The image shows appearance stationary grinding machine. Due to its rather impressive dimensions, in order to optimize space, a shelf for auxiliary tools is built into its structure.
A homemade grinding machine is designed in the form of wooden structure, similar to a workbench. To give greater stability, the legs of the machine are located at an angle.
The unit is driven by an electric motor. In the context of power characteristics, it would be advisable to take an engine with indicators of 3,000 or 1,500 rpm.
The convenience of using a flange motor lies in the fact that a rectangular plywood sheet attached to it allows for guaranteed perpendicular fixation.
An earring for the tension spring is attached to the plywood.
The working surface of the grinding machine consists of longitudinal bars. WITH inside bars there is a frame with transverse spars. It is designed to mount the engine. Therefore, the width of the frame is determined by the area attached to the gearbox chipboard sheet.
A hole for the spring is drilled in the side of the frame. It allows you to do possible connection earrings with an eccentric by means of a return spring.
On the side of the grinding machine there is an eccentric with a plumbing pin. One end of the return spiral is attached to it. The mechanism is designed to perform the operation of belt tension. Using the eccentric handle, the spiral is tensioned, and passing through the so-called “dead” point makes it impossible for it to arbitrarily return to its original position.
The sanding belt is placed on two drums. The first of them is made in the shape of a cylinder. A plywood sheet is glued to its outer surface. Pre-bored, made in diameter, which will allow you to put the cylinder on the spindle. Basic parameters of the drum: circumference width D – 120 mm; height H – 150 mm.
To prevent the belt from running away, the factory-produced grinding machine has barrel-shaped drums. Here a simpler method is used to achieve this goal. The boundaries of the cylinder are bordered by washers placed on the spindle. Their diameter should be larger than the diameter of the drum shoe.
On the other side of the unit, two-layer plywood is glued to the longitudinal bars. The thickness is about 40 mm. The driven shaft is inserted into a specially made hole.
The grinding machine shaft itself is multi-stage and machined from a metal blank. In its structure it has flanges, a “skirt” and a bearing.
Notice the thread on one end of the shaft. It is necessary for vertical fixation, carried out using a nut
The second drum of the grinding machine has the same dimensional parameters as the first. The only difference is that at the top and bottom, it has specially machined places for bearings. The cylindrical block mounted on the shaft is secured with a clamping nut. 
To achieve a greater effect, a special stop made of board was attached to the horizontal surface of the grinding machine. It is located between two reels. The main condition for installing the stop is the obligatory observance of perpendicularity relative to the base. Also, under no circumstances should he touch the reels. This is necessary to prevent the belt from falling and rolling the edges of the workpiece.
The working surface is covered with a kind of platform. It is made of Finnish plywood and has a specially cut curly shape. The platform acts as a work table and at the same time prevents the engine from falling out. Attached using self-tapping screws. 
An expansion table is mounted on the drive block side. It is very convenient when grinding internal radii. Its fastening is also done using self-tapping screws.
Grinding machine specially designed for the most affordable and popular tape sizes, which are generally always in stock. It is strictly not recommended to glue the tape yourself using rolled sandpaper, which is sold in stores. Since it has a completely different quality, it quickly becomes clogged with resin and dust. And therefore, it is not effective and in cost, it will ultimately turn out to be much more expensive.
To fully utilize the entire width of the belt, an inclined belt is used. It is attached to the desktop using a plumbing pin on one side, and clamped with a thumb on the other.
Several times, the mentioned plumbing pin performs fastening functions. On one side there is a large thread, like a self-tapping screw, and on the other it is metric.
Video: DIY grinding machine.
All materials in any production, in addition to manufacturing, require additional and finishing processing. Vivid examples of such treatments include grinding and polishing the product. These two types of mechanical action on the surface of the part bring its appearance to perfection. However, everyone knows that performing these operations by hand will take a lot of time and effort, and even processing can only be ensured by very experienced master. To facilitate this kind of work, people have come up with various devices and mechanisms to help them. Some of them will be discussed further.
General purpose and types of machines
The machine is intended for final processing of parts and workpieces made of different materials by exposing them to an abrasive or diamond-coated surface. The machine, its component mechanisms and I allow devices t maintain the accuracy of size and shape, and also ensure the creation of an ideal surface of a part or workpiece.
Using the machine, you can process flat parts, surfaces outside and inside, parts of various geometric shape, grind or polish threads and gear teeth. According to their own Characteristics of grinding machines are divided into:
- Cylindrical grinders.
- Internal grinding.
- Centerless grinding.
- Surface grinding.
- Special machines (for grinding threads, gears).
Grinding process
Grinding is the process of removing the top layer from the surface of a workpiece using abrasives or diamond chips. They are collected into a common mass on the working surface and held together with a binder. They ultimately form a grinding wheel or belt.
During operation, the abrasive surface is driven in a circular motion using an electric motor. When the surface of the workpiece comes into contact with the abrasive, the processing process occurs. There is a common belief that grinding with abrasives is friction processing. However, this is not true.
Each abrasive particle has sharp edges; when it touches a material (metal, plastic, wood, stone) it works like cutting tool and removes chips, like say a milling cutter or drill. Considering the considerable rotation speed grinding wheels, as well as the occurrence of chips as a product of grinding, it is necessary to take into account the possibility of injury from these very chips.
Safety precautions during operation
When working on the machine it is required Observe the following safety rules:
Necessity at work and at home
Today, grinding machines are used constantly in production shops. Depending on the scale of production, either one machine or all its varieties in complexity and size can be installed.
However, even in everyday life this equipment there is always a use. Some people have a bench sanding machine for metal processing in their garage. Others have several different designs installed in their workshop grinding machines on wood. Still others have a universal one in their possession, combination machine. There are power tools for manual grinding: drum type, belt grinder, band saw, small machines or large machines. And they are all in demand.
There are quite a few on the market wide range all kinds of similar equipment from many manufacturers. And their prices are quite reasonable. But these are general purpose machines. And if a person is engaged own business, or he has a hobby, then he needs a specially specialized machine. Here the price has already increased several times.
For this reason or based on own desires Many craftsmen make homemade products. Mainly for processing wood, plastic and metal, less often for cutting and grinding stone. And, in general, this is correct. After all, even a simple sharpening kitchen knives It’s easier and faster to do on a machine than by hand using a whetstone. Fortunately, its very simple design allows you to create a homemade machine for wood with your own hands.
DIY grinding machine For a tree it is not difficult to assemble. People also simply call it emery.
The main component is the engine. Surely many people have an old one on their farm. washing machine. Its motor is quite suitable for this purpose. If not, a new engine on the market will be quite expensive, but at any flea market you can find a used one in working condition. The electric motor must be strong from 750 W to 2 kW, not high-speed from 1500 to 3000 rpm, if three-phase, then you can always adapt it to 220 V. You will also need thick plywood, self-tapping screws, PVA glue, and tools, of course.
The task is simple: Make a hard drive with sandpaper glued onto it. To do this, draw a circle with a diameter of 150-170 mm on plywood; if the plywood is thick enough to hide the clamping nut, one piece is enough. If not, glue two identical pieces together with PVA glue. The motor spindle clamping nut must be recessed into the disc flush with its working plane.
From the same 15-24 mm plywood you need to make several parts:
- The frame to which the engine will be attached.
- Feed table with guides for changing the angle of inclination.
- Disk protection design.
- Base for attaching the entire machine to the workbench.
The disk protection can be made in the form of an arch with right angles or truncated ones. It, like the feed table, is attached to the frame. From additional accessories You can install a protractor stop on the feed table, which will allow you to feed the workpiece at a fixed, horizontal angle.
Paying tribute to aesthetics, it is advisable to polish every detail before assembly. But this is optional, but with the serving table this must be done carefully. A smooth surface will provide uniform and continuous movement of the part along the working surface of the disk.
The purpose of this machine is revealed in its very name- surface grinding, that is, for grinding flat surfaces of parts and workpieces. It can be disk, drum (like a thicknesser) or belt. Moreover, its working surface can be positioned vertically, horizontally or adjustable.
Some machine designs are made fully adjustable. But this is individual. Homemade cars everyone does it for themselves to make it more convenient to work. Designs with full adjustment are more difficult to manufacture. They have adjustable pressure on the drum or belt, that is, in other words, there is the possibility of fixed movement of the working surface along the vertical axis. And the tool rest has a movement mechanism in two directions, like the cutter holder carriage on lathe.
From the verbal description it is difficult to imagine what it looks like. And even more difficult to understand how it works. But today we have the Internet. There you can find videos where experienced craftsmen share their experience, explain in detail and show how to make such equipment. Detailed information provided drawings and diagrams with exact dimensions and instructions on what material to use for assembly. In general, if you have difficulty designing it yourself, you can always simply make someone else’s copy.
This machine was invented for processing long parts. The abrasive belt is based on a durable fabric fabric, fastened into a ring. There are different sizes. It is driven by the same electric motor with similar characteristics. But some craftsmen replace the engine with a drill. Good drill- a universal tool in many respects. However, such a replacement is more relevant for small size desktop machines, as a rule, are used by modellers.
How to assemble a belt sander with your own hands? The belt is stretched between two shafts or drum rollers. One of which is the leading one (it is mounted on the motor spindle), and the second is the driven one (it provides tension on the sanding belt). To prevent the tape from jumping off the drums, stopper washers are attached to their ends. It turns out something like a textile reel. With minor distortions, the tape wears out faster than the edges of the tape rubbing against the lock washers are destroyed. So this idea is quite viable and justifies itself.
Also, a support screen is installed between the drums on the back side of the belt, which ensures tight pressing of the entire plane of the workpiece to the surface of the belt. To reduce friction, the screen is carefully polished. It can be made from either light metal or hard wood.
The drive roller must be rubberized or made of hard rubber. This will ensure that the tape cannot slip across the surface of the roller. The entire structure can be positioned in different ways if necessary: vertically, horizontally or at an angle. A rigid hand rest, at an angle of 90 degrees, or an adjustable one, is attached to the common bed, as on all similar machines. The distance between the tape and the edge of the table at hand should not be more than 3 mm. Since rupture of the belt is not capable of causing significant bodily harm, protection is done only to remove grinding products.
Homemade grinder
A grinder is a high-speed belt grinder or universal machine. Working surfaces - disk and tape. The engine used is the same as on all machines. And high speed is achieved by using pulleys of different diameters. Pulley large diameter mounted on the motor spindle and is the leading one. The small pulley is a tension pulley.
On a universal machine, a disk is also attached to the spindle. You can also install an additional transfer roller, support mounts which will be spring loaded. This is done to quickly change the abrasive belt.
The grinder differs from other grinding machines in its processing speed and versatility. Using interchangeable belts for different materials, you can quickly process even high-alloy steel surfaces.
Treatment metal parts and preparations are performed in several ways. Special equipment is used to remove a small layer of material, sharpening or grinding. The cost of factory models is high, and they do not always have the required functionality. Therefore, many home craftsmen prefer to make a metal grinding machine with their own hands with certain operational and technical qualities.
Characteristics of grinding machines
For domestic use, it is recommended to choose simple diagram manufacturing - belt or disc grinding machine. The workpiece will be fed manually; additionally, it is possible to provide support table to fix it. There is no point in trying to make a complex internal grinding structure or with a honing function. Manufacturing costs will be high, and practical use for a home workshop is minimal.
- Electric motor characteristics. Power - up to 500 W, speed - 1400.
- The maximum belt speed is 330 m/s.
- Possibility to change the tilt angle of the moving belt up to 45°.
- The diameter of the grinding disc is up to 230 mm.
- Execution type: desktop.
- Availability of end and side tables. They will be used to fix the workpiece.
The simplest option for making a grinding machine is to use a sharpening machine. However, processing can only be carried out with the end of the disk, the width of which is limited. This scheme is only relevant for sharpening tools or processing small parts and workpieces.
Belt Sanding Machine
The best option for domestic use would be the tape model. Structurally, it consists of a system of shafts on which an abrasive belt is installed. Changing the angle of inclination and the degree of tension occurs using a spring mechanism. It is recommended to make a wooden frame, as it is easier than producing a steel body.
Used Consumables and components:
- Guide drums. They are made from hardwood. Recommended diameter: 15 cm.
- Bed. It is also made from wooden blanks. The configuration depends on the dimensions of the machine and is determined independently.
- Drum mounts. These could be pins with bearings.
- Electrical engine and a torque transmission mechanism. A belt drive is used. To adjust the speed, discs for a belt of different diameters are used, mounted on the electric motor shaft.
- Tension mechanism. Necessary for adjusting the tension of the sanding tape. It is a lever mounted on a frame with the function of changing the height position. The design includes springs for smooth tension changes and a lock.
The assembly of the structure is carried out in stages. According to the developed scheme, components are made. They are then mounted on the frame. It is recommended to place the electric motor start button in a convenient place for quickly turning on or off the equipment. You can also install a protective shield made of polycarbonate.
Disk model
In some cases there is a need to process large area metal blank. Using a belt sander will not be acceptable, since it is difficult to achieve uniform removal of material over the entire surface. For these purposes, a disk model is required.
You can do it in two ways:
- Modernization band press. The area of the frame increases; a shaft with fastenings of a wooden disk (with 4 screws) with a diameter of up to 230 mm is installed on it. The drive is a belt drive, with the same speed switching. Additionally, a support table is manufactured.
- . It consists of an electric motor, on the shaft of which a fastener for a wooden disk is mounted. The disadvantage of this design is that it is impossible to change the rotation speed of the grinding wheel.
Another design option for a grinding machine is to install the shaft vertically. An abrasive belt is attached to the outer part of the cylinder. Such models are used for processing wooden structures.
During the grinding process, the surface of wood or metal is brought to the desired degree of smoothness. The use of special mechanisms allows you to complete the work faster and better. And by making a grinding machine yourself, you can save significant money.
Types of grinding machines
Grinding is the final stage of processing the workpiece before applying a protective coating. The process is carried out using grinding tools and emery materials. All machines according to the type of surface being processed, the shape of parts and design are divided into:
- surface grinding;
- cylindrical grinding;
- internal grinding;
- specialized.
The equipment is designed to perform:
- peeling and cutting blanks;
- finishing gears, planes, torsion surfaces to final size;
- sharpening knives, drills, cutters.
Most often, craftsmen try to make drum-type and belt-type machines for wood on their own.
Features of Drum Sanding Machine
Working body drum machine- This is a drum-shaped sanding disc. As a rule, it is used to process long and flat wooden parts, including panels, slats, and boards.
Main components of the drum grinding machine:
- base;
- engine;
- grinding cylinder;
- a device for changing the speed of movement of the feed cylinder;
- working surface;
- feed cylinder;
- protective box;
- dust extraction;
- device for adjusting the height of the working body.
The design of the machine is not complicated, so you can make it yourself in your home workshop.
Selection of parts
The electric motor can be taken from a broken washing machine; a belt, pulleys and electrical elements will also be suitable from it. The optimal power of the electric motor is 250 - 300 W at 1.5 - 3 thousand revolutions, single-phase (to make it easier to connect) and asynchronous, it is more productive.
The drum is made from cylinder-shaped bars, wooden rings, a cardboard tube or a piece of plastic sewer pipe. The last option is the simplest, so more about it. The drum is placed on an axis made of a metal rod up to 20 cm long.
- We cut off a section from the PVC water pipe equal to the future length of the drum; it should be slightly shorter than the axis-rod.
- We cut out a pair of end caps from a board or plywood, equal to the cross-section of the pipe, and make holes for the axle in the centers.
- We fix the plugs with screws at the ends of the pipe (we recess the heads).
- We install the axis-rod and fix it with glue.
- Glue onto the surface of the pipe sheet rubber, which will improve the fit of the workpiece. The abrasive material can be attached to the drum with a stapler, in a spiral.
The body of a homemade machine is made of thick plywood or wood boards. You can also make a work surface from plywood. The body consists of a pair of side posts, a cross member and a base that provides rigidity. The working surface must be strong enough so as not to sag during sanding. The movable part of the table is mounted on hinges on the back side, and with an adjusting screw on the front side. Depending on the screw thread pitch, the grinding thickness can be adjusted.
Assembly
We attach the electric motor to the housing from below. A hole for the axle is provided in advance in the housing. The drum is installed in top part beds. The axle is placed at both ends on bearings in cages, fixed with screws to the side supports.
We install the pulleys on the axles and stretch the belt drive. We will install electrical wiring and a switch. We place the adjusting screws: one on the bottom and a couple on the sides.
Drawings and models of homemade machines
Making a belt sanding machine with your own hands
The structure of the tape machine is as follows: a work table is installed on the tabletop in various positions. The table moves using rollers along cylindrical guides mounted on supports. A sanding belt is placed on the pulleys located above the table, which is tightened with screws. The part is pressed using an iron against the abrasive, which moves in the transverse direction. The movement of the belt is ensured by an electric motor via a belt drive.
You can make such a device yourself. The main elements of the machine: engine, base and rollers. The electric motor will again fit from a washing machine (power up to 300 W, 1.5 thousand rpm). The base is cut out of metal and welded; it must be strong enough and not wobble. The dimensions of the worktop are approximately 16 x 18 cm. 3 holes are drilled at the end of one of the sides for attaching the platform with electric motors using bolts.
It is advisable to maximize the working area, this will increase the possibilities of using the machine. It is more convenient to grind parts when the length of the table is greater than or equal to the length of the workpiece.
At a speed of movement of the abrasive belt of about 20 m/sec, the diameter of the cylinders should be about 20 cm. With the correct calculation, you can do without a gearbox.
The leading cylinder is rigidly fixed to the engine pulley, the second is a tension cylinder. It rotates freely on bearings on a fixed axis. On the side of the movable cylinder, the working surface should be slightly beveled to achieve a soft touch to the abrasive surface. This is very important when working with glued joints.
Cylinders can be made from chipboard. Are being sawed out square tiles 24 x 24 cm of which the package is assembled on the axis and ground to a diameter of 20 cm. When turning the drum, it is important to take into account: in the middle its diameter should be 2.5 - 3 mm larger than at the edges.
This shape allows the abrasive belt to be positioned right in the middle. It is most convenient to use a 20 cm wide belt. In addition to sanding wood parts, this machine can be used to sharpen any cutters, as well as process curved parts.
The video demonstrates how to make a grinding machine with your own hands:
For small volumes of grinding, the need for which arises from time to time, many craftsmen use hand-made ones. As an abrasive tool in such devices, as a rule, belts and discs made of sanding paper and cloth are used. This is explained by the fact that they are very inexpensive and can be easily replaced if necessary to perform grinding with a different grit. In addition to grinding wood, metals and plastics, these homemade products can be used to sharpen metalworking and carpentry tools, as well as straighten turning tools and drills. Some homemade grinding machines have very simple design, and they can be assembled and disassembled as needed. Others largely replicate industrial designs and are excellent examples of amateur engineering creativity. Old electric motors from household appliances and powered power tools. In the simplest grinding machines, the drive part is often made of a drill or grinder.
There are two main layouts of a belt sanding machine: with a vertical arrangement of the working part of the sanding belt and with a horizontal one. Among the creators of homemade grinding machines, the first one is more popular, because it is suitable for different types processing and is much more convenient for sharpening tools, and dust is discharged downwards during the grinding process. As a material for the manufacture of the frame, main parts and rollers, many craftsmen very often use not metal, but plywood and wood. The latter option has a number of advantages:
- all components can be made in a carpentry workshop;
- It is much easier to adjust wood parts;
- wooden structure has less weight;
- The installation is vibration-resistant and easy to disassemble.
In order to make an efficient, reliable and safe grinding machine yourself, you must have at least some minimum engineering knowledge and skills in processing structural materials. Therefore, only the most important points manufacturing and assembly of the machine, the schematic layout of which is shown in the figure below.
Engine selection
As a rule, electric motors from disused drum machines are used as drives for homemade grinding machines. washing machines, as well as hand-held power tools. The power of the former is usually about 300 W at a rotation speed of about 3 thousand rpm. They are convenient for installation because they have special mounting tabs with holes on the body, as well as threads on the shaft for attaching a pulley. Power tools (usually drills and grinders) are attached to removable clamps or brackets. Their engines operate at higher speeds, so in grinding machines it is advisable to use models with adjustment of this parameter.
The drive rotation speed is the most important characteristic homemade machine, because it is used to calculate the diameter of the drive pulley that transmits the rotation of the sanding belt. Each type of abrasive belt is designed to operate at a specific linear speed, which is measured in m/s, and its operating speed is equal to the peripheral speed of the drive pulley. Therefore, if you have an electric motor with known characteristics, the design of a grinding machine should begin with determining its diameter.
In addition, based on the length of the sanding belt and the diameters of the pulleys and rollers, their center-to-center distances are calculated and the overall dimensions of the future grinding machine are determined.
Frame structure
The frame (bed) of the grinding machine is a supporting structure on which the electric drive, pulleys and rollers are mounted. The normal movement of the sanding belt, as well as the stability of the machine, depend on its rigidity and manufacturing accuracy. The contours of the frame usually repeat the kinematic diagram of the rollers that are located in its extreme points. Further, its design will be considered using an example homemade device made of wood and plywood, in which an electric drill is used as a drive. The manufacturing process of this grinding machine can be seen in the video (see below). At the end of the show there are sketches of all parts with dimensions.
The machine frame is a box-shaped structure, inside of which there is a drive pulley and two rollers. It consists of a curved sidewall broken C-shape installed on a wide base. The material used for all parts of this sanding machine is thick plywood. A work table with a slot for a sanding belt is attached to the lower ledge of the frame. The drive pulley is mounted on the vertical part of the frame, the guide roller is on the bottom end, and the tension and control pulley is on the top. The same shaped sidewall is hinged in the form of a door and completely covers the entire space with the pulley and rollers.
The undoubted advantage of this homemade belt sanding machine is that all its parts are made simple tool in a carpentry workshop, and during assembly a minimum of types of fasteners and metal components are used. Apparently, the master spent no more than two days on its manufacture.
From a safety point of view, the solution to completely enclose the rollers and belt seems ideal. And the significant disadvantages of this machine include only a small range of belt tension.
Video installation
Factory and homemade belt sanders usually use two to four rollers. various sizes. One of them is always a pulley on the drive axis and transmits movement to the sanding belt. Another one acts as a tensioner (sometimes combines this function with axial regulation). The rest are guides and can also be adjusted. One of the most common is the design of grinding machines with three rollers. In this case, each of them performs one of three functions. In this configuration, with the working part of the sanding belt positioned vertically, there is a tension roller at the top and a guide at the bottom.
After installing the pulley and rollers on the machine frame, they must be adjusted. During operation, the sanding belt moves at a speed of 10 to 30 m/s, and any deviation in the geometry of the relative position of the pulley and rollers can cause it to come off and break. Therefore, their axes must be set strictly parallel to the horizontal, and the planes of rotation along which the belt moves must clearly coincide vertically. The possibility of such adjustments should be provided for when developing the design of a belt grinding machine.
The simplest device among homemade products used by craftsmen is a disc grinder driven by a drill. Most often, this is simply a drill with a factory-made or home-made drill secured with a clamp on a board. And in such homemade products, a piece of board or a stack of plywood is used as a work table. The main advantage of such structures is the ability to quickly assemble and disassemble them or even make them anew.
However, there are also more complex designs: with a movable work table or a movable support in which the drill is fixed. The material for making homemade disc sanders is always thick plywood or wood, and assembly is done using screws and glue.
Because the different materials are ground at different speeds; in such devices it is recommended to use drills with variable speed control or conventional drills with dimmers.
Typically, the frame on which the drill is mounted is a rectangular piece of board with a device for fastening it. As a fixing device, either a metal bracket is usually used, which is used to press its body, or a wooden clamp with two semicircular recesses that cover the drill by the neck intended for attaching the side handle. Another option is to place the drill in a wooden box, in the front wall of which a hole is cut to the size of its neck. In this case, it is fixed with a strip, which is screwed to the ends of the side walls. For additional fastening and placing the drill in height, short bars and plates of plywood are used. Most often, the work table for such a homemade grinding machine is a simple structure of three rectangular pieces of plywood or chipboard with a slot for a disk, although some craftsmen make movable and inclined tables.
Disk design
As a grinding tool in homemade machines With a drill drive, disc attachments with a cylindrical shank are usually used. Many people independently make such a tool with discs of the size they need from plywood or plastic. Others use factory disc attachments with a soft pad when fine grinding or polishing is needed, or without it when the machine is used for roughing or rough grinding, as well as for sharpening and dressing tools.
The abrasive paper is fixed to the factory attachments using standard Velcro. On homemade ones, they are attached with glue.
Videos with sanding machines made of plywood and wood are most often posted by foreign craftsmen. Ours prefer metal constructions, and made using welding. What do you think is the reason for this? Please share your opinion in the comments to this article.