Sanding wood is a mandatory procedure prior to finishing. To perform the work, special machines are used that operate on different principles and grind the material in different directions. However, the price of such devices is quite high. For a home craftsman, it is not always advisable to purchase equipment that will be used occasionally. It is better to make a wood grinding machine with your own hands, which will cost much less and will allow you to get a completely effective device.
Operating principle
There are three main designs of wood sanding machines:
- Disk.
- Tape.
- Drum.
1-Disk machine 2-Belt machine 3-Drum machine
A disk machine is a rotating disk on the surface of which an abrasive (sandpaper) is fixed. Grinding is done by applying the edges or side surfaces of the part to the disk, for which a table or support bar is installed approximately in the middle. This design is optimal for sanding straight or convex edges.
The belt type consists of two drums mounted either vertically or horizontally. One of them is drive, the second is tension. The abrasive is a loop of sandpaper that is glued together using a template. The loop is installed on both drums and tensioned. After starting the engine, it forms a constantly moving strip of abrasive. Sanding occurs by pressing the tape to the surface of the part using a special clamp (“iron”). It moves left and right, ensuring that the sandpaper is pressed against all areas of the surface being treated.
The drum machine is used for grinding concave edges. It is a rotating cylinder of relatively small diameter (6-8 cm), on which the abrasive is installed.
The simplest designs are disk and drum. Making a tape machine is much more complicated, but its efficiency is much greater. Such installations allow high-quality grinding of panels and large-area parts, ensuring high surface quality.
To install a tape machine in a workshop, you will need a large area, which must be taken into account when choosing a design.
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, there is always a use for this equipment in everyday life. Some people have a bench sanding machine for metal processing in their garage. Others have several wood grinding machines of different designs installed in their workshop. Still others own a universal, combined 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.
The market offers a fairly wide range of all kinds of similar equipment from many manufacturers. And their prices are quite reasonable. But these are general purpose machines. And if a person runs his own business, or has a hobby, then he needs a specially specialized machine. Here the price has already increased several times.
For this reason, or based on their 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 simple sharpening of kitchen knives is 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.
Features and Specifications
The main feature of wood sanding machines is a specific method for adjusting the quality of processing. It occurs by changing the grain size of the abrasive. Typically, the process begins with sandpaper with a coarse grain, then successively reduces its size and completes the procedure by sanding with fine sandpaper. In total, 2-3 shifts are used, but there may be more gradual methods.
The second feature is the method of installing the abrasive. If a pre-glued loop is installed on a belt machine, then a circle of sandpaper must be secured to a plane on the disk structures. The best way is to use Velcro, but the easiest way is to stick the abrasive onto adhesive or double-sided tape. The second method is simpler, but also more expensive.
The technical characteristics of each machine are slightly different from each other.
For disk installations:
- Diameter of the working body.
- Rotational speed.
For band machines:
- Tape width.
- The size of the working base (the distance between the centers of the drive and tension drums).
- Loop speed.
- Range of movement of the desktop in the vertical and horizontal plane.
- Length of the blank for gluing the loop.
For drum machines:
- Working cylinder diameter.
- Cylinder height.
- Rotational speed.
All these parameters depend on the planned productivity, the size of the installations, and the size of the parts being processed. It is necessary to take into account the volume of expected work, the size of the parts, and the specifics of processing.
Expert opinion
Levin Dmitry Konstantinovich
The cleaner the surface should be as a result of grinding, the better the quality of the machine should be made. Beats, irregularities and other defects will cause scratches that can significantly deteriorate the quality of processing.
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:
- The abrasive side of the belt must be adjusted very precisely so that only the workpiece that is being sanded touches it.
- The tape must be evenly tensioned at any time and regardless of the type of work.
- The speed of movement of the machine should be different and should depend only on one thing: the type of part and the nature of the grinding.
Advantages and disadvantages
The advantages of grinding machines include:
- Quality and speed of processing.
- High performance.
- The ability to obtain the surface of the desired roughness.
- The ability to process not only the wood itself, but also pre-grind the finishing layer.
The disadvantages are:
- Release of a large amount of dust, requiring the organization of a dust removal system.
- Large quantities of consumables (abrasive) of several sizes.
- Difficult to manufacture and maintain (this especially applies to belt installations).
Considering the existing shortcomings, before starting assembly, you need to decide how necessary the machine is. If it will be used only occasionally, it is not practical to spend time on manufacturing - you can get by with hand tools.
What is necessary?
So, before you start making a belt sander from an angle grinder, you need to prepare all the component materials and tools. For this you will need:
- the grinder itself, which is the basis of the future device;
- bolts and nuts;
- Sheet steel;
- springs;
- square tubes.
Among the tools you will need:
- a vice on which most of the operations in the manufacture of the grinder will be carried out;
- drill;
- hammer;
- welding;
- set of wrenches;
- roulette.
DIY options
Let's look at how to assemble different types of grinding machines:
Disk
The easiest way to create a disk machine is an electric drill mounted on a table with a grinding wheel installed. Another available option is to fabricate and install a sanding disc onto the circular saw shaft. In this case, it is necessary to assemble a device to reduce the rotation speed (a system of reducing pulleys or an electronic device).
If you need to make a machine from scratch, you will have to assemble:
- Support platform with stand for electric motor.
- Stand or work table.
- A disc for installing abrasives with the possibility of mounting on the motor shaft.
Expert opinion
Levin Dmitry Konstantinovich
As a rule, plywood disks are made, which are installed on the shaft using a coupling and threaded fastening. This unit will have to be ordered from a turner. The height of the table should be such that the disk mount is below its plane.
Tape
To assemble such a grinding installation, you need to proceed in stages:
- Assemble the frame. It consists of two pedestals on which a drive drum with an electric motor and a drive drum with a tension device will be installed.
- Connect the cabinets with a frame on which the desktop will move (horizontally, perpendicular to the movement of the belt).
- Assemble a work table lifting device to adjust the height when processing large parts.
- Make a device for moving the “iron”.
- Make a protective casing and connect the dust extraction system pipe to it.
- Assemble the electrical system for starting and stopping the machine (start button, automatic machine, etc.).
The greatest complexity is presented by the drums for installing the abrasive, the tension devices for them and the table lifting/lowering system. They will have to be partially ordered from a turner, and partially assembled on site. It is unlikely that you will be able to find ready-made units, since they are very specific and rarely found on common mechanisms.
Drum machine
The simplest option would be to install the electric motor so that its shaft passes through the hole in the workbench. To do this, you need to assemble the frame in the form of a support platform with a stand and a vertical plate. Holes are made on it and the electric motor is attached. The drum is installed on the shaft using a threaded fastener. The easiest way to make it is from wood, or use a section from a plastic sewer pipe. Sandpaper is wrapped around the drum and secured with screws or small nails.
In all cases, it is necessary to ensure a low speed of movement of the abrasive. It is necessary to choose electric motors with a number of revolutions of no more than 1000. Band machines are especially dangerous. At high speeds, the edge of the belt can cut through any material and cause serious injury.
Material selection
The easiest way to make a machine at home is from wood. However, it should be borne in mind that it is light in weight and is not able to dampen the beating of the machine. Therefore, you will need high rigidity of the connections and strong fastening of the frame to the floor. Another option is a metal frame made from an angle, channel or I-beam.
Such a machine is more massive, heavier, vibration and beating will be easier to dampen. However, you will need welding work, cutting workpieces and other operations with metal, which is not accessible to everyone. The final choice is determined by the capabilities and preferences of the owner.
Construction of a homemade belt sanding machine
Grinding machine device.
The main parts of the machine are as follows:
- 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.
https://youtu.be/GwylmVI7PG8
Diagram of the grinding machine.
Stages of work:
- We make the frame of the base or bed. — we cut the corners according to the dimensions of the bed; — We weld the frame and corners; — we fix a chipboard board at the bottom of the frame to reduce vibration during operation.
- 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;
- We fix the electric motor to the working area lifting system.
- We fix the gear supports.
- We install a tape with an abrasive coating. — cut the tape with a margin of a few centimeters at an angle of 45°; — we glue it together with an overlap and coat the sides with glue with the abrasive washed off with water; — dry the gluing area with a hairdryer;
- We are preparing for a test launch of the machine. — we treat all machine parts with machine oil; — supply electrical power; - We do a trial run.
Popular models of factory machines
Let's look at the most popular models of grinding machines:
Disc (disc)
Jet JDS-12 220 V
Stationary machine with a massive cast iron frame. Capable of dampening vibration or beating when it occurs. Disc diameter - 30 cm. Engine speed - 1400 rpm. The table can be tilted from +15° to -45°.
S089A
Chinese disc grinding machine. Compact type, with a disc diameter of 305 mm and a power of 800 W. The base is made of cast iron. The work table has a slot for moving the stop with the ability to rotate at a certain angle to the disk.
Einhell TC-US 400
A combined type machine combining disc and belt types. The diameter of the disk is 15 cm, the blank for gluing the loop is 914 by 100 mm. The belt speed is 276 mmmin, the drum rotation speed is 1400 rpm.
Tape
Jet EHVS-80
Vertical type machine (drum axes). Tape speed - 16 ms. The blank for the loop is 116 by 2260 mm. Machine weight - 110 kg;
ShLPS-6M
Stationary grinding machine with horizontal belt arrangement. The diameter of the pulleys is 34 cm. The maximum size of the part during processing is length 2.5 m, width - 1 m. Table lift height - up to 40 cm. Belt blank - 7470x160 mm. Weight - 670 kg.
Drums
Jet JBOS-5 220 V
A drum machine that provides spindle rotation with simultaneous reciprocating movement in a vertical plane. Rotation speed - 1400 rpm, number of lifts - 30 pcs.min. The desktop can be tilted up to 30° to the horizontal;
Proma BO-25 25000370
Compact grinder with 370 W power. Equipped with a square work table measuring 37 by 37 cm, with the ability to tilt up to 45°. Spindle rotation speed - 1400 rpm. The weight of the machine is 35 kg.
The number of designs and models of grinding machines is constantly increasing. New developments are appearing with increased processing capabilities and quality. Manufacturers take into account the shortcomings of existing devices and produce more advanced, modified samples.
Making a grinder from a drill
To turn an ordinary household electric drill into a grinding machine, you need to equip it with a special attachment - a working drum or a special support plate, depending on the task at hand.
The support or sanding pad is a plastic or rubber base with sandpaper glued on and a shank for clamping into the drill chuck. Discs with a flexible shaft are suitable for working with a loose drill, while those with a rigid shaft are best used only for a well-secured drill.
Sanding drums for a household drill are structurally a regular cylinder, a shank and sandpaper glued to the cylinder. When using drums, the working surface of the grinder is parallel to the axis of rotation.
Care and maintenance
The operation of grinding machines is accompanied by the release of large quantities of dust. To remove it, powerful local exhaust units are used. If they are disabled, the equipment cannot be used - this threatens the health of the employee. However, it is impossible to completely get rid of dust, so after finishing work you should immediately thoroughly clean the machine using an industrial vacuum cleaner and brush.
The abrasive is replaced as it fails or according to technological processing conditions. To maintain productivity, you need to have a supply of ready-made discs with installed sandpaper, or glued sanding belts of different types. They are stored in a closed cabinet so that dust does not accumulate and the surface of the tape does not deform.
During operation, a significant charge of static electricity is generated. To remove it, high-quality grounding is required. It is necessary to periodically check its condition and restore if necessary.
Do you want to assemble a grinding machine yourself?
Of course! Not particularly
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 with your hands while the machine and working surface are operating.
- 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.
Let's sum it up
A homemade grinding machine requires sufficient space in the workshop and requires significant quantities of abrasive. When deciding to independently manufacture such a device, you should carefully weigh the need for this and your capabilities.
There are three types of design:
- Disc machines . Easy to make, can be made from a circular saw.
- Drums . Compact devices, ideal for grinding the edges of concave parts.
- Tape . Capable of grinding planes, providing high quality surfaces. They are the most difficult to manufacture due to the large number of specific components and parts.
Manufacturing a machine will require the use of certain tools and materials, the choice of which is determined by the capabilities of the owner. You won’t be able to do it entirely on your own; some components will have to be ordered from a turner. It is important to ensure a low speed of movement of the abrasive so as not to create the risk of injury or destruction of the workpiece.
Areas of use
The grinder is good and useful everywhere, including in the household - from competently sharpening 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.
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When carrying out 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 wide variety of manufacturing 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, removing local irregularities in the form of depressions and elevations, removing burrs and removing local deposits of varnish and primer, removing burrs, internal grinding and grinding of curves.
Belt grinding machines for metal work with various materials and formats that are common in metalworking: plain and alloy steel, non-ferrous metals in the form of quadrangular, round and flat workpieces. Grinding machines allow you to grind round timber and large diameter pipes efficiently and with minimal time.
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 leader and the other is the slave. 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, providing different modes of 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 of 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 grinding machines are usually equipped with special powerful hoods that remove most of it during the technological process itself. 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 an 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 wood dust generated during the grinding process is not able to get clogged between their grains. 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 the non-working surface of the skin there is a marking 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 with hot water over a distance of 80 to 100 millimeters, then the other end of the tape is applied to the exposed base lubricated 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 sandpaper in the form of a circle according to a template, the diameter of which is 60 - 80 millimeters larger than the diameter of the disc. 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 sanding tools that are placed in series on a bed 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 chosen 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 evenly on a metal milling machine; it is required for attaching 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 work table is, the more options you will have when choosing a technological method for grinding and processing the 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 a package of them 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.
The cutting tool must be glued end-to-end, with a thin, dense material, for example, a tarpaulin, placed underneath. It is recommended to use the highest quality glue you can get. Be sure to stretch rubber onto the rollers, 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 working belt.
