I have been making knives for several years now and always use 2.5 x 60 cm and 10 x 90 cm belt sanders in my work. For a long time I wanted to buy another one, with a tape width of 5 cm, as this would simplify my work. Since such a purchase would be expensive, I decided to make it myself.

Problems when designing a future machine:
Three limitations had to be overcome. Firstly, there was no 10 cm wide tape available locally; it could only be ordered online. This didn't seem like a very viable option to me, as there is no greater disappointment than finding out that the tape has worn out and needs to be replaced, and you have to wait a week or two for a new one to arrive. Secondly, there was a problem with the rollers. I searched but couldn't find any tape suitable for 10cm. Thirdly, the motor. A belt sander requires a fairly powerful electric motor, and I didn't want to spend too much money on this project. The best option for me it was using a used motor.

Solutions to design problems:
The first problem with the tape had a simple solution. Since a 20 x 90 cm belt was available for sale in hardware stores at a reasonable price, I could make two 10 cm ones from it. This imposed restrictions on the size of my machine, but due to price efficiency, this option was the best. The second problem was solved using a lathe. To do this, I watched a video on the Internet and realized that I could make the videos I needed myself. With the engine the task was more difficult. I had several electric motors in the garage, but for some reason I had to give them up. Finally, I decided on an old tile cutting machine that had a 6-amp electric motor. At that time, I realized that this power might not be enough. But since the work was at the experimental stage, I decided to first achieve a working version of the machine, and the motor could be replaced later. In fact, the motor is suitable for small amounts of work. But if you're going to be doing more intensive sanding on it, I'd recommend the 12 amp minimum.

Tools and materials

Tools:

  • Angle grinder with cutting discs.
  • Drill and drill bits.
  • Wrenches for 11, 12 and 19.
  • Lathe.
  • Vise.

Materials:

  • Electric motor (6 A minimum, or 12 A recommended).
  • Various bearings.
  • Nuts, bolts, washers, lock washers of various sizes.
  • Metal corner.
  • Sanding belt 20 cm.
  • 10 cm pulleys.
  • Powerful spring.
  • Steel strip 4 x 20 cm.
  • Beam 2.5 x 10 x 10 cm made of wood or MDF.

Electric motor for machine

I had a choice of several motors, but the electric motor that was on the tile cutting machine had a more suitable casing. To some extent, working on the machine was like an experiment, because I was not sure that the motor had enough power. Therefore, I settled on a modular solution with the frame for the belt mechanism as a single element, which can be removed and rearranged on a more powerful base. The rotation speed of the motor suited me quite well, but I was worried that 6 A would provide weak power. After a little testing, I saw that this electric motor was suitable for simple work, but for more intensive work, you need to choose something more powerful. When designing your machine, pay attention to this point.

As I mentioned, the motor housing was very suitable as it allowed us to create a vertical machine that would be easy to move.

First you need to free it by removing the work table, saw, protection, water tray, leaving only the electric motor. Another benefit of using this motor was that it had a threaded core with a nut to hold the saw in place, allowing the pulley to be installed without using a key (I'll explain what a key is later).

Since I had a pulley that was too wide, I decided to use the large clamp washers that are usually used to secure the saw, turning one over so that there was a wedge-shaped groove between them. I found the space between them to be too narrow, so I put a lock washer between them to widen it. The advantage to this method is that the pinch washers have a flat edge that locks with the flat edge to rotate with the core.

Belt

I used a 7 x 500 mm drive belt. You can use a standard 12 mm, but a thin one is more flexible and will put less strain on the motor. He doesn't need to rotate the grinding wheel.

Device of a belt grinding machine

The device is simple. An electric motor drives a belt, which rotates a 10 x 5 cm “main” pulley, which drives the abrasive belt. Another pulley 8 x 5 cm is located 40 cm above the main one and 15 cm behind it and is mounted on a bearing. The third 8 x 5 cm pulley rotates on a lever and acts as a tension roller, holding the abrasive belt tightly. On the other side, the lever is attached to the frame by a spring.

Determining the drive type

The main question was to rotate the main pulley directly with an electric motor or with the help of an additional pulley and drive belt. First of all, I chose a belt drive because I wanted to have the option of replacing the engine with a more powerful one, however, there was another reason. When you do intensive metal processing, there is a risk of encountering some problems. A belt drive will slip in such cases, while a direct drive will create big problems. With a belt, the device will be more secure.

Frame manufacturing and installation

It is important to mention that using a metal corner as a frame can have both advantages and disadvantages. The obvious advantage is that it is convenient to assemble, like a construction set in childhood. But the main drawback is that it is strong only in two directions, but weak when twisted. This means that we need to take this weakness into account and calculate what torque can be transmitted from the pulleys to the frame, and compensate for it using additional jumpers.

Cutting:
You can use a hacksaw to cut the corner, but an angle grinder with a cutting disc will make the job faster. After cutting all the pieces, I would recommend sanding down all the sharp edges to avoid cutting yourself during assembly. The holes can be drilled using a conventional drill and cutting fluid.

Main video

The main roller is the most important part of the project, as it receives torque from the motor and transmits it to the belt. I used an old bushing to secure it, but I recommend using a bearing instead. The bushings do their job, but they constantly overheat and require regular lubrication. Moreover, they can scatter dirty lubricant, which can be annoying during operation.

Shaft:
There are threads on the sides of the shaft with different directions so that the mounting bolts do not unscrew when rotating. If you cut off one threaded side like I did, leave the one that goes counterclockwise, otherwise you'll have to make a locking bolt (I'll describe how to make that later) and a cotter pin. The main pulley will be placed on the cut edge.

Pulley:
Continuing with the theme of reuse, I found an old pulley from another project. Unfortunately, I prepared it for the threaded pin that it was supposed to be held on, but, in fact, this is not a problem. I made a rectangular cutout in this pulley. I then used an angle grinder to cut a groove on the end of the shaft. By placing the key in the hole formed by the shaft groove and the rectangular cutout of the pulley, I securely fixed them relative to each other.

Making rollers for a grinding machine

I made the rollers from several pieces of 2.5 cm thick hardwood. But you can use MDF, plywood or other material. When laying layers, you need to make sure that the fibers are perpendicular, this will give the rollers additional strength and the layers will not crack.

It is necessary to make three rollers: the main roller, the top roller and the tension roller. The main roller is made of two 13 x 13 cm pieces of 2.5 cm thickness. The top and tension rollers are made of two pieces of wood measuring 10 x 10 cm.

Process:
Start by gluing together pairs of 13 cm and 10 cm pieces of wood, clamping them together with clamps. After the glue has dried, trim the corners with a miter saw, then find the center of each piece. Secure them in lathe and process until they measure 5 x 10 cm and 5 x 8 cm.

Upper and tension rollers:
Next, you need to install bearings in rollers measuring 5 x 8 cm. Choose a core or spade drill, and drill a recess in the center to the width of the bearing. The inner race of the bearing must rotate freely, so you need to drill a hole that goes through the roller through the inner race of the bearing. This will allow the bolt to go through with a minimal hole.

Main video:
This part is done a little differently. There are no bearings on it, but if the shaft extends less than 5 cm from the roller, you will need to grind the roller down to width. Measure the diameter of the shaft and drill the same hole in the center of the roller. Try to insert the shaft, it must hold tightly, otherwise the roller will shake.

Bolting the rollers

Next, you should fasten the two halves of the rollers with bolts; do not rely only on glue. Remember that the bolt heads need to be recessed into the wood, since the roller rotates in close proximity to the frame.

Tension lever

The lever is made of a metal strip measuring 10 x 30 x 200 mm with rounded edges. It is necessary to drill quite large holes in it, so I recommend using drilling machine and lots of lube. A total of 4 holes are needed. The first is at the pivot point. It is not in the center of the bar, but 8 cm from its edge. The second hole will be located on the edge closest to the rotation point. It will serve to attach the spring. Two additional holes need to be drilled at the opposite end, approximately 5 cm apart. They need to be a little wider in diameter as they will be used for tuning, which I will talk about next.

When all the holes are made, you can attach the arm to the vertical angle between the top roller and the base. The end on which the spring will be attached is directed towards the main roller. It should rotate freely, so I recommend using two nuts for fastening, not tightening the main one completely, and using the second one as a locknut.

Installation of rollers

The upper roller is attached statically and must be clearly in the same plane along with the tension roller and the main roller. You can do everything by eye, but I recommend checking everything well with a level. To align the roller, you can add a washer, or, if it is not enough, a bolt. They are inserted between the frame and the roller.

There is no need to install the tension roller completely. We still need to make a stabilizing device.

Belt stabilization

Wear on the rollers or uneven surfaces can cause the abrasive belt to gradually come off during operation. The stabilizing device is a device on the tension roller that allows it to be at an angle that keeps the abrasive belt centered. Its design is much simpler than it looks and consists of a locking bolt, a slightly free-playing tension roller and an adjusting bolt.

Drilling holes in bolts:
For this purpose, I made a device in the form of a wedge-shaped cutout in the board, which will help hold the bolt in place during drilling. You can do this manually, but I don't recommend it.

Fixing bolt

The retaining bolt is a simple bolt with a hole drilled in it and is installed on the bar through a wide hole that is located closer to the pivot point of the lever. Since it is located between the lever and the roller, its head must be ground off so that the roller does not catch it. The bolt must be secured as shown in the picture.

The bolt on which the roller is attached

It needs to be loosened a little so that the tension roller has a slight play. But to prevent it from unwinding, you need to make a castle nut. To do this, you just need to make cuts on the edges of a regular nut so that it looks like a crown. There will be two drilled holes in the bolt itself: one for the adjustment bolt and it will be lined up with the locking bolt hole, and another for securing the castle nut with a cotter pin.

Bolt for setting:
Once the tension roller is in place, you can install the adjusting bolt, which will pass through the holes of the retaining bolt and the bolt on which the tension roller rotates. The system works when you tighten the adjusting bolt, causing the axis of rotation of the tension roller to shift its rotation angle outward, thus causing the belt to move closer to the mechanism. A spring at the other end of the lever adjusts the tension in the opposite direction. I recommend securing the adjusting bolt with a locknut as vibrations can loosen it.

Note: It is possible to add a spring to the back of the idler pulley, but I have found no reason why this should be done. A small advantage will be that in this way the roller will have less play. But I will add that I did not do this, and I did not have any problems.

Completing the work of making the machine yourself

When everything is done, you need to check all the bolts again and make sure that the stabilization mechanism is assembled correctly. Then you have to turn the device on for the first time, which can be scary. It's like driving a car where steering wheel and transmission do not work. I recommend turning the motor on and off for very short periods of time to prevent the machine from spinning at full speed.

In fact, for myself the hard part It turned out to be the spring setting. If it is pulled too tightly, the tape will not be able to rotate... Too loosely and it cannot be held, it will fly off, which in itself is dangerous.

Ready!

That's all. You should end up with a decent, medium-power belt sander that can be converted to a more powerful one if desired.

I hope you enjoyed this master class. Thank you for your attention.

Nowadays, there are no surfaces that are not smooth. Smoothness is achieved through various grinding devices. Professional equipment costs a lot of money and not everyone can buy it; moreover, such machines have a fairly high weight and dimensions.

Fortunately, the skillful hands of our country have adapted to producing analogues of equipment for such a modest budget. Grinding machine also did not stand aside and was subjected to modernization of manual craftsmanship. It is with this homemade machine that we will continue to get acquainted.

There is a huge amount of sanding equipment that can make any wood surface very smooth. It consists of a frame on which there is a special frame with an electric motor (washing machine motors are used for homemade products) and a mechanism. The mechanism itself, in turn, includes shafts, pulleys and an abrasive belt.

Application area

They are used in all industries where wood is processed. Often, any rough products have an uneven and rough surface. Such blanks cannot simply be painted and put up for sale or installed anywhere. Therefore, for further processing of wood, all its surfaces can be sanded.

Grinding machines are also used for processing sagging and chamfering, and rounding corners. In addition, the grinding tool gives any surface a smooth leveling and calibration.

Types of wood sanding machine

Depending on the surface being processed, the following types of grinding machines are distinguished:

Belt sanding tool

This equipment uses an abrasive belt that is tensioned by two shafts. These shafts are driven by an asynchronous electric motor. During wood processing, the abrasive belt does not sag, but rests against the working plane, which has a low coefficient of friction. The tape can be positioned both horizontally and vertically. The advantage of this equipment is the processing of long workpieces.

Universal grinding unit

In this case, the machine has two working grinding surfaces. One is a tape surface, and the other is circular (disc). This universal machine created for the convenience of working on it. By the way, this configuration will significantly save your budget. This device uses only one motor. Based on this, when working on two working surfaces, the load on the motor will not increase much.

Drum grinding tool

In this case, the abrasive belt is wound on two rollers in a spiral manner. Under the rollers there is a tabletop with a smooth surface. The gap between the tabletop and the rollers is adjustable to the required distance. Using such a machine, you can calibrate the surface of a wood piece.

Disc grinding tool

Workspace of this equipment is an abrasive wheel. A circle with Velcro is attached to the axis of the electric motor, onto which the abrasive is attached. After starting the engine, abrasive wheel rotates around its axis, thereby performing grinding. This type of machine has the ability to regulate the processing speed, and the number of axis revolutions will not decrease.

Each of the four types of machines can perform certain operations. Now that we have an idea of ​​what grinding equipment looks like, it's time to disassemble the design of the machine.

In addition to the above machines, there are also portable ones. grinding machines. And that’s not all, in order not to spend money on machines, people came up with grinders from a drill, from Bulgarian. The fact is that attachments are attached to these tools and the same grinding is carried out.

Advice: If you still decide to purchase a factory grinding machine, then decide in advance on the work and loads that your device will undergo, and only then make a purchase. The same applies to homemade tools.

Calculation of power for the motor

Important! Before creating any homemade creation that performs grinding functions, it is extremely important to correctly calculate the power of the electric drive. After all, if the motor power is weak or, on the contrary, strong, then you will not be able to do any work.

Power calculation is carried out using a special formula, which belongs to the category of complex mathematical calculations.

The formula is as follows

P=q*S*(K+k)*U/1000*n

Where each designation means the following
  1. q - Means the pressure of the processed wood part on the plane of the abrasive blade (N/ square centimeter).
  2. k - Friction index of the reverse side of the abrasive work surface.
  3. n - Efficiency of the entire system.
  4. K - Indicator of the working plane of the abrasive relative to the workpiece. The priority is the density of the wood and its grain size. The limits of this indicator range from 0.2 to 0.6.
  5. S - The area of ​​the workpiece that comes into contact with the abrasive, measured in square centimeters.
  6. U - The speed of rotation of the abrasive, measured in meters per second.

When you calculate the required power of the electric drive of your future unit using the formula, you can safely begin assembling the machine as a whole.

It's time to get acquainted with the design homemade machine. Blueprints all four types of equipment can be found in free access for viewing and downloading, as well as downloading all kinds of photo scheme. As an example for visual study, consider a belt sanding tool.

Machine design and diagrams

Any assembly homemade equipment begins with the design of the frame or foundation of the future machine equipment. This can be done using metal material, or from wood material. The standard dimensions of the frame are 500 mm x 180 mm, and the thickness should be 2 cm.

After making the base, you can proceed to the next steps. An asynchronous motor can be installed in several places so that its operation is complete. Prepare a plane on the frame itself or make a platform for the motor, which will be attached to the end of the frame. The other side of the frame is designed to accommodate the shaft, with a pulley for the belt and rollers for the abrasive belt. The tape itself is installed with a slight slope. This is done so that the abrasive comes into smooth and accurate contact with the workpiece plane being processed.

Tip: Before installing the abrasive strip on the rollers, you need to wrap a thin strip of rubber around them. This will reduce the strip slipping during operation.

As we can see from the diagram and drawing, the design of the grinding equipment is quite simple. All varieties of these machines are assembled according to the same scheme.

Advice: In the process of assembling your future grinding unit, it is necessary to comply with all the necessary dimensions, and also the calculation of all parameters must be done extremely seriously.

When the design is familiar to us, we can move on to the assembly process.

Grinding machine assembly process

For assembly grinding tool The following items will be required:

  1. Wood board.
  2. Wooden blocks or metal profile pipe.
  3. Ball bearings.
  4. Electric motor.
  5. Rubber belt.
  6. Rubber belt.
  7. Metal pulley.
  8. Self-tapping screws, fasteners.
  9. Abrasive element.
  10. Working tools (drill, grinder, screwdriver, jigsaw, etc.).
  11. Welding machine (if the frame structure consists entirely of metal).

After we have decided on the materials and working tools, we can begin assembling all the parts and elements into one mechanism. To do this, the frame is assembled. It can be metal (consist of a metal profile pipe) or wood (consist of wooden blocks and solid wood).

When the bed is ready

You can begin installing the motor. The motor power should be no less than 2.5 kW and no more than 3 kW, with an engine speed of 1200 to 1500 rpm. A belt pulley is installed on the motor shaft. The motor is installed on one side of the frame. Motors are often used from washing machines used in everyday life.

On the other side

There is a shaft with bearings, on one side of which a pulley is attached, and on the other side a roller, on which an abrasive belt will later be placed. The shaft pulley and motor must be located in a flat horizontal plane. The belt tension mechanism should be located in the same area.

Next from wood

Either a stand is constructed from plywood or metal, on which the remaining rollers will be placed and the sanding tape will be put on. There must also be a tension mechanism. In addition, there must be a working bar against which the abrasive belt will rub.

A start button is installed on the frame, usually at the end. The electrical circuit of the machine must be grounded.

After that

Once everything is done, you can make the first start and configure the equipment properly. When the settings are made, the first workpiece is run and the result of the work is checked. If everything was successful, it means that you did everything right.

For visual clarity and a complete understanding of the entire assembly process, you can download video instructions.

General reviews and summary

As a rule, there are only positive reviews about this type of equipment on the Internet. Indeed, when in everyday life it is necessary to give this or that wooden thing a smooth surface, then the presence of sanding tools is indispensable.

Video reviews

Video review of a homemade grinding machine:

Video review on choosing grinding equipment:

Video review of the belt sanding machine:

Video review of eccentric sanders:

The cost of a factory-made grinding machine is quite high. If you can't afford a power tool, you can try making one yourself. On such a machine it will be possible not only to grind wooden workpieces, but also to sharpen the tool. There are three types of grinding machines you can assemble with your own hands: belt, disk and drum.

To assemble a belt-type grinding machine, you will need an electric motor, a durable frame and rollers on which the belt will rotate. Be sure to have a drawing or detailed diagram indicating all components and dimensions. We offer an example of a diagram of a machine with a wooden bed in the photo.

The next photo shows finished design machine In this embodiment, the arrangement of the three working shafts is designed so that the moving belt forms a vertical grinding plane. A belt drive is used as a drive.

The machine design can use four rollers. One of them is the leading one and is mounted directly on the electric motor shaft. The photo shows an example of such a design. Installing four rollers allows you to get two grinding planes: horizontal and vertical.

The wooden frame smoothes out the vibration of a running electric motor, however, wood is short-lived. It is optimal to cut a workpiece measuring 50x18 cm from steel 2 cm thick. One edge of the frame is made perfectly flat in order to attach a platform for the electric motor to it. For the next part, you will need steel 1 cm thick. The area is cut out 18x16 cm in size, and then secured to the frame with a bolted connection.

A large electric motor power is not needed for such a machine. The engine from the old one will do washing machine. If greater productivity of the grinding machine is required, then it is advisable to find an electric motor with a shaft speed of 1500 rpm with a power of 2.5 to 3 kW. High-quality grinding can be achieved by moving the sanding belt at a speed of 20 m/s. To achieve such parameters, working drums with a diameter of 20 cm are used. If you make the rollers thinner, you will have to reduce the speed of the motor shaft using a gearbox, which is extremely inconvenient.

The drive drum can be mounted on the motor shaft. If this option is not suitable, a separate unit is made. The drive shaft with bearings is fixed to the frame. A belt drive pulley is installed at this end, and a drive drum is installed at the other end. Then a pulley is also mounted on the electric motor shaft and a V-belt is put on. The driven rollers rotate freely on bearings.

The belt drive pulleys will have to be turned on a lathe, and the rollers can be made from square pieces of chipboard measuring 20x20 cm. The plates are stacked on top of each other until a total thickness of 24 cm is obtained. A hole is drilled in the center of the square plates, a threaded pin is inserted and the plates are pulled together tightly on both sides with nuts. The square blank is machined to form a drum with a diameter of 20 cm.

When grooving the roller, a thickening is provided in its central part. In relation to the edges of the drum, the difference should be 3 mm. Due to the thickening, the belt will not move off the rollers. The surface of the wooden drum is covered with rubber. An old bicycle tube will do. Rubber will prevent the belt from slipping on rollers.

To make a sanding belt, cloth-based sandpaper is suitable. You can cut a solid strip of the required length, the edges of which are glued end to end. If there is no long strip of sandpaper, cut a strip of durable fabric and sew it into a ring. The sandpaper is cut into rectangles and then glued onto a strip of fabric. When making a sanding belt, it is important to choose high-quality glue so that the sandpaper does not peel off.

Manufacturing of disc grinding machine

The disk machine is considered the easiest to manufacture. The principle of its operation is reminiscent of ordinary electric emery. Assembly of the grinding machine is presented in instructions with step-by-step photos:

  • The power plant of the machine is three phase electric motor. This choice is not accidental, since changing the phase when connecting allows you to organize reverse. The motor can be connected to a 220 V network via capacitors.

  • The working disk is cut out of plywood 1.5 cm thick. Two identical blanks are glued together. The result is a disk 3 cm thick. A hole is drilled strictly in the center, the diameter of which is equal to the thickness of the electric motor shaft.

  • To assemble the frame, it is better to use an edged board, and the guides and work table are cut out of 1.5 cm thick plywood. Wood for making the machine would be better suited than metal. Wood dampens engine vibrations.

  • The working disc can be used for grinding and even sharpening. It is important to choose the right abrasive materials. They must be Velcro and fit for their purpose. If you need to grind a product made of stone or granite, stick a “Turtle” diamond wheel onto the working disc.

  • To sand a wooden workpiece, glue a circle of sandpaper to the working disk.

  • There are similar Velcro circles for metal. This disc can be used to sharpen knives, axes and other tools.

When designing a disc sander, it is important to consider safety. The rotating working disk is covered with a protective arch on top. An adjustable heel is provided on the work table, which serves as a stop for the workpiece.

The tabletop of the machine should not be varnished or painted. Over time, an unevenly worn coating will create difficulties in moving the workpiece being processed.

Making a drum machine for sanding boards

To make a drum machine, a frame is assembled. You will need hardwood timber. An electric motor with a pulley is attached to the bottom of the frame. A drum with bearings will come from a used conveyor. The sandpaper is cut into strips and wound tightly end-to-end on the work roller. Along the edges of the drum, the paper is secured with clamps.

The work roller is attached to the frame from above. The machine table top will be located under it. A pulley is mounted on the drum shaft and a belt drive with a motor is created. The tabletop is made adjustable with screws so that you can sand boards of different thicknesses. To avoid vibrations of the machine, it is advisable to fix the legs of the bed to the floor.

If you try and make an effort, then any unit considered will work no worse than a factory-made grinding machine.

A belt grinding machine is used to perform the final processing of parts - their final grinding. The main area of ​​use of the tool is the furniture industry, processing of wooden parts. But it can also process metal elements using the appropriate abrasive material.

Using a belt-type grinding machine, the surfaces to be treated are leveled and their roughness is brought to the required level before applying coatings.

The working tool in a grinding machine is a belt with abrasive powder applied to its surface. It is made endless, placed on two rotating drums - the master and the slave.

The drive drum is driven by an electric motor, which transmits rotation to it through a belt drive. The tape can be positioned vertically, horizontally, or at an angle. The machine has a device for regulating the speed of the belt.

Having decided to make a belt sanding machine yourself, you need to decide: the maximum length of the processed surface in the parts; what kind of table to make (movable, fixed) or give preference to a free tape and refuse to make a table. The design of the machine must include an exhaust device for removing large quantity dust that is generated during its operation.

The main parts of a belt-type grinding machine that will have to be prepared or made are: bed, electric motor, rollers. The motor, for example, is suitable from washing machine, which has already reached the end of its service life.

The bed of the future machine can be made from sheet metal- its dimensions can be, for example, 50x18x2 cm. One side of the plate is made flat - this is necessary because a platform with an electric motor is attached to it. The platform for the motor is made of metal in the form of a plate measuring 18x16x1 cm and secured to the frame with several bolts.

The electric motor used has a power of 2.5...3 kW and is capable of providing a rotation speed of 1500 rpm. The speed of the belt when grinding should be 20 m/s. Based on this, the diameter of the pulleys is made equal to approximately 20 cm. Under such conditions, there is no need to install a gearbox in the craft, which makes it cheaper.

The drive drum and shaft shafts are directly connected; the slave is allowed to rotate freely, placing it on bearings.

Pulleys for a homemade belt-type grinding machine can be made from square pieces of chipboard. Central holes are drilled in them, combined, gluing, to a thickness of 24 cm. Then the package is machined, giving it a cylindrical surface with a diameter of 20 cm. In this case, the central part of the pulleys is made convex, increasing the diameter by 2...3 mm when turning.

A grinding machine is also called a grinder, which is translated from English grinder as crusher.

There are crushers for stones, crushers for meat - we have meat grinders, and there are garden crushers that produce wood chips. But if the word is used independently - simply grinder, only one thing is meant: a grinding machine in the field of metal processing.

Grinder is good and useful everywhere, including household– from competent sharpening of a high-quality knife or tailor’s scissors to grinding a complex part made of metal or other “difficult” material. In other words, the tool is needed and will be useful on the farm.

Moreover, it is quite possible to make it with your own hands. To do this, it is not at all necessary to have special equipment and solid professional experience.

Of course, you will have to tinker, but you will do exactly what you need and, most importantly, you will save a serious amount of money, up to several thousand American dollars.

Do we do it with a disk or with a tape?

Grinder drawing.

In terms of the breadth of the product line, only lathes can compete with grinding machines. There are a huge number of grinders on the market – of all shapes and sizes.

The most famous and primitive one is in the form of the famous emery - a pair of grinding stone wheels with a screwed-on motor. These machines are sold with a wide variety of schemes and operating principles.

But if you are planning to make a homemade sander, it is better to stop and choose between two options: disc or belt.

  • Disc grinder - a grinding layer of abrasive is applied to the disk, which rotates when turned on.
  • A belt machine in which the abrasive is applied to a belt wound on rollers.

Which one is better is a matter of debate. The correct criterion would be “which one is more necessary.” The choice should depend on what exactly you are going to sand. If these are relatively simple parts made of, say, wood, homemade disc wood sanders will be more suitable for you.

If you have serious grinding work ahead for precise finishing with complex parts, choose a tape.

It is necessary to take into account the difference between a suit and a tape, not only in terms of their functional features. Another important factor– drive power. If you are sanding small wooden sanders, you will have enough power in the range of 160 - 170 W.

This can easily be produced by a simple motor from a washing machine or even from an old drill.

For belt grinder Old household motors will not work in any way. There you will need an engine with a power of at least 400 - 500 W, and not a simple one, but a three-phase one with starting and running capacitors.

For grinding massive and large parts, higher power will be needed: up to 1200 W. Let us immediately note that purchasing capacitors for the machine will cost you not much less than the motor itself.

Selecting a feed

A machine with a tape is more versatile in terms of functionality: it does everything that disk models do, plus much more. Let us immediately note that there are a great many options for amateur models of belt sanding machines.

The fact is that the nature of this machine is very flexible, allowing you to use a variety of available materials, including finds in scrap metal dumps.

The main thing is to know and adhere to three rules:

  1. The abrasive side of the belt must be adjusted very precisely so that only the workpiece that is being sanded touches it.
  2. The tape must be evenly tensioned at any time and regardless of the type of work.
  3. The speed of movement should be different and should depend only on one thing: the type of part and the nature of the grinding.

Construction of a homemade belt sanding machine

Grinding machine device.

The main ones are:

  • A motor or motor-driven engine powered by electricity.
    It is better to install the drive next to the main diameter drive roller.
  • Base or bed.
    It is often fixed directly on the floor, sometimes this thing rides on wheels - whatever is more convenient and necessary for you.
  • Two tension rollers - driving and driven.
    Make of metal or very durable wood with a thin layer of cushioning rubber to prevent the tape from slipping onto the rollers or drum.
  • Spring and lever for the belt tension system.
    The spring is pressed, and the lever is attached to the base and driven roller.
  • Base for placing a motor with a drive.
  • For abrasive tape you need to use paper or cloth.
    Its width can be very different - in the range from 5 to 30 cm. Grit level - from 80.
  • Metal pipes with a thickness of 2 mm or more.
  • Metal corners in accordance with the dimensions of the machine.
  • Special magnetic stand for metal parts.
  • Rail type guides.

Diagram of the grinding machine.

Stages of work:

  1. We make the frame of the base or bed.
    – we cut the corners according to the dimensions of the bed;
    – weld the frame and corners;
    – we fix a chipboard board at the bottom of the frame to reduce vibration during operation.
  2. Making a work surface.
    – cut a steel sheet to size and weld it directly to the base;
    – weld the rail guides to the top of the frame;
    – we make a carriage from corners with wheels for moving along the guides of the bed;
    – on both sides of the working surface we mount and fix bearing supports;
    – fix the screw with the handle on the carriage;
  3. We fix the electric motor to the working area lifting system.
  4. We fix the gear supports.
  5. We install a tape with an abrasive coating.
    – cut the tape with a margin of a few centimeters at an angle of 45°;
    – glue it together overlapping with glue on the sides with the abrasive washed off with water;
    – dry the gluing area with a hairdryer;
  6. We are preparing for a test launch of the machine.
    – we treat all machine parts with machine oil;
    – supply electrical power;
    - We do a test run.

Safety precautions when working on a sanding grinder

Like any other work on any other machines, grinding on a homemade belt sanding machine is subject to fairly strict safety rules that must be strictly adhered to.

The principle of operation of the grinder.

These rules are as follows:

  • It is strictly forbidden to touch anything that moves or the work surface with your hands.
  • Wear safety glasses while working to protect against hot abrasive particles.
  • Carefully check that the connections and fastenings of all moving parts of the grinder are tight.
  • Monitor the condition of the braiding of electrical wires.
  • A protective casing is a must, even though it slightly narrows the viewing angle.