metal processing, but the grit size should be several times higher. For fine polishing, fiber or fan-shaped discs are used instead of abrasive.

Model Bosch PBS 75 AE

750 W Two-handed sander. For sanding various wooden surfaces, such as bar or log walls. Belt width of 75 mm. Equipped with a continuously variable speed control of the main shaft. The weight of the device is 5.6 kg.

  • Its high productivity makes it possible to sand large areas in a short space of time.
  • Removable front handle. This enables you to sand a wooden floor close to the wall.
  • Grinding belt is easy to change, saves time getting the machine ready for work.
  • Powerful dust extraction unit that collects nearly all dust generated while sanding. Bag can be easily removed for cleaning.
  • Smooth start system for sanding belt.
  • Plastic storage case. Easy to transport.
  • Relatively large weight. Working too long on vertical surfaces causes fatigue.
  • A short power cord limits your freedom of action. Additional belt extension cable has to be used.
  • Weak locking of the wheel, which regulates the speed. during grinding you must constantly monitor its position.
  • Increased noise level.

Conclusion. The Bosch PBS 75 AE 0.603.2A1.120 is more productive than other models in its class. This makes it a good choice for businesses that provide paid services and are interested in getting the job done quickly. Can be purchased at a rather high price. impractical for home use only.

Metabo BAE 75

A manual sander designed for all types of wood. Power rating of 1 kW. Standard belt width of 75 mm. The machine is equipped with electronic speed control of the main shaft and a system for constant belt speed. Weight 4.7 kg.

  • Excellent equipment set, including 6-point spanner, lengthways stop, adapters for dust extraction, additional handgrip.
  • Sophisticated ergonomics for comfortable operation. Effortless and fatigue-free grinding, even over extended periods of time.
  • Low noise level enhances the use of the machine.
  • Supplied with a device for transforming the machine into a stationary sander.
  • Long power cable that does not lose its elasticity.
  • Heavy. Prolonged grinding of vertical surfaces causes fatigue, which in turn reduces productivity.
  • Unfortunate location of the center of gravity. at the top. This is a frequent cause of the machine tipping over and the formation of unsightly notches on the sanded surface.
  • Easy turning of the knob for setting the speed of the main shaft. This makes it difficult to set the desired parameter.

Conclusion. Budget-friendly model that is suitable for both home and commercial use. In the latter case, a very valuable feature will be a good repairability. The Metabo BAE 75 600375000 is distinguished from other belt machines by its intelligent ergonomics. a feature that makes it an ideal tool for beginners.

Model Makita 9403

The 1200 watt sander with a large dust bag. Belt width 100 mm. Comes with additional handle. Belt speed up to 500 m/min. Weight 5.7 kg.

Additional equipment

Grinders are equipped with special dust collectors, which receive fine dust that flakes off the filler. It should be noted that the dust collector will function only if there are special holes in the abrasive for dust. It is also worth looking at the material from which the filter is made. If it is paper, it is not washable, and therefore this part will have to be replaced often. The plastic filter, on the other hand, is hassle-free: it can be washed and put back in place.

This machine is designed for finish grinding of wood. Makita BO3711″ grinder is a high-performance industrial equipment. However, this equipment is quite possible to use in conditions of a small room.

The size of abrasive paper for the device. 228×93 millimeters. The paper is fastened in special clamps. Oscillation frequency of 8,000 to 22,000 per minute. Oscillations are between 4 and 11 thousand per minute when in idle mode. The stroke of the platform is 2 millimeters. To operate the “Makita BO3711” you need a 190 Watt power supply.

The sander is equipped with a powerful dust removal system. The dust is discharged by means of a sanding plate. If you have to sand a large area, you can install a special bag for collecting dust.

Weight of the equipment is 1.6 kilograms. The design is distinguished by its ergonomic design and the presence of a soft handle framed in rubber.

It is advisable to choose the type of grinder and the model in question according to the nature and scope of work to be performed. You should also take into account the type of surface you are working on, and possibly your own personal preferences.

Vibratory grinders.

Vibratory sanders (flat sanders) are designed for fine finishing and polishing of flat surface. They can be used for grinding wood, stone, plastic, metal and composite materials. Vibratory grinders have a rectangular, soft base plate, which reciprocates at high speed with low amplitude. This amplitude is an important characteristic of vibratory grinders: the greater the amplitude of motion of the sole, the faster it is, but the surface is treated more roughly. Today, for our convenience, manufacturers equip such machines with frequency control.

Eccentric sander distinguishes itself from vibratory sander machines by the presence of an eccentric: it allows the base to make circular and reciprocating movements at the same time. This improves the performance of the sander and gives extra direction when sanding the surface. Eccentric grinders are suitable for work with curved and profiled surfaces. They are also used for polishing, grinding of metal, wood and mineral surfaces. Such machines are distinguished by the number of revolutions, power (from 170 W to 750 W) and the amplitude of the oscillation of 3. 7 mm. On the sole of the eccentric sander, with clips or velcro, fasten replacement sheets.

Before you buy a sander, first of all, decide for what kind of work you buy it. And before you start work, you should carefully study the instructions and safety rules, because, like any other tool, the sander can be dangerous.

Eccentric grinders

Five myths about eccentric grinders

How does the disk of an eccentric sander rotate around its axis like a planet around the sun, simultaneously making oscillating motions in tiny orbits. Due to this complex movement, the scratches from the sanding disc are located on the surface to be sanded chaotically, overlapping each other. With each transition to finer abrasives they become less and less noticeable and merge, and the surface appears smooth and shiny. It all seems quite clear, doesn’t it?? Not quite. In practice, there are endless questions about eccentric grinders. How fast should it move? How hard should it be pressed down? The machine must be switched on by pressing it against the workpiece or keeping it at a certain distance? Instead of spelling it out. which can be used by any craftsman (eccentric grinder testing details

Myth 1. Always run the grinder against the workpiece.

The reality. Starting outside of the workpiece is no worse.Operate the eccentric sander the way you feel most comfortable: on or off the workpiece. Most recent models have an integrated no-load function (electronic brake) to reduce the speed of the disc when working without load. This reduces the risk of depressions when the machine is operated outside of the workpiece.

However, it will not save the part if you put the sanding disk on it at a slant, or sand only with the edge of the sanding disk. Starting the machine on the workpiece can result in a few noticeable scratches that quickly disappear after a couple of passes (photo A). It’s much more important to fix the part firmly in place, using clamps or a special sliding mat to prevent it from shifting.

Angle Grinder Safety Chapter 6: Sanding and Wire Brushing

When you start sanding, don’t put too much pressure on the grinder and don’t let it linger in one place.It doesn’t matter where you turn the grinder on It’s important where you turn it off. Lift the power tool gently before turning it off, and you will have a successful sanding finish.

Myth 2. The machine grinds more aggressively when pressed.

The reality. A light touch is enough to get the best result.Pressing down on the tool slows rotation, which reduces efficiency and causes accelerated wear on the sole plate, bearings, abrasive discs, and the Velcro fastener to hold them in place.

Instead of being more aggressive, the tool removes less material under excessive pressure, leaving coarse scratches (photo B). And on some species (such as Douglas fir or American southern yellow pine), the surface becomes wavy when pressed hard (photo C). Don’t push the sander, let it do its job.

If there is a need for more aggressive sanding and it requires pressing the tool down or tilting it, it may be a sign of using too fine an abrasive or its blunting.Myth r. Sanding with abrasives smaller than 120 is useless.Reality. A finer sanding is required for a quality finish. Of course, you can apply lacquer layer by layer to make a coarsely sanded surface smooth, but this increases the cost of finishing. Wood that has been sanded with a grit size smaller than 120 looks darker and has shallow indentations; its grain pattern is less noticeable, and the rough surface absorbs more stain and varnish than the more lightly sanded one (photo D). Oil stains and penetrating finishes make the difference even more noticeable. It is advisable to finish the surface polishing with abrasive of 150-220 grit. At the same time the treated surface is smooth enough for good spreading and leveling of the lacquer layer and at the same time is rough enough for good adhesion.In some cases, you may need to grind with sandpaper with a grain size smaller than 220 units. For example, before applying aqueous finishes, it is useful to remove raised lint with an abrasive with 320 grit.No matter how smoothly you sand the wood, always use the progressive sanding method, going from larger to finer grit numbers without skipping a beat. When changing the sanding disc, vacuum the sanding dust thoroughly. Thus, during further processing, the particles of coarser abrasive particles will not be pressed into the surface.Myth 4. The grinding machine needs to be moved faster to accelerate the grinding process.The reality. On large surfaces. ride slowly, ride farther. Feed rate is how fast the tool moves over the surface of the workpiece. Although we cannot say that the same feed rate is required for all cases, the linear movement of the grinder at a speed of no more than 0.3 m/s gives the most uniform scratch pattern on the machined surface (photo E). Can the feed rate be increased?? Certainly. But to achieve the same sanding quality, additional passes are necessary, which will take longer. When machining large surfaces (e.g., stitches) it is better to start grinding from one corner and run the tool along the workpiece from edge to edge parallel to the edges, overlapping the trace of the previous pass by half to obtain an even coating.

Myth 5. Sanding paint between coats is not a job for sanders.

The reality. We always use an eccentric sander for this.

A light touch with the disc, a fine abrasive and no surface heating are three prerequisites for the successful use of electric surface sanders.

However, extreme caution is required so as not to penetrate the thin layer of coating We have achieved excellent results when sanding between coats of polyurethane varnish with abrasive discs with 400 and 600 grit.

For nitrolac you can use abrasives one or two numbers coarser, as the layers are firmly bonded together, hiding the traces of previous sanding. For curved parts, use a soft interchangeable sole, better suited to a flat surface.

Watch out for the heat, which softens the lacquer layer that causes the abrasive to get sullied faster. To avoid ruining the work, move the grinder without delay, without pressing it, and clean the surface with a vacuum cleaner and then with a soft cloth.

The structure of the machine

The support structure of the belt sander consists of a vertical column and a support. The first is a metal strip, the lower part of which is bent at an angle of 90º, and the second is a rectangular sheet of thick metal. The bent part of the stand acts as its support platform, with which it is attached to the front edge of the support. On the plane of the support is mounted drive, which acts as an angle grinder (angle grinder), connected to the mains through the speed regulator.

On the spindle of the angle grinder threaded drive pulley is mounted in the form of a metal roller, which sets the movement of the grinding belt. The drive pulley is mounted on top of the stand. Behind it is a T-beam, which is clamped to the support at its lower end and connected to the rack by a crossbeam. At the near end of the rocker is the idler roller, and at the far end is a spring that provides tension to the belt.

The most important and complex component of any belt grinding machine is the roller system over which the belt moves at high speed. The size of the driving pulley determines the linear velocity, so its diameter must be determined by calculation.

The linear speed of the belt is calculated by the formula: V = (π × D × N) / 1000 × 60, where V. speed (m/s), D. diameter of the driving pulley (mm), N. number of drive revolutions (rpm). Accordingly, the diameter is determined by the formula: D = V × 1000 × 60 / π × N (mm).

The recommended speeds for processing materials vary:

Since the main materials handled in the home shop are steel, wood, and plastic, the calculation will rely on a limit of 26 m/s. Our angle grinder has a maximum spindle speed of 11,000 rpm, so the calculated diameter will be 45 mm.

Many people try to make the rotating elements themselves from wood chipboard, plywood or plastic, or pick them up from the availability of used idlers in car repair shops. But since a specific diameter has been chosen, and one wants to make a belt grinding machine with the specified parameters with their own hands, it is best to order these products to a qualified turner.

All three rotating elements have the same diameter of 45 mm, but different design:

  • Drive pulley. Cylindrical shape with edges to prevent the belt from running off. Inside, a cup is machined deep enough to be fastened to the threaded end of the spindle with a long M14 nut. The total width of the working surface is 60 mm, the bead is 1 mm.
  • Drive roller. Outer surface identical to that of the drive pulley. Rotates on two bearings, recessed flush on both sides. As the shaft is used bolt with diameter of 8 mm with a short end thread, protruding beyond its size.
  • idler roller. The shaft and bearings are the same as the drive shaft. Outer surface barrel-shaped, without ribs, width 60 mm.

All three items are best inspected and assembled where they are made. Experienced craftsmen will surely help you properly seat the bearings and correct any shortcomings. In addition, it is necessary to make a hole in the bottom of the rack with a diameter of 42 mm to install the drive.

Components and accessories

All other elements of design can be made on their own or purchased in hardware stores and metal shops. To assemble the belt grinder with your own hands are needed:

  • Rotating elements. Described above.
  • angle grinder. E.g. Hitachi g12 sr2 manual angle grinder with 11,000 rpm and 650 W. Connects to power supply via a power controller.
  • Base. Metal sheet of 10 mm thickness, size 30 x 40 cm. Drilled 10 mm holes around the edges to attach it to the workbench. Two countersunk holes for screws are located at the rack mounting location and another at the actuator mounting location.
  • Stand. Plate thickness of 8 mm and a width of 8 cm. At the bottom, bent at right angles (4 cm shelf) for mounting on a support. The height from the fold to the top end. 65 cm. In the lower part there is a hole for the drive, and in the upper part. for fixing the driven roller. At the height of 20 cm from the bend. a hole for fixing the connection bar of the rocker post.
  • Tension roller bead. It consists of a stand (thickness. 8 mm, width. 3 cm, height. 25 cm) and an asymmetrical bar fixed at its upper end (through the sleeve with a bolt). A hole is drilled at each end of the crossbar: the long one is for mounting the tension pulley, and the short one is for mounting the tension spring.
  • Hardware and other materials. Screws, bolts, nuts, washers and sleeves needed for assembly, as well as wood pads and a clamp to secure the angle grinder to the support.

The list does not include materials for the work table, which is mounted in front of the fully assembled grinder. It must be made individually with reference to the installation site.

Selection of sandpaper

At different stages of grinding, as well as for different types of wood requires the use of an abrasive blade with different levels of grit.

The grit size of sandpaper can be roughly defined as the density of the grains.Number of abrasive particles used to fill one square inch of surface.

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The grit size can be identified by the marking on the back of the abrasive web. the number after the letter “P. The higher the number. the finer the abrasive material and vice versa, the lower the number. the coarser the grain.

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Dependence of the type of work on the level of grit:

  • 22. 36. coarse primary work;
  • 40. 60. rough sanding;
  • 80. 120. primary sanding;
  • 150. 180. finish sanding;
  • 240. 280. grinding of hard rocks;
  • 400. 600. polishing;
  • 1200. 1500. finish polishing.

When working with wood, you can not do without sandpaper with one level of grit. If the board is sanded immediately after sawing, it is required to pass at first the blades P40, P80 for rough sanding. If the board is smooth enough, you can immediately proceed to the fine processing of blades P120, P240.

Generally, this is enough to prepare the wood surface for painting or varnishing. But, if the surface initially there are strong contaminants, an old stale layer of wood, it is better to start with paper P24.

If it seems that the result after sanding P240 is not satisfactory, you want a smoother surface, you can pass the blade P400. But no more, t.к. Then the polishing of the surface begins, which can have a negative effect on the further process of priming and painting. Because the surface will be perfectly smooth, adhesion will suffer, and the paint can then just peel off.

Manufacturers of grinders

There are a large number of manufacturers of grinders on the market. Consider the major brands:

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AEG. Specialty appliances and power tools. This company has established itself as a quality supplier of equipment for woodworking, which can include grinders. A distinctive feature. powerful, reliable motors. Cordless models deserve special attention.

The warranty period is 12 months from the date of purchase.

BlackDecker. Specialization garden and power tools. The equipment belongs to the category of household. There are three categories they differ in color: red, silver, green. Factory warranty of 24 months.

Bort. Part of SBL Group. The range is quite wide: gardening equipment, power tools (drills, spray guns), household appliances (refrigerators, air conditioners, etc.), home appliances (refrigerators, air conditioners, etc.).д.), devices for automobiles. From 24 months warranty.

Bosch. Specializes in the manufacture of power tools, gardening equipment. There are professional and consumer lines. Price range is different. High level of service.

The warranty period can be up to 36 months.

Defort. Part of the SBL group. The range is quite extensive. gardening equipment, power tools, household appliances, automotive devices.

DeWALT. Specialization. professional power tools. One of the popular brands on today’s market that meets all standards of safety, reliability and durability.

The original tool has an embossed letter logo on each part of the body. Products are available only in yellow and black. Particular attention is paid to accessibility of maintenance, work safety, ecology.

FELISATTI. Specializes in professional tools and equipment for construction and woodworking. Great attention is paid to new technology. 24-month warranty period from date of purchase.

Hammer. The company produces professional household tools. Woodworking specialty. Warranty period 36 months.

Hitachi. Manufactures power tools and equipment for industry, medicine, construction, and household use. Reliability, quality and durability of the equipment has been proven by years of faithful service.

Guarantee period 36 months, 12 months on batteries.

Interskol. Russian manufacturer. Positioned in the middle segment in terms of both price and quality. Grinders of this factory have proven to be reliable. Produces tools for woodworking, concrete work, garden tools.

Kalibr. A Russian manufacturer that appeared on the market not so long ago. Inexpensive price and good quality. Guarantee period 12 months.

Makita. The company’s products are considered professional products. Tools are available gasoline, electric and cordless. Warranty period 12 months. In case of repair, its term is extended for the time spent in the service center.

Metabo. Makita products for construction, metalwork, gardening. Products are referred to professional line. Warranty period of 36 months, including lithium batteries, which serves as a quality guarantee.

Skil. Make gardening, household and professional tools. Has a warranty period of 12-24 months, but from the date of purchase by the first customer. Т.е. Considering that the first buyer is a dealer, the equipment can be delivered to a consumer with a warranty period from the dealer.

The list of represented manufacturers of grinders is far from complete. It should be noted that sometimes a well-known brand can hide low-quality equipment. To double-check, you can ask the dealer’s service center if and what problems have been reported with this or that particular device.