On large and small industrial enterprises There has always been a need to have grinding machines in the equipment park different types, including tape. IN last years, in connection with the development of small businesses, handicraft workshops, and simply for performing minor work on grinding any parts, desktop small-sized grinding machines began to be produced belt type. It’s a necessary thing, of course, but it’s spoiled by one nuance: high price. And this applies not only to foreign models; prices for domestic analogues also bite sharply. Here, inevitably, many craftsmen begin to think about how to make a tape grinder with their own hands.
How does the grinder work?
A benchtop belt grinder or, simply put, a belt grinder, is drive device, where the role of the power unit is performed by an electric motor. The tool is intended for processing, finishing and grinding flat surfaces, removing the layer of rust or paint coating present on the workpieces. It is used to process burrs and sharp edges of steel, cast iron, aluminum or non-metallic parts.
Design
There is nothing particularly complicated in the design of a belt grinder. The device consists of a motor, drive and guide rollers. A sanding or roughing belt of the required grain size is passed through them.
When the engine is turned on, the drive roller mounted on its shaft begins to rotate, and through the tensioned working belt, the rotation is transmitted to the guide rollers. By pressing the part to be processed in the working area against the belt, the operator performs the required operation, changing the position of the workpiece relative to the surface of the belt if necessary.
By adjusting the distance between the guide rollers, it is possible to process surfaces with defects of different depths. During prolonged use, the sanding belt may not stretch much. To compensate for possible slack, the design has a tension mechanism. Typically, such a function is assigned to a roller located at the same distance between the leader and the slave.
The grinding machine is supplied with a support table, which also serves as a surface for fixing the workpiece. As a rule, such a table should be able to rotate 90 degrees about one axis. In this case, it is possible to process two perpendicularly located planes without reinstalling the part on the support table.
Although it is necessary to wear safety glasses when working on such machines, it would be a good idea to install a folding clear glass made of acrylic, to avoid eye damage from scale particles, paint flakes or metal dust. For example, you can look at the installed safety glasses on industrial machines where a round emery stone is installed as a working element.
Of course, a grinder control panel is required! For safety reasons, it is recommended to mount it on the machine frame in close proximity to working area operator. Portable machines are equipped with a stand made of durable steel with mounting holes on the base, allowing you to fix the unit on a wooden surface.
If you look at the design details, you can immediately notice some visual instability of the assembled grinding device. Side clearance installed rollers significantly exceeds the supporting surface on the base. In addition, the absence of a support table makes it difficult to effectively process relatively large surfaces, and holding the part in a canopy is inconvenient and quite dangerous.
An increased length of the working belt leads to additional losses due to friction. Must be used in drive power unit more power, and this increases energy costs. The tension unit is simple and functional. Adjusting the tension is a matter of seconds. The machine is supplied with replacement grinding attachments, with which grinding can be done even on internal surfaces. Despite this, the cost is 100 thousand rubles. makes me think.
Tape selection
To choose the right belt grinder, it would be a good idea to first determine the overall dimensions of the surfaces of the products to be processed, and then become familiar with the sizes of commercially available sanding belts.
Endless sanding belts differ in three parameters: length, width and grit level. The currently produced size range of sanding belts for such machines is as follows: 610 mm, 915 mm, 1230 mm, 1600 mm, 1830 mm in length; width dimensions are limited to 50 and 100 mm, although others can be found.
Anyway, following criteria must be observed:
- The tape should be on elastic fabric base.
- Maintain maximum angular speeds of at least 1500 rpm.
- Possess great abrasive resistance.
- The maximum relative tensile strength is at least 15%.
- Heat resistance during long-term operation.
When choosing a belt, it is necessary to take into account that the most optimal size of sanding belts for a homemade grinder is 1230 mm. Shorter abrasive belts wear out faster because they do not have time to cool sufficiently during idle move. As for longer ones, their use will lead to an increase in the dimensions of the entire structure, which is unacceptable; however, this does not provide any improvements.
The parameters of the mechanical tensile strength of the tape are very important. The use of composite tapes, even glued with the most advanced composition or double tape, strictly not allowed! When the joint is stretched during operation, the tape increases in length and the tension weakens. In this case, the tape may come off the guide rollers or break, and at such a speed this is fraught with serious consequences for the operator and others. Taking into account the high speed of movement of the belt along the surface of the guides and drive roller, the applied specific force on the abrasive surface should not exceed 0.8 kg/cm 2 . Approximately this parameter corresponds to the mechanical strength of an electrocorundum sanding belt: 800-900 MPa.
Advice: before installing the tape on the grinder, it is recommended to hang it on a cylinder with a diameter of about 60 mm. This ensures natural stretching of the abrasive element before work.
DIY grinder: drawings with dimensions + assembly instructions
During development Special attention is paid to the configuration of the rollers, the method of fixing the product and optimal power power unit. More about this.
Making rollers
Particular attention is required in the manufacture of the main, driving roller, acting as a pulley! It must be fairly massive. This will allow you to avoid an unnecessary jerk during the starting moment due to the present inertia of the resting state. The speed is gradually increased to the desired values. If we take into account the use of a standard power unit in the drive design, with a slip not exceeding 9% at a nominal 1500 rpm, the speed will be no more than 1400 rpm maximum.
One more nuance! Steel or cast iron are not suitable for the manufacture of a driving part, because during startup there will be a heavy load on the engine, or it will not be able to turn the too heavy blank at all.
There are two options to solve this problem:
- Make a hollow steel roller to reduce mass according to the principle: larger diameter - deeper cavity. Exact dimensions can be calculated using a reference book, although particular accuracy is not necessary.
- Second option: making a roller from duralumin grade D16 and higher.
It is advisable to carve an end groove on the pulley, the dimensions of which will be identical to the dimensions of the belt intended for use. This will help prevent uncontrolled belt derailment if the rollers are incorrectly positioned in the plane of rotation.
Of considerable importance surface roughness degree rollers. Recommended limit values: Ra1.25-Ra2.5. Increased roughness will lead to premature wear of the belt base, and roughness below the designated limit will contribute to unnecessary slippage during long-term operation.
The rollers must be installed using closed-type bearing units based on self-aligning bearings with a stationary outer ring. With this installation, abrasive or other particles cannot get on the roller shaft. When selecting bearings, it is necessary to take into account the compliance of their load-bearing parameters with maximum number revolutions of the power unit.
The rollers can be secured using conventional cotter pins or using a shoulder at one end of the axle, as prescribed by the standard. The drive roller must have a groove for a key common with the motor shaft.
Motor and turntable
If you are going to assemble a belt grinder with your own hands, then you should pay special attention to the choice of drive! Most often, a 0.75 kW engine is used (although up to 1.5 kW is not prohibited) with a speed of 1500 to 3000.
Please note that the belt may not withstand high speeds. As a rule, engine power is selected depending on the intended operations on assembled machine. If roughing work predominates, when the load on the drive is large, the power unit is installed more powerful, but with fewer revolutions, and if just surface grinding is required, the parameters remain within the limits mentioned above.
The grinding process is characterized by considerable contamination in the form of microscopic dust particles, so the motor must be a closed type with its own fan for airflow! It is better to ignore the recommendations of “experts” about using a motor from a used washing machine.
To design a homemade grinder, you need drawings with dimensions; in addition, it’s a good idea to think about safety precautions and ease of use. assembled device. This requires:
- Rotary table.
- Pressing plane on the back side of the tape for support.
For the first task, the table bracket must be mobile, with the ability to rotate 90 degrees and fix at extreme points. The recommended table thickness is at least 15 mm, preferably using alloy.
For the clamping plane, a machine frame ground near the support table is suitable.
The abrasive belt of a grinding machine is a consumable material; you have to change it quite often when actively using the grinder. If you have a sheet of sandpaper of suitable grit and length on hand, but there is no desire to buy a new tape, then you can always glue it yourself. Let's look at how this can be done.
In order to glue the tape for the sanding machine you will need:
1. Long leaf sandpaper.
2. A small vulcanizer, maybe homemade.
3. Pencil, ruler and scissors.
4. Glue.
Preparing the tape for gluing
1. A strip of sandpaper to the required length and width is torn off or cut off from a sheet of sandpaper.
2. At one of its ends, on the back, non-abrasive surface of the tape, mark a cutting line at an arbitrary angle to its side.
3. Cut the tape along this line.
4. The ends of the tape are combined by twisting one of them 180˚.
5. On the back side of the uncut end, also draw a cutting line, using the cut end as a ruler.
6. Cut the second end of the tape along the drawn line.
7. Be sure to check the accuracy of the coincidence of the cut ends when they are closed into a single strip.
8. At one end of the tape, draw a bend line parallel to the cut line at an arbitrary distance from its edge.
9. Bend it tightly along this line onto the back surface of the tape.
10. Check the uniformity of the bend.
11. Use a knife to remove abrasive grains from the surface of the tape fold.
This is necessary so that it is more noticeable.
12. In the same way, mark the fold line at the second end of the tape at the same distance from its edge as at the first,
bend it and remove the abrasive from the fold line.
13. Straighten one of the bent ends of the tape and place it on the platform of the vulcanizer connected to the network. The edge of the platform should coincide with the line of the former fold of the belt from which the abrasive was removed.
14. Press the end of the tape to the platform with some flat weight and wait for the glue holding the abrasive grains on it to weaken. Their slight blackening can serve as a guide.
15. Scrape the abrasive from the heated end of the tape with a knife.
16. The same operations are performed with the second end,
after which the vulcanizer is turned off and the overlap of the ends of the tape is checked.
Gluing
To glue the ends of the abrasive tape, it is recommended to use especially strong waterproof adhesive “Moment 88”.
Glue it together as follows:
1. Apply glue to the surface of one of the ends of the tape, cleaned from abrasive.
2. Distribute it over the surface with the other end of the tape, also cleared of abrasive grains. As a result, the glue covers the surfaces of both ends prepared for gluing.
3. After five minutes, apply the ends coated with glue to each other “overlapping”, squeeze them tightly,
and then check the quality of gluing.
4. If the glue still “does not hold” and the ends of the tape “diverge” when tensioned, then apply the glue to the tape again, wait for it to “dry”, and then press the ends together again. This is done as many times as necessary to ensure that the ends of the tape hold each other tightly when tensioned. This multi-layer application of glue makes the tape in the gluing area, where there are no abrasive grains, more rigid.
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 a 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. Or just sharpen scissors or a 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 hard disk; in the second - on an elastic band running around a system of pulleys and rollers. The disc type is more suitable for grinding simple wooden parts and coarse or medium clean metal parts. 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 shank of a metal-based grinding disc. 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 drive for a home 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 an 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 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 makes it possible to successfully use scrap 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 the belts 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 design 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 fairly popular BTS50 grinder is made using a coaxial rocker design. 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 to a skilled craftsman, let's say, point cutting edges and blades with literally micron precision.
In industrial grinders for home use the 3-rocker design 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 drive pulley large diameter and thereby prevent the tape from slipping. A belt slip during operation is almost certainly a damaged part. Most washing machines with 2-3 speed asynchronous motors for 220 V are 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 having released 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 turned 90 degrees, moved up 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 consumable material for a belt grinder is a tape (not counting grease 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 sandpaper on textile based. It is highly desirable - flexible, unimpregnated. In general, the procedure for making a grinder belt with your own hands is as follows:
- 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.
- Gray 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 permissible limits The belt speeds 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. It’s just that mass production of complex profile rollers is 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. Lengths and widths are made 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 page.
- //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)
Ready-made abrasive belts for household grinders and home grinders can be easily purchased in a store or at the construction market. But the price of the issue is not always satisfactory. And the distance to the destination can be decent.
Therefore, it will be cheaper to glue abrasive tapes with your own hands. For homemade belt sanders, abrasive belts made from sandpaper also in most cases have to be glued together yourself, since it is not always possible to find a suitable size.
Some craftsmen prefer to glue the tape joint to joint, placing a lining of sandpaper underneath. However, it is better that the seam is overlapped. How to properly glue abrasive tape from sandpaper for a grinder and sander, read on.
Glue the abrasive tape yourself
First of all, cut it sandpaper into strips of the required width. The length must be measured a little with a margin, taking into account the overlap, which is 2 cm. Another important point- the angle at which the parts of the sandpaper will be glued together should be “friendly” with the diameter of the installed rollers.
Before gluing, one part of the sanding belt must be cleaned of abrasive. To do this, moisten the gluing area with acetone and leave for a few minutes. Then we remove the “grains” using saw blade hacksaws for metal.
At the second end of the sandpaper you need to remove a small chamfer for better grip. You also need to clean the sandpaper with inside. Then you can proceed directly to gluing the abrasive strip for the grinder and the blade.
Vlasenko 13-11-2007 14:12
A question for those who have glued fabric-based tapes themselves...
What did you glue it with? Width of the sizing area? Seam durability?
You don’t need to mention the bevel angle of the gluing zone and cleaning it from abrasive
Thanks in advance for the first-hand information...
Serjant 13-11-2007 14:24
To search.
discussed several times.
Vlasenko 13-11-2007 15:16
Sergey, Sorry...
Strangely enough, I know how to use search...
I am interested in specific information and results of use from those who did it PERSONALLY, and not rehashes from other sources and discussions...
Serjant 13-11-2007 15:37
people told me what and how they glued it.
That's why I sent it to the search.
Vlasenko 13-11-2007 15:48
quote: people told me what and how they glued it.
I read these posts...
Three posts on PVA, moment and cyacrine, plus some links to knife and foreign countries - not a lot and everything is known...
But from " personal hands" O
quote: Seam durability?
Generally zero
Vlad Klem 13-11-2007 16:11
I'm also wondering if anyone has experience with gluing? I tried gluing with instant and cyanoacrylate and PVA and even with special two-component adhesives (specifically for gluing tapes) and they all broke, if not immediately, then after a very short time of work. It’s not for nothing that companies like “Liner-Belt” or “Clarey” keep their gluing technology secret.
So if anyone has a stable positive result, please share.
SiDiS 13-11-2007 17:41
I have more than 4 years of experience using glued tapes. The experience is positive. Cons: on small grit numbers it hits noticeably (with 250 grit)
It tears extremely rarely and, oddly enough, not along the seam, but behind it, if the skin is thin. On a skin with a hard base, it either does not tear at all (99%), or at the seam. This happens under very heavy loads and/or on a sharp edge of the workpiece.
For gluing, thin synthetics with cotton (from thin shirts) and “moment” are best suited.
Vlasenko 13-11-2007 17:55
Dmitry, as far as I understand, your “contact Moment” performed better than PVA with thermopolymerization?
The fact that it breaks after the seam is quite understandable... There is a step on the edge of the seam and on it (from the abrasive side) the base wears out faster during work...
Vlad Klem 13-11-2007 18:04
SiDiS
So I didn’t understand. You glue at the joint with the overlay, or overlapping and also with the overlay.
SiDiS 13-11-2007 18:36
I use the usual standard “moment”. I haven’t tried PVA, and even with terpolymerization, there’s more than enough time. I glue it end-to-end on a bias (about 45 g). The thickness at the gluing site increases by about 0.1 mm
bayan 13-11-2007 21:14
Just today I also tried to glue it end-to-end on a fabric base, but the overlap didn’t work - I couldn’t clean off the abrasive. I really liked the result - there was almost no fighting. I glued it to 88. Let's see how long it lasts...
grga 14-11-2007 02:30
For several years now I have been gluing with an overlap, first cleaning off the abrasive. At the lower end completely, at the upper end partially, there is no runout, the tape does not break. PVA glue, but this is not necessary, because... I have used others too, PVA is just more accessible to me. I remove the abrasive with a piece of old whetstone with grain of brutal sizes and using 646 solvent (in a respirator with filters, of course). The angle is approximately 60 degrees. , overlap width 30 mm.
There is a little trick when cleaning: at the gluing site, folds are made (with the abrasive facing out) every 3-4 mm and when folded, the abrasive flies off with a bang, you just need to rustle a large pebble on them. Then, having such cleared stripes, the rest flies off more easily. The main thing is not to damage the fabric, which is why I refused to use a grinder - it is difficult to catch the moment when, instead of forming a circle, it begins to remove layers of fabric from the tape.
Gadyukin 14-11-2007 12:54
I tried to glue it with an overlap (about 20mm), Moment glue, and removed the abrasive from the lower end using a drill with a diamond attachment. The tape is still alive, the only problem is the lack of a normal scissor, I made it from a domestic one. Now there is an idea to glue with mastic on a rubber base (in tubes for a gun) intended for installing heavy panels of artificial and natural stone, after drying it remains elastic. By the way, on the newly purchased tapes, such an innovation appeared - the butt gluing at the bottom is glued with some kind of slippery synthetic fibrous material, the fibers on it are oriented along the tape.
Vlad Klem 14-11-2007 15:26
It may also be that all Corvettes have a tape 100-150mm wide.
Therefore, the gluing area is quite significant, as a result, the specific tension load on the tape is small. I have a 50mm or even 30mm tape. And the load on it from the tension roller is decent. Maybe that’s why the tapes, glued on their own, tear along the gluing.
SiDiS 14-11-2007 15:29
I have a tape width of 40-50 mm
Vlasenko 14-11-2007 15:38
quote: I have a 50mm or even 30mm tape. And the load on it from the tension roller is decent.
Why is there a decent load? Is the pull roller small in diameter and there is not enough contact area of the clutch to pull it at the correct tension?
How do you glue it yourself? Butt or overlap?
SiDiS 14-11-2007 16:31
due to smaller cross-sectional area/seam length than 100 mm wide tapes
Vlasenko 14-11-2007 16:46
quote: due to smaller cross-sectional area/seam length than 100 mm wide tapes
That's not what I meant when I asked about the load...
To remove metal across the entire width of the tape, there is some kind of load per unit width (friction from abrasive stripping)... With the same specific force, the use of narrower tapes requires less effort to pull it...
So I’m wondering why Vlad is getting a decent load from the TENSION... IMHO this could be due to the need to increase the friction on the broaching roller (so that there is no slipping), and the friction depends on the contact area on it (and, accordingly, on its diameter) ...
Vlad Klem 14-11-2007 18:37
Error in reasoning. Take any material, for example Ф=20mm and Ф=50mm, and pull it with constant force. Where will the specific load on the material be greater? Exactly the same with narrow and wide tape. The specific load of a narrow belt will be as many times greater as the width of the belt is smaller. At the same load of belt tension. These are the pies.
Vlasenko 14-11-2007 19:11
quote: Error in reasoning.
And what is the mistake?
The rotation speed of the pulling shaft is constant... The power on the shaft is obviously higher than the total load on the tape... (practically does not affect the speed of the shaft) -> the pulling force per unit of shaft width is also constant -> With the same load per unit of tape width at the removal point we get that per unit. width of the seam, the load is also constant...
Yes. in this case, the total rate of material removal will depend on the width, but in reality you don’t press the wedge as hard as you can, but so that it removes efficiently, and this is a certain optimum in terms of the pressure of the workpiece to the abrasive, i.e. on a wide belt, press harder...
Big_hunter 14-11-2007 19:25
Well, I'll tell you. Previously I glued it (now I already know that it was cyanoacrylate) with a “second”. But with preliminary impregnation of the surfaces to be glued with it. The tape works, but still breaks over time. Having visited a relative’s carpentry workshop, I saw a grinder 5 meters long and a tape width of 25 cm. They glue the tapes themselves. The staff was interrogated with passion. Now I do this:
overlapping gluing with a depth of 1.5 cm, I cut the tape at the gluing site on both sides at an angle of 45 degrees, wash off the abrasive with 646 solvent, Titibond 2 glue, spread it to achieve a single axis of the tape at the gluing site, cover the gluing site on both sides with newspaper and on five I bake for about minutes with an iron. The main thing here is not to overbake so that the glue does not become brittle. You really need to take into account the thickness of the tape, the temperature of the iron, environment etc. In short, experience is a friend of difficult mistakes...
Before the introduction of best practices, I used titibond type liquid nails, also holds up well, but the gluing is thicker and the tape hits a little at the junction.
Gadyukin 15-11-2007 19:46
Are there any pictures of the packaging for Titobond 2?
Vlad Klem 15-11-2007 20:17
If you want a picture, we have them. This glue is called Titebond II Premium Wood Glue.
I don’t know how it sticks. But you can try.
Serjant 15-11-2007 20:25
But I know..
I glued the bed on it. This is some kind of fuck-up and not resin. impossible to tear off.
Vlad Klem 15-11-2007 20:54
Well, if even “Sergeant” has adapted this glue for the sexodrome (and the loads there are decent), then perhaps tomorrow I’ll take a walk to the “Kashirsky Dvor” and buy some pizirek entiva glue.
And then you can take three tram stops and get to Moskvoretsky.
Vlasenko 16-11-2007 02:27
quote: Perhaps tomorrow I’ll take a walk to the Kashirsky Dvor and buy some pizirek entiva glue.
Vlad, after the experiments, write down the results - it’s interesting...
Vlad Klem 16-11-2007 19:17
So, today I took a walk to Expostroy on Nakhimovsky Prospekt. Luckily it's close to home. Titebond II... for some reason it wasn’t there (in small packages) in large 3l ones. in bulk, but they offered me a newer glue of this series “Titebond 111”, they say that compared to Titebond II it glues one and a half times stronger. From Expostroi I drove to the Moskvoretsky market (several stops on the 52nd tr-se). And there is this Titebond II wagon and a small cart, in all sorts of packages. So I bought that too. Now let's start experimenting.
On Moskvoretsky, one seller, passionate about all sorts of adhesives, fillers and protectors, offered me glue (polyurethane) from the “liquid nails” series, which, as he assures, if you glue two steel sheets together and then try to tear them, the gap will not be due to the glue, but on steel. Exaggerates of course, but it’s an interesting thing. I wrote down the glue data, I’ll dig deeper into the Internet and look at the characteristics.
These are the Titebonds:
Vlad Klem 18-11-2007 22:50
I was at Kashirsky Dvor today, buying some metal. I first went through the rows and bought 36-grit sandpaper; 80 and 120. rolls 200mm wide. Just get 4 strips of 50mm each. I will practice gluing. In any case, if it works out, it will be three times cheaper than at Klarey. And also, felt was sold there, in ribbons. Width 50mm. length 2m. and 7mm thick. I bought one tape to try. I'll try to glue it on the grinder. I wonder if anyone here has used such tapes.
Andy 18-11-2007 23:34
Bare felt without a base? Won't it stretch?
We are waiting for the results of gluing the sandpaper. (triple savings sounds delicious)
Vlasenko 19-11-2007 12:20
quote: Bare felt without a base? Won't it stretch?
I think that, if necessary, a simple keeper tape can be sewn along the edges from the inside of the felt, although 7 mm is a little thick...
Such a ribbon would ideally be made from felt cloth from an officer's overcoat...
Vlad Klem 19-11-2007 01:02
I didn't think about the "stretch" thing. But the proposal from the side of the substrate to attach the keeper tape is just right. Or maybe stick it with tape.
Ramzay 1 19-11-2007 11:30
Good luck to everyone, over the weekend I glued the tapes with instant (crystal) and titibond.
They all work great, only with titibond the seam is a little hard.
I glued it into a 15 mm pad and removed the abrasive with a solvent.
Question: is there a solvent that easily removes the abrasive after I have to scrub hard.
Ramzay 1 19-11-2007 11:32
quote: Originally posted by Vlasenko:
Bare felt without base
I glued the felt onto the worn tape with 88 glue, everything was ok