Sharpening and setting the saw
The main cutting element of any hand saw. A series of teeth that are cut into the blade and are wedge cutters. Wood, in the manufacture of all kinds of products from it, is sawn along, across and at an angle Θ to its fibers, in this regard, a distinction is made between transverse, longitudinal sawing and sawing at an angle to its fibers and in each case use the corresponding type of saw, which differs from others in the shape of the teeth.
When crosscutting, cross saws are used, the cutting edges of the teeth of which, when moving in the wood, cut its fibers like a knife and form a cut. Longitudinal sawing differs from transverse sawing in that the direction of movement of the saw is parallel to the grain of the wood. The leading edges of the teeth of the longitudinal dust planes the wood like knives in a plane, and, going deeper, form a cut. When sawing wood at an angle Θ universal (mixed) saws with teeth, which are an intermediate form of teeth of transverse and longitudinal dust, are used for its fibers.
Sharpening teeth dust. It is a kind of art that requires loyalty of hands, a good eye, and attention. It is not difficult to learn this business, you must have the desire and clearly adhere to the following rules:
- The saw blade must be firmly fixed in a special device made of wood, which is also stable to set on a well-lit work table. Sharpening teeth and dust on stools or knees does not give a satisfactory result.
- You should use a personal file, followed by cleaning the sharpened edges of the teeth with a velvet (with a fine notch) or file. It is desirable that the file is new, sharp and with a fitted handle. If at the right time there was no such thing, then you can also use Pre-owned, but always brushed with a steel brush and Rubbed with charcoal, so that the file does NOT get clogged and does NOT become dull. When sharpening a tooth, the file should grip its metal and remove its layer depending on the pressure. And if it slides over the tooth, and not removing the metal, then the saw teeth are overheated or the file is worn out. In this case it is necessary to repeat the sharpening with a new file. If in this case it slips over the tooth, then it remains to take another dust.
- The file handle is clamped with the right hand, and the end is held by the left hand and the file is directed to the saw teeth. In work with a file, depending on the type of saw is described below.
- The pressure of the file on the teeth should be smooth and even and only to one side. When Returning the file to its original position It must not touch the teeth.
- It is necessary to try to grind the metal from the edges of the teeth of at least the same thickness, driving the file the same number of times with the same pressure, which allows you to keep the angles, pitch and height of the teeth after sharpening.
- Burrs are formed on the edges of the tooth from the side of the file exit, which reduce the sharpness of the tooth, and if they are NOT removed, then during the operation of the saw they crumble, and the teeth become significantly dull. To remove burrs, the edges of the teeth are sharpened with a file with a velvet notch and deburred from the side edges with a wet donkey.
- After sharpening the teeth, check their sharpness. Look at the point of the needle and the edge of the razor blade: they are sharp, not shiny in the light. And if they are blunt, then rounded surfaces appear on the tip of the needle and on the edge of the blade, which reflect light and shine well. The quality control of saw teeth sharpening is based on this principle. For this, dust is placed in front of the eyes and its teeth are examined along the canvas. If their cutting edges and tops are NOT shiny, then the saw teeth are sharpened satisfactorily, and if some of the teeth are shiny (often this is), then they need to be sharpened with a velvet file, deburred and re-check the light reflection from their edges and tops.
Cross saws. The teeth of the transverse dust are sharpened using a triangular file with a fine notch with a point angle of 60.
To sharpen the teeth, dust is clamped into a special device that allows you to set its blade at an angle of 45-50 to the plane of the desktop. The file is parallel to the work table at an angle of 60-75 to the saw blade and thus sharpen the left edge A1A2B2B1 in the first tooth.
Saw teeth are sharpened in several stages. First, with a file, they pass along the left edges of the odd teeth located in the far row, adjusting the hands to the same movement. Then they pass the file along the right edges of the same odd teeth, completing the sharpening of the main cutting edges with very sharp peaks. After finishing the sharpening of the odd teeth, the saw blade in the sharpening device is turned over and thus the even teeth that are in the far row are sharpened. When sharpening transverse teeth, dust must be carefully observed so that sharp main cutting edges with a dihedral angle are obtained in each tooth φ = 60-75 , short cutting edge and sharp point.
Longitudinal saws. Longitudinal dust teeth in which the angle π
How to determine the moment when time sharpens a hacksaw
In order not to shorten the service life of the hacksaw blade, it is necessary to sharpen it only when it can no longer perform a high-quality cut, or requires more effort while working with it. The main signs of a blunt saw are the following:
- The tip of the teeth is rounded, their shape is distorted;
- The sound of the saw has changed: there is a feeling that the wood is NOT cut, but is torn along the fibers;
- The cutting speed has decreased compared to a new hacksaw;
- Notches and scuffs began to appear on the cut;
- The hacksaw periodically wedges even with an even cut.
If at least one of these symptoms appears, then the hand saw needs service. This includes both direct sharpening of the teeth and their correct setting.
How to sharpen a hacksaw on wood and spread the teeth
Hacksaws of various types are used in everyday work in personal plots, summer cottages, as well as during repairs in which natural wood is used as the main material. The saw requires periodic maintenance. At a certain moment, you need to sharpen the hacksaw on wood, since it began to perform its function worse than before. In order not to spoil the canvas and return the tool to its former performance, you need to follow a few simple tips.
Sharpening the saw with your own hands
The saw is prepared for sharpening by fixing it in a vise, the jaws of which should ideally be made of wood so as not to damage the saw surface. Step-by-step instructions for sharpening a do-it-yourself hacksaw for wood are as follows:
- The hacksaw is fixed as close as possible with the teeth to the jaws of the vice, but so that their distribution is not disturbed when the wrench is clamped at an angle of 90 to the surface of the workbench.
- The file is taken in the working hand with the handle, with the other hand it holds the tip from the back. This will distribute the effort evenly.
- Sharpening a conventional hand saw is performed at an angle of 15-30 to the prongs. If the wear is NOT too strong, native the sharpening angle will be clearly visible.
- The angle of the file to the blade should be about 30-45. To do this, you need to become so that the working hand is below the auxiliary.
- The file should only move away from itself, with the same effort and number of movements for each tooth. For a sharp Needle file, 3-5 strokes are usually enough to straighten a single tooth.
- Thus, one side of the canvas is passed, after which it is turned over, fixed in the same way, and the actions are repeated for the second side.
If, when performing sharpening work, Apply an uneven force or make a different number of movements with a file, this can lead to displacement of the teeth in relation to each other, distortion of their size and shape. In the end, such a hacksaw will require professional regrinding, or even completely unsuitable for further use.
Required sharpening tool
To perform such a seemingly simple operation will require a rather impressive list of tools. However, if any of them is at hand, you can try to find a replacement. What you cannot do without is a workbench with a vice, since only with their help can dust be rigidly fixed for work. The rest of the list looks like this:
- Device wiring, which, if absent, can be replaced with high-quality pliers. In this case, you yourself will have to determine the Approximate distance from the center for each tooth;
- A sharpening bar with sandpaper or a set of files and files;
- A hammer;
- Additional light source;
- In some cases, you may need a caliper and protractor to make accurate measurements.
A separate mention is the method of sharpening hand saws using an angle grinder. In this case, you will need the presence of the angle grinder itself, a workbench and a pair of clamps, since the blade will need to be fixed horizontally.
General requirements for sharpening
Sharpening a hacksaw. Quite a painstaking process in which accuracy is important. To make it easier, only good files and Needles with sufficient sharpness should be used. If the dust has to be sharpened frequently, the best solution would be to have a separate set of tools for this job. Before sharpening, it does NOT hurt to look at the teeth of the hacksaw. If their shade is darker than the canvas. So they are hardened. Sharpening such a hacksaw on wood will not work.
When sharpening at home, remove the metal evenly. For each individual tooth, an equal number of file passes are made, no matter how worn out it was before correction. In this case, you must not change the sharpening angle set by the inclination of the file, or rotate it around its axis. Movements should be performed strictly from oneself, since it is with this technology that the effectiveness of removing the metal of the hacksaw is achieved, and the employee can confidently control the tool in his hands.
In order to avoid additional difficulties during sharpening, the saw blade should be firmly fixed in a vice. It is desirable to have a direct light source, which will allow NOT to peer at the work results.
It all starts with checking the distance between the teeth. It is designed so that the saw does NOT wedge in the kerf. Adjust it to match the type of wood with which you most often have to work. If you have to work with hard wood, the teeth are set apart at a distance 1.5-2 times greater than the thickness of the blade. For soft wood, the teeth should be separated into a hacksaw at a distance of 2-3 times more.
One of the key points in routing is maintaining uniformity. If the saw teeth are bent at different distances from the center, it will lead to permanent wedges and a deterioration in the quality of the cut and the speed of cutting wood. Therefore, it is recommended to use a device for setting the teeth, which is called. Wiring. Thanks to the stop, it is impossible to bend the tooth to a greater distance than provided by the standard.
The teeth are divided into two groups through one and are bent sequentially along the entire length of the cutting side of the blade. First, this procedure is carried out for one group, in which the set teeth must be bent in a certain direction, then it is repeated for the opposite direction.
Since the saws differ in shape and purpose, they also have different teeth. And to sharpen a hacksaw qualitatively, you need a different tool.
Triangular File with one working side. The profile of this tool is NOT standard, if for an ordinary triangular file all sides are equal and are working, then this Needle file has one working side, and in shape it is an isosceles triangle with a very large base.
With such a triangular file with one working side, it is convenient to machine fine or oblique teeth. When working, it acts only on the treated surface, on others it only slides. No risk of grinding off adjacent teeth.
Plain Triangular File. A compact tool that is convenient for sharpening most standard wood saws.
Plain Triangular File
Triangular file. Ideal for sharpening large-tooth saws.
What should turn out
When sharpening, you need to ensure that the teeth of the hacksaw are sharp and resemble a shark’s tooth in shape. Only such a tooth is good to saw. The hacksaw will not slide on wood, but will bite into into it. And then it will become clear why correct saw to saw myself.
Tooth set pliers. Nice tool. Its cost can be compared with the price of a hand saw of 300-500 rubles. It is very convenient to use, inserts the saw tooth to the side will be what you need.
Hacksaw set. Also a good thing and inexpensive. The average price fluctuates around 100 rubles. The design is elementary: several slots and an adjustable protractor. The tooth is inserted into a suitable slot and the pressure on the handle is set. Exposed Protractor provides uniformity.
The technology is simple: the blade is inserted between two teeth and by turning the ax, the teeth are bent to the sides.
Setting the teeth with an ax
The saw can be set using a self-tapping screw. It is more secure. This requires a long screw. To make it easier to hold. Before work, it needs to be slightly modified. You need to grind off his hat a little on one side. Make it flat. This is necessary so that when it is applied to the tooth, it does not slip and does not deform the latter.
Place the hacksaw flat on soft wood (pine, spruce). Holding the screw on the leg, apply a hat to the tooth and hit it with a hammer. The tooth is folded back. The operation is performed through the tooth. After the saw blade is turned over, and the operation is repeated in the same way.
Tooth setting with a self-tapping screw
To sharpen the dust, you need to firmly fix it so that it does not vibrate when exposed to a file. Otherwise, the quality of work will be low.
They fix the hacksaw blade vertically, often in a vice, in homemade clamps, but if there is neither one nor the other, then you can do without them.
Fixation method without special tools. At the edge of the workbench. The hacksaw blade is laid so that only the saw teeth hang from the edge of the table. However, the handles of the saw are always thicker than the blade, and then the place next to it cannot be put tightly to the workbench. Therefore, you need to use the corner of the table, and then the saw handle will not interfere.
If there is a clamp, then you can fix it like this.
And this is a method without a clamp, fixation is made only by the hand of the sharpener. It is quite convenient and safe.
Securing the saw without a clamp
A file or file is taken in the right hand, and, presses the hacksaw blade with his left hand, they begin sharpening.
The saw teeth go through one. The movement of the file with this method is done upside down. The file is applied to the sharpened tooth and with a downward movement is forced downward.
The file must be held tilted in two planes. Horizontal. It’s about 30 degrees. In vertical. About 60 degrees. The angles of inclination are individual for each saw, because they can differ both in the shape of the tooth and in its size.
Sharpening the left edge of the tooth.
Sharpening the left edge of the tooth
Sharpening the right edge of the tooth.
Sharpening the right edge of the tooth
This is what should be obtained: the case from the file pointer. Machined teeth, left. Comments.
The point is the file pointer. Machined teeth, left. Comments
Bow-type saws are more bulky devices that act as an analogue of a jigsaw.
The main purpose of this type of dust. Create an accurate cut when working with surfaces at any angle
Due to the solidity of the design and the threaded connections of the handles, bow-type saws are able to easily overcome knots, performing spraying along the radius and curved patterns.
Depending on the purpose and design of the saw, there may be:
- Sweeping. For slitting;
- Transverse. For sawing workpieces across wood fibers;
- Circumferential. For cutting holes, performing rounded and shaped sawing;
- Spike. For cutting connecting pins, as well as cutting out simple geometric shapes on the workpiece.
Only with an onion-type hacksaw can you cut the material up and down, sawing blanks with complex fishing lines and performing the work alone without involving an assistant.
Both narrow and conventional saws tend to bend as the rigidity of the work material increases. In THESE cases, it is effective to use canvases equipped with a backing, which acts as a kind of stiffening rib.
Hand saws, equipped with a back, are designed to create shallow cuts in a wooden surface of any thickness
The presence of the backing prevents the dust from making a cut deeper than the width of the blade, since it prevents the cutting blade from going further into the tree.
Types of hand saws for wood
A small, narrow saw is a structure that consists of a straight flat blade and a handle. She performs delicate work: through cuts, cut out curved parts.
This type of tool is intended for sawing wood pieces, the thickness of which does NOT exceed 8-10 cm, dusting of small branches and small works in the garden
In the manufacture of narrow models, manufacturers install blades with triangular double-sided teeth, or with parallel sharpening. The disadvantage of the tool is that when acquired in the process of work, the canvas is able to deviate from a given direction.
Parameters of teeth on the blade
The determining indicator of the productivity of the tool and the accuracy of cutting wood is the size of the teeth.
The teeth of a hacksaw for woodworking have a double function: they cut the wood and simultaneously remove the sawdust
Sawing accuracy is determined by the indicator TPI. Teeth per inch.
There is an inverse relationship between these technical parameters:
- Blades with coarse teeth set a high speed of work, but the saw cut turns out to be rough and sloppy;
- Fine-toothed hacksaws guarantee a clean and precise cut, but at low operating speeds.
When determining the required size of the teeth, one should be guided by the type of material being processed. For example, when working with chipboard, where high cutting accuracy is required, choose a tool with a high TPI 7-9, but for sawing logs and working in the garden, where cleanliness of the cut is not so essential. TPI 3-6.
When choosing the optimal hacksaw option, be guided by the rule that the minimum log thickness should in any case be greater than the pitch of three teeth
If we compare a hardened and a regular tooth, the difference is that in the first variant, subject to domestic use, the product does NOT dull for a long time. But a hacksaw with a hardened tooth cannot be re-sharpened. When it becomes badly dusty, you just have to throw it away.
A regular tooth lends itself to sharpening. It can be periodically performed using a special file marked with an accident (for sharpening dust). To sharpen the blade, it is enough to perform a few movements on each tooth.
Depending on the type of teeth used, there are three types of hacksaws:
- For rip sawing. The products are equipped with teeth in the form of an oblique triangle and look like hooks. The tool allows you to cut wood along the grain. Such saws are sharpened on both sides of the tooth, due to which they are able to cut both when going forward and in the opposite direction.
- For cross cutting. The tool teeth are made in the form of isosceles triangles. This design allows for easy sawing of the material both when the cutting edge is carried forward and backward. But this type of tooth is only suitable for working with dry workpieces, not fresh wood.
- For mixed sawing. Products have a combined composition, in which triangular edges are combined with slightly elongated semicircular notches. This solution allows the semicircular teeth to perform a guiding cut when the hand moves forward, and when returning. Expand the channel in triangular shape, removing chips and sawdust from it.
Some types of modern tools are equipped with teeth, which are made in the shape of a trapezoid. This solution allows you to make the blade more durable and wear-resistant.
But it should be borne in mind that sharpening such a blade is very problematic, since it is difficult to give the desired shape with trapezoidal teeth. This significantly reduces the life of the product, after which you have to change the blade or purchase a new tool.
For cutting fresh branches, it is more convenient to use blades equipped with triangular teeth, processed by parallel sharpening, in which each element is sharpened only on one side and in a staggered manner
Often on the market you can find a modernized type of hacksaws.
The modernized hacksaws can be easily distinguished by groups of teeth located on the blade, between which the gaps are clearly visible
Upgraded hand saws are effective for cutting raw wood. Wet chips through the gaps between the teeth in the process of cutting easily come out of the cut, and not obstructing the movement of the tool.
How a hacksaw blade should be?
The main part of the tool is a hacksaw blade. The first thing to look for when choosing a product. Blade length. The possibilities of its application largely depend on this parameter. At the same time, the longer the blade, the more spring it has, which also complicates the process, especially when working with hard wood species such as ash, maple or oak.
Long stroke makes it possible to apply less effort when cutting, since in one stroke the cut is made with a large number of teeth
To cut small elements such as plinths, bars or narrow slats, you can do with a hacksaw with a blade length of 25-30 cm.When planning to use the tool for more serious construction work, choose a product with a blade of 45-50 cm.
When determining the length of the hacksaw blade, be guided by the rule that the length of the saw is 2 times the diameter of the processed elements. Failure to comply with this recommendation will only complicate your work. The teeth of a short hacksaw will jam inside the wood, and each will have to make a lot of effort to advance the tool to free it from sawdust. Uncomfortable work will cause premature fatigue.
Traditionally, the width of the fabric of the product varies in the range of 10-20 cm. Models with a thinner fabric are not allowed for technical reasons, since they fail at the slightest bend. But it should be borne in mind that too wide canvases are inconvenient for manual work.
Of no small importance is the material for making the canvas, which is most often the role of alloy steel, as well as its degree of hardening
Tool alloy steel with high m silicon and carbon grades is used for hacksaws:
- 65G, 60 C2A;
- 8 HF, 9 HF, 9 XC;
- U7, U7A, U8, U8A, U8G, U8GA, U9A, U10
Metal hardening is carried out due to the action of an alternating magnetic field on it, in which a high frequency electric current appears. Spreading over the surface, it heats the surface layer of the metal, which after cooling is hardened.
The standard parameter is considered to be the hardness of the metal at 45 HRC, but it is still preferable to choose products, the hardness of the fabric of which is 55-60 HRC. A hacksaw with a blade of high hardness will have sufficient flexibility, but at the same time High tooth stability. On visual inspection, such a tool can be identified by the darkish shade of sharpened teeth.
Saw band design
The band saw belongs to the category of cutting tools and is an integral part of specialized equipment for wood processing. It is a closed belt with teeth on the outer edge.
For manufacturing, special grades of steel are used. 9HF, B2F or S75. During the production process, the teeth are treated with high-frequency currents. This increases their hardness. It is this fact that affects the spread of the cutting edges and maintainability. Often, several types of steel are used in the manufacture. The main tape is made of spring-loaded, and the cutting part. Made of steel with large m tungsten or cobalt.
Features of the use of band saws for wood:
- Wood requirements. Than it is harder. The faster the blade becomes dull;
- Installation conditions. The tension indicator must be observed. If it is less than required. Sagging will occur. Strong tension will increase the likelihood of blade breakage;
- Periodic sharpening. This will require a special machine.
The implementation of the last point will increase the service life of the tape structure. However, sharpening yourself is problematic. It is necessary to choose the correct layout, observe the angle of processing of the blades.
Saw band setting
Before forming the cutting edge, make sure the teeth are set correctly. During the entire period of operation, due to constant loads, their location may change. Therefore, the geometry is adjusted first, and then. Sharpening.
The setting is a bend of the teeth to the plane of the main blade. This procedure is performed only on a specially designed machine. In case of large discrepancies along the entire length of the belt, premature damage or breakage of the belt is possible. Therefore, before that, you should decide on the type of wiring.
The angle of inclination must correspond initially. The type of wiring is also taken into account, which can be as follows:
- Classic. Alternate bending of the blade teeth to the right and left sides;
- Cleansing. The first and second teeth are deflected to the right and left, while the third remains unchanged. This technique is used for saws, which are designed for processing hard rocks;
- Wavy. The setting angle for each tooth is individual. As a result, they form a cutting edge that resembles a wave. The most difficult type of wiring.
During the bend, not the entire tooth is subjected to deformation, but only part of it. Often the deviation occurs at 2/3 of the total height.
Do-it-yourself divorce and sharpening of band saws on wood
The service life of a band saw for wood directly depends on the quality of its sharpening. It can be performed both independently and by resorting to the services of specialized companies. In the first case, you need to get acquainted with the technology and a number of features in detail.
Cutting shape and sharpening angle
The first step is to determine the type of saw band. The main indicator is the shape of the teeth. Depending on this parameter, they are divided into dividing, joiner’s or intended for sawing logs. The manufacturer defines the initial geometry and routing angle. It is recommended to find out these data at the stage of purchasing components. They are needed to determine the parameters of the machine.
For hardwoods, the rake angle should be as low as possible. This ensures optimal contact of the processed material with the metal. If you plan to process soft varieties. To increase the processing speed, you can use models with a large rake angle.
The defining parameters for self-updating of the cutting edge are:
- Tooth pitch. This is the distance between the cutting elements of the structure. Common values. 19, 22 and 25 mm;
- Tooth height. Size from base to top;
- Angle. The main value that you need to know to form the cutting plane. For joinery models, it is 35. In dividing saws, the angle is 18 up to 22. In structures for processing timber. ten.15 ,
- Divorce. Defines the deviation of the tooth from the general plane of the blade.
In order to eliminate resonance in some types of cutting tools, a variable pitch of the teeth is made. This does not affect manual sharpening, but requires careful setting of parameters during automated.
Choosing the right type of grinding wheel is important. It must correspond to the grade of steel from which the band saw is made. For tool steel structures, corundum wheels are used. If you want to improve the cutting properties of bimetallic models. Use CBN or diamond wheels.
Depending on the technical capabilities, it is possible to perform a full-profile processing or each cutting part separately. In the first case, you will need an elbor circle, the end of which has the same shape as in the saws. For the second option, each tooth is processed.
You will first need a machine. It must have the function of regulating the speed of rotation of the disk and changing its position on the tool. After fixing the blade in a special bed, follow these steps according to the following instructions.
- Emery goes down. At this time, the leading edge is machined with a cutting edge.
- Formation of a slice in the pad. This is done without breaking away from the canvas. This stage allows you to remove microcracks and irregularities. An important point is the reduction of surface tension, which is the main prerequisite for deformation of the web.
- The circle moves up. The back of the tooth and its cutting edge are machined.
All other teeth are renewed using the same technique. It is important that the values of the entry and exit angles are the same everywhere. Otherwise, with differences in geometry in one of the parts, performance will deteriorate.
With prolonged contact of the circle with metal, the temperature on the surface of the latter can sharply increase. To eliminate this effect, use special coolants coming directly from the machine. The feed is made constantly to avoid the formation of a glow zone. In this part, the mechanical strength will be deteriorated.
In order to avoid chipping, check the presence of metal components before processing the wood. Also, special attention is paid to fixation and uniform feeding of the workpiece for sawing.