Sharpening carbide-tipped circular saws
Circular saws are tools that are used regularly in the woodworking and construction industries. A circular saw works with a variety of materials and the quality of the cut is of great importance. Sooner or later, the question of restoring the saw teeth arises. The ability to carry out this work at a high professional level will make it possible to use the cutting tool for a long time.
You can sharpen the tool with your own hands (if it does not have a winning coating) at home on your own. And also in such cases, you can use a simple machine on which you can successfully sharpen any edges. It is very important to choose the right circle.
They are of the following types:
Grinding equipment for soldered discs is not cheap and can only be found in specialized technical centers.
Recovers to move the sharpening independently:
- It costs extra labor;
- Manual movement accuracy will be poor;
- If there is no skill in sharpening circles, then it is recommended to turn to professionals.
There are rules:
- The main defect occurs on the edge from above, that is, the edges are rounded within 0.11-0.31 mm. this is the starting point from which sharpening should be started;
- Both the front and rear parts should be processed, this should be done at least 26 times;
- The size does NOT exceed 0.051-0.151 mm;
- Front and back faces are processed identically;
- After the end of the cycle, you should implement the finishing process, that is, clean the surface with “zero” sandpaper.
The work on creating a new configuration requires compliance with the rules and has its own complexity.
- Read the requirements, in particular, check the number of revolutions. It is clear that for metal this figure will be noticeably lower. Wooden elements are processed at a high speed.
- The material from which the drinks are made can withstand heavy loads, its service life is significant, but even it sooner or later gets defects, chips and cracks appear.
- A sure sign that the material is beginning to “get tired” is the appearance of micro burrs and roughness on the surface. Defects will appear in THESE places after a while.
To correctly implement sharpening, you should know what teeth are:
- A bevel tooth from the back;
- In the form of a cone;
How to sharpen:
- The disc should be thoroughly cleaned using alcohol or chemicals;
- All work planes are processed;
- To remove metal, let’s say 0.051-0.151 mm;
- Sharpen, perhaps no more than twenty-five times;
- You can sharpen with a special file, if there is practical experience;
- Carbide teeth are recommended to be sharpened on separate equipment;
- Victorious solders can be “taken” only by using a special machine in which there is a diamond wheel.
There are several types of tooth set.
- Wavy, each tooth is straightened at a certain angle of inclination, thus, a semblance of a wave appears.
- Protective, two teeth have tilt angles, the third tooth is present without tilt. This method is effective even when working with mahogany and oak.
- Classic, when the teeth are variable. angles of inclination to the left and right.
- Tilt in the frontal plane.
- Tilt in the back plane.
There is one more parameter. this is the taper angle, but it usually “works” as an additional tool.
For manual sharpening you will need:
- Wooden blocks (2 pieces measuring 52×32 mm);
- Drill, screwdriver;
- Crown for a screwdriver;
- A hacksaw to work ceramics;
- Screws or self-tapping screws.
The surface of the stand is the same as the surface of the disc. The circle lies on a stand, the sharpening plane should be at an angle of 90 degrees to the saw blade. Such a simple device is equipped with a swivel unit. This secure fixing allows you to evenly process all the teeth of the tool. With the help of a marker, you make markings, which makes it possible to correctly determine the angle of inclination.
Varieties of dust
If the disc is correctly sharpened and the teeth are set according to the template, then it can process the workpiece in any direction with wood fibers.
There are such types of tools:
- Saw with carbide discs;
- Discs made of solid metal;
- Discs with teeth treated with hard material;
- Discs with heavy-duty brazed teeth.
Hard woods are processed with discs, which have special grooves. Technological breaks prevent deformation of the tool, and do not allow it to overheat during the production cycle. And also vibration, noise background is significantly reduced, the quality of the mowing line formed by the cut is improved. The saw has teeth that are machined at a specific angle, each tooth has multiple cutting edges.
There is a main edge, additional ones are mated with it, and intersecting planes are formed:
The planes themselves also vary in different mates.
The teeth can be straight and are usually used for pre-cutting the material. These teeth provide a low cut. However, the performance in such teeth is quite high.
Beveled teeth provide a more accurate line and are suitable for materials such as:
- PVC sheets;
The teeth provide a smooth cut, while the material does NOT chip.
There are also discs in which there is a bevel at the leading edge of the cutter, there is also a bevel with a trailing edge. Variants of alternating different teeth with different bevels are possible. Such tricks ensure a clean cut, but remember: the denser the material, the faster such teeth become blunt.
Trapezoidal tooth. This tooth configuration ensures long tool life. A complex design is often used, when trapezoidal and straight teeth alternate. The second ones carry out the primary with slots, which makes it possible for the teeth of a straight shape “polishers”.
Cone-shaped tooth. these teeth are auxiliary and are designed to work with materials on which there is a laminated surface. They ensure correct spray without chipping.
Sickle tooth. in this case, the teeth are bent, which makes it possible to accurately spray the material across the wood fibers.
All equipment that provides sharpening has one principle of operation. Differences are only present in equipment performance.
The tool kit includes an abrasive disc and a grinding material.
Using machines to sharpen teeth provides a number of advantages:
- The ability to adhere to a given angle,
- Increases the efficiency of production operations and their speed;
- It is possible to use a variety of discs.
The machine can even work with hard metal coatings. Grinding wheel grit varies. As an example, we can say that if the diameter is 126 mm, then the speed can be 2300 rpm.
The rotation speed of the disc can deviate within the range of 510-720 rpm, it all depends on what coefficient of fragility the disc has.
Here the functionality of the installation depends on whether the workpiece or the spindle will move. The movement of the entire device is also possible.
The angle of inclination can be measured using a pendulum protractor, some units have a built-in scale to determine the angle of inclination of the teeth.
Teeth are usually sharpened first from the front, then from the rear.
The units have circles of the following parameters:
- Thickness from 15 to 42 mm;
- Outer diameter 11-252 mm;
- Mounting hole (16, 20, 33 mm).
Much depends on the performance characteristics of the abrasive, they should be emphasized.
Determination of the degree of wear and the angle of sharpening
Circular saws, sooner or later, lose their performance characteristics during operation, it is possible to effectively extend the service life of the tool if it is properly sharpened again. This operation is simple, in many cases you can do the work yourself.
First of all, you should have an idea: what parameters the working disk of the unit has. The second most important parameter is the sharpening angle, what parameters does the tooth itself have.
Before you start working, you should test the tool, the concepts of how relevant its restoration is. The disc should be inspected by removing it from the machine. An important indicator is the change in size, this can be seen even with a cursory examination.
The knobs themselves are made of ultra-strong steel of the brand:
- 50 HVA;
And also some other steel grades are used.
This material stands out for its strength and wear resistance, but it also requires preventive treatment.
The teeth themselves have a standard prescribed in GOST 9768-78, however, each manufacturer has a differentiation in the angles of inclination and shape.
In the absence of a template, it will be necessary to determine the parameters of the teeth yourself. For this there is a tool. a pendulum protractor. With this tool, you can precisely align the sharpening angle.
Another option is to take a new disc and use it as a template. You should take a letter from thick cardboard, draw precise outlines on it with a pencil. Then, using a pendulum angle meter, the exact configuration of the soldering should be established. It is recommended to save this sample, it will be possible to work with it in the future, Using as a reference.
After the end of the work, it will be necessary to test the obtained sample, compare with the standard. The angle of inclination in such saws ranges from 15 to 25 degrees.
Consider when starting work: the rake angle can be negative. Similar models are used to work with PVC letters, as well as with soft metals.
The need for a procedure
Circular saws are needed both in private households and in production. When building a house, creating furniture, cutting boards, beams. a similar tool is required everywhere. Sharpening a circular saw correctly requires practical skills and knowledge.
Circular saws compare favorably with the second cutting tool:
Disc circular devices have significant performance, and their service life is also much longer. Sharpening circular saws is an important necessary step, without it the tool will not work fully. Thanks to various carbide-tipped nozzles and victorious coatings, cutting can be carried out both with wood and with metals.
To sharpen discs with different attachments, special equipment is required. If the processing of the disk is done “according to science”, it will greatly extend its service life.
Timely sharpening of circular saws is performed with several obvious signs.
- The engine begins to experience unnecessary stress. The reason is simple. the teeth are dull, and additional resources are required to process the material. There is a danger: if the disk is damaged, if the engine shutdown relay is missing, the machine may fail.
- If chipping and chips form on the cut, and the cut itself becomes too wide, then this is a sure sign. the tool should be repaired.
- There is a foreign smell of burnt material, and dark spots are visible on the cut line.
- The time it takes to process the part increases.
And finally, a few tips from experts:
- The frontal part should be monitored more closely;
- When working with massive elements, the lateral planes are exposed to heavy loads;
- Rounding along the radius is NOT more than 0.21 mm;
- The teeth are most reasonable to handle both from the front and from the back;
- Metal removal parameters must NOT exceed 0.151 mm;
- The disc is cleaned before starting work, also should check all the corresponding corners;
- Sharpening teeth at the right angle requires practical experience, in the absence of such, it is better to take the disc to a workshop;
- Circles on which there is diamond dusting should be cooled with a special coolant liquid;
- The unit designed for sharpening circular knives is capable of working with the workpiece in only one plane;
- The teeth must not be allowed to wear out before rounding by more than 0.21 mm, otherwise it will be difficult to make a normal sharpening;
- Usually a disc has a resource of no more than 36 sharpenings, and it does not matter which unit is used for processing;
- It is important to ensure that the metal during processing does not receive any defects (chips, cracks, notches), their appearance can provoke further destruction of the material.
How to Sharpen Carbide Tipped Circular Saws. Next.
Material and properties of carbide teeth
In domestic saws, sintered tungsten-cobalt alloys of VK (VK6, VK15, etc.) are used as the material for cutting plates. The number means the percentage of cobalt). In BK6 the hardness is 88.5 HRA, in BK15. 86 HRA. Foreign manufacturers use their own alloys. VK hard alloys consist mainly 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.
Fasten the carbide plates to the disc by high-temperature brazing. As a material for soldering, at best, silver solders are used (PSR-40, PSr-45), at worst. Copper-zinc solders (L-63, MNMTs-68-4-2).
Saw blade sharpening process
The saw is installed on a mandrel, clamped using a tapered (centering) sleeve and nut, then set in a strictly horizontal position using the mechanism (3). This ensures the bevel angle of the front plane (ε1) Equal to 0 °. In machines for sharpening discs, and not having a built-in angular scale in the tilt mechanism, this is done using a conventional pendulum goniometer. In this case, check the horizontal position of the machine.
By turning the screw (4) of the mechanism providing horizontal movement of the mandrel with the circle, the required rake angle is set. In other words, the saw moves to a position in which the front plane of the tooth fits snugly against the working surface of the wheel.
A marker is made to mark the tooth from which sharpening begins.
The engine is turned on and the front plane is sharpened. Bringing the tooth into contact with the circle and Several movements of the saw back and forth while pressing the tooth against the circle. The thickness of the metal to be removed is regulated by the number of sharpening 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, rotated by one tooth and the sharpening operation is repeated. And so on until the marker mark does NOT make a full circle, indicating that all the teeth are sharpened.
Tooth sharpening, skewing along the front plane. The difference between sharpening a skewed tooth and sharpening a straight one is that the dust must be installed not horizontally, but with an inclination. With an angle corresponding to the bevel angle of the front plane.
The tilt angle of the saw is set using the same pendulum protractor. First, a positive angle is set (in this case 8 °).
After that, every second tooth is sharpened.
After sharpening half of the teeth, the tilt angle of the saw blade changes from 8 ° to 8 °.
And every second tooth is sharpened again.
Rear sharpening. To sharpen a tooth along the back plane, it is necessary that the saw blade sharpening machine allows setting dust in such a way that the back plane of the tooth is in the same plane with the working surface of the abrasive wheel.
Sharpening circular saws
Basic principles of sharpening
When cutting massive workpieces, side edges are also subject to rapid wear.
Do not dull the saw too much. The radius of curvature of the cutting edge should NOT exceed 0.1-0.2 mm. In addition to the fact that when working with a very blunt saw, productivity drops sharply, it takes several times longer to sharpen it than to sharpen a saw with a normal bluntness. The degree of bluntness can be determined both by the teeth themselves and by the type of cut, which they leave.
Correct sharpening of circular saws consists in ensuring the maximum number of sharpenings, which in the optimal case can reach 25-30 times, while ensuring the proper sharpness of the cutting edge. For this purpose, it is recommended to sharpen the carbide tooth on the front and back planes. In fact, the teeth can be sharpened along one front plane, but the number of possible sharpenings is almost two times less than when sharpening along two planes. The figure below illustrates why this is happening.
The last pass when sharpening saw blades is recommended to be done along the back plane of the tooth. Standard metal removal rate. 0.05-0.15mm.
Before sharpening, remove any dirt such as resin from dust and check the sharpening angles. On some saws they are written on the disc.
If there is no saw blade sharpener
Precisely maintain the required sharpening angles, keeping the dust in your hands by weight. An unbearable task even for a person with a unique eye and enviable firmness of hands. The most reasonable thing in this case. Make the simplest sharpening device, which makes it possible to fix dust in a certain position in relation to the circle.
The simplest of such devices for sharpening circular saws is a stand, the surface of which is flush with the axis of the grinding wheel. Put a saw blade on it, you can ensure the perpendicularity of the front and rear planes of the tooth in relation to the saw blade. And if the upper surface of the stand is movable. By pivoting one side and the other. Resting on a couple of bolts that can turn in and out. Then it can be installed at any inclination, getting the opportunity to sharpen an oblique tooth along the front and back planes.
True, in this case, one of the main problems remains unresolved. Keeping the same front and rear sharpening angles. You can solve this problem by fixing the center of the saw with the abrasive wheel in the desired position. One way to implement this. Make a groove on the surface of the stand for the mandrel on which the saw is installed. Move the mandrel with the circle along the groove, it will be possible to maintain the required rake angle of the tooth sharpening. But for sharpening circular saws with different diameters or sharpening angles, it must be possible to either move the motor or the stand and the groove with it. Another way to ensure the required sharpening angle is simpler, and is to install the fixing disc in the desired position on the table. At the end of the article there is a demonstration of such a device.
Equipment and materials for sharpening saw blades
When using abrasive wheels (especially diamond), it is desirable to cool them with coolant.
With increasing temperature, the microhardness of abrasive materials decreases. An increase in temperature to 1000 ° C reduces the microhardness by almost 2-2.5 times in comparison with the microhardness at room temperature. An increase in temperature to 1300 ° C causes a decrease in the hardness of abrasive materials by almost 4-6 times.
The use of water for cooling can lead to rust on the parts and assemblies of the machine. To eliminate corrosion, soap and certain electrolytes (sodium carbonate, soda ash, trisodium phosphate, sodium nitrite, sodium silicate, etc.) are added to the water, which form protective films. For normal sanding, soap and soda solutions are most often used, and for fine sanding. Low-concentration emulsions.
However, when sharpening saw blades at home with a low intensity of sharpening work, they do not resort to cooling the wheel so often. Do not want to waste time on this.
To increase the productivity of grinding with abrasive wheels and reduce specific wear, you should choose the largest grain size, which ensures the required surface cleanliness of the sharpened tooth.
To select the grit size of the abrasive, in accordance with the sharpening stage, you can use the table in the article on sharpening bars. For example, in the case of using diamond wheels for rough grinding, wheels with a grain size of 160/125 or 125/100 for finishing can be used. 63/50 or 50/40. Wheels with grit sizes 40/28 to 14/10 are used for chipping.
The peripheral speed of the wheel when sharpening carbide teeth should be about 10-18 m / s. This means that when using a 125 mm diameter wheel, the engine speed should be around 1500-2700 rpm. Sharpening of more brittle alloys is carried out at a lower speed from this range. When sharpening carbide tools, the use of hard modes leads to the formation of increased stresses and cracks, and sometimes to chipping of the cutting edges, while the wear of the wheel increases.
When using machines for sharpening circular saws, the change in relation to the position of the saw and the grinding wheel can be realized in different ways. Moving one saw (the motor with the wheel is stationary), the simultaneous movement of the saw and the motor, only the movement of the motor with the wheel (the saw blade is stationary).
A large number of sharpening machines of various functionality are produced. The most complex and expensive programmable complexes are capable of providing a fully automatic sharpening 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 per tooth), feeding for grinding (putting it in contact with the wheel) and controlling the thickness of the metal removed from the tooth. Produced by the worker manually. It is advisable to use such simple models at home, when the sharpening of circular saws is occasional.
An example of a simple machine for sharpening circular saws 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 mounted. The turning mechanism (3) is used to change the angle of inclination of the blade (when sharpening teeth with a beveled front plane). The screw (4) moves the saw along the axis of the abrasive wheel. This ensures the setting of the required rake angle. The screw (5) is used to set in the desired position of the limiter, which prevents the disc from excessively entering the interdental cavity.
Carbide tooth geometry
The following types of teeth are distinguished by shape.
Straight tooth. Typically used in rip saws where quality is not critical.
Oblique (beveled) tooth with left and right angles of inclination of the posterior plane. Teeth with different inclination angles alternate with each other, which is why they are called alternately cut. This is the most common tooth shape. Depending on the size of the sharpening angles, saws with alternating teeth 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 as scoring saws when cutting boards with double-sided lamination. Their use allows you to avoid coating chips at the edges of the cut. Increased bevel angle Reduces cutting force and reduces the risk of chipping, but at the same time reduces tooth life and strength.
Teeth can be inclined Not only back, but also front plane.
Trapezoidal tooth. A feature of THESE teeth is the slow speed of blunting of the cutting edges in comparison with alternating cut teeth. They are usually used in combination with a straight tooth.
Alternating with the latter and slightly rising above it, the trapezoidal tooth performs rough sawing, and the straight one following it. Fine. Saws with alternating straight and trapezoidal teeth are used for cutting boards with double-sided lamination (chipboard, MDF, etc.), as well as for sawing plastics.
Conical tooth. Tapered saws are auxiliary and are used to cut the lower layer of the laminate, preventing it from chipping when passing the main saw.
In the vast majority of cases, the front face of the teeth is flat, but there are saws with a concave front face. They are used for fine cross-cutting.
Sharpening angles of teeth
The sharpening angles are determined by the purpose of the saw. Those. The cutting of which material and in which direction it is intended. Rip saws have a very large rake angle (15 °.25 °). In cross-sawing dust, the angle γ usually ranges from 5-10 °. Versatile saws designed for cross and rip sawing have an average rake angle. Usually 15 °.
The values of the sharpening angles are determined not only by the direction of the cut, but also by the hardness of the material being cut. The higher the hardness, the smaller the front and back angles should be (less sharpening 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.
Sharpening quality control
GOST 9769-79 establishes certain values of tolerances for sharpening parameters. The face runout of the tops of the teeth does not have to 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 dial gauge.
The deviations of the sharpening angles should not exceed:
- For the front corner. ± 1 ° 30 ‘;
- For the back angle and bevel angles of the front and rear planes. ± 2 °;
Saw Blade Wear Signs
Circular saws, subject to all the rules of operation and careful care, have reliability and durability, but, like any tool, they require preventive maintenance from time to time. If difficulties become noticeable during the operation of this equipment and dark marks appear on the surface of the material, it means that the edges of the cut are burnt from the excessively heated saw teeth. Combined with smoke and an unpleasant odor during operation, which can occur from overheating of the engine casing, this most likely indicates that the tool requires immediate sharpening.
Circular disk layout.
A dull disc increases the load on the mechanism many times over and can lead to its complete failure. Most of the wear occurs on the top cutting edge of the teeth on the circular saw blade. To prevent the bluntness of the tool from becoming excessive, you should regularly check the radius of rounding of the cutting edge, which according to the Rules should exceed 0.1-0.2 mm. It is possible to determine that an urgent sharpening of a circular saw is needed by the shape of the cut itself. Regular sharpening of the disc will not only prolong the life of the equipment, but will also increase productivity, as well as reduce the time and effort spent on cleaning up completely worn out tools.
How to properly sharpen a circular saw with your own hands?
A circular saw, which, according to old memory, is still called a circular saw, is an indispensable tool for the owner of a private household. It copes equally well with wood and drywall, non-ferrous metal or acrylic glass, but one of the conditions for high-quality and trouble-free operation is regular sharpening of the cutting blade. The cleanliness and durability of this tool is much higher than that of other types of sawing products for hard materials.
A circular saw (circular saw) is designed for cutting a wide variety of materials. In the process, the teeth become dull and need to be sharpened correctly.
The circular is in no way inferior to the popular chain chainsaw, and even surpasses it in many ways in capabilities. With its help, you can make a transverse, longitudinal or oblique cutting of the material required for the construction or manufacture of joinery. The number of teeth on a circular saw blade depends on the hardness of the material being processed, but in any case, its smooth movement can only be ensured by correct setting and sharpening of the teeth.
Do-it-yourself circular saw sharpening
The method of sharpening a circular disc depends on the availability of the necessary tools at hand. If it is not possible to use a special machine for this purpose, then a good result can be achieved having a minimum set in the form of a file, a vice and a pair of wooden blocks to secure the disc.
Circular disc sharpening scheme on the machine.
It will be more convenient to sharpen the part if you do not remove it from the machine, but first you must not forget to disconnect the equipment from the power supply. To begin with, you need to ensure that the disc is securely fixed using wooden blocks placed under it on both sides. A toothed disc, which is separate from the saw, is placed in a vice, clamped with wooden wedges. It is better to mark the first tooth, from which processing will begin with a bright marker, so as not to perform actions on the second circle.
Work should be started from the back surface. When sharpening the teeth, it is necessary to control the uniformity of the applied forces as much as possible and try to maintain the same number of file movements in each case. In order to train your hand in this action, you can use an old hacksaw for a start, which will not be spoiled by a complaint.
Quality control on the point of the disc is carried out during a trial cut. Uneven material advance and extraneous noise may indicate that the teeth are at different levels. This can be detected by bringing the marker close to the cutting edge of the blade and making it a full turn in the opposite direction of normal operation. Teeth that have received marks require re-filing.
Types of setting circular saws
The complexity of the wiring process is due to the need to move the teeth to the side at the same distance. This can be achieved by using a factory circulating dust distribution device. Each tooth should be started from the middle of its size. For wood materials of different density, the degree of setting the teeth should be different, or, without going into details, we can say that they are bred wider for sawing soft species than for hard ones.
There are three main wiring methods:
- Stripping type wiring. This method boils down to the fact that the tooth after two remains in its place without change, the rest are rejected in different directions. This saw preparation is good for working with solid wood.
- A variant of the classic setting, when the saw teeth alternately move to the right and then to the left. This versatile method can be applied to almost all types of dust.
- The so-called Wavy layout, a distinctive feature of which is the retraction of the teeth not at a strictly defined distance from the center, but at different distances with a deviation of 0.3-0.7 millimeters.
Do-it-yourself dust sharpening at home
When working with a disc, the main thing is not to spoil the cutting surface, and this can easily happen if the hand trembles, the feed angle is violated. In order to avoid negative consequences, you should study the sharpening methods, and then everything will turn out right. Distinguish between a manual method of restoring cutting elements of a circular saw and a method using sharpening equipment.
How can you sharpen a circular saw
- Special wheels for sharpening saws, made on the basis of diamond abrasives.
- A normal file for sharpening a saw, but it also needs pressure to hold the saw and a block of wood used as a guide.
- Processing on professional equipment. The fastest and highest quality way of sharpening, but requiring large material costs for purchasing a tool.
When to sharpen a circular saw
There are very definite signs by which one can judge the state of the instrument. Dust sharpening is necessary when the following is clearly manifested:
- During operation, smoke appears, a specific smell of burnt wood, the casing covering the saw teeth begins to heat up quickly.
- When moving the tool along the workpiece, you need to Apply Significant efforts, as it were, to push the dust forward.
- After cutting the material and visual inspection of the sawn edge, black carbon deposits or a lot of chips, fiber scuffing, chipped areas are visible.
- When you carefully examine the saw teeth in a magnifying glass, you can see that the cutting parts have NOT sharp, but rounded edges.
All this requires an immediate cessation of work, otherwise there is a great risk of damage to the material and wear of the circular saw to a state where sharpening will no longer help her.
It is possible to independently sharpen the teeth by hand using a file, so that it is of high quality, if they do not have a slant, that is, the surface of the front face is perpendicular to the surface of the blade. The process looks like this:
- A block is prepared from dense wood with a section of somewhere 50×50 mm and a length of 100 mm. The sides of the bar Must be located strictly perpendicular to each other.
- Mark any tooth with a marker, which will be reportable and the first to be processed.
- The saw blade is clamped in a vice together with a bar in such a way that the front edge of the workpiece is flush and in the same plane with the surface of the bar (in this case, the bar acts as a guide for the file).
- A thin file (its thickness should allow it to fit freely into the cavity between adjacent teeth) is applied to the surface of the tooth to be treated and at the same time to the bar and methodically back and forth, sharpening is carried out.
- This is how each tooth is gradually sharpened, Monitor the condition of the bar and, when working out its surface, slightly shift the plane.
General rules for sharpening circular saws
- First of all, the main faces are processed, of which the front wears out more.
- In extreme cases, with severe wear of the side faces, correct them.
- At a time, they remove no pains 0.15 millimeters of the saw metal thickness.
- When finishing the edges with an electric tool, overheating of the metal is not allowed, in which case its properties deteriorate.
- To ensure the maximum service life of the saw, when it can be sharpened up to 30 times, both edges should be sharpened: both the front and the back, removing the same amount of metal.
- Sharpening the dust of the circular is not allowed with tools NOT intended for this, for example an angle grinder and a disc for cutting metal.
After carrying out the basic sharpening operations, you can refine the teeth with fine sandpaper. The quality control of the sharpening of the tool takes place in working conditions If everything is in order, the material will be cut clean, smooth, without visible defects and blackening.
How to properly sharpen a circular saw blade
The sharpening of circular saws must be carried out regularly to avoid damage to the building material. We will tell you how to properly sharpen a saw blade with and without solders, what equipment and tools to use.
The disc tool for sawing wood is always useful in construction. The circular saw is convenient in that it allows you to quickly cut the material with minimal effort and time. As for the quality of the cut, we can say that it is perfect, but only when the saw is serviceable and well sharpened. Otherwise, it is even dangerous to work with such a tool, so you should sharpen the circular saw.
Determining the need for a sharpening operation is not difficult: a blunt tool cuts the workpiece poorly, which immediately catches the eye. There are two options here: either send the disc to a workshop, which is not always beneficial in terms of time and money, or sharpen the circular saw with your own hands. This may seem daunting at first glance. But if you delve into the essence of the saw device in more detail, it will not be difficult to perform tool maintenance at home.
The main sharpening angles of circular saws
The front face, and that the first one cuts into the workpiece along the movement of the saw, forms the main cutting edge with the rear face. The angle at which the front face meets the material is called the Y-angle (attack angle). The angle between the back face and the front face is the taper angle. If you subtract the rake angle and the taper angle from 90 degrees, you get the clearance angle.
In practice, it is important to observe these angles when sharpening for each type of disc. It is according to the front angle that the saws are divided into types:
- Longitudinally cutting where the rake angle should be within 15-25 degrees.
- Transverse cutting, where it is permissible to sharpen the front face of the tooth at an angle of 5-10 degrees.
- Universal discs, which are easy enough to cope with both longitudinal and transverse cuts, their rake angle should be maintained in the region of 15 degrees.
The angle of the bevel of the rear and front planes is also important: the sharper it is, the easier it is for dust to enter the material, but wear is faster.
With the help of a special machine, circular saws can be sharpened very easily and quickly. The main thing is not necessary here. Watch the angle of the disc feed. Once having set it, the operator only has to move the teeth into the processing area and make light presses of the tooth plane against the rotating diamond disc.
This equipment can be used to sharpen carbide-tipped circular saws and conventional circular saws. The simplest machine for grinding operations of circulating dust has the following structural elements:
- An electric drive with a grinding wheel mounting system is a stationary part of the equipment.
- A stand that moves along the guides. its task is to feed the saw blade into the processing area.
- Saw blade holder on a stand, which is designed to keep the blade in a constant position when it is fed to the sharpening wheel.
If you have additional questions about sharpening saws or you have your own experience in carrying out such operations, please respond in the comments! Your comments are important to us!
How to sharpen a circular saw blade correctly and at what angle
The use of circular saws is especially common in construction. Most of the work requires cuts and changes in the shape and size of the finished materials. The circular saw helps you tackle these tasks quickly and get quality results. But the instrument is NOT capable of serving forever, sooner or later it may become dull. It is for this that you need to know exactly how you can eat saw teeth in a domestic environment.
- How to determine wear?
- Types of cutting teeth
- Sharpening principles and angles
- How to sharpen: basic methods
- Manual way
- Using a machine
Types of cutting teeth
There are four planes on the surface of the teeth. front, back and two side.
At the moment of intersection with each other, they create a single cutting edge, due to which the sawing of surfaces occurs.
There are several forms of teeth:
- Straight tooth. Most often it is used only for a quick longitudinal cut. During such work, quality and accuracy are practically NOT important.
- Oblique tooth. The back plane in such a part is tilted to the right or left. On saws, these teeth often alternate, which is why they got the name “variable cut”. These teeth are most commonly used in tools. The size of the corners can be different, this is due to the coating of the treated surface. wood, chipboard, plastic. They are used for longitudinal and transverse movements. A large angle of inclination on the tools is used when cutting boards with double-sided lamination. This helps to avoid chipping of the material. The larger the chamfered corner, the easier the saw will cut through the surface. But this greatly increases the likelihood of tooth breakage. On some products, the teeth are inclined Not only at the back, but also at the front.
- Trapezoidal tooth. The main advantage of this type is that the edge blunts slowly. But they are rarely used separately, usually alternated with straight teeth. During the operation of the device, the trapezoidal teeth are located above the straight ones, therefore they take over the main (rough) sawing work. Straight teeth for finishing. This saw design is used for sawing plastic, chipboard and MDF.
- Conical tooth. This type of tooth is considered optional because it only helps to cut the lower part of the material (most often laminate). This design allows you to protect the surface from chips and cracks. Bevel teeth usually have a straight front edge, but it can also be concave. This type is used for finishing the saw cut.
How to determine wear?
Checking the saw blade for wear is an important issue that should be given special attention. Deep damage leads to the inability to sharpen the circle. There are three main signs by which you can understand that the dust needs to be sharpened or replaced:
- Excessive heating of the protective cover and formation of smoke. The circular saw has a special cover, which signals that the saw has become blunt due to heating. In especially difficult situations, smoke may appear from it.
- Sometimes the saw device involves a mechanical feed (if you need to adjust the pressure with your own hands). In such a situation, wear can be noticed if the pressure has to be increased.
- If carbon deposits form on the workpiece when sawing wood and a strong unpleasant odor.
All situations that are described above tell the user to sharpen the device.
It is allowed to sharpen the saw with your own hands only when using the Special tools. For this, there is a grinding machine that helps carry out the process on an automatic machine, and not manually. Then the result becomes more accurate.
In addition, other improvised devices are used for sharpening:
- Installation pressures;
- Piece of wood.
It will NOT work to replace the listed devices. If at least one of them is available, then sharpening will NOT work.
Sharpening principles and angles
There are four main sharpening corners on the saw edges. Together with the shape of the tooth, they can be the main operational characteristics of the tool. The following are used to describe each tooth:
- Front and back angle.
- Cut angles of the front and back surfaces.
These characteristics may depend on the type and weight of the circular saw, its purpose, as well as the density of a particular surface.
Sharpening angles in the diagram
Based on the parameters indicated above, all circulars can be divided into several types:
- For slotting longitudinal holes. When performing this task, use a rake angle of 15 to 25 degrees.
- For cross-cutting. In this situation, the rake angle can vary from 5 to 10 degrees.
- Universal sharpening. Saws are sharpened at an angle of 15 degrees for any operation.
The size of the sharpened angle is set Not only from the direction of movement of the saw, it is also related to the material of the workpiece. When cutting through very hard materials, the smallest angle should be chosen. To work with softer products, the angle increases.
Special machines for sharpening saw edges are rarely used in a domestic environment, because their cost is high. Therefore, in the absence of such a device, you can cope with sharpening with improvised devices, for example, an angle grinder. At the same time, it is forbidden to hold the circle in your hands without fixing the Ego with anything. Otherwise, it will NOT be possible to achieve a sufficient cutting angle for further work with the material.
To securely fix the circle in the correct position, use a flat stand.
- The surface of the stand coincides with the level of the grinding wheel wasp;
- On it, the gear circle is placed in such a way that the sharpening plane becomes perpendicular to the saw blade;
- The design of the device is complemented by a swivel joint.
The stand will help you to comfortably position the saw blade for cutting abrasive material. Before starting work, clear markings are carried out. A colored marker is used for this. They draw a mowing line, which will allow the element to be sharpened at the desired angle. Pressures will help secure the disc to the surface.
Sharpening circular saw blade angle grinder:
How to sharpen: basic methods
There are two methods available for sharpening circular saws. manual and machine. In order to sharpen the disc correctly at home, you need to take into account some of the nuances.
Using a machine
When the craftsman has access to a specially designed grinding machine, the processing of the elements is quick and efficient. This device is small in size, so it is comfortable for a beginner to work with it. There will be NO problems even when used in a domestic environment.
When buying such a device, look at the abrasive wheel. To select it, certain nuances are taken into account:
- It is best to purchase a wheel made of diamond-coated CBN or green silicon carbide;
- If the carbide wheel is sharpened, problems may arise even when using the machine.
The very process of using a sharpening machine is extremely simple. The operator must comfortably position the disc on the device and clamp it with the introduction of a special retainer. Before starting work, it is recommended to mark the first tooth with a marker. This will help NOT to get tangled during sharpening, AND not to check teeth that have already been processed. To select the sharpening angle, a special meter is provided on the device. The required angle should be set on it, after which the device will complete the task on its own.
The circular saw is a useful tool that is essential in construction. It helps to cut through surfaces, as well as change their shape and size. To sharpen the discs, use special machines or materials at hand. Doing the work with your own hands is not so difficult, you need to adhere to the listed recommendations and are not afraid.