How to Sharpen a Bow Saw Blade
A hacksaw (saw) for wood is in almost any home. It is one of the most common tools. Already in childhood, any person gets acquainted with her. The question immediately arises, how to sharpen a hacksaw on a tree.
The hardened teeth of a hacksaw are not subject to sharpening.
In various operations with wooden products, a hacksaw is actively used. Over time, the cutting surface becomes dull and sawing a tree becomes harder. Even a very simple sawing board requires a long time and considerable effort. In this case, there is no other way but to sharpen a hacksaw on a tree.
Features of wood hacksaw
The shape of the teeth of a saw for cutting wood.
A hacksaw is a saw made in the form of a steel blade, one of the edges of which performs the function of cutting. The cutting element of any hacksaw is a series of teeth cut at the edge of the blade at a certain angle. Large, medium and small teeth are distinguished by size. They have the following parameters: large. cut in the amount of 3-6 pieces per 1 inch with a step of 4-8 mm; small. in increments of 2-2.5 mm; medium. in increments of 3-3.5 mm.
Depending on the purpose of the hacksaw, the shape of the teeth can be different. When sawing wood across the fibers (transverse hacksaw), the cutting elements should be in the form of an isosceles triangle with an apex angle of about 40º for soft woods and 50-60º for hard woods. The teeth in this case are located vertically. For sawing wood in the longitudinal direction, a hacksaw with inclined cutting elements (longitudinal hacksaw) is used. The angle of deviation from the perpendicular is 10-20º. When sawing wood in both directions, you can use a hacksaw of a mixed type with a tilt of the cutting elements of not more than 10º.
To eliminate the effect of jamming of the blade during sawing, a wiring is made on the cutting edge. It is achieved by alternately tilting the teeth in different directions. The width of the wiring (the width of the hacksaw along the outer surface of the split teeth) must exceed the thickness of the steel sheet by 1.5-2 times. All teeth on the side edges are sharpened one-sided. The angle of sharpening is 60-75º. The top is pointed.
The need for sharpening a hacksaw
The scheme for sharpening a cross saw.
During operation of the hacksaw, the cutting edge of the blade is subject to wear. Firstly, the pointed tip of the tooth is rounded. Secondly, the lateral cutting edges of the teeth become dull and partially lose their function. Wear can be uniform and manifest on all teeth, but local is also possible, affecting only some of the teeth. In addition, tooth wiring parameters change over time. Some of them can increase the angle of inclination and this slows down the sawing. Often there is a decrease in the width of the wiring, which leads to wedging of the blade during sawing.
The moment when it is necessary to sharpen a hacksaw on a tree is determined in a practical way. First of all, sawing becomes a difficult process, requiring great effort. It is difficult to cut wood perpendicularly. When sawing, the blade is difficult to hold along the line. it begins to walk in different directions. Frequent jamming of the hacksaw blade is felt. An experienced worker can determine the wear of the cutting edge by changing the color of the teeth and the sound that occurs when sawing. All this suggests that it is time to sharpen a hacksaw.
Hacksaw tooth wiring requirements
Wiring and template for checking the correct breeding of the saw: a. wiring; b. template: 1. Projection; 2. Nut of the set screw; 3. Saw blade; 4. record; 5. Spring.
Hacksaw wiring sets the total width of the cutting part, determining the width of the cut. In turn, the wider the cut, the easier (without excessive friction) the movement of the blade during sawing, but this increases the complexity of sawing, due to the larger amount of wood. Based on practical considerations, it was found that the optimal wiring width should exceed the thickness of the hacksaw blade by 1.5-2 times when sawing hard wood and by 2-3 times for softwood. With a common blade thickness of 1 mm, the tooth layout in one direction should be 0.25-0.5 mm in the first case and 0.5-1 mm in the second.
The wiring quality significantly affects the sawing process. All teeth must be alternately bent in opposite directions by an equal amount. If some of them are bent to a larger angle than others, then they will impede the movement of the canvas and wear out faster. When reducing the width of the wiring, the width of the cut will not allow the blade to move freely, which will also make sawing more difficult.
Important: it is impossible to bend the teeth towards their base, as this can lead to their destruction, the tooth is bent in its middle part.
To prevent the tooth from breaking during wiring, do not bend it whole.
Before sharpening the cutting element, it is necessary to check and correct the wiring of the teeth. The quality of the wiring is checked visually and by measuring the width of the wiring.
Hacksaw teeth are bred using a special tool. wiring. Elementary wiring is a small metal plate with a handle. A slit is made in the plate, with a width slightly larger than the thickness of the hacksaw blade. To improve the quality of breeding, you should use a wiring with an emphasis, which, using the wing nut and screw, is set at the right distance and, thus, controls the amount of bending.
The tooth breeding itself is performed in the following sequence. The saw is clamped in a vise so that only the teeth are above the jaw lips. They are alternately captured in the slot of the wiring and bend in the middle part at a given angle in the right direction. When using wiring with focus, the teeth are first bent to one side. Then the emphasis is rearranged, and another group bends in the opposite direction. Bending a tooth is a smooth movement.
The quality of the tooth alignment is checked visually and by measuring with a caliper. A simple test is recommended to check for excessive bending of individual elements. After wiring, the saw extends between the jaws of the vice, spread apart by a width equal to the width of the wiring. Excessive bending of the tooth will not allow to move the blade.
Link Height Alignment
If the teeth of a hacksaw have different heights, then when sawing they perceive the load unevenly. This increases the wear of higher elements and reduces the functional ability of the hacksaw, as lowered teeth practically do not participate in the sawing process.
It is advisable to check and straighten the height of the cutting elements before sharpening the hacksaw. The easiest way to check is as follows. The saw is firmly pressed against a sheet of paper laid on a flat, smooth surface. The profile is printed on paper, and a visible arrangement is shown by which the size of the teeth can be compared. If teeth with an increased height are identified in comparison with others, then the saw is clamped in a vice, and with the help of a flat file they are shortened.
General sharpening requirements
For sharpening the teeth of a longitudinal saw, files or rhombic files are used.
The hacksaw is sharpened using a device that allows you to securely fix the saw at an angle of 45 and 90º to the table surface. The device itself must be well fixed to the desktop. A workplace requires good lighting.
We can recommend the following design of a homemade device. On a wooden base with a size of 20×55 cm and a thickness of at least 20 mm, two rectangular triangles (with an angle of 45º) of a metal strip (for example, 20×3 mm in size) are fixed. A supporting wooden plate with a size of 15×40 cm and a thickness of at least 15 mm is installed on the triangles. A pressure wooden plate of the same size is attached to the base plate through hinges from below. Fixing the base plate when clamping the saw is done with bolts with wing. When the angle is set to 45º, the base plate is attached to the inclined strip of the triangle, and when the angle is set to 90º. to the vertical.
Files of various shapes and with different notches are used as sharpeners. Files should have a clear relief notch. When sharpening, file movements should be smooth. Metal removal is performed when moving the file only from yourself.
Sharpening the teeth of a hacksaw on wood
The scheme of the device for sharpening a saw.
When sharpening the teeth, the hacksaw blade on the tree is fixed between the plates of the device so that the teeth protrude above the plate to a height of 15-20 mm. Sharpening rules for different types of saws are different.
When sharpening the transverse hacksaw, the blade is set at an angle of 45º. Sharpening is done with a file of a trihedral type with an angle at the top of 60º. The file is sent to the tooth at an angle of 60-75º. First, the left edges of the distant teeth (odd) are sharpened with a few file movements. Then the hacksaw is turned over and the left sides of the even cutting elements are sharpened. When sharpening, sharp side edges and a sharp peak should be obtained.
When sharpening a longitudinal hacksaw for wood or a hacksaw of a mixed type, the blade is installed vertically. In this case, it is recommended to use a file of a rhombic type with a small notch or file. The file goes parallel to the table. The sharpening process is similar to the sharpening of a cross saw.
Burrs appear on the edges of the teeth that are opposite to the sharpened ones, which must be removed with a file with a velvet notch or an emery bar. The quality of sharpening is checked by touch and by color. Well sharpened edges do not shine when light enters.
To sharpen a hacksaw for wood, special attention should be paid to the preparation of files. The following file types will be required:
- rhombic and flat with an average notch;
- triangular with a velvet notch;
- files with small and large notches.
In addition, it is necessary to prepare:
- emery bar;
A hacksaw for wood can serve for a long time and effectively if the question of how to grind is timely solved. The process of sharpening saws is not complicated, but requires accuracy and care.
Wood is a unique natural material that is very widely used in various sectors of the national economy. It is easy to process, it is environmentally friendly. For processing, a wood hacksaw is often used. an easy-to-use tool that does not require special possession skills. Nowadays, electric saws, jigsaws and other power tools have received wider application than wood hacksaws.
Nevertheless, traditional hacksaws are found in all workshops, in every household, as they are used for quick cutting without long preparations. They are not only sawed with wood, but also used in the processing of chipboard, plastic, various types of flooring and so on. If you need to perform work that does not require the connection of powerful equipment, or if the access of the power tool to the object is difficult, there is no alternative to a hand-saw-hacksaw. Of course, to achieve high results, any saw needs timely sharpening.
Why and when to sharpen?
Qualified specialists know the following symptoms, indicating the imminent failure of the saw:
- when sawing wood, the hacksaw begins to sound different;
- visually it becomes noticeable that the tips of the teeth are rounded, have lost sharpness;
- the color of the teeth changes;
- sawing force increases;
- the direction of the saw is poorly maintained;
- Frequent tooth jams occur in wood.
Breeding of teeth must necessarily precede the process of grinding teeth. When breeding, the deviation of the teeth from the plane of the hacksaw to the left and to the right at a certain angle should be achieved. Too small deflection angle of the tooth will lead to the fact that the teeth will be "planted" in the tree. And, on the contrary, too large a deflection angle of the teeth makes the cut too wide, increases the amount of waste (sawdust) and requires too much muscle energy for stretching the hacksaw. The purpose of sharpening teeth is to restore the following tooth geometry:
- profile angle;
- cutting angle of cutting edges.
Important! Hardened prongs cannot be sharpened. They are black with a bluish tint.
During the breeding of the saw, one should not forget about the uniformity of the bending of all the teeth at the same angle so that there is no increase in resistance to broaches and high wear of the metal. It is necessary to begin to bend the teeth from the middle. If you try to bend them at the very base, you can damage the blade. The teeth deviate from the blade through one, that is, each even tooth to the left, each odd to the right. Visually and without the use of tools, only an experienced carpenter can determine the wiring. Such skills come only after breeding the teeth of many dozens of hacksaws.
Video: How to Sharpen a Bow Saw Blade
In the absence of such experience, a special tool comes to the rescue. The most affordable option is a regular flat steel plate. A gap is made in it, into which the hacksaw blade should enter practically without a gap. The wiring process is as follows:
- the hacksaw is clamped so that the teeth are slightly visible above the clamp;
- each tooth is clamped by a wiring groove and bends to the middle;
- the dilution angle should be constantly monitored;
- each even tooth in a row bends to the left, then each odd tooth. to the right or in the reverse order.
At different tooth heights, sawing wood will not be effective, since teeth of a higher height will wear out more due to a greater load, and teeth of a lower height will not participate at all. The broaches of the canvas will be uneven, twitching. There will also be complaints about the accuracy of sawing and the quality of the surfaces of the cuts. Align the teeth in height before sharpening. The height is checked as follows:
- the teeth are pressed against the paper, which lies on a flat surface;
- the canvas is imprinted on it;
- the profile of the impression determines the height of the teeth.
To align the teeth with a difference in height, the blade must be clamped in a bench vise and grind off excess metal. If the teeth have a large difference in height, you need to select the average value and try to level it to the maximum possible number.
How to sharpen a hacksaw?
To sharpen with minimal loss of time and quality, you need to use such special devices and tools as:
- bench vise;
- protractor and caliper;
- it is possible to use equipment that allows you to fix the hacksaw blade with an angle of 90 or 45 degrees.
Be sure to use the following files:
- with a triangular section;
- with a rhombic section;
- set of files.
When sharpening a hacksaw on a tree, a simple vise is also used, which is quite uncomfortable and long, as well as a multi-axis type vise, since their bed is rotated and fixed at the necessary angles to ensure the movement of the tool strictly in the horizontal plane. It is recommended to organize additional lighting of the working space with the help of electric lamps. Throughout the entire sharpening time, the file / file must move without jerking, it is necessary to ensure constant pressure, movements must be made without deviations from a constant angle. The process of sharpening is only the movement of the file "on my own." The file / file must be returned by air, while there should be no contact with the hacksaw.
Hacksaws are used for various purposes. The wood is sawed along or across the fiber. Accordingly, the teeth will also be different.
Sharpening the teeth of a cross-cut saw
When sharpening such teeth, a fine-cut trihedral file is used. The direction of movement of the tool is an angle of 60 degrees. The hacksaw is fixed in the device at an angle of 45-50 degrees to the workbench. The file / file must be driven strictly horizontally (keeping the angle of 60–75 degrees to the hacksaw), starting sharpening from the first left tooth. You need to start with "adjusting the movement of the hand with the tool", for which they are carried out along each left side of the odd row of distant teeth, which will give the necessary movements to the movements of the hands. After that, the same thing is repeated, grinding the right edges of the odd teeth to complete the sharpening of the cutting edge and sharpening the vertices. Having finished sharpening the teeth of the odd row, the hacksaw is turned over in the fixture and the same steps are repeated for the even row, which is a distant row in this position.
Hacksaw for longitudinal cutting
The teeth of the hacksaws for longitudinal sawing have an angle of less than 60 degrees, so they use files with large notches or a small file with a rhombic section. Trihedral files in this case are categorically not recommended. For sharpening, the hacksaw is vertically fixed in the device. There are two methods to sharpen a hacksaw, which are distinguished by giving different sharpening angles.
- Straight. The file / file is placed at an angle of 90 degrees. They give him a direction parallel to the hacksaw, sharpen both the rear and front cutting surfaces of each tooth. This is repeated for the entire far row of teeth. Then the hacksaw is turned in the clamping device 180 degrees and the same operation is repeated for the other teeth, which will make up the far row.
- Squint. This method differs from the direct only in the angle of the direction of movement of the tool to the plane of the blade. the sharpening angle decreases from direct to 80 degrees. The process is exactly the same, but the teeth after sharpening resemble the teeth of a bow saw.
If necessary, restore the sharpness of the teeth using large-sized notch files or small-handed diamond-shaped files. For hacksaws of mixed type, there are the same two options as for longitudinal and transverse hacksaws. They are distinguished by slightly different sharpening angles (90 and 74–81 degrees, respectively).
Hacksaws for wood are classified not only according to the purpose of use, they can also vary according to other criteria.
- The length of the canvas. The comfort of the worker depends on how many teeth are located on the saw blade in a row, since with a longer length fewer saws are made, and the tooth gets clogged with such a saw with less intensity. There is a general law that states that the length of a hacksaw blade on a tree should be twice as long as the item being sawed.
- Tooth size. Size directly affects the cut time and is inversely proportional to its quality. High-quality and clean cuts are made with a small hacksaw, but with a lower speed and with the application of large forces. A saw with a large tooth spends less time sawing, but it gives a ragged edge of the cut and its rough surface. Typically, the parameter of the teeth of hacksaws for wood from foreign manufacturers is TPI (teeth per inch or “teeth per inch”), that is, the more cutting edges are located on 1 inch of the blade, the larger the TPI value, the smaller the tooth.
It is worth paying attention to the table of correspondence of inches to millimeters.
- Tooth shape. This parameter determines how the cut will go relative to the wood fiber of the tree type and the vectors of the applied efforts (from yourself or yourself). In addition, there are hacksaws for universal sawing, which have different types of teeth.
- Steel grade from which the hacksaw blade is made. Steel is classified according to many parameters, but it is worth paying attention only to how steel was processed. red-hot, not red-hot or combined (not all hacksaw is hardened, but only its teeth).
When sharpening the teeth, the hacksaw blade is clamped so that no more than a centimeter of the tooth protrudes above the vise. When sharpening, it is recommended to choose a triangular section of the file / file. To ensure proper quality, when sharpening, you must follow the following sequence:
- sharpen the left edge of each even (farthest from the worker) tooth;
- reinstall the canvas by turning it 180 degrees;
- again sharpen the left edge of each even tooth, which again will be in the far row;
- finish the cutting edge and sharpen the teeth.
It is worth paying attention that at an angle of 90 degrees, longitudinal or universal saws are fixed. When sharpening, a diamond-shaped file is used. Work with it should be done exclusively horizontally. As a result, sharpened edges sometimes have bulges. Such burrs need to be smoothed out with a file with the smallest notch or with an abrasive bar having minimal grain size.
How well sharpened the teeth of the hacksaw are checked as follows:
- gently run your hand along the canvas. if the skin feels a pointed edge and there are no burrs, scores. everything is in order;
- by shade. well-sharpened faces when light falls on them do not glare, they should be matte;
- trial sawing. the hacksaw should go straight, the sawn material should have a smooth, even surface, there should be no disheveled fibers;
- the finer the notch the tool has, the sharper the saw will be sharpened.
Important! They sharpen it strictly with the movement of the tool "from yourself."
It is worth paying attention to the following tips of professionals:
- only quality tool kits are recommended for use, used solely for the purpose of sharpening saw teeth;
- for each tooth there should be an equal number of movements with a file / file; this rule applies even if you get the impression that you must repeat the passage;
- during one pass, it is forbidden to change the arm and angle at which the tool moves, until one side of the hacksaw blade is completely gone;
- it is forbidden to change the side of the file / file, that is, it is necessary to pass each side with the same side of the tool;
- compliance with the correct geometry of each cutting segment of a hacksaw for wood gives significant positive effects. both the durability of use, and wear resistance, and low loss of waste material, and even cut.
It can be said that it’s not so difficult to handle (spread and grind the teeth) such a simple tool as a hacksaw at home with your own hands. Observing the general rules, possessing certain practical skills and the simplest adaptations, it is quite possible to give the tool a second life with your own hands and avoid additional costs by buying a new carpentry saw.
How to sharpen a hacksaw at home, see the next video.
For sawing building materials from wood, as well as trees, a tool such as a hand saw is used. Despite the fact that electric and even gas saws, jigsaws and circular saws have long been developed, a hand saw in wood remains an indispensable tool in the arsenal of every craftsman. With the active use of this tool, it becomes necessary to sharpen the teeth. How to sharpen a hacksaw on a tree yourself at home, we will consider in the material.
Appointment and device of a saw
Hand hacksaw for wood is used for sawing various wood materials. It is a blade with teeth in the lower part. On the one hand, the tool is equipped with a handle, with the help of which the master holds it during the sawing work. Convenience and comfort of work with a saw depends on the quality of the handle.
The number of manufacturers of hacksaws for wood is quite large, but they all differ not only in names, but also in quality. All of them are intended for sawing wood, chipboard, logs, laminate, as well as tree trunks. Hacksaws are divided into such types as: classical, circular, archery, as well as with a pickaxe and a reward. An important role in choosing a tool is played by the thickness of the blade. After all, a thin web during the sawing of wood can break, and thick enough difficult to work.
Important! Hacksaws for wood should be sharpened periodically. Sharpened files include such blades that did not pass the hardening stage. If the links of the web are hardened, then it is impossible to sharpen them.
Why and when to sharpen
The tool under consideration is subjected to various loads during operation, which leads to blunting of the teeth. If you saw with a saw whose teeth are blunted, the result will be much less effective than sharp. In addition, it is not recommended to use a saw with blunt teeth for the following reasons:
- Decreased tool performance. Not only the master’s strength will be spent, but also his time.
- Decrease in accuracy. It is impossible to smoothly saw wood materials with a hacksaw with blunt teeth, and even more so do it carefully.
- Danger of using the tool. During the work, the file will get stuck, jam, go off the cut line, so such work can be dangerous for the master.
A sharp hacksaw is not only easier to work with, but also much safer. To determine that the time has come for sharpening the hacksaw blade on a tree, you should pay attention to such factors:
- The canvas makes a characteristic dull sound. If the master often uses a hacksaw, then it will not be difficult for him to determine such a sound.
- The tips of the teeth are rounded.
- Sawing when trying to saw wood, refuses to perform its task.
These factors indicate that it is time to sharpen a hacksaw on a tree with your own hands. But before taking on the file, you should determine whether these links are to be sharpened.
Sharpening a hacksaw on a tree begins with a procedure such as tooth biting. Hacksaw teeth are wired for purposes such as ensuring the blade free travel without jamming. The layout is the bending of the teeth in different directions, alternately, by one amount. This leads to the fact that the width of the cut is increased, which means that during the sawing process the process of removing chips is accelerated.
It’s important to know! The wider the wiring of the teeth, the less chance of jamming the blade.
The magnitude of the tooth divorce depends on the thickness of the blade, and is usually 1.5-2 mm. To bend the teeth by the same amount, you will need to use a special device. This device is a metal plate with a special slot. The canvas is clamped in a vice so that the links protrude slightly. After this, the process of bending the teeth is carried out. Sharpened teeth also need to be bent at the same distance.
How to sharpen a hacksaw on a tree
To sharpen a hacksaw on a tree, the canvas should be fixed in a vice in the same way. For sharpening the links of the saw, files or triangular files with a small notch are used. Not many people know how to properly grind a file on wood, so you should pay as much attention to this process as possible.
- Initially, you need to pick up a file. A file with a small notch should be used, which should be held with one hand on the handle, and the other at the tip of the tool.
- The sharpening angle is determined, which usually ranges from 15 to 30 degrees. The angle is usually determined by eye, but if this is difficult to do, then you can use special home-made devices, for example, a wooden block. To do this, the bar is grinded until it has the shape of a rectangular triangle with angles of 30 and 60 degrees.
- The most important thing when working with a file is the pressure on it. To ensure uniform sharpening, you need to perform the same number of file passes on each tooth. With experience, you will learn how to ensure uniform removal of the top layer of metal.
- Using the prepared tool, the grinding angles are controlled. Similarly, the process is carried out on the reverse side of the canvas.
Now you know how to sharpen the teeth of a hacksaw blade on wood. But the process does not end there, since it will be necessary to align the teeth in height. If they have different heights, then the uniformity of sawing will be violated. If there are links that are higher than the others, then their shortening is performed using the same file. The check is carried out using a sheet of paper, to which the sheet should be attached with its teeth down. After that, the sizes are compared, and the shortening procedure is repeated.
How to sharpen a saw: practical recommendations
When carrying out work on sharpening a hacksaw, you should adhere to the following recommendations:
- The device is tightly fixed to the work surface in a vise.
- Providing good lighting for the workplace.
- Files are used for sharpening links and files with various notches. The smaller the notch, the better. It all depends on the degree of blunting of the teeth.
- Metal removal is carried out only when the file moves away from itself in one direction.
- After the work is completed, it is necessary to check the quality. To do this, take a look at each link in the world. If the tooth shines, then it is sharpened correctly, as in the photo below.
In conclusion, it is worth noting that many craftsmen do not consider it necessary to sharpen a hacksaw. This is incorrect, since the efficiency of the work depends on the quality of the sharpening.