Wood grinder: types, purpose, choice

On the farm, you often have to grind something, clean off the old paintwork. Most of all work with wood. Few manufacturers sell perfect products. Except a carpenter. And if there are perfectly processed boards, then their price is such that you involuntarily want to grind them yourself. Even taking into account the fact that the work is boring and uninteresting. Therefore, a wood grinder is one of the tools that should be in the home arsenal.

Types, purpose, features of work

There are different types of grinders that do the same type of work but with different results. There is a tool for rough (preliminary), medium (intermediate) and fine (finish) grinding. Part of the tool can even perform polishing.

To choose a wood sander, you first need to decide what type of work you need it for. For rough grinding – smoothing out irregularities, differences in height – one type is suitable, for finishing grinding – bringing to the ideal – another type. Moreover, both tasks can be solved using different types of equipment.

angle grinder

The well-known grinder can also be used for grinding wood. With the function of rough grinding, it copes well. Of all the possible tools, this one is the most productive. If you need to quickly level large wooden surfaces – grinding the floor, walls, log cabins – this is work for the angle grinder. Minus – the surface is very uneven, it takes a long time to level all the pits and humps. If it still “passes” on a log house, then for any carpentry work the result is unsatisfactory. If only it is possible to purchase another tool, it is not worth using an angle grinder for grinding wood.

For grinders there are special nozzles for grinding wood. The best option is petal or plate-shaped circles with sandpaper of different grain sizes. When they are installed, the working plane is below the protective cover, it is safe to work, you can move in any direction. It is necessary to carefully handle places with protruding heads of nails and self-tapping screws. We lower the tool from above, carefully move it. A sharp movement easily breaks the grinding wheel, so be careful.

By changing the grain size of the grinding wheels used, it is possible to carry out coarse and medium (intermediate) grinding. The work will take less time than if any other wood sander is used. But it may take more time to bring to a flat surface, since, with a lack of experience, there will be more flaws.

When sanding wood, the sandpaper is clogged, the speed of work is reduced. In addition to slowing down, there is another sign – the smell of burnt wood. It is not necessary to immediately change the disk, you can restore its performance. To do this, grind the metal for several seconds. Everything stuck – resin, wood fibers, dust – burns out, the surface is cleaned, the processing speed increases again. This trick, by the way, can be used with other grinders.

If you often have to clean and change circles, a Velcro nozzle is installed on the grinder. Replacing the sandpaper is much easier and faster – peeled off / stuck – a matter of seconds. But working with a nozzle is more dangerous. Due to its height, the grinding area is above the level of the protective cover; it does not fulfill its functions. During the start, it happens that an unreliably fixed circle or even the nozzle itself flies off. They have a small weight, injuries are not serious, but it’s still an injury. An angle grinder with a smooth start helps to reduce risks, but all the same, you need to work with gloves, protective clothing with tightly buttoned sleeves, boots that cover your legs, and goggles.

Belt sander

It is called so due to the fact that the sandpaper has the form of a tape, continuously moving with the help of rollers. Therefore, such a wood grinder is also called “endless”.

A wood belt sander is designed for rough and intermediate surface leveling. By setting sandpaper with a finer grit, you can achieve a medium finish. This is enough for joinery that does not go under painting. To bring it to perfect condition, you need a different type of wood grinder. Moreover, to eliminate long longitudinal scratches, you will have to carry out stepped grinding, changing the grain size several times – the scratches remain deep.

What is the advantage of a wood belt sander? It has good performance. The tape on it is installed in such a way that it turns out to be sanded close to the wall with one side. What are its shortcomings? Due to the design, not all points can be “reached”. For example, corners, shaped recesses, grooves and other small details. It is not always possible to “crawl” between two parts (when processing railings, for example). Another drawback is that most of the belt grinders have a solid mass, it is difficult to work with them on weight, sanding vertical surfaces. But on a horizontal plane – they are the most productive.

The next disadvantages are a high level of noise, not the biggest grinding spot. It is so noisy that it is extremely uncomfortable to work without headphones. Why a small spot of polishing, because in appearance it is quite large? Even with a large belt width, it only sands in the center – the front and back part is not used due to the fact that it is raised to feed the rollers.

There is a belt sander for wood features in the work. To reduce the depth of the furrows that it leaves, it must be driven along the fibers. Then finishing polishing takes less time. And one more thing – if you gape in the process of work and leave the machine in one place for a long time, a solid “pit” is formed. Despite this, it is the most productive wood sander that is often used.

Orbital (eccentric)

The orbital sander for wood has a round sole with Velcro, on which sandpaper discs are attached. The discs are the same as for the grinder, so they are interchangeable. There are holes in the sole of the machine to remove dust. Dust is collected in a bag, a cassette-type container, almost all models allow you to connect a construction vacuum cleaner.

The work of an eccentric wood sander is based on the simultaneous rotation and movement back and forth (reciprocating movements). This achieves a fairly good speed for intermediate and finishing wood processing. When working with a grinder of this type, the platform moves in a spiral or orbit. Therefore, this tool is also called orbital sanders.

Eccentric sanders are good for processing curved or profiled surfaces – the machine is small in weight, it makes little noise, it is easy to control, the angle of the disk can reach recesses, cutouts, etc. With all this, it also handles large planes at a good pace. When using coarse grit sandpaper, it can be used for both coarse and intermediate sanding. The speed is less than that of the tape, but also quite acceptable. There are such machines with different radius of movement (eccentricity) – from 3 to 8 mm. By selecting this parameter, the main purpose is determined (more on this below).

The disadvantages of this type of machine are the impossibility of processing in the corners. The round platform is simply not included. Also – there is an area of ​​uncertain grinding along the edges – it will not be possible to grind close to a wall or a vertical surface.

Vibrating

The sole of a vibratory grinder can be rectangular or triangular. During operation, it makes circular movements with a small amplitude – it vibrates, which gave the name to this type of equipment. This wood grinder is used for fine finishing – for varnishing or painting, but it has low productivity.

A vibratory wood sander with a rectangular surface allows you to process large areas, but with its help it is not possible to grind wood near vertical planes and walls – it starts to beat against an obstacle. Triangular in this regard is more suitable for working in corners and hard-to-reach places, but you still can’t bring it tightly to the wall.

Another disadvantage of vibrators is the so-called “lambs”. If a grain of sand or other solid fragment gets under the surface, it leaves small circles on the wood – “lambs”. It is difficult to remove these traces. You have to use sandpaper of progressively smaller grit, gradually removing scratches. But if in the process something gets under the sole again, the process repeats again. Therefore, before work, the surface is thoroughly cleaned and a plyos is usually connected – for quick and timely removal of foreign fragments.

Oscillation

Strictly speaking, this is not a grinder, but you can grind with it. Moreover, those places that are not available for other types of machines are corners (even sharp ones), places directly at vertical walls. For grinding, a triangular platform of a special shape is installed on the tool, on which sandpaper on a self-adhesive basis is fixed.

During operation, the platform moves in a horizontal plane with a very small amplitude – the vertices of the triangle deviate by about 1,7 ° (this is an average of 2,5 mm). Due to this small movement, polishing occurs. Such a machine can be sanded in corners and close to vertical surfaces. Moreover, you can remove not only wood, but also smeared and dried glue. In general, an oscillation machine is used for finishing grinding in hard-to-reach places – due to low productivity and a grinding spot, it is unrealistic to process more or less large surfaces with it.

What type of grinder to choose

Summing up, we can say that for housework and construction, ideally, two grinders are needed – for rough and fine finishing. The most commonly used pair is tape + eccentric. If you are planning to start making furniture, then you cannot do without an oscillatory one.

If you do not like the result of the belt sander, you can purchase two orbital sanders with different eccentricities. For rough grinding, a tool with an eccentricity of 6-8 mm is suitable, for finishing grinding and even polishing – 2-4 mm. The only downside to this solution is that good eccentric sanders are expensive.

If the budget is limited, and the farm has a grinder (angle grinder), rough grinding can be done with it, and for intermediate or finishing, use orbital or vibration. Just keep in mind that vibration is the least productive, albeit the cheapest. If possible, buy an orbital one – it is more versatile and gives better results.

Technical Selection Criteria

Any tool is divided into classes that differ in working resource (and price). So a wood grinder can be household or professional. Household are designed for short continuous work with interruptions. Basically, it is recommended to work no more than 3 hours a day, periodically taking breaks of 15 minutes.

Professional models are designed to work for 8-12 hours, breaks are rarely needed or not needed at all. The working resource of such a tool is many times greater. For this, durable and reliable (read – expensive) materials are used. In addition, the productivity of such equipment is much higher, as a rule, there are a greater number of adjustments.

When choosing, the first thing to decide is what class your car should be. I must say that some manufacturers have a good household class, and some also have semi-professional lines. This is an intermediate class, as a rule, for private use it is optimal in terms of price / quality combination. Some models are used even by professionals.

General selection options

Although wood grinders differ, there are some common points that you need to pay attention to when choosing. Here they are:

• Power consumption. This is a proxy for performance. The smallest wood grinder has a power of 120 W, the most powerful is about 1,2 kW. But the power also depends on the type, so tape ones are usually more powerful, because more effort is required to stretch the tape, and energy is also spent on the operation of the compressor, which removes dust from the working area. So the power of the grinder should be compared with the same type of models, but not with different ones.
• Cord length. Everything is simple here. The longer the cord, the more mobile the tool.
• The presence of rubber pads on the handles. They contribute to a more comfortable grip of the equipment. Handles should fit well in the hand.
  

• Weight. On the one hand, a heavy tool requires considerable effort. On the other hand, it is more stable and easier to manage. Less weight is only desirable if you will be processing large vertical planes (walls) or ceilings.
• Smooth start. With this function, the engine speeds up gradually during start-up. This increases its resource.
• Possibility of connection to the vacuum cleaner. Almost all wood sanders are equipped with removable bags to collect dust from the working area or cassette containers. But with intensive work, it is easier to connect a vacuum cleaner and not bother with emptying the bag every time. So for professionals this parameter is important.
• Engine speed control. Increases/decreases the speed of vibration or belt movement. Useful for choosing the parameters of the work. Wood is usually sanded at high speeds, but they must be selected so that the tool does not tremble in the hands.
  

• Motor overheating protection. On the one hand, a useful thing that extends the life of the tool. On the other hand, overheating stops do not improve mood.

These are the general points that you need to pay attention to. Now about what is important for different types of grinders.

Tape

When choosing a belt sander, you need to look at the following parameters:

• The length and width of the tape. Tape width – from 6 mm to 100 mm. A narrow blade can handle small parts, a wide blade increases productivity. The length of the tape depends on the model. It is clear that the longer the tape, the longer it works without replacement. When buying a second belt type grinder, try to find a model with the same length – fewer consumables will be required.
  

• Power consumption – from 500 W to 1200 W. The higher the power, the higher the productivity and endurance of the tool, the longer the period of work.
• Tape centering mechanism. It happens manual (in household models) and automatic (in professional). Holds the tape in place. More reliable – automatic.
• Additional handle. The tool is heavy, it is not always convenient to hold it with one hand. An additional handle (removable or stationary) allows you to better control it and work in a non-standard position (on verticals, inclined planes, on the ceiling).
  

• Adjustable belt speed, minimum and maximum values. The grinding speed depends on the belt speed. But at high speeds, the processing is quite rough. By changing the grain size of the sandpaper, it makes sense to change the speed of its movement. The stiffness of the wood also affects the selection of speed. Therefore, it is convenient to have an adjustment of the speed of the tape, since you can choose the desired mode of operation.

You also need to pay attention to how convenient it is to change the tape. There are also models that allow you to quickly change the brushes. Sometimes spare brushes are even included.

Popular models of belt grinders

Eccentric (orbital)

In addition to all the general parameters described, there are some nuances in choosing an eccentric wood sanding machine:

• The amount of eccentricity. That is, the amplitude of the deviation during circular motion. It is from 2 mm to 8 mm. The larger this figure, the higher the processing speed, but the lower its “purity”.
• Sole diameter. There are 90 mm, 100 mm, 125 mm and 150 mm. Professionals prefer to work with a sole diameter of 150 mm. They have the highest performance and for this size there is a large selection of sandpaper of different grits, there are no problems with spare parts.
  

• The presence of a platform braking system. This option distinguishes a good tool from a bad one. Needed to prevent spontaneous rotation and a smoother start.

The selected model still needs to be tested in the store. To do this, install a disc of sandpaper on the platform and turn on the tool. Vibration should not be felt at all. This means that it is well balanced and will work comfortably.

Popular Random Orbital Sanders

Vibration

First of all, you need to choose the shape of the sole. It can be rectangular (most often), square or ironing. The system for attaching sandpaper here is clamping, just a piece of sandpaper of the right size is pulled and fixed with clamps. For normal operation of dust removal in stretched paper, holes must be made in the right places (holes in the platform). It is best to connect a vacuum cleaner to remove dust, since the presence of dust under the platform leads to a large number of scratches. That is, instead of grinding, we get a damaged part. This is an important point.

What to look for:

• A vibrating wood sander can have a power from 130W to 600W. More powerful – heavier.
  

• Sole size. There is a certain set of dimensions from which you have to choose. A small sole is a tool that is more maneuverable and easier to control, a larger one is more productive.
• stroke amplitude. This is how much the platform moves when it vibrates. It can be from 1,5 mm to 5 mm. The smaller the amplitude, the cleaner the processing, but the lower the performance.
• Stroke frequency. Displays how many times per second the platform moves forward. Usual numbers are from 6000 rpm to 26 rpm. Well, if there is an adjustment. And it’s great if it’s smooth.

The vibration grinder is used only for finishing grinding and is characterized by low productivity. Only paper with fine grain can be placed on it. Rough processing should be carried out with another tool.

Popular models of vibratory grinders