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.
Tools
Anyone who was involved in construction work, repairs, restoration of old doors, windows, window sills, etc., was certainly faced with the need for the working surface to be flat, smooth and sliding. Previously, we took sandpaper in our hands, if the surface was large, then we strengthened the sandpaper on a wooden trowel and, stocking up with great patience, began the monotonous, monotonous work of sanding. Now, a lot of devices, so-called grinding machines and machines, have been created to help professionals and amateurs. Using them for certain grinding operations, we make the process of manual labor easier for ourselves by transferring some of the simple functions to the machine. Today we will talk about grinding machines that are used for processing wooden products.
Table of contents:
Purpose, classification and areas of application of grinding machines
Grinding machines are used to reduce the surface roughness of workpieces, as well as to obtain accurate dimensions. Typically, grinding is the final stage of processing pre-prepared parts.
When working on grinding machines, grinding materials and tools are used.
Sanding materials – special powders, pastes, sanding cloths.
Grinding tools include cutting, polishing and grinding tools, wheels, bars and segments.
Depending on their purpose, machines are divided into several types:
— specialized grinding machines.
The classification of machines is based on the following characteristics:
-type of surface to be ground (internal or external, cylindrical or flat);
- type of parts that this machine can process (cylinders, shafts, rollers, racks, etc.);
— design features of machines (centerless, planetary, two-column);
— features of the elements of the processed parts (slots, threads, profiles, etc.).
The area in which grinding machines are used is very wide. Recent advances in machine tool construction, as well as the production of parts by casting, stamping, rolling, turning and carpentry, make it possible to use grinding machines instead of turning and milling machines (horizontal boring machines). Nowadays grinding machines can perform the following operations:
— cutting and peeling of workpieces;
— precise processing of various planes, wheel teeth, rotational surfaces, etc.;
Drum grinding machine: purpose and main elements
The drum grinding machine belongs to the surface grinding machine in type, and to the calibration grinding machine by class. The main tool of the machine is the grinding wheel, which is made in the shape of a cylinder (drum). Typically this machine is used for woodworking. Using it, it is very convenient to sand and calibrate boards, slats and other flat and long wooden parts, such as panel surfaces made of chipboard, MDF, solid wood, veneer, etc.
The main elements of a drum grinding machine are:
— a bed on which all components and parts of the machine are mounted;
— a motor that ensures rotation of the grinding and feeding drums;
- a mechanism that ensures a change in the rotation speed of the feed drum
— device for dust removal;
— mechanism for changing the height of the grinding drum.
You can see how a drum sanding machine works in the video.
Some models of drum-type grinding machines presented on the Russian market
Today, on the Russian market of grinding equipment, the drum grinding machines section presents products from various manufacturers. The leading place here is occupied by products under the JET brand. The American company JET, part of the Swiss holding WMH Tool Group AG, today presents the following industrial and household drum grinding machines:
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.
Correct operation of equipment is the key to successful operation
The process of installing a wood sanding machine with your own hands must meet all the requirements of safety regulations. Every master should remember this in order to prevent injuries in the workplace:
The manufactured machine is made from high-quality materials and has a reliable design
During surface treatment, do not touch the working tool or moving parts of the mechanism with your hands. When working with homemade grinding equipment, you need to wear safety glasses. For woodworking, you cannot use discs designed for metal processing, since they have a different surface structure. Before starting work, it is important to check the serviceability of the structural parts. The use of a protective guard for grinding wheels increases work safety.
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.
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.
The simplest grinders based on low-power electric motors
Somewhere in the far corners of the garage there may be a weak motor stored, which was forgotten as unnecessary. And it can be turned into a small section. a device that is useful in some cases. The alteration is simple, the main thing is the grinding wheel. In its role, they use a factory one, adapted to the device, or make it independently from a suitable material.
Winchester from a computer in an unusual role
An old, outdated PC, which is covered with dust as it is no longer needed, will now surprise no one. But it contains a unit that will still serve in the household - this is a hard drive. It is equipped with an electric drive, which is used to manufacture the simplest electric machine.
Winchester grinding machine - installation sequence
The steps are simple:
- Disassemble the device, remove the cover and remove everything that is on the left side of the disks.
- Draw a 9 cm circle on abrasive paper and cut it off. Where the compass leg stood, make a hole the size of the spindle. Place double-sided tape on the hard drive plate and secure with sandpaper.
- To protect the operator's eyes, a screen made of aluminum can is installed. Connect to the computer's power supply.
The design will not surprise you with its power, but you can sharpen a knife or a small drill.
Polishing device from a car electric motor
You may find fan motors in the garage. It can be used to make cosmetic repairs to your car and for other household purposes. A neat little sander will eliminate the need to buy an expensive orbital unit to smooth out a small scratch or chip yourself, then paint.
There is a power source in the garage - it's a car battery. Multi-core copper wiring is required of such length that it reaches anywhere in the machine. The engine is powered by placing alligator clips onto the battery terminals or through the cigarette lighter socket. A toggle switch is screwed to the motor with electrical tape to control the device.
A car electric motor is useful for a small electric motor
The working body is a circle. It is better to use a ready-made one with Velcro, which is sold for an angle grinder. Only the fastening needs to be done differently. There are many options, but in any case it is necessary to grind the sleeve. Its internal diameter must correspond to the size of the electric motor shaft, and the mating must be the same - key or thread.
When you plan to use the device not only in the garage, they make a portable version. A household battery is used as a power source. Both the motor and the switch are mounted on a piece of plywood, the wires are fixed with staples. With this device you can sand wood and metal surfaces and perform body work.
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.
General information
Types of grinding machines
Modern manufacturers can provide three types of machine designs, namely belt, disk and cylinder. Each species has special, highly specific varieties.
For example, belt sanding machines are produced in the following design:
- Narrow-belt (you can grind wooden structures that have complex geometric shapes).
- Devices equipped with a fixed table (can only process wood pieces that have a flat, rectangular surface).
- Machines that are equipped with a freely moving bed (it is used for grinding large wooden structures - panels, doors and slopes).
The nature of the tasks that can be solved by such a device determines the class of equipment.
There are main classes (or “models” as they are also called), and these are:
- Belt grinding machines.
- Vibrating tools, for example, delta grinders.
- Disc-type grinding machines (eccentric and orbital).
- Special devices for angular grinding.
- Combined type grinding systems.
Despite the variety of ready-made factory tools, amateur craftsmen prefer for home operations to use a machine for wood and its grinding, which will be made by hand.
Operating principle
The operation of a belt-type grinding machine is based on the principle of counter-movements of the abrasive belt, which is located on two rotating drums, and the wood part being processed. Both drums are located at some distance from the desktop surface.
Incorrect selection of parameters greatly impairs the quality of grinding. For example, with a low pressure on the workpiece or a high rotation speed of the main drum, certain places on the workpiece will remain unprocessed, that is, they will not be polished. Conversely, with very strong pressure of the tape on the surface and low speed of the tape, burns may appear and even the color of the wood may change. For this reason, when assembling a mini grinding machine with your own hands, you should provide the ability to adjust the parameters.
Design Features
The machine design will depend on the chosen principle for processing the part. If you have chosen the principle of belt grinding, then the machine will contain such elements as an electric motor, two shafts (driven and driven), a housing, a base (bed), as well as a working surface and an abrasive belt. In disk-type machines on a frame with an engine, discs are used as a grinding device, which rotate with abrasive wheels attached to them.
Application area
Each of the manufactured machines will perform a predetermined list of operations. The drum-type system will produce very high-quality sanding on wood flat pieces, and it can also sand particle board, MDF or OSB, even if they are covered with veneer. Processing of large, long, non-standard wood products (for example, linear structures) is done using profile grinding equipment. Finished workpieces can be transported to the grinding unit using a transport chain. To grind the surface of wood products that have a complex geometric shape (artwork or decorative frames), belt sanding machines are used, which are equipped with a freely moving table.
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
Remodeling household power tools
Almost every owner has an angle grinder. It can be used for rough finishing - cleaning rust from metal and walls before plastering. Not suitable for delicate work, for example, bodywork - the speed is too high. One careless movement and there is a hole in the car. If you equip it with a voltage regulator, which is found on professional models, then delicate grinding will be possible for a household angle grinder.
Anyone who has at least a little knowledge of radio engineering will assemble the device with their own hands. You will need running parts that can be easily purchased or soldered from old products. No explanation is needed for anyone who can read electrical diagrams.
Diagram of a homemade speed controller for an angle grinder.
The operating procedure is as follows:
- soldered using a printed circuit board or surface mounting;
- thyristors are installed on radiators;
- carry out testing with a 40–60 W light bulb (it should smoothly change brightness when turning the trimming resistor);
- After successful testing, the device is mounted under the tool housing.
The proposed circuit is simple; it is connected to the mains power supply of the angle grinder.
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.
