In order to sharpen a saw blade with victorious solders, it is necessary to take into account some of the features of this product and select the tool as carefully as possible.
Tooth material and shape
Saw blades are steel blades, the tips of which are high temperature welded cutters.
As a rule, these parts of the tool are made of sintered tungsten-cobalt alloy (grades VK, VK6, VK15, etc.). Carbide alloys are also used. But it should be borne in mind that the strength depends on the grain size of the carbide phase.
The very same soldering (tooth) has the following planes:
- Front;
- Back;
- Two side (auxiliary).
That is, crossing, they form two cutting edges:
- Home;
- Auxiliary.
Measuring the degree of sharpening of a circular saw
In most cases, circular saws with victorious solders are rarely used, but for significant amounts of material and for a long time. Therefore, it is quite normal that the incisors begin to grind over time. This product should be sharpened as needed. Determining the degree of sharpening is quite simple:
- When sawing the material, irregularities, notches, chips begin to appear, and when cutting wooden objects - a characteristic smell and black marks on the material;
- The work on the machine becomes more difficult as more effort is required, resulting in a heavy load on the motor.
Important! Lack of observation of the sharpness of the disc cutters can lead to the fact that the product can no longer be sharpened or repaired at all. Therefore, it is worth carefully monitoring the condition of the instrument.
It should be noted that, as a rule, these machines are equipped with protective relays. But if there are none, the device can fail faster if sharpened incorrectly or at the wrong time.
Materials used and the sharpening process of a circular saw blade
When working with a circular saw, most often the main edge becomes dull. In the process of cutting, the main emphasis is on it, so it is necessary to ensure that it does not round off by more than 0.3 mm, since difficulties may arise during the subsequent sharpening of the cutters, not to mention a decrease in productivity.
Auxiliary planes are also subject to wear (albeit to a lesser extent), especially when working with massive products.
To sharpen the teeth of circular saws with victorious teeth, high-strength materials are used - diamond wheels, silicon carbide (green) wheels, etc.
Important! Before starting the process, you must make sure that the device is clean, that is, make sure that there is no dirt or water on the surfaces to be treated. And it will also be useful to treat the diamond wheel with a cutting fluid, since there is a high probability of rust formation when cooled with plain water.
When choosing an abrasive wheel, you should pay attention to the fact that its surface is slightly grainy, because this is how the desired surface cleanliness of the sharpened tooth is achieved. Otherwise, when working on the material, chips, notches and other defects will remain.
To process victorious tints, the speed of rotation of the sharpening circle must be at least 15 m / s, that is, with a diameter of 120 to 125 mm, the speed of rotation must be at least 1500 rpm.
There are special devices for sharpening soldering - grinding machines, the advantage of which is:
- Variability of movement of both the machine tool and the abrasive wheel;
- Ensuring an even sharpening angle.
Further actions are performed manually - turning the saw in a circle (per tooth), subsequent grinding, checking the volume of metal removed. Such mechanisms are great for handling soldering at home.
Sharpening types
The process itself is subdivided into three types:
1. Sharpening the front surface of a straight tooth
The tooth and the abrasive wheel are set perpendicular to each other, bearing in mind that the saw itself must be in a horizontal position. In the event that the machine does not provide an angular tilt scale, you can use a pendulum goniometer. Next, you need to firmly fix the tools.
The process itself is the contact of the abrasive wheel and the ground surface back and forth by means of a mechanism in the machine, while simultaneously pressing the tooth to the wheel in manual mode. This process is repeated with each saw tooth.
For convenience, you can make a mark on the tooth from which sharpening began.
2. Sharpening of the tooth beveled on the anterior surface
This type of sharpening provides for the execution of the same actions as before, with the difference that the angle of inclination must be changed in accordance with the location of the teeth. You can measure the slope with a pendulum goniometer. First, the positive angles of the tooth are sharpened through the tooth.
- Every second soldering is sharpened;
- Then the angle changes to negative;
- The remaining teeth are machined.
- Rear face sharpening
This process provides for the possibility of changing the position of the disc so that the back plane of the soldering is in contact with the abrasive wheel.
If you don't have a sharpening machine, you can make everything with your own hands. How to sharpen a disc with your own hands:
- Make a support for the saw that will hold the saw in place. This device must firmly hold the saw, otherwise the process will pose a danger to the performer;
- Adapt the stand on which the disc itself will be located (if necessary, the angle of inclination can be changed to the supports);
Important! The abrasive saw and saw blade should be perpendicular to each other.
- Fix the circular saw in its center so that it touches the circle in the desired position (to maintain the same front and rear sharpening angles).
It should be remembered that after sharpening, no chips, cracks, gaps or other defects should remain on the victorious teeth. If no glare is visible on the cutter, then the work is done correctly.
It should also be noted that the sharpened plane of the tooth and the material subsequently processed are dependent on each other - if the material of the workpiece is hard, then the soldering should not be too sharp.
- How to sharpen
- It's important to know
- Assembling a homemade sharpener
The saw blade must be sharpened from time to time. Sharpening circular saw requires certain knowledge, special equipment. There are machines designed for this purpose.
Types
Circular saw sharpening machines - a group of devices for renewing the sharpness of cutting elements. Depending on the functional features, they are:
- Automatic. The units are installed in large enterprises.
- Semi-automatic, mechanical (tools for hand sharpening cutters). They are distinguished by low productivity, they are mainly used in home workshops.
When sharpening rip saw chains, other devices are used that can sharpen each tooth with files.
All equipment including an electric drive is similar in principle of operation. Only the performance is different. So, low-power household samples can function continuously for up to 20 minutes. After that, they must be turned off for the same time to cool.
Professional tools can work up to 8 hours. They only need a few short breaks of 20-30 minutes. Some units have an abrasive wheel for sharpening, a sanding belt of a similar action.
In most cases, the sawing tool can be sharpened on machines, the main element of which is a grinding disc. Belt units are more suitable for industrial use with large amounts of finish grinding.
Sharpening machines are equipped with circles that differ:
- thickness - 16–40 mm;
- outer diameter - 12–250 mm;
- mounting hole - 12,7,16, 20, 32 mm;
- material of manufacture.
You need to pay special attention to what the abrasive is made of: the result of the work depends on the quality... In addition to conventional cutters, there are circles on which there is a reinforcing brazing - a plate made of hard alloys. Most often there are corundum, diamond circles. They do a good job of sharpening carbide tipped blades for cutting extremely hard materials.
The circle for installation must be purchased taking into account the characteristics of circular saws. The abrasive belt is selected according to the dimensions of the machines. The grain size is also taken into account, which affects the nature of the grinding.
How to sharpen
The abrasive disc is cleaned of dirt, remnants of the removed material, the angle of inclination is set. Sharpening starts from the front of the tooth. The maximum permissible metal layer for removal is up to 0.20 mm.
It is necessary to ensure the correct feed of the cutting element to the grinding wheel. The sharpened wheel must be in full contact with the abrasive. During work, you need to ensure that the blade does not overheat. Avoid raising the temperature of the material to critical levels by adjusting the speed of rotation of the abrasive element, wetting it with a small amount of water before work.
Wheels with diamond plating, processing victorious cutting tools, are usually cooled with a special liquid (coolant). The process can be considered complete when a uniform burr appears over the entire surface of the blade edge. The final sanding is done by hand.
It should be remembered that the machine can only process the workpiece in one plane at a time.
It's important to know
The main saw wear occurs on the top edge of the teeth. It comes into contact most of all with the material being processed. Due to constant contact with hard surfaces, the rounding of its central edge can reach 0.3 mm. This is a critical indicator. It is necessary to ensure that the central protrusion is rounded by no more than 0.2 mm, otherwise it will be difficult to sharpen the element well, it will take a lot of time.
The degree of wear is usually determined by the condition of the teeth, the quality of the cut. Each cutting blade has a resource. In most cases, these are 30–35 sharpenings.
It is impossible to allow the formation of notches, chips, other defects that violate the integrity of the metal on the cutting edge during its processing with the help of machine tools.
Assembling a homemade sharpener
They resort to making a homemade sharpening machine when there is no factory equipment at hand, and the cutting wheels have to be sharpened from time to time. A dull circular saw blade can be sharpened on the device.
For assembly you will need:
- electric drive,
- support,
- tilting mechanism,
- screw stops.
The circle must be fixed to the engine. The disc blade is installed on the support, while the screw stops provide the movement of the cutter along the axis of the circle, creating the required angle of inclination. Correct fixing of the saw blade to the abrasive is a basic requirement for sharpening. In order for the angles to be respected, an adjustable stand is required, fixed in the same plane with the circle on the frame of the device. When installing the disc on a stand, you need to ensure that the teeth are located perpendicular to the plane of the machine.
When assembling the saw blade sharpener yourself, it is recommended to use the drawings and diagrams.
Sharpening can also be done with mechanical devices. But when using special units, the operating time is reduced, the sharpened cutter will have a sharper edge.
A circular saw (the modern name is a circular saw) is a much more efficient tool in comparison with reciprocating, rip-type and chain saws. Cutting quality and ease of use are beyond doubt. With a circular saw you can perfectly cut large workpieces, cut at different angles and work with a wide variety of materials.
The circular saw allows you to cut the material both along and across the fibers with the same accuracy and quality. Of course, you can get a clean cut only with properly sharpened teeth. Circular saws fall into three categories:
- All-metal
- All-metal with hard materials spraying in the work area
- Tungsten carbide saws
The presence of technological grooves on the saw blades is very important
- It takes a lot of force to advance the workpiece while cutting.
- Chips, cracks appear on the cut
- Drive motor gets very hot during operation
- You can smell burnt material
- Dark marks from overheating are visible on the cutting edge
In addition, the sharpness of the teeth can be checked tactilely and with a magnifying glass. The radius of rounding of the cutting edge should be in the range of 0.1-0.2 mm. When sawing workpieces of large thickness, not only the main working edge is exposed to wear, but also the side edges.
IMPORTANT! Always use the correct disc for the material when working. Otherwise, you will mistakenly send a working disc for sharpening.
General rules for sharpening a circular saw
The discs are sharpened a limited number of times. With each procedure, the size of the tooth is reduced. Sooner or later, the tooth is grinded to a critical value, after which the use of the disc becomes impossible.
IMPORTANT! It is unacceptable to work on a blunt disk. In addition to reducing the quality of the cut, sharpening overly dull teeth will require more metal to be removed.
In order to extend the resource, sharpening is performed on two working surfaces of the cutting edge. In this case, the thickness of the removed surface is halved.
Schematic representation of correct sharpening of teeth
If you do not violate the rules of processing, sharpening can be done up to 25 times. Before sharpening, the disc must be cleaned of dirt. Mechanical processing is undesirable; it is better to use detergents containing solvents. The standard amount of removal of the tooth surface is 0.05-0.15 mm.
The sharpening angles are individual for each disc, and are indicated in the passport or directly on the sidewall.
Saw blade marking with sharpening angles
For sharpening discs, there are special ones that mechanically control the selected angles for each tooth. Depending on the intensity of use, the grinding machine can be automatic or manual. At home, as a rule, inexpensive models are used, in which the rotation of the disc to the next tooth and the control of the thickness of the grinded metal is carried out manually.
In such devices, the disc is fixed perpendicular to the grindstone, the angle and pitch of the tooth are set. The master runs the sharpened surface over the grindstone a fixed number of times and moves on to the next tooth.
Grinding discs are made of CBN, silicon carbide or diamond-coated. It makes no sense to talk about the fundamental advantage of one material over another. There are only application features. For example, diamond whetstones are capable of working harder teeth but are susceptible to overheating.
You can sharpen by hand using a quality file. In this case, it is better to leave the disc in the machine. The first tooth is marked with a marker, the disc is fixed with wooden blocks, a clamp or a vice. A fixed number of file passes must be made on each tooth surface. Then rotate the disc by one tooth and repeat the procedure.
How to sharpen a circular saw with your own hands video
Sharpening carbide tipped discs
Many do-it-yourselfers face the problem of sharpening victorious-soldered discs. If you sharpen with standard abrasives, you have to carry out the procedure longer, and the material can "release" from overheating. Diamond grinding wheels do much better, but the cost is too high. Sometimes it is more profitable to buy a new victory disc.
The choice is up to the owner of the saw, but the general advice is as follows:
When sharpening discs with victorious solders, in any case, you will have to use the machine, regardless of its technical level. If you have such a machine, buy a diamond abrasive and sharpening discs of any hardness will not be a problem. If there is no machine, it is better to contact a specialized workshop for sharpening discs with victorious solders.
You can spend money on the purchase of equipment of any complexity, the main thing is that it does not stand idle and is in demand. For large volumes of work, it is more profitable to have your own grinding machine for circular saws. If you are only doing periodic repairs, it’s cheaper to go to a workshop.
Any cutting tool tends to become dull during operation. This also applies to carbide saw blades, which must be sharpened regularly in order to cut the wood quickly and efficiently.
The easiest way to sharpen teeth on a circular saw is to use a regular file. But when working with your own hands, on bringing the cutting tool into working condition, there are many difficulties that can only be dealt with by a good specialist with sufficient experience. It is much easier, faster and more efficient to use a homemade circular saw sharpener or a circular knife sharpener for this operation.
If there is a home-made electric sharpening machine for circular saws, regardless of whether it is a factory tool or a home-made one, you should know the basic principles of using such equipment. Especially when there is a need to sharpen the teeth of saw blades, which have different geometries and sharpening angles.
1 Shapes of teeth on saw blades
There are several of them, and they appeared as a result of optimization the impact of the cutting edge on the material being cut, which can have various properties.
The main tooth shapes are:
- straight - used for rip sawing when high quality is not required;
- oblique (beveled tooth) - has a variable right and left angle of inclination of the rear (sometimes front) plane. Used for sawing both longitudinal and transverse directions. The most common form for circular saws. This configuration is convenient to use when cutting slabs with double-sided lamination, as it does not chip along the edges of the cut;
- trapezoidal - characterized by a long retention of the cutting edge in a sharp state. Usually, on saw blades, teeth of this shape alternate with straight teeth, slightly rising above them. Trapezoidal teeth, in this case, make rough sawing, and straight teeth, finishing;
- conical - this shape of the teeth is used for auxiliary operations. For example, a layer of laminate is notched to prevent the appearance of splinters during the main sawing.
The leading edge of all teeth is flat, but in some types of circular saws, it is concave.
This allows for a high quality finish cross-cut.
1.1 Sharpening angles
Sharpening the teeth of a circular saw is carried out taking into account the four main angles that are formed at the intersection of the planes:
- rake angle;
- back angle;
- bevel angles of the front and rear plane.
As an auxiliary, the angle of sharpening is also taken into account, which is set by the value of the front and rear angles.
The sharpening angles depend on the purpose of the saw:
- for rip sawing, a rake angle of 15 to 20 degrees is suitable;
- when crosscutting - from 5 to 10 degrees;
- with universal application, on average - 15 degrees.
It is important to consider the sharpening angles not only in the direction of the cut, but also in the hardness of the wood - the harder it is, the smaller the front and rear angles should be.
2 Equipment for sharpening saw blades
These are the sharpening machines for circular saws, which structurally executed in the following variations:
- when sharpening, only the saw moves (the motor with the grinding wheel is stationary);
- both the sharpened saw and the motor with a circle can move;
- only the motor with the grinding wheel attached to it moves (the saw blade remains stationary).
As a standard example of a sharpening machine, a device that consists of two units - an engine, with a grinding wheel mounted on its shaft, and a support on which the sharpened circular saw is mounted can serve.
To ensure angular sharpening in this device, a system must be provided that allows you to change the angle of inclination of the blade (for teeth with a beveled front plane).
2.1 JMY8-70 machine
The JMY8-70 electric sharpening machine, which is made in China, has a fairly large number of positive reviews. Some craftsmen take his device as a basis when they assemble a homemade machine for their own needs with their own hands.
The JMY8-70 machine is designed for sharpening circular saws that made of hard high-speed alloys. The machine can handle the front and rear planes of the teeth, as well as perform angular sharpening.
Main advantages:
- has a diamond grinding wheel with a diameter of 125 mm;
- equipped with an inclined saw holder, which allows for angular sharpening;
- the body is made of cast steel used in the aviation industry;
- installed on rubber pads, which significantly reduce the impact of vibration on the processed material;
- has a simple adjustment that even a non-specialist can handle.
The manufacturer, upon shipment, completes the machine with detailed instructions, which describe in detail all possible functions of the device and how to perform them.
Specifications:
- the grinding wheel has dimensions - 125 × 10x8 mm;
- the grinding wheel can be rotated up to 20 degrees;
- diameter of the sharpened saw - from 70 to 800 mm;
- grinding wheel rotation speed - 2850 rpm;
- weight - 35 kg.
2.2 Homemade sharpening machine
A lot of people, when working with their own hands, use hard alloy circular saws not regularly, but from time to time. Therefore, it makes no economic sense to buy factory equipment. A homemade sharpening machine is a great solution that will allow you not to turn to third-party organizations.
The main argument is that when sharpening a circular saw with your own hands on a regular grinding wheel, it is very difficult to maintain the required sharpening angles. Therefore, an adaptation is needed that allows you to fix the saw blade in a specific position in relation to the grinding wheel.
A homemade machine on which you can sharpen circular saws with your own hands can consist of the following units and parts:
- a fixed electric motor with the possibility of attaching a grinding disk to its shaft;
- a table-stand, the surface of which is located at the same height in height with the axis of rotation of the grinding wheel;
- tilting the stand using hinges on one side and rotating (height-changing) screws on the other. This will allow you to perform angular sharpening along the front and rear planes;
- clips to secure the saw blade. To do this, a groove is made on the surface of the stand for the mandrel on which the saw is installed. Moving the mandrel, together with the disk, along the groove will allow you to maintain the required angle of sharpening of the teeth;
- a device for moving an electric motor or a stand for angle sharpening of circular saws with different diameters;
- the presence of stops for reliable fixation of the tool during work.
2.3 Sharpening circular saw blades
The sequence of operations when sharpening the front plane of the tooth of a carbide circular saw:
- the saw is placed on a mandrel and secured with a tapered sleeve with a nut;
- it is set clearly horizontally using a pendulum goniometer, while the bevel angle of the front plane is equal to zero;
- moving the mandrel horizontally with the mounted disc, the specified rake angle is set. Simply put - the disc moves in such a way that the front plane of her tooth fits snugly to the surface of the grinding wheel;
- using a marker, a mark is made - from which tooth the sharpening began;
- when the electric motor is on, several movements of the saw are made forward and backward, pressing the sharpened surface to the working surface of the grinding wheel;
- the thickness of the metal removal is regulated by the clamping force and the number of translational movements;
- after the first tooth is sharpened, the saw is removed from contact with the grinding wheel and rotates around its axis by one tooth, which will be the next when sharpening;
- the operation is repeated according to the number of teeth on the saw blade.
Sharpening circular saws
Material and properties of carbide teeth
In domestic saws, sintered tungsten-cobalt alloys of grades (6, 15, etc., the figure means the percentage of cobalt) are used as a material for cutting inserts. Hardness 6 is 88.5 HRA, 15.86 HRA. Foreign manufacturers use their own alloys. Cemented carbide is composed primarily of cobalt cemented tungsten carbide. The characteristics of the alloy depend not only on its chemical composition, but also on the grain size of the carbide phase. The smaller the grain, the higher the hardness and strength of the alloy.
The carbide plates are attached to the disc using high temperature brazing. At best, silver solders (PSr-40, PSr-45) are used as soldering materials, at worst. copper-zinc solders (L-63, MNMC-68-4-2).
Carbide tooth geometry
The following types of teeth are distinguished in the form.
Straight tooth... Typically used in fast rip saws, the quality of which is not particularly important.
Oblique (oblique) tooth with left and right angles of inclination of the rear plane. Teeth with different angles of inclination alternate with each other, due to the fact that they are called alternating. This is the most common tooth shape. Depending on the size of the grinding angles, alternating tooth saws are used for sawing a wide variety of materials (wood, chipboard, plastics). both in the longitudinal and transverse directions. Saws with a large flank angle are used for undercutting when cutting double-sided laminated plates. Their use avoids chipping along the edges of the cut. Increasing the bevel angle reduces the cutting force and reduces the risk of chipping, but at the same time reduces the strength and toughness of the tooth.
The teeth may be inclined not only towards the rear, but also towards the front plane.
Trapezoidal tooth... A feature of these teeth is the relatively slow speed of blunting of the cutting edges compared to alternating teeth. They are usually used in combination with a straight tooth.
Moving with the latter and slightly rising above it, the trapezoidal tooth performs a through cut and a straight line, following it. clean. Saws with alternating straight and trapezoidal teeth are used for cutting plates with double-sided lamination (chipboard, MDF, etc.), as well as for sawing plastics.
Tapered tooth... Tapered tooth saws are auxiliary and are used to pick up the bottom layer of the laminate, which protects it from chipping during the passage of the main saw.
In the vast majority of cases, the front of the teeth is flat, but there are saws with a concave front surface. They are used for cross-cut finishing.
Grinding angles of teeth
The grinding angles are determined using a saw. those. one for cutting the material and in which direction it is intended. Rip saws have a relatively large rake angle (15 ° to 25 °). In cross-cut saws, the γ angle usually ranges from 5-10 °. Versatile cross and rip saws have an average rake angle. usually 15 °.
The values of the grinding angles are determined not only by the cutting direction, but also by the hardness of the saw material. The higher the hardness, the smaller the anterior and posterior angles (less tapering of the tooth).
The rake angle can be not only positive, but also negative. Saws with this angle are used for cutting non-ferrous metals and plastics.
Basic principles of sharpening
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When sawing solid workpieces, the flanks are also subject to rapid wear.
Do not overtake the saw. The radius of curvature of the cutting edge should not exceed 0.1-0.2 mm. In addition to the fact that when the blade is very dull, productivity drops dramatically, it takes several times longer to grind it than sharpening a normal dull blade. The degree of dullness can be determined both by the teeth themselves and by the type of incision they leave.
Correct sharpening of circular saws should ensure, at the same time, that the cutting edge is properly sharpened to ensure the maximum number of cutters, which in the optimal case can be up to 25-30 times. For this purpose, it is recommended to use a carbide tooth, which should be ground along the front and back planes. In fact, teeth can be ground along one front plane, but the amount of possible sharpening is almost half that when sharpening on two planes. The figure below clearly shows why this is happening.
The last run when sharpening saw blades is recommended to be done on the back plane of the tooth. Standard value for metal removal. 0.05-0.15 mm.
Before sharpening, the saw must be free of dirt such as resin and the values of the grinding angles must be checked. On some saws, they are written to disk.
Equipment and materials for sharpening saw blades
When using abrasive discs (especially diamond wheels), it is advisable to cool them.
As the temperature rises, the microhardness of abrasive materials decreases. An increase in temperature to 1000 ° C reduces the microhardness by almost 2-2.5 times compared to the microhardness at room temperature. An increase in temperature to 1300 ° C leads to a decrease in the hardness of abrasive materials by almost 4-6 times.
How to sharpen saw blades yourself with a simple tool
Sharpen tungsten carbide disks very easily with the help of the simplest device, but such disks times
How to sharpen a saw blade with your own hands
Dull saw blade on my Makita 2704. There is no finance to buy a disc from Makita or SMT at the moment
Using water for cooling can lead to rust on machine parts and components. To eliminate corrosion, water and soap are added to water, as well as some electrolytes (sodium carbonate, soda ash, trisodium phosphate, sodium nitrite, sodium silicate, etc.), which form protective films. In conventional sanding, soap and soda solutions and fine sanding are most often used. low-concentration emulsions.
However, when grinding saw blades at home with low intensity grinding work, the wheel is often not used to cool the wheel. not wanting to waste time on it.
To increase the grinding ability of abrasive discs and reduce specific wear, select the largest grain size that provides the required surface finish of the sharpened tooth.
To select the grit size of the abrasive according to the grinding stage, you can use the table in the article on grinding rods. For example, if you are using diamond wheels, you can use 160/125 or 125/100 grit wheels for roughing. 63/50 or 50/40. Wheels with grit sizes from 40/28 to 14/10 are used to remove teeth.
The peripheral speed of the wheel when sharpening carbide teeth should be about 10-18 m / s. This means that when using a circle with a diameter of 125 mm, the engine speed should be around 1500-2700 rpm. Sharpening of more brittle alloys is performed at a lower speed from this range. When sharpening carbide tools, the use of hard mods leads to the formation of increased stresses and cracks, and sometimes to grinding of the cutting edges, while the wear of the wheel increases.
When using saw blade sharpeners, the relative position of the saw blade and the grinding wheel can be changed in different ways. movement of one saw (the motor with the circle is stationary), the simultaneous movement of the saw and the engine, only the movement of the motor with the circle (the saw blade is stationary).
Machines of various functions are produced. The most complex and expensive programmable complexes are capable of providing a fully automatic grinding mode, in which all operations are performed without the participation of a worker.
In the simplest and cheapest models, after installing and securing the saw in a position that provides the required sharpening angle, all further operations. turning the saw around its axis (turning on the tooth), feeding for grinding (contact with the wheel) and controlling the thickness of the metal removed from the tooth. are made by hand. It is advisable to use such simple models at home when the sharpening of circular saws is episodic.
An example of the simplest machine for is the system, the photo of which is shown in the photo below. It consists of two main units. motor with circle (1) and support (2), on which the sharpened saw is installed. The rotating mechanism (3) serves to change the blade angle (when sharpening the teeth with a beveled anterior plane). The screw (4) moves the saw along the axis of the abrasive wheel. This ensures that the set value for the front grinding angle is set. The screw (5) is used to set the stopper in the desired position, preventing excessive penetration of the disc into the interdental cavity.
Saw blade sharpening process
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The saw is mounted on a mandrel clamped with a tapered (centering) sleeve and nut, and then installed in a strictly horizontal position using the mechanism (3). This ensures that the angle of inclination of the front plane (ε 1) is equal to 0 °. In grinding disc machines that do not have a built-in angular scale in the tilt mechanism, this is done using a conventional pendulum goniometer. In this case, check the levelness of the machine.
The rotation of the screw (4) of the mechanism providing horizontal movement of the mandrel with the circle sets the required cutting angle. In other words, the saw is moved to a position where the front plane of the tooth fits snugly against the working surface of the wheel.
The marker marks the tooth from which sharpening begins.
The engine is on and the front plane is pointed. inserting the tooth into contact with the wheel and several movements of the saw back and forth while pressing the tooth on the wheel. The thickness of the metal to be removed is controlled by the number of grinding movements and the force of pressing the tooth against the abrasive wheel. After sharpening one tooth, the saw is removed from contact with the wheel, it includes one tooth and the sharpening operation is repeated. And so on, until the marker makes a full circle, showing that all the teeth are pointed.
Tooth sharpening is inclined on the front plane... The difference between sharpening a beveled tooth and sharpening a straight tooth is that the saw cannot be set horizontally but tilted. with an angle corresponding to the angle of inclination of the front plane.
The saw blade angle is set using the same pendulum goniometer. First, a positive angle is set (in this case 8 °).
After that, every second tooth is sharpened.
After half of the teeth have been sharpened, the tilt angle of the saw blade changes from 8 ° to 8 °.
And every second tooth is sharpened again.
Rear plane sharpening... To sharpen a tooth on the back plane, it is necessary that the saw blade grinder allows the saw to be positioned so that the back plane of the tooth is in the same plane with the working surface of the abrasive wheel.
If there is no machine for sharpening saw blades
Maintain the required sharpening angles while holding the saw in your hands with the weight. The task is impossible even for a person with a unique eye and enviable rigidity of hands. The most reasonable thing in this case. to create a simple sharpening device that allows you to fix the saw in a certain position relative to the circle.
The simplest of these tools for grinding is a stand, the surface of which is at the same level as the axis of the grinding wheel. By placing the saw blade on it, you can ensure that the front and back planes of the tooth are perpendicular to the saw blade. And if the upper surface of the stand is made mobile. fixing one side to the hinged, and the other. Supported by a couple of bolts that can be screwed on and off. then it can be installed at any angle, giving the ability to sharpen an oblique tooth on the front and back planes.
True, in this case, one of the main problems remains unresolved. Extracting the same front and back corners. This problem can be solved by fixing the center of the saw in relation to the abrasive wheel in the desired position. One way to do this. Make a groove in the arbor support surface on which the saw is mounted. By moving the frame with a circle in the groove, it will be possible to maintain the required cutting angle of the tooth. But for sharpening circular saws of different diameters or sharpening angles, it must be possible to either move the motor or the support, and with it the groove. Another way to provide the desired sharpening angle is simpler and install on the step of the stops, which fix the disc in the desired position. There is a video demonstrating this adaptation at the end of the article.
Quality control of sharpening
GOST 9769-79 sets certain tolerance values for grinding parameters. The final blows of the tips of the teeth should not exceed 0.2 mm (for saws with a diameter of up to 400 mm), radial. 0.15 mm. The beating is checked using a conventional indicator.