Upon closer examination, it turned out to be excellent material.
External diameter 45 mm. Inner diameter 30 mm. The thickness of the rubber coating is 3 mm. The thickness of the duralumin tube is 4 mm.
I cut off a 40 mm piece, gave it to a turner, who machined the spaces for the 32 mm bearings and, at the same time, lightly machined the barrel.
A crown for drilling holes for sockets. Diameter 80 mm. Cost 45 Nr. Plus a victorious drill in the weld. Easy tuning from a turner led to this result.
Tape 533 x 75 mm, cut lengthwise/in half. Fitting
A piece of tile also went into use.
Result
When I did it I was afraid that the engine power would be insufficient. Nothing like that. It gnaws metal (quick cutter, file) like a beast. Satisfied. But I have already started to improve it. I want to make it possible to use 610 mm tapes. I hope to finish it next week. Of course I'll show you.
Grinder (English) literally – crusher. Meat grinder is a meat grinder, rock (stone) grinder is a stone crusher; stick (wood) grinder – garden crusher of branches and twigs into chips. But there is also a completely unambiguous meaning of the word grinder: in mechanical engineering and metalworking it is grinding machine. A useful household item. For example, it is impossible to guide a dull meat grinder knife on a whetstone manually. On a manual knife sharpener - somehow possible, having solid working skills. And on the grinder - no problem. The same thing - if you need to polish a part complex shape without disturbing her profile. Either just sharpen the scissors or professional knife. It is best to edit various types of wood and metal cutters on a grinder. It is quite possible to design and assemble a grinder with your own hands, without having complex equipment and skills to work on it. In terms of money, this will mean savings of 50-90 thousand rubles. up to 3-6 thousand USD.
To make a grinder yourself, you will need to order a maximum of 4-5 turned parts, and it is often possible to do without external turning at all. For example, how to make a simple grinder literally out of trash, see the video below:
Video: DIY belt grinder made from trash
Or another option, how to make a stronger and more durable grinder from scrap metal:
Video: scrap metal grinder
Disc or tape? And drive
There are almost more types of grinding machines used in industry than lathes. The emery known to all craftsmen - a motor with a pair of grinding wheels (or one wheel) - is also a grinder. For yourself at home, it makes sense to make either a disk end grinder (plate grinder) or a belt grinder. In the first, the abrasive is applied to a rotating HDD; in the second - on an elastic band running around a system of pulleys and rollers. Disc is more suitable for grinding simple wooden parts and coarse or medium purity - metal. Using a belt grinder, it is also possible to produce precise and clean finishing of profiled parts of complex shapes, incl. large-sized, see below.
A disk grinder is very easily obtained from the same emery or a motor of suitable power, see below. You need to order an adapter from the electric motor shaft to the disc shank grinding wheel on a metal base. Or under a clamping chuck, then on the same motor it will be possible to build a mini lathe, see figure:
A worn-out “plate” is suitable: a disk made of thin (4-6 mm) fibrous plastic is glued to the edge of its side, and an abrasive is placed on it. How to make an end grinder, see next. video clip.
Video: homemade end grinder
The difference between a disk and tape grinder is not only in the possibilities of use. If we take ordinary household crafts, then for a disk grinder a drive power of 250-300 W on the shaft is enough. For small wooden parts - and 150-170 W. This is a motor from an old washing machine, a straight (ordinary) drill or a screwdriver. But for a belt grinder you will need an engine from 450-500 W: three-phase with batteries of starting and operating capacitors. If you plan to process large items, then the motor power is from 1-1.2 kW. Moreover, capacitor batteries for both will cost not much less than the engine itself.
Note: a 100-200 W drive uses a mini-belt grinder (see below) for precise knife dressing, grinding/polishing jewelry, etc.
A drill or screwdriver as a grinder drive is also convenient in that it allows you to quickly change the speed of movement of the abrasive (see below) using a standard speed controller. You just need, firstly, to make a holder for the drill that rigidly fixes the tool. Secondly, an elastic transition coupling from the drill to the disk shank, because It is difficult to achieve their precise alignment without special equipment, and runout will negate the accuracy of processing and can damage the drive tool.
Drawings of a drill holder for using it as a home drive metal cutting machine are given on the left in the figure:
Since shock and irregular alternating loads on the drive in a grinder are an order of magnitude lower than, say, in lathe, the drill holder for it can be made of hard wood, plywood, chipboard, MDF, on the right in Fig. The diameter of the mounting (large) hole is along the neck of the drill. It is highly advisable to use a drill without impact mechanism and with a steel shell on the neck (for installing the front handle).
coupling
For the adapter coupling, you will need a piece of steel rod (not necessarily turned) of the same diameter as the shank of the grinder drive shaft, and a piece of PVC-reinforced hose (garden irrigation) with a clearance such that it stretches tightly over the rod and the shank. The length of the “free” hose (between the ends of the rod and the shank in it) is 3-5 cm. The length of the protruding part of the rod should be sufficient for reliable clamping in the drill chuck. After assembling the coupling in place, the hose on the shank and rod is tightened tightly with clamps; can be wired. Such a coupling completely counteracts the misalignment of the drive and driven shaft up to 1-1.5 mm.
Tape is still better
A belt grinder allows you to do everything a disk grinder can do, and much more. Therefore, next we will focus on how to make a belt sanding machine with your own hands. Amateurs, focusing on industrial designs, sometimes make very intricate grinders, see figure:
And this is justified: the design and kinematics of the belt grinder are very flexible, which allows you to successfully use available materials and old scrap metal. You just need to follow 3 principles:
- Do not do as in the second photo from the left: the abrasive side of the tape should only touch the workpiece. Otherwise, the abrasive will eat both the guide rollers and itself. The accuracy and cleanliness of processing during one work operation will be unpredictable;
- The design of the machine must ensure uniform tension of the belt, regardless of the nature of the operation performed;
- The speed of the belt must correspond to the nature of the operation being performed.
Kinematics and design
As mentioned above, there are many designs of grinders. When considering what and how to build a grinder for yourself, it is better to focus on industrial designs designed to be fully mechanized for precise and clean grinding of large-sized profiled parts: once it “sands” the blade of an airplane propeller or wind turbine properly, it can handle any other work.
Kinematic diagrams of grinders for the specified purpose are shown in Fig.:
Basic kinematic diagrams of belt grinding machines (grinders)
Pos. A is the most complex and perfect, with three rocker arms. If the length of the tension roller rocker arm is approx. 2 times less than the working one, then by adjusting the tension of the springs, it is possible to achieve uniform tension of the tape when the working rocker moves 20-30 degrees up and down. By tilting the bypass rocker, firstly, the machine is reconfigured for belts of different lengths. Secondly, in the same way you can quickly change the belt tension for different operations. The working branch of the belt can be any, except for the one running from the drive pulley to the tension roller, i.e. A grinder with 3 rocker arms is both horizontal and vertical.
The scheme with a coaxially swinging rocker arm (item 2) is simpler, cheaper and in terms of processing accuracy is not inferior to the previous one, if the length of the rocker arm between the axes is at least 3 diameters of the workpiece. To reduce the profile by grinding, the stroke of the rocker arm is limited by stops within 10 degrees up and down. The pressure of the belt to the part is most often gravitational, under the weight of a rocker arm with a bypass pulley. The tension of the belt can be quickly changed within certain limits by pulling the rocker up with a weak adjustable spring, partly compensating for its heaviness. The grinder of this scheme can work as a grinder for small parts from a sliding table. In this case, the rocker arm is rigidly fixed horizontally, and work surface the belt will run around the idler pulley. For example, the quite popular BTS50 grinder is made according to the scheme with a coaxial rocker. The disadvantages of the scheme are, firstly, the technologically complex rocker arm joint, which is coaxial with the drive shaft. Secondly, the need for an elastic band: if you make the idler pulley sliding and spring-loaded, the processing accuracy decreases. This drawback when processing small parts is completely eliminated by an additional tension roller, see below.
The scheme with one misaligned rocker arm is used quite rarely in industry, because in principle, it does not allow achieving uniform tape tension. However, it gives accuracy that is quite sufficient at home and allows you to build a very good simple grinder.
What's good for what?
Now let's see what is possible to “squeeze” out of this or that circuit from the point of view of an amateur master. And then we’ll try to figure out how to make a grinder belt ourselves and do without custom-made turned parts.
3 rocker arms
Competent amateurs build their grinders exactly according to the scheme with 3 rocker arms, on the left in Fig. below. Not all propeller blades can be ground, but in this case another advantage of this scheme applies: if the grinder is used as a vertical grinder, then the working branch of the belt is elastic. This allows a skilled craftsman, for example, to direct cutting edges and blades with literally micron precision.
In industrial grinders for home use the 3-rocker arrangement is also widely used (in the center) for the same reasons. Repeating them yourself in most cases is quite possible. For example, the drawings of the KMG grinder, popular abroad, can be downloaded.
The dimensions are, however, inch - the machine is American. For the drive, in any case, it is possible to use an angle drill-grinder (on the right in the figure, it is quite suitable in terms of power) with homemade pulley and rollers, see below.
Note: if you are making a stationary drive, try to get an asynchronous motor at 2-3 speeds from an unusable washing machine with a horizontal tank. Its advantage is low speed. This makes it possible to make a large-diameter drive pulley and thereby eliminate belt slippage. A belt slip during operation is almost certainly a damaged part. Most washing machines have 2-3 speed asynchronous motors for 220 V - Spanish. Shaft power – 600-1000 W. If you come across one, don't forget about the standard phase-shifting capacitor bank.
Coaxial rocker
IN pure form Amateurs do not make grinders with a coaxial rocker. A coaxial hinge is a complicated thing; you can’t make an elastic band yourself, and store-bought ones are expensive. Grinders with a coaxial rocker are most often used at home in the version for small precision work from the table, i.e. with a rigidly fixed horizontal rocker arm. But then the need for a rocker arm as such disappears.
An example is a mini grinder, the drawings of which are given in the figure:
Its features are, firstly, an overhead bed for the tape (item 7), which significantly expands the possibilities of use. For example, the plane iron is straightened on this grinder with an angular stop literally by itself. IN in this case the grinder works, so to speak, like a self-propelled whetstone (emery block). Having removed the bed, we get a grinder with an elastic band for precise grinding/polishing of rounded small parts. Secondly, the tension shaft (item 12). By clamping it to the groove with nuts, we get a relatively fixed tension of the tape for working with the bed. And after releasing the nuts, we switch the grinder to the gravitational belt tension mode for fine work. Drive - not necessarily through a pulley (pos. 11). You can screw it directly onto the drive shaft shank (item 16) from the drill through the adapter coupling, see above.
A specialized tool grinder (for example, for guiding and straightening turning tools) generally loses any semblance of the original design. A high-speed motor is used for it (200-300 W is enough power). The drive pulley is, accordingly, of small diameter. The bypass pulley, on the contrary, is made larger and heavier for inertia. All this together helps reduce tape runout. The tension roller for the same purpose, plus for greater uniformity of belt tension, is moved further away and spring-loaded with a long, not very strong spring. How to make a grinder for processing incisors, see the video below.
Video: grinder for making cutters
One rocker
In amateur practice, grinders with a misaligned rocker arm are good because they do not require precise parts at all. For example, hinges can be made from card loops. At the same time, the processing accuracy remains sufficient for ordinary amateur requests.
In this case, the original scheme is also modified: the rocker arm is rotated 90 degrees, moved upward and spring-loaded, on the left in Fig. It turns out to be a simple vertical grinder. And, importantly, it works without problems with homemade non-stretchable tape. A tension spring (in the center) or a compression spring can provide tension to the tape. Its strength is not so important, as long as the tape does not bend excessively during operation. No adjustments are required during use.
Consumables and parts
The only one consumables for a belt grinder - tape (not counting lubricant for bearings and hinges. The tape can be ordered to the desired length (see at the end), but you can also make it yourself from textile-based emery cloth. It is highly desirable - flexible, unimpregnated. In general, the procedure for making a tape for a do-it-yourself grinder it’s like this:
- We cut the workpiece - a strip of the required length and width.
- We prepare a mandrel (not necessarily round) with a length along the generatrix slightly less than the length of the tape.
- We outline the mandrel with the workpiece inside out.
- We bring the ends of the workpiece exactly end to end and securely fasten them.
- Place a piece of glue stick for a hot glue gun on the joint.
- Heat with a construction hairdryer until the glue melts.
- We apply a patch of thin fabric to the joint.
- Press with something hard through the Teflon film until the glue hardens.
There are three significant points here. The first is to use a rough PET film with a thickness of 25-50 microns (sold) instead of fabric for the patch. It is very durable, but just try running your finger across a PET bottle. Not very slippery? Rough PET film cannot be stretched under tension even over polished metal. And instead of a patch, it is better to seal the back of the tape with a continuous strip of PET film with an overlap of 2-3 cm. The runout of the tape will be no more than 0.05-0.1 mm. This is less than from the thinnest calico and even less than the error in the thickness of the blank skin.
Second, insert the finished tape into the machine and grind something indecent with it without strong pressure. The scar on the seam will be sealed, and the tape will become no worse than the branded one.
But the most important thing is elasticity best glue for gluing the grinder tape, it is not expensive and difficult to use thermo- or mounting, but ordinary PVA. If the tape is covered with a lining along the entire length of the back, then its PVA strength will be more than enough. How to glue PVA grinder tape, see video
Video: gluing grinder tape with PVA glue
Pulley
Formative ( side surface cross-section) of the grinder drive pulley should be straight. If you use a barrel pulley, the belt will bend like a trough along its entire length. The rollers prevent it from slipping, see below, but the generatrix of the pulley must be straight.
A pulley for a grinder that is not intended for particularly precise work, firstly, does not have to be turned. In a scheme with 3 rocker arms, the beating of the belt from its misalignment will go out on the rollers before it reaches the working branch. In a simple vertical grinder, the beating of the belt will be sufficiently damped by the tension spring. Therefore, it is quite possible to make a pulley for a grinder without a machine, see video:
Video: drive wheel on a grinder without a lathe
Secondly, the pulley, rollers and, in general, all the parts of a home grinder can be made from plywood. In production, this is certainly not an option, even if a plywood grinder is offered for free with an additional payment: the grinder needs a salary, and the wooden grinder in the workshop will completely wear out before it pays for it and itself. But you won’t be running a grinder at home every day in 3 shifts. And no tape slips along the plywood pulley. Incl. homemade. So you can safely make a grinder pulley from plywood:
Video: pulley for grinder made of plywood
It is much more important to correctly calculate the diameter of the pulley based on the engine speed and the required belt speed. A running belt that is too slow will tear the material being processed; too fast - it will erase itself without really processing anything. In which case, what tape speed is needed is a separate conversation, and a very difficult one. In general, the finer the abrasive and harder the material being processed, the faster the belt should move. How the belt speed depends on the diameter of the pulley and motor speed, see figure:
Fortunately, for most abrasive-material pairs, the permissible belt speed limits are quite wide, so choosing a pulley for the grinder can be easier:
Video: what wheel is needed for a belt grinder
Rollers
The rollers of the grinder, oddly enough at first glance, are its most important parts. It is the rollers that keep the tape from slipping and ensure its uniform tension across the width. Moreover, there can be only one video in kinematics, see, for example, the video above about the grinder for incisors. Only barrel rollers can cope with this task, see below. But the “trough” of the belt after any roller must straighten before it reaches the working area.
Rollers with flanges (sides, edges) will not hold the tape. The issue here is not only and not so much with the misalignment of the roller axes: the grinder belt, unlike the drive belt, must withstand the loads from the parts being processed without slipping. If you make videos with flanges, then if you barely touch the tape with something, it will creep onto the flange. In the grinder you need to use Type 3 barrel rollers (highlighted in red on the left in the figure).
The dimensions of Type 3 rollers are also given there. It is advisable to take the diameter of the rollers no more than 0.5 of the width of the tape (so that the “trough” does not go far), but not less than 20 mm for turned steel and not less than 35-40 mm for plywood. The tension roller (the probability of the tape slipping from it is greatest), if the working branch of the tape does not come off it, can have a diameter of 0.7-1.2 its width. Plywood rollers are made in the form of a thick shell into which the bearing is pressed; then the roller is mounted on the axle (in the center in the figure) and processed cleanly, see e.g. track. video:
Video: barrel roller for grinder
Not every turner can turn a profile roller barrel exactly according to GOST even on a machine. Meanwhile, there is a way to make videos for the grinder without significant difficulties. The same PVC-reinforced garden hose will help out, on the right in Fig. previously. A section of it is pulled tightly onto a roller blank with a straight generatrix and cut off with a margin along the edges to the thickness of the hose wall. The result is a roller with a complex profile of the generatrix, which holds the tape even better and gives it a smaller “trough”. Don't believe me? Try to get to an airplane or missile graveyard and dig around in them. You will find rollers with exactly the same generatrix profile. Just in mass production rollers complex profile much more expensive than Type 3 barrels.
And another option
All critical parts of the grinder - a solid belt, pulleys with a coating that prevents it from slipping, rollers - can be purchased separately. They won’t be that cheap, but still not thousands of foreign ones and not dozens of native leather jackets. The remaining parts of the grinder, either flat or from corrugated pipes, are made using a regular tabletop drill or drill. Here's where you can order parts for the grinder:
- //www.cora.ru/products.asp?id=4091 – tape. They make lengths and widths according to the customer's wishes. Consult on abrasives and processing modes. Prices are reasonable. Delivery time - questions to Ruposhta.
- //www.equipment.rilkom.ru/01kmpt.htm – spare parts (components) for grinding machines. There is everything, the prices are divine. Delivery - see previous.
- //www.ridgid.spb.ru/goodscat/good/listAll/104434/ – the same, but foreign made. Prices are higher, delivery is the same.
- //www.pk-m.ru/kolesa_i_roliki/privodnye_kolesa/ – drive wheels. You can find ones suitable for grinding.
- //dyplex.by.ru/bader.html, //www.syndic.ru/index.php?option=com_content&task=view&id=36&Itemid=36 – spare parts for grinders. They do not make ribbons to order - choose from the catalogue. Rollers without axles; axles sold separately. The quality is impeccable, but everything is very expensive. Dispatch - within 2 weeks to the border. Then - their customs, our customs, Rusposhta. Total approx. 2 months It may not arrive if some local bureaucrat considers the product sanctioned. In this case, there are no problems with the return of payment due to the complete absence of real opportunities for the average citizen to receive one. (2 ratings, average: 5,00 out of 5)
Among folk craftsmen, one of the most common homemade products is a belt grinder, which is commonly called a grinder, sander. Make necessary details and assembling a grinder with your own hands is generally not difficult, especially for those who have certain design skills and have necessary tool and equipment. Depending on the goals of the home craftsman, as well as the volume and duration of grinding work, the sizes, design and materials from which a homemade grinder is made can be very diverse.
Some create machines that are practically no different from factory ones, using milled parts or complex metallic profile. Others use wood and plywood to make the frame and rollers. In addition, on the Internet you can find many video clips in which the authors demonstrate their grinder made from scrap metal and leftovers. various materials, stored in the yard or workshop. In fact, what the grinder frame is made of does not matter very much. of great importance. The main thing is that it is strong enough, and the rollers are located in the same plane, have free rotation and are securely fixed. The maximum number of revolutions of the grinder drive is also very important, since its main technological parameter - the linear speed of the grinding belt - depends on this. The parts and components necessary for this device can be manufactured with my own hands or buy ready-made ones.
There are many images of 3D models, drawings, sketches and even assembly drawings of grinders posted on the Internet various designs. Each of them has its own characteristics, but in principle they all consist of several main components (see figure below):
- Drive with electric motor.
- The bed is on a stable base.
- Drive pulley.
- Tension roller with tension adjustment mechanism.
- Guide rollers (usually one or two).
- Device for moving and tilting guide rollers.
- Support table.
Before you start designing your grinder, you need to decide on the range of lengths of sanding belts that you plan to use. Both the overall size and layout of the future machine, as well as the characteristics of the tension mechanism and the device for moving the guide rollers, depend on this parameter. The length of the tape used is equal to the sum of the center distances, adjusted for the dimensions of the pulley and rollers, and must take into account the strokes of the adjustment and tension mechanisms.
One of key points when designing a grinder, this is the calculation of the linear speed of movement of the grinding belt, which directly depends on the engine speed and the diameter of the drive pulley.
When grinding various materials, it is necessary to take into account that each of them has its own physical characteristics and therefore must be processed at a certain speed. The maximum grinding speeds for the most common materials are approximately equal (or close), but the lower limits vary significantly (indicators in m/s):
- hardwood and plywood - 15÷30;
- varnish coatings - 5÷15;
- wood soft and coniferous species- 12÷20;
- carbon steel products - 25÷30;
- plastics - 10÷20.
When making a grinder with your own hands, as a rule, old electric motors from household appliances are used (most often from sewing and washing machines), or hand-held power tools (drills and grinders) are used as a drive. That is House master is limited in advance in the choice of engine rotation speed, therefore for him the main design parameter in the design of his machine is the diameter of the drive pulley, on which the linear speed of the sanding belt directly depends.
The drive pulley diameter (in mm) is calculated using the following formula:
Here V is the required speed of the abrasive belt in m/s, and N is the rotation speed of the drive pulley in rpm. Below is a table of the dependence of linear speed on this diameter.
When using your own electric motor to reduce or increase the rotation speed, you can make a drive with a belt drive and pulleys of appropriate diameters. For range control, a stepped pulley is usually used or several replaceable pulleys are made. But the best choice for these purposes is a frequency regulator, the description and diagrams of which can be easily found on the Internet.
If the drive is a power tool, then perhaps the most suitable option there will be a simple electronic regulator. Such a device is inexpensive - 500–800 rubles, but along with the number of revolutions it significantly reduces power.
Homemade grinder with a washing machine engine
With a drive pulley size of 70÷100 mm, the motor for the grinder must spin up to at least 3000 rpm. According to their characteristics, asynchronous electric motors from old automatic washing machines with a power of at least 300 W meet this requirement (albeit not fully). These are quite simple, reliable and unpretentious devices, which are one of the most common used electric motors. Their output shaft has threaded connection, onto which a pulley for driving the grinder is easily attached.
When using commutator motors from next-generation washing machines, you cannot do without a separate speed controller, since their rotation speed usually lies in the range from 11 to 18 thousand revolutions per minute. These compact and powerful devices have their drawback: with constant use under load, their brushes quickly wear out.
In the video (see below), a folk craftsman demonstrates a self-made grinder with a motor from a washing machine, a convenient tensioning device, an electronic speed controller and rollers on bearings with a diameter of 65 mm (a tension roller from a Gazelle). The result is a completely workable option with a high-quality and functional support table, which rotates ninety degrees and moves along guides.
How to make a grinder from a drill
The need for sanding wood and metal products does not occur very rarely. But buying a factory grinder, as a rule, is not economically viable, and making a stationary installation for small volumes of occasional work seems impractical. Therefore, craftsmen quite often use simple in design versions of grinders driven by hand-held power tools. They are usually made from scrap materials, which often include wood, plastic and plywood.
This grinder is easy to make with your own hands, even at home. Moreover, when grinding small products made of wood or plastic, such a device is in no way inferior in its characteristics to a stationary grinder. There should also be no problems with selecting the grinding speed, since most modern drills have a built-in regulator (in extreme cases, you can use an external dimmer). In addition, such a grinder is very simple in its design, so it can be assembled and disassembled as needed.
Do-it-yourself grinder from an angle grinder
A stationary grinder made from an angle grinder is used in the same cases as from a drill, i.e. when it is necessary to perform small occasional work that does not require special quality. But at the same time, the Bulgarian has its own characteristics, which include very high speed drive rotation. Therefore, when using it, a speed controller may be required. Very often, this power tool is used as part of “electric files”: narrow and long belt grinding attachments for grinders, which are used for processing hard to reach places, as well as small holes and openings (see photo below).
The main design difference between an angle grinder and other types of power tools is that its output shaft is turned at an angle of 90º to the axis of the electric motor and, accordingly, to the housing. For this reason, it is called an angle grinder - an angle grinder. This feature is perfect for longitudinal fastening of the drive roller and the “electric file” blade. The result is a tool that is elongated in a line and very comfortable to use. The same attachment for a drill is located at a right angle to the body, which is quite inconvenient for work.
Making a grinder from Chapai
Grinders “From Chapai” ( trademark ByChapay©) enjoy absolute authority among specialists for their thoughtful design, functional versatility and high quality manufacturing. The family of these machines was developed by Andrey Chapai, an engineer and entrepreneur from Kovrov, who died at the beginning of 2017. Today his wife continues to produce and sell them.
From a technological point of view, the “Ot Chapaya” grinders are an example of a mechanism thought out in every detail. These devices have a rotating frame, the ability to tilt the belt, adjust the working height, and are also equipped with various devices: a pressure table, contouring rollers, a grinding wheel, etc. It is impossible to make such a machine with your own hands without the use of special equipment. As a rule, craftsmen who make grinders of this class borrow from Chapai Constructive decisions, and also copy the general layout and individual elements. But they have to order most of the parts from factories with equipment for cutting thick metal, milling and turning.
Rotary table for grinder
For accurate and uniform grinding, the part must be rigidly fixed in relation to the moving abrasive belt. Therefore, any grinder includes a rotating support table (or, as turners call it, a “handle”). Usually it's flat metal plate length 15÷30 cm, width 5÷10 cm and thickness 5÷10 mm. The table should have a recess at the end to fit the width of the belt, an adjustable tilt towards the grinding plane, and also move back and forth and up and down. Some support tables have the ability to rotate 90 degrees to the right and left side, but how necessary such an option is, the master himself must decide. Moreover, its implementation on home workshop equipment can be quite complicated.
In foreign videos, craftsmen widely use rectangular pipes and various figured profiles. This simplifies both the design and manufacture of the machine. Our craftsmen use such materials much less often: they mainly use channel, strip and corner. Of course, you can refer to the difference in price, but the grinder requires very little metal, so this explanation is questionable.
Grinder is a grinding machine used in the final finishing of crafts - for grinding elements. You can do it yourself, especially if you have an old washing machine and it has a working electric motor. Moreover, one that will allow you to grind the ends of parts, which is difficult to do with factory products.
The engine used in the craft has a power of 180 W and a speed of 1350 per minute. Small machine made on its basis will sand wood without any problems, plastic parts, products. If metal ones are a priority, then the motor needs to be more powerful - 300 W and at high speeds.
Assembling the grinder is not difficult, but you will have to contact a turner who will help turn the pulleys. True, they can be replaced with plywood ones made independently.
During work, they use materials: steel angle, plates; sheet metal; bolts, nuts and washers; washing machine motor; sanding belt; furniture gas support (for tensioner); working steel or aluminum wheels (made on a lathe or ordered by a turner).
Tools you will need: welding machine; drilling machine; Bulgarian; spanners.
First they work on the electric motor. A U-shaped bracket is welded under it from sheet steel. They are secured to it with bolts or studs that tighten the engine housing. The bracket is then welded with the bottom or screwed with the sides to the base - a rectangular plate made of thick sheet metal.
The machine frame is made. Use sheet metal thick, eliminating deflection and springiness of parts. Cut out the base - the plate. Holes are drilled in its corners and the legs are screwed through them. To reduce vibration of the future machine, they must be made of rubber.
A stand is cut out of a sheet of steel and welded to the base. To increase its stability, add corners and a scarf.
Pulleys made of steel, aluminum different diameters. The larger one is placed on the output shaft of the motor and secured with a screw. To do this, make an additional hole and cut a thread corresponding to the screw. The upper pulley consists of two bearings and a spacer sleeve. The position of the upper pulley is fixed with a nut.
Assemble the top assembly. The larger pulley mounted on the motor shaft is the drive pulley. They provide the ability to change its horizontal angle, which is necessary for centering the belt. The assembly is made from parts cut from a sheet of metal, which are fastened with bolts.
Install the belt tensioner. They use gas pressure, which is available in different types furniture. It can be purchased at a store that sells furniture components. Instead of support, you can use a spring or an old pump (you will have to redo it a little).
