Homemade disk grinding machine made by a craftsman with his own hands: detailed photos production with description.
I decided to make myself in the garage — a grinding machine. In the bins I found an old Soviet-made engine, power about 1 kW, 1420 rpm.
So I completely disassembled this electric motor and cleaned it of rust, sandpaper and files.
On junction box the nut was lost, I had to put the nut from the adapter on the plastic pipe.
Polished the case with GOI paste.
Then I cleaned and painted the casing, used a primer, paint and varnish.
I ordered a plan-washer from a turner. Outer diameter - 100 mm, 4 holes and one in the center, all with a diameter of 4 mm, the thickness of the washer itself is 4 mm. However, it turned out that the plan-washer is put on the engine shaft with at least a little effort, but by hand, but it is necessary that with a slight interference. The foil does not fit, too tight, so I applied a layer of primer.
Then he made a working surface - a chipboard disk. Bought 2 pieces Chipboard thickness 16 mm, for large sandpaper and small. 5 or 6 layers of PF-170 varnish were applied around the circle.
To accurately install the disk, I did this: in the center of the plan washer (into a pre-drilled hole during manufacture) I drove a short nail out of a nail, and combined it with drilled hole in the center of the disc, marked and drilled 4 holes in the disc for mounting.
He drowned the screw heads and put them on epoxy resin so that they do not rotate when tightening the nuts.
The bed was made from the door of an old cabinet.
Installed capacitors.
I glued sandpaper No. 60 to the disk with PVA glue. Maximum size disk that can be used - 330 mm.
Grinding equipment is used for finishing parts. The machine performs finishing technological operations in the manufacture of wooden and metal products. A significant advantage of such a device is the possibility of its self assembly. A home-made unit is somewhat inferior in performance to factory models, but it will cost much less.
The working principle and characteristics of the grinding machine
Grinders differ from each other in design and scope. general characteristics tool - a similar principle of operation. The working mechanism rotates and the abrasive material grinds the surface of the part.
When choosing finished equipment or making a machine with your own hands, it is necessary to take into account the main characteristics of such equipment:
- Power. When using the machine at home, a power of 400 watts is sufficient. To perform production tasks, high efficiency and productivity of the unit will be required - at least 1 kW.
- The speed of rotation of the working mechanism. The grinding abrasive element performs up to 3000 revolutions per minute per minute. The higher the rotation speed, the better quality processing. Experts recommend using units with an indicator of at least 500.
- processing area. This parameter is determined based on the scope. The larger the width of the drums or sanding belt, the larger the products will be sanded.
- Device dimensions. Dimensions are an important parameter, which largely depends on the area of \u200b\u200bthe workshop or workshop. At self-manufacturing the machine is designed so that after its installation there is enough space for placing tools, workpieces, consumables and other equipment.
Features of different grinding machines
Depending on the configuration of the abrasive unit, the following types of machines are distinguished.
tape device- grinder. The machine is equipped with an abrasive belt, which wears out over time and requires periodic replacement. Using the unit, you can remove a layer of rust from metal, correct the dimensions of the product in some planes, clean and shape wooden parts.
Positive aspects of tape machines:
- universality;
- small dimensions and light weight;
- the possibility of self-production;
- Adjustable belt length for sanding and polishing items of various sizes.
Advice. When equipping belt grinding equipment, it is better to choose graphite abrasives - they are the most wear-resistant.
drum machine works on the principle of a drill. The grinding part of the device rotates from the engine at a speed of about 2000 rpm. The main purpose is the calibration of flat long workpieces. A drum-type unit is more difficult to manufacture, but such a home-made wood grinder will allow you to process slats, shield surfaces made of MDF, chipboard, veneered material and wood.
disk device(dish machine). It is quite possible to assemble the unit yourself, as it has a simple device. Disc machines are characterized by the following features:
- compact dimensions and ease of use for domestic purposes;
- good performance with a powerful electric motor;
- the possibility of polishing workpieces cone-shaped, spherical and cylindrical shape.
Combined grinding machine - a combination of the functions of flat and cylindrical grinding equipment. One device is equipped with a grinding wheel and an abrasive belt. This option is best suited for small workshops and garages, where the installation of two units at once is problematic.
Homemade belt sander
Accessories for belt type devices
Homemade grinding machine for metal or wood has the following design:
- The bed is the base of the machine. The working base of the structure is usually made static - it is screwed to the floor. Sometimes the equipment is additionally equipped with wheels for ease of movement.
- Working platform for the subsequent placement of the electric motor.
- Electrical engine. As a rule, the drive is installed near the larger diameter drive roller.
- Leading and driven tension roller. In self-manufacturing, you can use improvised materials made of metal or high-density wood. To prevent the tape from rolling off the shaft, the diameter of the central part of the rink should be 2 mm smaller than at the edge. To prevent slippage of the tape on the drums, it is desirable to wind a thin layer of rubber.
- The belt tensioning mechanism consists of a lever and a clamping spring. The lever is fixed to the frame and the driven tension roller.
Important! For processing steel or wood, paper-based or fabric-based tapes are used. Tape width - 5-31 cm, length - from 11 cm, grain size from R-80.
Manufacturing technology of the belt assembly
Homemade belt grinders for wood or metal can be made from the following materials:
- electric motor with a shaft speed of about 1300-1600 rpm;
- steel pipes not less than 2 mm in thickness;
- corners with a section of 50 * 50 * 5, 25 * 20 * 1.5 - the number is determined by the dimensions of the equipment;
- magnetic stand for fixing metal blanks;
- bearing supports, ball screws;
- shafts for fastening the tape;
- rail guides.
Work sequence:
The described type of machine is more suitable for grinding flat metal workpieces.
Homemade drum sander
Drum-type equipment device
The drum grinder belongs to the class of calibration models. Main element devices - sanding drum giving smoothness to wooden surfaces.
Elements of the basic configuration:
- bed;
- engine;
- planer drum with emery tape;
- feed drum with conveyor belt;
- mechanism for adjusting the speed of the drum;
- stands for fixing the position of the grinding drum;
- protective cover;
- dust extractor.
Homemade wood grinder: drawing
Step-by-step instructions for creating a machine
Stage 1. Motor selection. Fits old engine washing machine. Remove the pulleys, belt and electrical part from the equipment. It is desirable to give preference to an asynchronous single-phase electric motor of 200-300 W, 1500-2000 rpm.
Stage 2. Drum making. Suitable for creating pvc pipe, wooden rings and other improvised items. drum set PVC is made as follows:
- From plastic pipe cut a piece of the desired length with a diameter of 10 cm.
- Prepare end caps from wood with holes in the center of 2 cm.
- Fasten the end elements to the pipe with screws.
- Pass a steel bar 15-20 mm thick through the hole.
- Stick a rubber sheet on top of the pipe.
- Using a stapler, fix the sandpaper on the drum.
Stage 3. Preparation of the desktop and bed. The body is made of wood:
- “Cut out” the wooden canvas into side panels (2 pcs.), spacer, details of the worktop (base and movable component).
- Assemble and strengthen the structure with a cross member. The internal spacer will additionally act as a support for the adjustment screw.
- To be able to control the course of the working surface, its movable element is fixed with a piano loop to the base. An adjusting screw is installed on the feed side of the workpiece.
Stage 4. The assembly is performed in the following sequence:
Stage 5. Fixing the protective cover and commissioning.
DIY grinding tools
In addition to overall machines, small practical devices for polishing metal products or grinding some parts can also come in handy in everyday life. Many of them are quite possible to do with your own hands.
Mini grinder and "polishing" for metal
A mini-grinder is useful for home craftsmen and lovers of alterations - the device is used for high-quality cleaning of surfaces before soldering. Required Parts can be taken from an old Soviet tape recorder.
Glue fine-grained sandpaper onto a wooden round plate. This will be the working part of the grinder. To start the machine, you will need a small motor with a shaft diameter of 1.5 mm and a button. Solder the start button to the electric motor.
A 7 V AC adapter is suitable for power supply. One contact of the adapter is soldered to the switch leg, and the second to the electric motor. Fill the soldering points with hot glue. After it dries, wrap the body with heat shrink or electrical tape. Finishing stage- fixation of the working grinding element.
Homemade disc grinder
A disc grinder of low power is useful for turning small-sized wooden products. For the machine shown in the photo, a 90 W three-phase transformer was used, launched through a capacitor. An engine with a speed of 2750 per minute is connected in a triangle with a starting capacitor and reverse. Connections are soldered and hidden in heat shrink.
The base is fixed on four steel rods - if necessary, quickly installed and removed. A mandrel for M14 is attached to the shaft, it is possible to install different nozzles from a grinder.
Safety precautions when working on homemade grinding equipment
When performing work on the machine, it is worth adhering to a number of rules that will help protect yourself and others from possible injuries:
- Do not touch work surfaces and moving parts with your hands.
- Protective goggles must be worn during operation to prevent particles of hot scale and abrasive from getting into the eyes.
- Before starting work, it is necessary to check the reliability of the fastening of the shafts, tape and disk.
- It is important to control and check the integrity of the wire braid. If the slightest malfunction is detected, work must be suspended.
- A protective cover must be used. The element somewhat narrows the view, but greatly increases the level of security.
Homemade vertical grinder: video
Nowadays, there are no surfaces that are not smooth. Smoothness is achieved through various grinding devices. professional equipment it costs a lot of money and not everyone will be able to buy it, moreover, such machines have a fairly high weight and dimensions.
Fortunately, skillful hands our country adapted to produce analogues of equipment for such a modest budget. The grinding machine also did not stand aside and was subjected to a 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 makes any wood surface very smooth. It is a platform on which special frame with an electric motor (motors of washing machines 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 draft 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 sags and chamfering, rounding corners. In addition, the grinding tool gives any surface smooth alignment and calibration.
Types of wood sanding machine
Depending on the surface to be treated, the following types of grinders are distinguished:
Belt sander
This equipment uses an abrasive belt, which is pulled by two shafts. These shafts are driven by an asynchronous electric motor. The abrasive belt does not sag during wood processing, but rests against the working plane, which has a low coefficient of friction. The tape can be placed 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 tape surface and the other is circular (disk). This universal machine created for the convenience of working on it. By the way, such equipment will significantly save the budget. In such a device, only one engine is used. 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 tape is wound on two rollers in a spiral manner. Under the rollers is a tabletop with a smooth surface. The gap between the tabletop and the rollers is adjustable to the required distance. With the help of such a machine, it is possible to calibrate the surface of a wood blank.
Disc grinding tool
The working area of this equipment is an abrasive wheel. per axle electric motor a circle with Velcro is fixed, on which the abrasive is fixed. After starting the engine, abrasive wheel rotates around its axis, thereby carrying out grinding. This type of machine has the ability to adjust the processing speed, and the number of revolutions of the axis will not decrease.
On each of four kinds machines can perform certain operations. Now that we have an idea of what the 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. grinders. And that's not all, so as not to spend money on machines, people came up with grinders from a drill, from Bulgarian. The fact is that nozzles are fixed on these tools and the same grinding is carried out.
Tip: If you still decide to purchase a factory grinder, then decide in advance on the work and loads that your machine will undergo, and only then make a purchase. The same applies to homemade tools.
Motor power calculation
Important! Before creating any homemade brainchild 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 vice versa strong, then you cannot do any work.
The calculation of power is carried out according to a special formula, which belongs to the category of complex mathematical calculations.
The formula looks like this
P=q*S*(K+k)*U/1000*n
Where each designation means the following
- q - Indicates the pressure of the processed wood part on the plane of the abrasive cloth (N / square centimeter).
- k - Friction index wrong side abrasive on the working surface.
- n - Coefficient useful action the entire system.
- K - An indicator of the working plane of the abrasive relative to the workpiece. The priority is the density of the tree and its graininess. The limits of this indicator range from 0.2 to 0.6.
- S - The area of the workpiece that is in contact with the abrasive, measured in square centimeters.
- U - The speed of rotation of the abrasive, measured in meters per second.
When you calculate with the formula required power electric drive of your future unit, you can safely begin to assemble the machine as a whole.
It's time to get familiar with the design homemade machine. Blueprints all four types of equipment can be found in free access for viewing and download, as well as download all kinds of photo scheme. As an example for visual study, consider a belt sander.
The design of the machine and its schemes
Any build homemade equipment begins with the design of the bed or the foundation of the future machine equipment. This can be done with a metal material, or from wood material. The following dimensions of the frame are used as standard 500 mm x 180 mm, while 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 bed itself or make a platform for the motor, which will be attached to the end of the bed. The other side of the bed is designed to accommodate the shaft, with a pulley for a belt and rollers for an abrasive belt. The tape itself is installed with a slight slope. This is done so that the abrasive smoothly and gently comes into contact with the machined plane of the workpiece.
Tip: Before installing the abrasive strip on the rollers, it is necessary to wind them thin strip rubber. This will reduce strip slip 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.
Tip: In the process of assembling your future grinding unit, you must comply with all the necessary dimensions, and you must also calculate all the parameters very seriously.
When the design is familiar to us, we can proceed to the assembly process.
The assembly process of the grinding machine
To assemble the grinding tool, you will need the following items:
- Wood board.
- Wooden bars or metal profile pipe.
- Ball bearings.
- Electric motor.
- Rubber strap.
- Rubber belt.
- Metal pulley.
- Self-tapping screws, fasteners.
- abrasive element.
- Working tool (drill, grinder, screwdriver, jigsaw, etc.).
- Welding machine (if the frame structure consists entirely of metal).
After we have decided on the materials and working tools, we can begin to assemble all the parts and elements into one mechanism. For this, the frame is assembled. It can be metal (consist of a metal-profile pipe) or wood (consist of wooden bars and solid wood).
When the frame is ready
You can start installing the motor. The motor power must be at least 2.5 kW and not more than 3 kW, with the engine speed between 1200 and 1500 rpm. A pulley for a belt is installed on the motor shaft. The motor is mounted on one side of the frame. Motors are often used from washing machines used at home.
On the other side
A shaft with bearings is located, on one side of which a pulley is fixed, and on the other side a roller, an abrasive belt will be put on it in the future. Shaft pulley and motor pulley must be in a flat horizontal plane. The belt tensioner should be located in the same area.
Coming from wood
Either a stand is constructed from plywood or metal, on which the remaining rollers will be placed and an emery tape is worn. There must also be a tension mechanism. In addition, the presence of a working bar is mandatory, on which the abrasive belt will rub.
On the frame, as a rule, from the end, a start button is installed. Electrical circuit machine must be grounded.
After that
Once everything is done, you can make the first start and configure the equipment properly. When the setting is done, the first workpiece is run and the result of the work is checked. If everything worked out, 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 feedback and summing up
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 smooth surface, then the presence of grinding tools is indispensable.
Video reviews
Video review of a homemade grinding machine:
Video review on the choice of grinding equipment:
Video review of the belt sander:
Video review of eccentric sanders:
- Machine assembly materials
- Engine selection
- Assembly of drums and tape
- Assembly process
The main function of wood sanding machines is to finish natural material with abrasive elements. Machines and fixtures of various types can have a wide range of capabilities and allow you to sharpen knives, grind decorative and furniture products, and also perform internal and external polishing of the workpiece.
Ultra-fine polishing, which gives products a perfectly smooth surface, is possible for modern units.. One of the advantages of such equipment is excellent performance and high efficiency both in the rough roughing process and in high-speed grinding.
In production, you can often find a calibrating, disc and oscillating (spindle) type of grinding units. No less popular is the disc grinder, belt grinder and drum polisher. The kinematics of all grinding devices without exception, whether it is a calibration or polishing sample, is based on rotation or movement. wood detail along a straight or arc path and simultaneous rotation of the working part of the unit, but this applies to stationary machines. If it means hand tool, then we are not talking about the movement of the workpiece, but it moves exclusively Sander. Returning to stationary wood grinding machines, we note that it is better to perform high-quality surface treatment of large-sized products on tape samples. Factory equipment is not cheap, so many owners of small home workshops are increasingly interested in how to make a belt sander on their own.
The design of the belt units
To have an idea about the manufacture of a grinding unit with an emery belt, you need to familiarize yourself with its design, which includes:
- abrasive belt stretched horizontally or vertically on the bed;
- a pair of drums (drive and tension cylinders). In this case, the kinematics provides for the launch of the leading element with the help of an electric drive that transmits torque by means of a belt drive;
- metallic or wooden table, and the first option makes it possible to work with more complex details;
- an electric motor with a power of at least 2.8 kW, due to which the sanding belt (emery) can move at a speed of 20 m / s;
- extractor hood that removes wood dust.
There is a close relationship between the length of the working tool and the bed, as well as similar parameters of the workpieces that are subject to processing on this unit. Every experienced master will confirm that working with the equipment is more comfortable if the processed wooden element inferior in length to the working surface. A properly assembled homemade belt sander will allow you to easily level the surface and remove all errors, making it even and smooth. Also, belt units will quickly and efficiently remove old paint and varnish coatings, cope with the processing of edges and ends, polish curvilinear figures and polish a flat wooden furniture element.
Machine assembly materials
Many novice carpenters make a grinder from a drill, but we propose to create an improved tool. Before assembling a belt sander with your own hands, you need to decide on the material for the manufacture of its main components. For example, it is better to make a desktop from thick metal, giving preference overall dimensions canvases within 500x180x20 mm. We draw your attention to the fact that the larger the bed, the more functional it is and the more diverse the details will be, the processing of which is planned.
Table
The production of the working surface is as follows:
- Cut off one of the sides of the metal sheet.
- Conduct markup.
- Three holes are drilled at the end of the cut web, through which the work surface is bolted to the bed.
Engine selection
A home-made wood sanding unit is equipped with an engine, and in this case, an electric drive from washing machine, although you can pick up any motor with a power of about 2.8 kW, capable of averaging 1200-1500 rpm. The drive is tightly fixed in a stationary state to the frame.
Assembly of drums and tape
Now we have to make two drums for a surface grinding unit, which will require chipboard sheet, from which blanks of 200x200 mm are cut out and a package with a diameter of 240 mm is assembled. After assembly, the structure is machined to a diameter of 200 mm. The master cylinder is mounted on the drive shaft, and it is he who will set the abrasive material in motion. The tension element is fixed around the axis of the frame on bearings.
Make sure that the tape can easily touch the tabletop, which is achieved by providing a bevel on the side of the drum.
When assembling the drums, do not forget that their inner diameter must exceed the outer diameter by a few millimeters. This is necessary so that the tape is placed in the middle of the cylinder and does not slip off. Now we need a sanding belt, for which abrasive emery material, cut into strips, and then glued together with a high-quality adhesive, is suitable.
Drum grinding unit
Just like industrial designs, household units can have different configurations, although, as noted earlier, their kinematic scheme and principle of operation are similar. Above, we told you how to assemble belt sanding equipment, and now we will find out what to make a homemade drum sander from.
In this case, instead of a stretched abrasive belt, the homemade product is supplied with a disk, shaped like a drum, with which wooden blanks are polished. As in the previous case, this simple type of aggregates is created quickly and without much difficulty, besides, here we also do not need complex scheme or tricky drawings.
Assembly process
When building a drum grinder with your own hands, you can use asynchronous motor from the washing machine, and in addition to it from old typewriter remove pulleys, belt and useful electronic parts. Sanding drums are usually made from cylindrical bars, wooden rings, cardboard or plastic pipe.
Starting to make a wood grinding machine, a segment is cut off from the pipe, equal to the length of the main grinding element, so that it is slightly shorter than the rod, on which it will be fixed in the future. End caps are cut out of a sheet of plywood, equal to the diameter of the pipe, with holes in the middle. The plugs are fixed in the end sides of the pipe with screws.
Now you can install the axis of the rod, fixed with reliable glue. The surface of the pipe is covered with sheet rubber, which will ensure a better fit of the workpiece. The emery cloth is attached in a spiral to the surface of the drum with a stapler, and the grinding drum is ready.
Corps and working surface units are made of wood or thick plywood. The movable part of the desktop is attached to the adjusting screw in front, and sits on hinges at the back. The engine is hung on the lower part of the body, where a hole is made in advance, and the drum, made by hand, is attached to the upper part of the frame. The rod (axle) sits on both sides of the bearings fixed to the side posts. At the final stage, pulleys are installed on the axle and the belt drive is pulled. To consolidate the knowledge gained, we suggest watching the video.
The cost of a factory-made grinder is quite high. If a power tool is not affordable, you can try to make it yourself. On such a machine, it will be possible not only to grind wooden blanks, but also to sharpen tools. You can assemble a grinding machine with your own hands in three types: belt, disk and drum.
For grinding machine assembly belt type you will need an electric motor, a solid frame and rollers on which the tape will rotate. Be sure to have a drawing on hand or detailed diagram with all nodes and dimensions. We suggest looking at the photo for an example of a machine diagram with a wooden frame. 
The following photo shows the finished design of the machine. In this embodiment, the location of the three working shafts is made so that the moving belt forms a vertical grinding plane. A belt drive is used as a drive. 
Four rollers can be used in the design of the machine. One of them is leading and mounted directly on the 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 smooths out the vibration of a running electric motor, however, the wood is short-lived. It is optimal to cut a workpiece with a size of 50x18 cm from steel 2 cm thick. One edge of the bed is made perfectly even in order to fix the platform for the electric motor to it. For the next part, you will need steel 1 cm thick. The platform is cut out with a size of 18x16 cm, after which it is fixed to the frame with a bolted connection.
A large electric motor power for such a machine is not needed. Suitable engine from an old washing machine. If you want to great performance grinder, then it is desirable 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 emery belt at a speed of 20 m / s. To achieve such parameters, working drums with a diameter of 20 cm are used. If the rollers are made thinner, it will be necessary to reduce the speed of the motor shaft using a gearbox, which is extremely inconvenient.
The driving 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 on the frame. A belt pulley is mounted from this end, and a drive drum is installed from the other end. Then a pulley is also placed on the motor shaft and a V-belt is put on. The driven rollers rotate arbitrarily on bearings.
Belt pulleys will have to be machined on lathe, and 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 stud is inserted and the plates are tightly tightened on both sides with nuts. A square blank is machined so that a drum with a diameter of 20 cm is obtained.
During the groove of the rink, 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 tape will not move out of the rollers. Surface wooden drum covered with rubber. An old bike tube will do. The rubber will prevent the belt from slipping on the rollers.
For the manufacture of sanding belt suitable for sandpaper fabric basis. You can cut a single strip of the required length, the edges of which are glued end-to-end. If there is no long strip of sandpaper, cut off a strip of strong fabric and sew it into a ring. sandpaper cut into rectangles, and then glued to a strip of fabric. When making a sanding belt, it is important to choose a quality adhesive so that the sandpaper does not peel off.
Making a disc grinder
The disk machine is considered the easiest to manufacture. The principle of its operation resembles an ordinary electric emery. The assembly of the grinding machine is presented with an instruction with a step-by-step photo:
- The power plant of the machine is a three-phase electric motor. This choice is not accidental, since a phase change when connected allows you to organize a reverse. The motor can be connected to a 220 V network through 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 bed, it is better to use edged board, and the guides and the desktop are cut out of plywood 1.5 cm thick. Wood for the manufacture of the machine better fit than metal. Wood dampens motor vibrations.
- The working disk can be ground and even sharpened. It is important to choose the right abrasive materials. They must be Velcro and fit for purpose. If you need to grind a product made of stone or granite, a Turtle diamond wheel is glued onto the working disk.
- To grind a wooden blank, a sandpaper circle is glued onto the working disk.
- There are similar circles on Velcro for metal. On such a disk, you can sharpen knives, axes and other tools.
When designing a disc grinder, it is important to take care of safety. From above, the rotating working disk is covered with a protective arch. An adjustable heel is provided on the desktop, 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 make it difficult to move the workpiece.
Production of a drum machine for grinding boards
For the manufacture of drum machine assemble the frame. You will need a beam of hard rock tree. From below, an electric motor with a pulley is attached to the frame. A drum with bearings will fit from a used conveyor. The sandpaper is cut into a tape and wound tightly end-to-end on a working roller. At the edges of the drum, the paper is fixed with clamps.
Attach the working roller from above to the frame. Under it will be the tabletop of the machine. 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 boards of different thicknesses can be sanded. 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 considered unit will work no worse than a factory-made grinding machine.
