Sanding is one of the wood processing methods that allows you to give the workpiece a perfectly smooth surface. A universal-to-use wood sanding machine will be distinguished by its functionality and ease of operation. To process lumber, you can use units manufactured by specialized manufacturers, or you can make such equipment yourself, which will allow you to save significantly.

Types of woodworking machines

Currently, there are numerous types of sanding machines that are designed to perform various types of work with wood. They differ in their design and are intended for domestic and industrial use. You can easily select both highly specialized models and universal machines, which are intended for complex wood processing.

If necessary, you can make a homemade grinding machine for metal or wood, made on the basis of a drill, a motor from washing machine or using other equipment.

Disc units

The working surface of self-made grinding machines for metal and wood is made in the form of an island metal disk onto which the abrasive is attached. Due to its simplicity of design and versatility of use, equipment of this type has gained wide popularity in the market today.

This machine consists of an electric motor, on the axis of which a circle with a fixed working surface is put on. Abrasive attachments and sanding paper are attached to the working axis, which allows processing of wooden workpieces. Despite the simplicity of the design, such machines are distinguished by their versatility of use and can perform high-quality wood processing, giving the workpieces a perfectly flat and smooth surface.

The advantages of surface grinding technology include:

  • Versatility of use.
  • Efficiency.
  • Reliability.
  • Simplicity of design.

A feature of this type of equipment is the ability to adjust the processing speed of wooden workpieces without changing the speed of the working element. When working with such a machine, you can move the workpiece along the radius of the circle, which allows you to change the intensity of processing of products. At the periphery of the disk, the linear speed will be higher, which can significantly speed up and simplify wood processing. But inside the circle, where the linear speed is lower, final sanding is performed, removing the thinnest layer of wood.

Belt installations

Belt surface sanders have two shafts with a continuous belt of sandpaper stretched between them. Processing of workpieces is carried out by exposing them to sandpaper, which removes thin shavings from wooden workpieces, giving them a perfectly flat, smooth surface. The working surface of disc machines can be vertical or horizontal, while some models allow you to change the direction of movement of the belt. With the help of such equipment, it is possible to process long-length products, aligning their ends. The simplicity of the design allows you to make your own belt sanding machine for home use.

Drum models

The main purpose of units of this type is horizontal leveling using a jointer. This type of equipment is used mainly in industrial workshops, which is explained by the complexity of its design and narrow specialization drum units. Using drum sanding machines, wooden products of the same type with the same thickness are manufactured and processed.

Manufacturing of grinding machines

Industrially manufactured machines offered today in specialized stores are distinguished by their versatility in use, functionality and efficiency. Their only drawback is their high cost, therefore, if it is necessary to perform various types of grinding work, most homeowners decide to manufacture homemade equipment, which in its parameters and quality of processing is practically not inferior to factory units.

Structurally, a do-it-yourself metal grinding machine will consist of the following components:

  • Metal or wooden frame.
  • Electrical engine.
  • Drive shaft.
  • Working surface.
  • Sanding belt.

When making a drum sanding machine for wood with your own hands, you need to determine the power of the electric motor used. It is recommended to choose electric motors that develop around 3 kW and are capable of maintaining a clean rpm of 1,500 rpm. Based on such a drive, a functional, durable and reliable grinding machine can be manufactured that can cope with processing wooden products. The easiest way to make such equipment is based on an electric motor from an old washing machine.

The frame of the grinder can be made of lumber or a metal corner, welded and additionally covered with plywood. It is necessary to select the dimensions of the bed based on the dimensions of the drive used, as well as the dimensions of the wooden workpieces processed on the unit. When making a bed, you need to focus on the existing project documentation, which will allow you to correctly manufacture the load-bearing base of the machine, which will subsequently be able to withstand significant loads.

The shaft of a manual and automatic belt grinder, which is directly connected to the electric motor, can be turned on a lathe or using ready-made blanks from industrial equipment. The shafts of the calibrating drum sanding machine must be located strictly in the middle of the main drive, which subsequently guarantees high-quality processing of wooden workpieces.

The optimal width of the sanding belt used will be 200 millimeters. It can be done from emery, which is cut into strips and then the abrasive tape used is glued from them. The material should be glued end-to-end, and a dense material should be placed on the back side, which will ensure the strength of the seam.

By making a sanding machine with your own hands, you can significantly simplify the processing of wooden blanks, leveling boards and removing chips from lumber. Making such a unit with your own hands will not be difficult. On the Internet, you will need to select a schematic drawing for the manufacture of the machine, and using an electric motor from an old washing machine, make the simplest equipment, which in its functionality and quality of processing will not be inferior to factory-made equipment.

During construction and repair work Men often need to process wood, stone or metal. For quality work, it is advisable to purchase a belt sanding machine. But what to do when finances do not allow you to make such a purchase? To do this, it is enough to build a belt sanding machine with your own hands.

Purpose of a belt sanding machine

Wood is widely used in a variety of production organizations. Many different parts and products are made from wood. In order to properly process a wooden blank and give it the appearance of a finished product, it is customary to use various equipment, including belt sanders.

Belt grinding equipment is typically used in the final stages of production, when parts are subjected to finishing machining. Such devices are convenient to use in the production of furniture and various consumer wood products. Depending on the material used, belt sanders work with wood or metal.

The main purposes of using wood grinding machines are the final leveling of the surface, bringing their roughness level to the required value, obtaining even and smooth surfaces of wood products and wood materials before veneering or after coating with varnish and other finishing materials, removal of local irregularities in the form of depressions and elevations, peeling off burrs and removing local deposits of varnish and primer, deburring, internal grinding and grinding of curves.

Belt grinding machines for metal work with various materials and formats that are popular in metalworking: plain and alloy steel, non-ferrous metals in the form of quadrangular, round and flat blanks. Grinding machines allow efficient and effective minimal costs time to grind round timber and large diameter pipes.

Depending on the type of processing and type of feed, belt grinding machines are intended for:

  • for grinding curved surfaces with a free sanding belt;
  • for processing a flat surface with a fixed table, manual movement of the iron and table, as well as mechanized movement of the work table and manual movement of the iron;
  • for processing panel and block parts, their ends and side edges;
  • for intermediate sanding of paintwork.

Belt Sanding Machine Design

Belt grinding machines are produced by modern foreign and domestic manufacturers in a wide range. Grinding machine prices vary widely. They also differ in possible performance and design. However, they also have something in common. They are united by the fact that absolutely all machines have an abrasive belt as a working element, which is most often connected into a ring and placed between rotating drums.

One drum is the master drum and the other is the slave drum. This means that the first of them is equipped with a mechanical transmission, which is most often based on a belt drive, through which torque is transmitted to it from an electric motor. Any belt sanding machine is designed in such a way that the speed of movement of the drive drum, and therefore the speed of movement of the abrasive belt, can be changed, ensuring different modes surface treatment.

The abrasive belt can be positioned vertically or horizontally. In addition, equipment modifications are available for sale in which the working element is installed at a certain angle. The abrasive belt is mounted on a frame, on which the workpieces are usually located. Workpieces can be held by the operator manually or with the help of special devices that make the work easier for consumers and make the processing procedure more efficient and safe.

The machine table is made from metal sheets or thick boards. If the design provides for the table to be made of metal, then it will be possible to sharpen more complex products. The length of the working part of the belt grinding machine and the grinding belt itself primarily depends on the length of the products that will be sanded on the machine.

If the part has a shorter length than the working surface of the machine, then it will be much more convenient to process, and the processing will be of higher quality. For example, with a sanding belt length of 4.5 meters, you can easily process wooden workpieces that are 200 centimeters long.

Belt grinding machines are divided into equipment with a fixed and movable work table and devices with a free belt. A special group is wide-belt grinding machines, in which the caterpillar-shaped table is also a feeder. For machines with tables, the belt is placed horizontally; for designs with a free belt, it is installed in different ways.

Since the grinding process inevitably generates a lot of dust, all belt sanding machines are usually equipped with special powerful hoods that remove most of it during the process. technological process. Grinding machines are powered by an electric motor, which has a power of about 2.8 kilowatts. With a high-power motor, the normal speed of the belt reaches 20 meters per second.

Abrasive belts for grinding machines

The cutting tool of belt grinding machines is a sanding belt, which consists of a fabric or paper base and abrasive grains that are attached to it using adhesives. Abrasive belts are manufactured using two methods: mechanical and electrical. The first method consists of uniformly pouring abrasive grains onto a base that is covered with glue, and the second method occurs in electric field, which orients the grains upward with their sharpest edges to improve the cutting properties of the grinder.

Abrasive grains are poured onto the base in a bundle tightly or sparsely. The most effective is considered to be an abrasive belt with a sparse backfill, when the grains occupy less than 70% of the area, because it is not capable of clogging between the grains wood dust, formed during the grinding process. Natural minerals or artificial materials that have high hardness, for example, green and black silicon carbide, white and normal monocorundum, as well as normal electrocorundum, can be used as abrasive materials.

For the purpose of gluing grains, synthetic resins and hide glue are used. As a base, fabric such as calico and twill, or special grade paper is used. The size of the abrasive grains is indicated by a number that corresponds to the size of the sieve cells in which these grains are retained, and is displayed in hundredths of a millimeter.

If you are interested in how to make a belt sanding machine, then you should pay attention to the following sizes of grinding powders and abrasive grains and their classification: grinding grain - from 2000 to 160 microns, grinding powders - from 125 to 40 microns; micropowders - from 60 to 14 microns, very fine micropowders - from 10 to 3 microns.

Sanding paper is supplied to woodworking enterprises in sheets or rolls. On no work surface The skins are marked with the specified characteristics of the skin and the manufacturer. For a belt sanding machine, skins are used in rolls and cut into strips of a certain length and width. The length of the cutting tool is determined depending on the method of its connection - lap or butt at an angle.

The ends are cut off when gluing end-to-end at an angle of 45 degrees and then glued onto a canvas lining with a width of 80 to 200 millimeters. At one end of the tape, when gluing with an overlap, the abrasive grains are removed hot water over a distance of 80 to 100 millimeters, then place the other end of the tape on the exposed base coated with glue. Compress the joined ends and dry them using a special device or a size press.

Sheet sandpaper is used for combined belt-grinding machines. For grinding discs It is customary to cut the skin in the form of a circle according to a template, the diameter of which is 60 - 80 millimeters larger than the diameter of the disk. Using a rectangular template, blanks are cut for the reel. After cutting, they have smooth edges without tears. The presence of unglued ends or seals when gluing tapes can cause premature rupture of the tape.

The skin is cut into sheets using wide-belt sanding machines according to a template made of plywood or aluminum sheet. The skin is cut in such a way that the edges are smooth and the difference in the length of the side edges is no more than 1 millimeter. One of the beveled edges is cleaned, removing abrasive to a width of 20 millimeters. The cleaned edge and longitudinal edges are covered with a strip of tracing paper, 40 millimeters wide, which protrudes beyond the edge of the sandpaper by about 10 millimeters.

Lubricate the beveled edge with tracing paper with glue and leave it in the air, depending on the viscosity and type of glue. Then the beveled edges are joined and a strip of sandpaper is applied to the joint, the joint is compressed and held in a press. It is customary to hang finished endless belts on special brackets and keep them for at least a day in a dry room before installing them on a grinding machine.

Operating principle of a belt grinding machine

A belt sanding machine consists of a table top with a work table for mounting the cutting tool. This table is fixed in different positions relative to the tabletop. The material for the tabletop is usually laminated chipboard with a thickness of 25 millimeters. The worktable on rollers is moved manually or laterally by a mechanical drive along round guides that are attached to supports.

Above the table there is a working belt mounted on non-drive and drive pulleys. The sanding belt is tensioned and adjusted using a screw device with a pneumatic cylinder. Double belt sanders have two identical grinding tools, which are placed sequentially on the frame and have sanding belts that move towards each other.

Grinding is carried out by the transverse movement of the work table and the longitudinal movement of a short iron, which presses the belt to the material being processed. The sanding belts are driven by an electric motor via a belt drive. The waste generated during grinding is collected by a dust collector, which is connected to the exhaust network.

When assigning a grinding mode, it is recommended to select the grain size of the sandpaper, the feed speed and the pressing force of the belt to the product based on the specific roughness and properties of the material being processed. The grain size of the skin is usually selected depending on the hardness of the materials being processed and the required surface roughness. The clamping force and feed speed are interdependent quantities. With little force and high feed speed, some areas of the surface may not be sanded; with high pressure and low feed, burns and blackening of the material are possible.

Before installing the tape, check the quality of its gluing. Do not use incorrectly glued or torn sanding belts with uneven edges. Using the handwheel, you can reduce the distance between the pulleys and put on the belt. The gluing area is placed so that the outer end of the seam on the abrasive side is directed against the working movement of the sanding belt.

The belt tension can be adjusted by moving the tension roller for the belt grinder or the non-drive pulley. It is not advisable to tighten the tape too much, as this will cause it to break. But the sanding belt, with low tension, slips along the pulleys and heats up very quickly. The tension force is set depending on the strength of the base of the cutting tool and is determined by the arrow of its deflection with slight pressure on it.

How correctly the belt runs can be checked by turning the pulley manually or briefly turning on the electric motor. When the belt slips, the pulley axis is turned by a handle at a small angle and secured with a locking device. After setting up the belt grinding machine, the dust suction system is turned on, a trial processing of the parts is carried out and their quality is checked.

A manual feed belt grinder can be operated by one worker. By moving the product relative to the cutting tool in the longitudinal direction and rotating the part around its axis, the operator sequentially brings into contact with the tape all areas that form the surface to be processed. If you slow down or move carelessly, sanding may occur.

It is customary to grind individual sections of a part in several passes. High-quality leveling can be achieved by properly regulating the pressure applied to the handle of the iron and the speed of movement of the table and iron. The pressure must be reduced as you approach the edges to prevent them from being sanded off. To increase the quality and productivity of grinding, small bars are placed on the table in a row, several pieces at a time.

Belt grinding machines with mechanical feed of products are serviced by two operators. One of them places the part on the conveyor, orients it along the width of the work table and directs the product under the clamping elements of the machine. When being picked up by a conveyor, parts must not be moved laterally.

It is not allowed to feed into the machine workpieces that have unequal thickness and parts with gross surface defects. The feed rate and pressure of the clamping beam, as a rule, are not regulated during processing. The second operator receives finished parts and ensures that unacceptable edge rounding and sanding does not occur.

Making a Belt Sanding Machine

The price of belt grinding machines from an industrial manufacturer is quite high, so when they are used infrequently, craftsmen involuntarily think about whether to buy the equipment or not. An alternative to buying an expensive machine is to assemble it yourself. The main parts of the machine are the frame, rollers and engine.

The motor can be removed from an old washing machine. Cut the frame from thick iron measuring 500 by 180 by 20 millimeters. Cut one side straight milling machine for metal, it is required to attach the platform with the motor. The dimensions of the working platform are approximately 180 by 160 by 10 millimeters. Make markings and drill three holes in the end of the evenly cut frame. It is necessary to tighten the platform to the frame with three bolts.

Remember that the longer the desktop is, the more you will get more possibilities when choosing a technological method for grinding and processing a product. If the length of the workpiece is less than or equal to the length of the work table, then you can achieve a perfect grind much easier than when moving a large workpiece.

The engine must be placed tightly on the frame. It should have a power of approximately 2.5-3.0 kW and a rpm of about 1500. If you choose a sanding belt speed of approximately 20 m/s, then the diameter of the drums should be about 200 millimeters. Thus, if the engine speed is sufficient, a gearbox for the grinding machine is not required.

One of the two drums will play the role of a drive drum, which should be firmly fixed to the engine shaft, and the other tension drum should rotate freely around a fixed axis on bearings. The table on the side of the driven drum should have a certain bevel, which will ensure smooth contact of the sanding belt with the surface of the work table, this is especially true for a glued joint.

You can make a tension drum and a drum that guides the sanding belt from chipboard. To do this, you need to cut blanks from the slab with overall dimensions of 200 by 200 millimeters and assemble a package of 240 millimeters from them. Square tiles or their package should be folded on an axis and machined to a diameter of about 200 millimeters.

Remember that in the center the diameter of the drum should be 2-3 millimeters larger than at the edges. With a similar surface geometry, the flexible sanding belt will be located in the middle of the drum. The optimal tape width is 200 millimeters. From a roll of emery cloth that is 1 meter wide, you can easily glue 5 similar tapes together.

Glue cutting tool it is necessary end-to-end, placing a thin dense material, for example, a tarpaulin, underneath. It is recommended to use the highest quality glue you can get. To the skating rinks in mandatory stretch the rubber, the width of which reaches 30 millimeters. Rubber can be taken from the inner tubes of a moped or bicycle.

On a homemade belt sanding machine, in addition to grinding wooden products, for which it is actually intended, it is very convenient to sharpen tools with cutting surfaces - chisels, knives, axes, pruners. Another advantage of this grinding machine is the ability to work with parts that have a curved surface - to do this, you need to grind the workpiece with the back side of the work belt.

A useful thing in the workshop. For those who work with wood, such a device is a must-have, as it is universal, which greatly simplifies the work. But, unfortunately, such machines are quite expensive and therefore have to be invented. This article will talk about a functional, and most importantly convenient, grinding machine, with detailed drawings and photos. Each point is discussed in detail, and if something is not clear, you can always watch the video.

Introduction

There are many options for different grinding machines, but the most important thing is that it is easy to use. This design option meets many requirements and impresses with its simplicity, but at the same time functionality. A distinctive feature of this design is that a conventional drill is used as a driving element, and its installation takes less than one minute, and most importantly, it is easy to remove from the machine and use for your own purposes.

This article will describe everything step by step steps creating a universal grinding machine, but before starting work, you need to prepare well and calculate the full scope of work.

Preparation for work

You can’t do without tools, so you need to prepare high-quality and serviceable hand and power tools, namely:

  • A sawing machine (or from a jigsaw;
  • Milling machine;
  • Grinding machine or ;
  • Drill or (and of course);
  • Jigsaw with ;
  • Drilling machine;
  • . for example, the “Cyclone” type.
  • Various hand tools(tape tape, pencil, screwdriver, etc.).

Before starting work, it is important that all the material is at hand, then the work will proceed quickly and smoothly. Thus, to assemble a stationary grinding machine we will need the following material:

  • sheet (size 25*36.5 cm);
  • fasteners (bolts, nuts, screws, etc.); sealed bearings;
  • furniture footers;
  • metal stand;
  • sanding belt.

In order to make any workpiece from, you need to know the basic characteristics of the material. In the article "" some characteristics were given (dependence of thickness, number of layers, deviations, thickness variations, etc.). An additional table might be helpful:

Plywood grade

 Bakelized plywood Aviation plywood Construction plywood
Sheet thickness* 5-18 1-12
Water resistance High Above average FSF – increased FC – average
Density, kg/m3 About 1,000 500-650 Depending on the type of wood: softwood plywood density– 660density of hardwood plywood - 800
Tensile strength, MPa Along the fibers – 80 Shirts – 65-80 —

Main structural elements

The manufactured machine has quite simple design, and consists of the following elements:

  1. Base;
  2. Tabletop for placing workpieces;
  3. Two side housing covers;
  4. One driving roller and two driven ones;
  5. Mechanism for adjusting the position of the tape.

Making a grinding machine

Side covers

Before making a cut, you need to apply markings. To do this, you need to decide on the size and shape of the workpiece itself. Below is a detailed drawing of the part.

An example of marking the side cover of a grinding machine is shown in the photo below.

For more convenient sawing of internal parts and critical elements, you can drill holes with a jigsaw and a sawing machine. For accurate and high-quality work, it is better to use a substrate. Please note that the cutout for the movable roller is needed only on one workpiece.

The main parts of the part requiring holes are shown in the photo.

Afterwards, on only one of the blanks, we cut out a smaller hole for the bracket. It is better to do the work with a jigsaw, and it is better to secure the structure with clamps.

The second part of the lid is not needed yet, since the main work will be carried out on one part of the wall. After which you can begin gluing the base for the bearings. To glue the squares together, use regular PVA glue, wood glue or any other intended for wood. The size of the wooden squares is 5*5 centimeters.

After which, the glued elements must be secured with clamps or left under pressure for a while. It is important to ensure reliable contact when gluing workpieces.

It's time to cut out the hole for the bearing. Best of all, a router will handle this task. After cutting, excess elements can be removed using a knife or other cutting tool.

As a result, if all the work was done correctly, you will get the following design.

We press in the bearings on both sides, as shown in the photographs. These bearings will be designed for the drive shaft.

After that, using a hexagon, the fittings are installed in a pre-prepared hole.

Just as in the case of bearings, furniture fittings are installed on both sides.

The next step that needs to be done is to install the shelves. The largest shelf consists of a board and has a size of 32.5 * 6.5 cm and a thickness of 1 cm. It is installed using four screws, as shown in the photo.

The second shelf measures 22.8*6.5 cm, with the same thickness. Attaches with three self-tapping screws.

And the last shelf has dimensions of 10.2 * 65 cm, 1 cm thick and is attached to two self-tapping screws.

After which, both workpieces are completed, and now you can move on to the next stage - assembling the mechanism for adjusting the position of the sanding belt.

Assembling the belt position adjustment mechanism

We begin assembling the main moving element of the stationary grinding machine. To begin with, you will need to glue two bars together. The larger beam measures 6.8*4 cm, the smaller one measures 3.2*3.8 cm. The smaller beam must be located exactly in the center of the larger one.

While the moving element dries, you can begin gluing the retainer. To do this, you need to glue two cubes measuring 2*2 cm and thickness 1.8 cm on two sides of a 7.8*2 cm beam. It should look like in the photo.


Next, we drill a hole on the side, but not through it, and also install the footers. A handle will be inserted into it to adjust the tape. After all the steps completed, the part is ready.

Then, you need to make a hole for the drive nut in the clamp, this is done in two stages. The first involves drilling out the seat with a feather drill or a Forstner drill.

If all steps are performed correctly, you will get the same workpiece as shown in the picture below.

Everything is ready, and you can start pressing in the nut. It is important to install the nut evenly so that it “sits” in the special hole and is “flush”. It should look like this:

The blanks are completed, you just need to place them on the wall of the future grinding machine. But before that, you need to drill a hole in the side. It will help you install the sanding belt position adjustment knob.

We install the latch, with a movable element, using two self-tapping screws. It is important that the moving part is placed on the correct side. The fitting should be directed towards the hole. This is what should happen in the end.

Two blanks will be enough. We drill a through hole in the middle and insert a bolt into it. After that, we install the handles in the side fitting of the movable element and in the drive nut of the clamp. As a result, we get the following design.

Making rollers

Rollers are the movable and most important element of the entire system. Therefore, it is important to make them as high quality as possible. As with the handles, we make them using a core drill. You need to cut out six parts of the driven rollers.

Just like other parts of the stationary sander, they can be glued together with PVA glue or wood glue. To compress the workpieces when gluing, it is better to use screws and nuts with washers. The photo below shows how to do this.

After gluing, you can remove the screws and prepare the rollers for further work. In the driven rollers you need to install two bearings, in the drive roller you need to install two drive nuts. The procedure was carried out before, so there is no point in describing it again. The result should be the following:

Everything is installed, which means you can tighten one bolt and nut on all the rollers of the grinding machine. It is important to tighten the nuts so that the bearing can move freely. Now you can proceed to the penultimate stage.

Installation of rollers

First, you need to install the drive roller into the cover where the bearing is located. Just as shown in the photo.

The last shelf is attached to the top and our machine takes on a similar shape. The time has come for the final stage.

The final stage

The first thing you need to do is attach the second cover of the machine on the hinges.

Then place the base of the machine on self-tapping screws for greater stability.

After which the sanding belt is installed and fixed.

Then the table top is made. It is important that the tape moves freely and should not catch.

And at the end, a stand for the drill is installed.

Conclusion

Bottom line

Our handmade grinding machine is ready! If you follow all the instructions described above, you will get a real friend and assistant who will rightfully take its rightful place in the workshop.

Dimensions

Here is a table with the overall dimensions of our homemade tool:

Dimensions of walls and adjacent elements:

Bracket element dimensions:




Tabletop dimensions: VKontakte

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 of 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 any 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. Mount them in the lathe and turn them 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 upper 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.

It is not necessary 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.

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.

Old household motors are in no way suitable for a belt grinder. 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.