The main cutting element of any hand saw is a series of teeth cut on the blade and representing cutters in the form of wedges. 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, there are transverse, longitudinal sawing and sawing at an angle to its fibers, and in each case, use the appropriate type of saw, which differs from others in shape teeth.
a - cross sawing; b - longitudinal sawing; 1 - wood; 2 - propyl; 3 - marking line for sawing; Θ - the angle of inclination of the marking to the wood fibers in mixed sawing.
When cross sawing, cross saws are used, the cutting edges of the teeth of which, when moving in 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 saws plan the wood, like knives in planers, and, deepening, form a cut. When sawing wood at an angle Θ, universal (mixed) saws with teeth are used to its fibers, which are an intermediate form of the teeth of transverse and longitudinal saws.
Saw sharpening
During operation, the saw teeth become dull, the cutting front and side edges are rounded, the saw becomes heavy and it has to be pressed hard. Experienced craftsmen can easily determine the sharpness of the saw by the brilliance of the cutting edges and tops of the teeth and by the sound of the saw. To restore the cutting ability of the teeth, they are sharpened with files or needle files, giving them sharpness and maintaining their parameters: angles, steps and heights.Sharpening saw teeth is a kind of art that requires fidelity of hands, a good eye, and attention. It is not difficult to learn this business, you must have a desire and strictly adhere to the following rules:
- The saw blade must be firmly fixed in a special fixture made of wood, which is also stable on a well-lit work table. Sharpening saw teeth on stools or kneeling 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 needle file. It is desirable that the file is new, sharp and with a mounted handle. If at the right time there was none, then you can use a used one, but be sure to brush it with a steel brush and rub it with charcoal so that the file does not clog and become dull. When sharpening a tooth, the file should cling to its metal and remove its layer, depending on the pressure. And if it slides over the tooth without removing the metal, then the teeth of the saw 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 slides over the tooth, then it remains to take another saw.
- The handle of the file is clamped with the right hand, and its end is held with the left hand and the file is directed to the teeth of the saw. How to 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 uniform and only in one direction from itself. When returning the file to its original position, it should not touch the teeth.
- We must try to grind metal from the edges of the teeth of a minimum of the same thickness, driving the file the same number of times with the same pressure, which allows you to maintain the angles, pitch and height of the teeth after sharpening.
- Burrs form 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 the burrs are removed from the side edges with a wet whetstone.
- After sharpening the teeth, it is necessary to check their sharpness. Look at the point of the needle and the edge of the razor blade: sharply sharpened, they do not shine in the light. And if they are blunted, then rounded surfaces appear on the tip of the needle and on the edge of the blade, which, reflecting light, shine well. On this principle, the quality control of sharpening saw teeth is built. To do this, the saw is placed in front of the eyes and its teeth are examined along the blade. If their cutting edges and points do not shine, then the teeth of the saw are satisfactorily sharpened, and if some of the teeth are shiny (often the case), then they must be filed with a velvet notch, deburred, and re-check the reflection of light on their edges and points.
Crosscut saws. The teeth of the cross saws are sharpened using a finely cut triangular file with a 60° apex angle.
To sharpen the teeth, the saw is clamped into a special device that allows you to install its blade at an angle of 45-50 ° to the plane of the desktop. The file is led parallel to the desktop at an angle of 60-75° to the saw blade and thus the left side A 1 A 2 B 2 B 1 is sharpened in the first tooth.
1 - saw blade; 2 - sharpened tooth; 4 - a device for sharpening; 5 - desktop for sharpening saws; 6, 8 - directions of the file 7 in relation to the working table and the saw teeth being sharpened; 9 - the line of the bending of the teeth when they are divorced
Sharpen the teeth of the saw in several stages. First, a file is passed along the left edges of the odd teeth located in the far row, setting the hands for the same movement. Then they pass with a file along the right edges of the same odd teeth, completing the sharpening of the main cutting edges with very sharp peaks. After the sharpening of the odd teeth is completed, the saw blade in the sharpening device is turned over and thus the even teeth that are in the back row are sharpened. When sharpening the teeth of crosscut saws, it is necessary to carefully monitor that sharp main cutting edges with a dihedral angle φ = 60-75 °, a short cutting edge and a sharp top are obtained in each tooth.
Longitudinal saws. Longitudinal saw teeth, in which the angle π To sharpen the teeth, the saw blade is mounted vertically in a clamping device, which, in turn, is fixed on the desktop. Below are two methods of sharpening the teeth of longitudinal saws, differing from each other only in the value of the sharpening angle φ, i.e., the directions of the file in relation to the saw blade.
The first method is direct, in which the file or file is directed horizontally at an angle φ = 90 ° to the saw blade and a small layer of metal is removed from the front and back faces of the tooth, sharpening the cutting edges.
7 - the direction of movement of the file
In this way, all the teeth located in the far row are sharpened. Then the saw blade in the clamping device is turned over and the teeth of the other row, which are in the far row, are sharpened. This method is used by most modern carpenters and amateurs when sharpening the teeth of longitudinal saws.
The second method is oblique, differing from the first only in the direction of the file in relation to the saw blade, that is, the sharpening angle, which is chosen within φ = 75-80 °.
8 - the direction of movement of the file
The front and rear faces of the teeth are also sharpened, first one row, and then the other. With this method of sharpening the teeth, side edges are obtained, and it is used by cabinetmakers when sharpening bow saws.
Mixed saws. To restore the cutting qualities of the teeth, they are sharpened like the teeth of longitudinal saws, using rhombic files with a fine or needle files with a coarser notch. As with sharpening longitudinal saws, two methods are used: straight and oblique, differing from each other in the value of the sharpening angle φ, which are equal to 90 ° and 75-80 °.
The sharpening angle φ \u003d 75-80 ° is used by cabinetmakers when sharpening the teeth of tenon and fine-toothed bow saws. After sharpening the teeth, remove the burrs from the cutting edges and check the sharpness of the teeth in the light.
Saw sharpeners. To sharpen the teeth, the saw blade is installed in a clamping device, which, in turn, is fixed on the desktop. The figure below shows a clamping device used when sharpening the teeth of bow saws and hacksaws and allows them to be set at an angle of 45 ° and 90 ° in relation to the work table.
Clamping device for sharpening hacksaws: a - general view; b - details; 1 - desktop; 2 - the basis of the clamping device; 3 - hacksaw; 4 - wing nut; 5 - clamp; 6, 10 - clamping and support strips connected on hinges 7; 8 - directing triangle; 9 - hairpin M6.
The device consists of a base with dimensions of 550x200 mm, made of plywood with a thickness of about 20 mm. On the basis, two rectangular guide triangles with equal legs are installed, welded from a steel strip with a section of 20x3 mm. To install the guide triangles at the base of the device, there are four M6 studs screwed on with PVA glue. In turn, to the guide triangles with the help of M6 bolts with wing nuts, the support and clamping strips are attached, interconnected on hinges measuring 400x150 mm, made of plywood 15 mm thick. The saw for sharpening is laid between the slats with the teeth up. Its blade is set so that the teeth protrude 15-20 mm above the clamping bar. This clamping device allows sharpening saws to be set at a 45° angle (this position is shown in the figure) and at an angle of 90°. To do this, you need to change the positions of the guide triangles based on the device, which is clearly visible in the figure. When sharpening the teeth of transverse saws, the support-clamping bars are set at an angle of 45 °, and when sharpening the teeth of longitudinal and mixed saws - at an angle of 90 °.
The device in the position of the bars at an angle of 90° can be used both for leveling the height of the teeth and for setting them.
The figure below shows a jig for sharpening the teeth of two-handed saws and large hacksaws.
Clamping device for sharpening two-handed saws and large-sized hacksaws: a - general view; b - details; 1 - saw (hacksaw); 2 - clamping bar; 3 - rack; 4 - crossbar; 5 - wing nut.
The fixture consists of two racks 1100 mm long with a section of 60x40 mm, two transverse bars about 550 mm long with a section of 40x30 mm and two clamping bars measuring 450x150 mm, made of plywood 15 mm thick. Racks and a crossbeam are connected among themselves on screws. The assembly of the device is carried out in the following sequence: the lower crossbar is screwed to the racks at a small height from the floor, then the right leg is placed on it and the place of attachment of the second crossbar is marked so that the knee right foot hit the second crossbar. This ensures the rigidity of the rack, leaning against the table or workbench. Sharpening saws are laid between the clamping bars with the teeth up and clamped with M8 bolts with wing nuts. Having finished sharpening on one side, without removing the saws from the clamping bars, turn the device over and continue sharpening on the other side.
Saw layout
For free movement of the saw in wood and in order to avoid it being clamped in the cut, as it deepens, its teeth are parted, that is, they are bent alternately in different sides by the same amount. As a result, the width of the cut becomes greater than the thickness of the saw blade, free gaps form on both sides of it, and the saw moves back and forth, almost not touching the cut surface with its blade, and only its cutting edges gradually remove the wood layer by layer.
The wider the set of teeth, the wider the cut and, accordingly, less likely jamming of the saw in it. However, a too wide kerf, due to the large amount of tooth set, requires more effort to advance the saw in the wood.
When using an unset or slightly set saw, which happens after its repair or long operation, when the tooth setting is greatly reduced, the width of the cut is close to the thickness of its blade, and the friction that occurs between the walls of the cut and the blade causes it to heat up and expand and, ultimately account, jamming of the saw in the cut, which will require an incredible effort to advance. Probably, each of us experienced this trouble when sawing damp wood with a low-set saw. And yet, if there is no free gap in the cut for the saw blade, then it is difficult to control it and leads it away from the intended direction.
The saw teeth are set using a special tool called a set. Some of its designs allow you to select the amount of set on one side with the help of an adjusting screw, which ensures the same bending of the teeth.
The saw teeth are set in a special wooden clamping device, in which the saw blade is set so that only the teeth protrude slightly from it, and the device itself is mounted on the desktop. The set of teeth is formed by alternately bending them in different directions along the retraction line, which is approximately at half of their heights, but the entire tooth cannot be retracted - it will break at the base. It may be that when bent back, some teeth protrude more than others, and they will slow down when sawing, reduce the quality of the surface of the cut and quickly become dull. To avoid this, the teeth are aligned by pulling a hand vise between the jaws, opened by the amount of divorce. As a result, all teeth are aligned, and their set becomes uniform.
The value of saw teeth set is determined by the elastic recovery of wood in the cut, which is the greater, the softer and wetter it is. Therefore, for such wood, the divorce should be greater than for hard and dry. The amount of teeth set on one side and the amount of cut in the wood is determined by the formulas:
Δ=k a and b=a+2 Δ
where a is the thickness of the saw blade (mm), k is a coefficient depending on the condition of the wood, k = 0.25-0.4 for hard and dry, and k Example. Determine the amount of divorce on one side for a bow saw and a hacksaw with blade thicknesses of 0.6 and 0.9. Sawn wood: dry and hard for a bow saw and wet for a hacksaw. We choose the coefficient for the bow saw k=0.35 and k=0.5 for the hacksaw. Then for a bow saw, the amount of divorce on one side and the amount of cut are equal:
Δ=0.35 0.6≈0.2;
b=0.6+2 0.2=1 mm;
and, accordingly, for a hacksaw:
Δ=0.5 0.6=0.3;
b=0.9+2 0.3=1.5 mm.
You should not choose any amount of divorce for saw teeth, without taking into account the condition of the wood being cut, as this affects the quality of the cut and the effort to advance the saw. Saw with big size it is difficult to cut hard wood - it turns out a wide, uneven, ragged cut of poor quality, the saw moves hard, you have to put a lot of pressure on it, and as a result, its teeth quickly become dull. Therefore, the master must have in his household several saws with different sizes of divorce: for dry and wet wood. And if he has one saw with a small divorce and it is necessary to cut wet wood along the fibers, then in this case, in the process of sawing, a wooden wedge is inserted into the cut, which is advanced behind the saw so that it does not pinch, and additionally lubricate its surface with laundry soap.
Saw setters. Divorce saws are performed using a special tool called wiring. The figure shows general views simple wiring and wiring with emphasis.
Tools for setting saw teeth: a - slotted simple wiring; b - wiring with emphasis; 1 - slot; 2 - handle; 3 - stop with a wing nut (4) and a screw (5) for fixing the amount of divorce.
A simple wiring is made in the form of a small free-form steel die with a wooden or metal handle. The die has several slots of different widths.
The use of such a wiring is very simple: a slot is selected in the wiring corresponding to the thickness of the saw blade, and, having captured half of the saw tooth with it, carefully bend it in one direction or another. When bending the teeth, it is necessary to strive to ensure that their slope is the same along the entire length of the saw.
The process of setting saw teeth greatly facilitates the use of setting with a stop, which ensures the same bending of the teeth. Before starting work, the tool is adjusted to a certain amount of divorce, and then the stop is fixed in the desired position with a wing nut and a screw. The saw teeth are set in a wooden (carpentry) and locksmith vice or in special clamping devices in which the teeth are sharpened. When using a bench vise, plywood strips are laid between their jaws, corresponding to the size of the saw blade. The saw is clamped in a vise so that its teeth are very close to their jaws.
Height alignment of teeth
To align the saw teeth in height, a saw blade with teeth is pressed against a sheet of paper laid on a flat and smooth surface. If the tops of all the teeth are printed evenly on the paper, then they have the same height and such a saw cuts with high quality. If not all the teeth are imprinted on the paper evenly, then they are leveled in height with a file. Saw teeth with different heights when sawing wood are in different conditions: they saw differently and are also loaded differently. The unevenness of their heights ultimately affects their wear resistance and the quality of the cut surface. Teeth that differ from others by a significant height carry the maximum load, and as a result they wear out quickly. And the teeth, inferior to others in height, do not participate in sawing wood at all. The operation of leveling the teeth is performed after their divorce, before sharpening.Saw tooth shape
Crosscut saws. Crosscut saws are a very widely used tool in the construction of all kinds of wooden structures, the manufacture of furniture, and in the household. As the name suggests, they are used to cut wood across the grain. The teeth in them are a series of isosceles triangles or rectangular, hypotenuses facing each other. The figure below shows the various tooth shapes most commonly used in crosscut saws.
Varieties of saw teeth for cross sawing: a, b - simple triangular; c, d - triangular sparse and with wolf teeth; e, e - rectangular, facing each other with hypotenuses and sparse.
Each tooth can be imagined as an acute-angled knife with an apex angle β, sharpened from the sides with one-sided sharpening with a sharpening angle φ = 60-75° (the sharpening is shaded), and each of them contains two front and two side faces.
1 - saw blade; 2 - sharpened tooth.
For example, in the drawn tooth, the front faces are A 1 B 1 B 2 A 2 and A 1 B 3 B 4 A 2, the side faces are A 1 B 1 B 3 and A 2 B 2 B 4. Edges A 1 B 1 and A 1 B 3 are the main cutting edges, and edge A 1 A 2, resulting from sharpening the two front faces, is called a short cutting edge. Each tooth, having the above cutting edges, cuts wood when it moves in both directions, that is, from itself and towards itself. For example, in the drawn tooth, the cutting edge A 1 B 1 cuts the wood fibers when the saw moves to the left, and the cutting edge A 1 B 3 - when the saw moves to the right, and the short cutting edge A 1 A 2 delaminates the cut fibers and removes them in the form of sawdust from the resulting cut.
The teeth of the cross saws, which are isosceles triangles, are characterized by the taper angle β, the rake angle γ, the cutting angle δ, the pitch t and the height h. Points A 1 , A 4 , A 5 are the tops of the teeth. The angle of sharpening β characterizes the ability of the saw to cut this or that wood. Usually in crosscut saws for soft and wet wood, the angle β is taken equal to 40 °, and for dry and hard wood - 50-60 °. The angles in the tooth triangle are dependent on each other:
γ=β/2 and δ=90°+γ
Longitudinal saws. In longitudinal saws, the teeth are incisors in the form of inclined wedges. The figure below shows two types of teeth, the first - the most common in saws, and the second - with a deep cavity, used in saws for sawing soft woods (linden, aspen, alder), which abundantly emit sawdust.
1 - saw blade; 2 - tooth; 3 - line of tooth tops; 4 - canine tooth cavity.
Each tooth in the longitudinal saw, like a wedge, has four faces: front A 1 A 2 B 2 B 1, back A 1 A 2 B 4 B 3 and side B 1 A 1 B 3 and B 2 A 2 B 4.
Ribs A 1 A 2 , A 3 A 4 are the main cutting edges, and ribs A 1 B 1 , A 2 B 2 , A 3 B 3 , A 4 B 4 are side cutting edges. The teeth in longitudinal saws, like cutters on planers, cut wood when moving only in the direction of the inclination of the teeth, in which the main cutting edges, while cutting, form the bottom of the cut, and the side edges form its walls, and when they move back, they idle, sliding along the kerf and not sawing the wood.
The positions of the cutting edges of the tooth form angles between themselves: α - clearance angle formed between the back face and the cutting plane; β - sharpening angle between the front and rear faces; γ is the rake angle between the front face and the perpendicular to the cutting plane; δ - cutting angle; π is the angle between the front and rear faces of adjacent teeth. Considering the triangle of the rip saw tooth, we find the relationship between the angles:
α + β + γ = 90°; α + β = δ; π The quality of the cutting surface and the performance of the sawing process depend on the correct choice of the angular values of the cutting tooth of the saw. The most important of all angles is the taper angle β, with a small value of it, sawing wood occurs with less effort, but the strength of the tooth decreases, it crumbles, quickly becomes dull, and it has to be sharpened often. With a large value of this angle, the strength of the tooth increases, but the sawing force increases. Typically, the taper angle should be at least 20°.
With an increase in the cutting angle δ, the quality of the cut surface increases, but the sawing force increases, the cutting angle can be reduced due to the back angle, but at the same time, friction between the tooth and the wood increases and the tooth heats up excessively, is released, and its strength decreases, so the cutting angle δ is taken within 40-75°.
The angle γ determines the inclination of the tooth, its value is taken within 10-20°.
Thus, the values of the angles α, β, γ for the teeth of longitudinal saws are interconnected, and they are determined by practice - for example, the teeth of bow longitudinal (sweeping) saws are determined by the angles α=20-30°, β=50-60°, γ=8- 10°, and the teeth of rip saws - with angles α=20-40°, β= 40-50°, γ=10-20°.
Mixed saws. In hand saws, tooth designs are widely used, which can be used for both longitudinal and transverse sawing of wood. The figure below shows some of the tooth shapes used in mixed saw blades.
If the teeth of rip saws can be characterized as acute-angled wedges, then the teeth of saws for mixed sawing can be represented as rectangular or obtuse-angled wedges with a cutting angle δ=90°+γ. Angle γ - front, equal to zero or a negative value within 10-15°. They cut wood with these saws in the same way as longitudinal saws, when moving only away from themselves, and when moving towards themselves, they idle.
Each tooth in a mixed saw has four faces: front A 1 A 2 B 2 B 1, back A 1 A 2 B 4 B 3 and side B 1 A 1 B 3 and B 2 A 2 B 4.
Ribs A 1 A 2 , A 3 A 4 are the main cutting edges, and ribs A 1 B 1 , A 2 B 2 , A 3 B 3 , A 4 B 4 are side cutting edges. When sawing wood along the fibers, the main cutting edges form the bottom of the cut, and the side edges form its wall, and when sawing wood across the fibers, the side edges A 2 B 2, A 3 B 3, A 6 B 6 cut the wood fibers from the sides of the cut, and the main cutting edges A 1 A 2 , A 3 A 4 delaminate the cut fibers and remove them in the form of sawdust from the cut.
The teeth of saw blades for mixed sawing are determined by the taper angle β, the cutting angle δ and the rake angle γ. The angles δ and γ are related by the dependence δ= 90°+γ. The quality of the cutting surface and the performance of the sawing process depend on the correct choice of the angular values of the teeth. In practice, the following angles are chosen: in bow saws β=60°, γ=-10°, hacksaws β=45-50°, γ=0° or -(10-15°). Saws with teeth with a rake angle γ=-10° are widely used in bow saws (thorn, circle) as universal for sawing wood in any direction.
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A hand saw, at first glance, is a fairly simple tool that does not require special maintenance. Nevertheless, few people know about the criteria for choosing a saw and its types. Like other tools, a hand saw has certain signs of quality and characteristics.
The main parameters of a hand tool for sawing wood
A hacksaw is one of the most essential tools in every man's inventory. This device allows you to easily change the size of wood and plastic lumber. With the help of a hacksaw, you can perform a lot of operations in construction, file branches in the garden, shorten the poles of the fence, and so on.
A hand saw is used to work with lumber
But when buying such a seemingly simple tool, not everyone thinks about how to make the right choice and what criteria should be taken into account. The hacksaw has its own special parameters that can affect the quality of work. There are four basic parameters when choosing a hacksaw: blade length, tooth size, steel type and handle type.
Blade length
For convenience, the length of the hacksaw blade is chosen so that it is twice the size of the material at the cut point. This allows you to effectively remove sawdust during operation due to the fact that all the teeth of the blade will come out of the board / log. In addition, this ratio of the size of the hacksaw and lumber contributes to a greater range of hand movement. This, in turn, takes much less effort. In construction, a universal hacksaw with a blade length of 45–50 centimeters is most often used. To work with small bars and boards, a canvas 30–35 centimeters long will suffice.
Tooth size
This is perhaps the most important parameter. After all, the speed and accuracy of the cut depends on the size of the tooth.. The number of teeth per inch of blade is commonly referred to as TPI. For more precise work with the material, it is necessary to use a hacksaw with a large TPI coefficient, that is, with a large number of teeth. When choosing a blade with a TPI of at least 7–9, and a distance between the teeth of no more than 2–4 mm, the surface at the cut will be more even and without torn edges. For working with large cants and garden trees, a blade with a TPI of 3-6, a tooth spacing of more than 4 mm, will work well. The use of such a hacksaw will reduce the effort expended and increase the speed of cutting the working material..
Tooth Pitch Correspondence Table
| 1 TPI = 25.5mm | 10 TPI = 2.5mm |
| 2 TPI = 12mm | 11 TPI = 2.3mm |
| 3 TPI = 8.5mm | 12 TPI = 2mm |
| 4 TPI = 6.5mm | 13 TPI = 2mm |
| 5 TPI = 5mm | 14 TPI = 1.8mm |
| 6 TPI = 4mm | 17 TPI = 1.5mm |
| 7 TPI = 3.5mm | 19 TPI = 1.3mm |
| 8 TPI = 3mm | 22 TPI = 1.1mm |
| 9 TPI = 2.8mm | 25 TPI = 1mm |
Tooth sharpening
Plain triangular shape hacksaw teeth is taken as standard. The teeth are made in the form acute triangle or isosceles, depending on the purpose of the cut. Such a blade can be sharpened with particular ease by repeating all the corners of the teeth. Such a blade can be used for both longitudinal and transverse cuts to avoid coarse notches.
The teeth of a classic hacksaw are made in the shape of a triangle and can be sharpened
Video: self-sharpening the teeth of a hacksaw for wood
But modern hacksaws, unlike classic ones, have hardened teeth with a non-standard trapezoidal shape. Such saws are endowed with increased strength and are resistant to wear. Their steel cannot be sharpened, and it is very difficult to keep all the angles of the sharpened teeth.
Modern hacksaws are made with hardened teeth in the shape of a trapezoid.
Steel type
For the production of hacksaw blades, it is most often used stainless steel high grade. Usually saws for wood are made of steel with a hardness of HRC45. Very often, manufacturers combine steel in the canvas. In a hacksaw with a combined blade most of also made of steel 45, but the cutting part of steel 55 and 60. When hardening the cutting edge, wear resistance increases. This type of tool can be easily distinguished from a regular hacksaw by its dark hardened teeth.
The first forged saws were made back in Ancient Greece. Forging gave high hardness of the metal and improved the quality of the tool.
Handle type
The ease of use of the saw depends on the correct choice of the saw handle. Handles are made of wood or plastic. Very important point- the surface at the grip point should be such that the hand does not slip. This is eliminated by making scars on the handle, or by covering it with a rubber layer. The hacksaw can be both a classic cast and a reversible blade. The latter allows you to replace the canvas, which is very convenient.
How to choose a hand saw
By combining all the basic parameters of the saw, everyone can easily decide for themselves which one suits them best. When choosing a tool, you need to decide for yourself which saw is more suitable - carpentry or joinery. If the most important thing is the speed of cutting, then, of course, you need to purchase a carpentry. The carpenter's saw has fewer teeth per inch, which contributes to faster productivity and removal of sawdust. If the priority is the accuracy of the cut, then you should use the carpentry.
The quality of a hacksaw can be determined simple ways. First you need to visually verify the evenness of the canvas. Then you need to bend the canvas with a little effort and release it as soon as resistance appears. After the blade wins back and calms down, you should again look at the evenness of the blade. If it deviates slightly from its original position, then the tool is of poor quality and it is not recommended to buy it.
If you need a rip saw, you need to choose a hacksaw with sharp teeth. The teeth of such saws are sharpened only on one side, so the cut will be made only in one direction - away from you.
The teeth of the ripping blade are sharpened in the shape of an acute triangle
Rip sawing cuts parallel to the grain of the material. For rip sawing, circular saws and bow saws are well suited.
Hacksaws for cross cutting are the most common. Their teeth are shaped isosceles triangle and sharpened on both sides. This allows cutting in both directions..
For cross cutting, the teeth of the blade are made in the form of an isosceles triangle and sharpened on both sides.
In crosscut sawing, the material is cut across the fibers. For such sawing, classic hacksaws, hacksaws with a back, and with a large thickness of the material, two-handed saws are suitable.
The price of the saw is also an equally significant factor when choosing. A more expensive hacksaw gives a guarantee of reliability and wear resistance. Those saws that are much lower than the average price are made from cheaper raw materials and do not guarantee you long-term service.
What types of hand saws are supposed to be used
- The classic hacksaw is the most common of all. It has a long and wide canvas. If the blade is too long, the hacksaw may tilt to the side when cutting. Extra care must be taken to avoid deviation of the cut line from the initial markup. Such a hacksaw is suitable for working with timber, boards, chipboard and so on.
- Hacksaw with back. This saw model has a rigid edge-nozzle, which minimizes the frequency of vibration of the blade. And also such a hacksaw has smaller teeth and a higher TPI coefficient. They are designed for sawing plywood, chipboard with a layer of coating and sawing profile strips.
- Saws for fine sawing have an adjustable handle. They are needed for cutting grooves, grooves and sawing straight and profile strips.
- Circular hacksaw, or hacksaw with a narrow blade. It is also used for cutting grooves, as well as for sawing parts with rounded places and large holes.
- A bow saw is well suited for cutting knots and rough parts of the material, as well as for sawing parts out of plywood and wood. Such a hacksaw is distinguished by a thin blade fixed on both sides in a frame. It is worth noting that you need to work with it very carefully because of its increased fragility.
- Award - has two handles. The appearance of such a saw is in many ways similar to a planer. It is used for cutting spikes and grooves, deepening holes and slots in materials of any hardness.
- Garden saw with a curved blade. Most often, for greater convenience, they are foldable. This saw is great for gardening. The saw blade is made of chrome steel. Widely spaced teeth with an inclination towards the handle will allow you to conveniently cut knots and branches, focusing on yourself during cutting.
- A two-handed saw has the highest performance. It has two wooden handles. To make a cut with such a saw for greater efficiency, you need two people. A two-handed saw is often used for sawing large logs and trees.
- A hand or pocket chain saw is a small piece of chain with two handles at the ends. It is convenient to work with such saw both to one, and together. A log or bough is wrapped around a chain and cut with the help of handles. A hand chainsaw, like a folding saw, is well suited for gardening.
Photo gallery: varieties of hand saws
This classic hacksaw is easy to sharpen This hacksaw has hardened teeth and increased wear resistance A hacksaw with a back or a butt minimizes blade vibration during operation A hacksaw with a narrow blade is well suited for cutting holes and grooves 
This saw has an adjustable handle, which allows you to work at the right angle. The bow saw is well suited for cutting plywood parts. This type of saw is similar to a planer and is used to cut spikes and slots. A two-handed saw is suitable for sawing large logs. 
Garden saws with a curved blade are good for cutting twigs and small tree branches. 
The hand chainsaw is compact and well suited for sawing logs on a hike and branches in the garden.
Thus, having carefully studied all the nuances regarding hand saws, everyone can choose for themselves the most suitable option. Right choice tool will provide you with high-quality and pleasant work.
A circular saw blade is a working body designed for. It is an integral part, without which it is impossible to carry out any workpiece processing operations. saw blades used in and hand cutting tools.
Depending on the type of disk, the following can be processed: 
- wood of various species;
- wood products - sheets of chipboard, OSB, plywood, laminated flooring and other similar materials;
- polymeric substances and products from them, for example, organic glass, polystyrene;
- natural stone material, such as marble;
- soft metals - aluminum, copper alloys;
- products based on iron alloys - pipes, sheets of corrugated board, etc.
The cutting tool has certain characteristics, parameters, dimensions, purpose, properties of the material from which it is made.
The main parameters of the disk for a circular saw
Outer (outer) diameter
Determined by the internal size of the protective cover 
– a blade with a larger diameter will not fit on a saw with a smaller casing. The main dimensions of the cutting tool for hand-held circular saws are in the range of 130-250 mm. The outer diameter does not significantly affect the cutting speed, but determines the depth of cut. With an increase in cut significantly, the metal of the disk and the workpiece itself are heated.
Internal, landing diameter
It has several sizes: 16, 20, 22, 30, 32. Important parameter- the diameter must correspond to the size of the power shaft on the saw, under which the blade is selected. On some models of disks, there are additional holes that fix the disk on the pins.
Number of teeth on the disc
Influences parameters such as cutting speed and 
processing cleanliness. With a decrease in the number of teeth, the processing speed increases, the conditions for chip removal improve, but the cleanliness of the cut worsens. With an increase in the number of teeth, the cut is cleaner, but the load on the engine increases. Conventionally, according to the quantitative ratio, disks can be divided into three groups:
- a large number of incisors, is in the range of 80-90 pieces;
- average quantity (40-80 pieces);
- small quantity (10-40 teeth).
Discs with an average number of incisors are classified as a universal type. They can process soft and hard wood, perform transverse and longitudinal cuts, and can be used to process various wood products.
Tooth tilt
Determined by deviation from disk radius 
cutting edge surface. When deviating to back side tooth slope is called negative, when reverse side slope is positive. For longitudinal sawing, it is more expedient to use a tooth with a positive slope, since in the process of processing a kind of capture of the material occurs, the disc runs over the part, which contributes to a faster cutting of the workpiece as a whole. The slope of the tooth is divided into:
- standard slope - the angle varies from 5 ° to 15 °;
- positive, aggressive slope is 15-20°;
- the normal, negative angle lies between 0° and -5°.
Tooth configuration
Each type of cutter is designed and made to solve a specific task. Subdivided:
Disc thickness
Specifies the actual kerf width.
The standard size is 3.2mm. In addition, the thickness of the disc affects the strength of the cutting tool itself. Reducing the parameter leads to heavy operating modes, overheating of the disk and to a breakdown. Larger size causes an increased consumption of the processed material, that is, “transfer to chips”.
Circular saws are used in the processing of various materials. Accordingly, the cutting tool is made for specific tasks.
Types of discs for a circular saw
monolithic disk. They are made from quality 
high carbon or high speed steel. They are used for processing wood and products from it, as well as for cutting products made of polymers. They have a number of advantages:
- inexpensive;
- simple sharpening of teeth - you can perform this operation yourself, without the presence of complex special devices;
- regrind many times, therefore, they have a fairly large resource of work.
Disc with teeth reinforced with carbide. The blade is made from durable tool steel. Soldering is steel alloys with high content tungsten or cobalt carbides. Thanks to this decision, these discs have become the most common. They have a number of advantages:
At the same time, there is a significant drawback - such disks are relatively expensive and require special equipment.
When choosing a drive, consider technical specifications circular saw:
- engine power;
- maximum number of revolutions;
- landing size on the motor shaft;
- internal diameter of the protective cover.
Engine power affects the type of disk - 
negative angle, a large number of teeth create heavy load on the engine, which will have to work in the "peak" mode.
The number of revolutions or speed of rotation of the spindle is related to certain disc sizes that the manufacturer recommends. Installing a cutting tool with deviations from the recommended ones can lead to an abnormal operation mode, as a result of which the disc, saw blade and damage to the processed material are possible.
The mounting dimensions of the disc (inner diameter) and the corresponding one on the motor shaft must match, otherwise the tool cannot be installed on the saw.
The outer size of the disk cannot exceed the inner size of the casing - if this parameter is violated, the tool will not be installed on the saw.
A number of factors affect the type of disk: 
- type of work performed, material being processed;
- device, design of the cutting tool;
- number of teeth, their design.
Performed work and processed material. Since the discs are produced differently, it is necessary to determine the types of operations (what types of cuts will be carried out), and also take into account what the cutting tool will process.
Depending on the type of operations and material, the type of disc is selected: solid or hard-alloy tipped.
The processing mode and the type of material determine the number of teeth, their type and inclination. The most popular is the average number of teeth with a trapezoidal sharpening with a positive angle of inclination.
Disc build quality
There are several signs by which you can almost accurately determine whether the product is of high quality or made "on the knee": 
- The disc must be marked, and the inscription is applied with a laser tool, and not with paint.
- The canvas must be subjected to a grinding and polishing procedure - the purity of the processing can be seen with a glance if you “play” with the disk in the light.
- The cutting tool disc is subjected to balancing and calibration procedures - the operation is conditionally similar to balancing an automobile wheel. The cutting tool after such processing will not “beat”, vibration will not occur during operation.
- To compensate for possible thermal expansions, special slots are made on the disk, ending with small discharge holes.
- Some manufacturers reinforce the disc with several circular stiffening rings.
- Another indicator of quality is the name of the manufacturer, his trademark. To date, these are European, American, South Asian, Russian and Chinese manufacturers (listed in descending order of quality). By the way, some Russian manufacturers produce products that are comparable in some respects to European or American ones.
In general, choosing the right blade for a circular saw is almost a science. If there is no experience, then it is better to turn to professionals for advice, and those who have the skill of working on a circular saw for at least 2-3 years.
Video on replacing a circular saw blade.
K category: Joinery
Sawing by hand
Sawing is one of the types of cutting, in which the separation of wood occurs with the formation of a cut and with the separation of sawdust. The cut is limited by three faces, of which the lower one is called the bottom, and the other two are called the side surfaces.
Sawing is used to cut boards along the length into segments, sawing boards or sections along the width into bars or slats, trimming parts along the length, trimming edges, sawing boards and plywood, as well as curved and openwork sawing.
Saw for manual sawing (it is a steel band, on one edge of which there are teeth-cutters sequentially one after another (Fig. 38). Between the teeth there are depressions, the so-called sinuses. Each tooth of the saw has three cutting edges corresponding to the number of cutting planes.
The cutting edge of the tooth, which serves to form the bottom of the cut, is called the short, or front cutting edge, the side surfaces of the cut are formed by the side cutting edges of the tooth. The lateral cutting edge is formed by the front face and the lateral surface of the tooth.
The dimensions of the saw tooth are determined by the pitch and height. The pitch of a tooth is the distance between the tops of two adjacent teeth. The height of the tooth is the distance from its top to the base, determined by the perpendicular lowered from the top of the tooth to the base line.
The front face of the saw tooth for longitudinal sawing is called the breast, the back is called the back. The teeth of the saw blades have different shapes.
For longitudinal sawing, saws with an oblique (inclined) tooth are used. The cutting edge of such a tooth is its front, short, edge. The side edges chip off the sawdust. Sharpening of saw teeth for 'longitudinal sawing' is carried out at right angles to the saw blade. Such sharpening is called a straight line. The teeth work only when the saw moves forward, i.e. in the direction of the inclination of the teeth. Pointing angles at the teeth of saws for ripping soft woods from 40 to 50° and hard woods up to 70°. Cutting angle up to 80°.
Rice. 1. Saws: a - saw tooth elements; b - saw tooth angles: 1 - for longitudinal, 2 - for mixed, 3 - for transverse sawing
For cross sawing, saws with a tooth in the form of an isosceles or equilateral triangle are used. For such teeth, the side edges are cutting. Teeth sharpening is done obliquely at an acute angle to the saw blade. The top of the tooth is a trihedral incisor. Oblique sharpening, often called boring, or raznotochka, is performed through the tooth. The teeth of such a saw work when moving in both directions. The angle between the cutting side edges of the saw teeth for transverse sawing is 60-70°, and the angle of sharpening between the chamfer and the side edge of the saw blade is from 45 to 80°. Cutting angle over 90°.
For mixed longitudinal-transverse sawing (according to curved outlines), saws with a tooth in the form of a right-angled triangle are used. Teeth for mixed sawing are cut with all edges of the breast. These teeth are sharpened at a right angle to the saw blade or with a small bore (75-80 °). The teeth of such a saw only work when moving forward. The angle of sharpening of the saw teeth for mixed sawing is 50-60°; cutting angle 90°.
Rice. 2. Bow saw
Hand saws
Hand saws come with a stretch thin blade and a loose, thicker blade. Tension saws include all bow saws; to saws with a free blade - hacksaws.
A bow saw (Fig. 2) consists of a wooden machine (beam) and a saw blade stretched on it. The bow consists of two uprights, a spacer, two handles, a bowstring made of string or wire, and a twist.
By purpose, bow saws are divided into transverse, slotted, tenon, fine-toothed and rotary.
Crosscut saws have a length of 750-800 mm, a blade width of 20-25 mm and a blade thickness of 0.4-0.7 mm. Their teeth have the shape of an isosceles triangle 5 mm high, pitch 4-5 mm, oblique sharpening (boring).
Opening (sweeping) saws are used for longitudinal sawing of long boards, they have a length of 1000-800 mm, a blade width of 45-55 mm and a thickness of 0.4-0.7 mm. Their teeth have an oblique shape, height 5-6 mm, pitch 5-6 mm, sharpening angle 40-50°, cutting angle up to 80°, straight sharpening. The tooth setting is equal to twice the blade thickness. Saws work quickly, give a rough cut, require a lot of effort.
Tenon saws are intended for clean filing of ends and sawing of tenons, they have a length of 600-800 mm, a blade width of 40-50 mm and a thickness of 0.4-0.5 mm. Their teeth have the shape of a rectangular triangle with a height of 3-4 mm, a sharpening angle of 80-85 ° (to the blade), a bore. The tooth setting is 12/3 of the saw blade thickness. Compared to a split saw, a tenon saw requires significantly less effort when sawing.
Rice. 3. Knife saws: a - wide, b - narrow, c - backing, d - awards
Fine-tooth saws are used for clean cross cutting, have a length of 700 mm, a blade width of 30-40 mm and a thickness of 0.4-0.5 mm. Their teeth have the shape of a rectangular triangle with a height of 2-3 mm, a pitch of 2-3 mm, a sharpening angle of 60-80 °, a bore. The tooth setting is 1/3 of the saw blade thickness. The saw requires little effort when sawing.
Rotary (circular) saws are designed for figured sawing, have a length of 350-500 mm, a width of 4-15 mm, a thickness of 0.4-1 mm. Their teeth have the shape of a rectangular triangle with a height of 2-3 mm, a pitch of 2-4 mm, a sharpening angle of 50-60 °, straight sharpening or a small boring.
Knife saws (hacksaws) can be wide and narrow.
Wide hacksaws (Fig. 3, a) are used for transverse, rectilinear sawing of boards. The thickness of the web is up to 1.5 mm. Saw length 400-700 mm. The teeth of wide hacksaws have the shape of an isosceles triangle with a 55° taper angle. The tooth set is 0.4-0.6 mm per side.
Narrow hacksaws (Fig. 3, b) for figured sawing are used in cases where sawing is carried out along the inner contour of the workpiece. Narrow hacksaws are usually made smaller than wide ones (300-400 mm). The thickness of the web is 1.5 mm. Divorce is made very small; teeth have the shape of a right triangle.
Back saws (Fig. 3, c) have a thin rectangular blade 0.6-0.8 mm thick. A steel butt is riveted to the upper edge of the back saw to give it rigidity. The saw teeth are in the shape of a right triangle with fine pitch and very little setback. The teeth cut when moving away from you. Back saws are used for fitting joints, shallow sawing, sawing small parts and miter cuts for corner joints.
Awards (Fig. 3, d) with a blade fixed in a wooden frame are used for sawing slots (grooves, grooves) to a certain depth not across the entire width of the treated surface. They cut with an award along the ruler at any angle to the plane during the initial movement of the saw only towards itself. The breasts of the teeth are directed towards the worker. The teeth are in the shape of a right triangle with fine pitch and very little setback.
Plywood file - a special award with small teeth located along a curved convex line. Serves for cutting planed plywood.
To eliminate jamming of the saw in the cut, the shape of its teeth is changed or their wiring is made (Fig. 4, a, b, c, d). For the same purpose, a saw blade is made of a trapezoidal section with teeth arranged at a wider base.
The amount of divorce of all teeth must be the same, otherwise the less bent teeth will not participate in sawing, and the most bent teeth will carry a large load. The saw teeth are set with special wiring, clamping the saw blade at the base line of the teeth in a wooden vice (Fig. 5). The best sets provide the same amount of set for all teeth. On fig. 6 shows the universal wiring. When working with it, the saw blade is clamped in a vice fixed in a workbench.
Rice. 4. Different kinds changes in the shape of the saw teeth: a - wiring, b - flattening, a - trapezoidal broadening, d - times. vodka with side cut for cross cutting
Rice. 5. Saw tooth setting
Rice. 6. Vise
After divorce, the teeth of the saw are sharpened. This is done with a trihedral file with a fine notch. With straight sharpening, the file is held perpendicular to the blade, and with oblique sharpening, at an angle of 45-80 ° (Fig. 8, a, b). With direct sharpening, the edges of the file during operation should coincide with the breast and back of the tooth (Fig. 8, c). The file is pressed against the saw tooth when moving away from you, and when moving back, it is lifted so that it does not touch the saw.
For the saw to work well, it is important that the teeth are not only sharpened and set, but have the same height. During the operation of the saw, the teeth are worked out differently, therefore, before sharpening, they should be aligned in height or planed off. The tool for jointing saws is a file inserted into a wooden block (Fig. 9).
Rice. 7. Universal wiring: 1 - bending lever, 2 - plate for adjusting the width of the saw blade passage, 3 - adjusting screws, 4 - hinged adjuster. divorce amount adjuster, 5 - scale for setting the divorce amount, 6 - screw with stop for teeth of different sizes, 7 - spring
Rice. 8. Sharpening saws: a - the direction of the file with straight sharpening, b - the direction of the file with oblique sharpening, c - the position of the file on the saw teeth
Rice. 9. Device for planing saw teeth
Working with hand saws
There are three main types of manual sawing of wood:
a) longitudinal with a horizontal position of the material;
b) longitudinal in the vertical position of the material;
c) transverse.
The least time-consuming is the longitudinal sawing of the board in a horizontal position. Before proceeding with sawing, cut lines are marked on the selected board with the help of a thickness gauge. The marking of the cutting line is done in such a way that after sawing there is some stock of material left for further processing. Then the board is fixed on the workbench along its front edge in such a way that the part to be sawn off protrudes beyond the edge of the workbench. The board is fixed with a clamp or a bench blade.
The saw blade is rotated at a certain angle with respect to the plane of the beam and pulled. The spreading saw is held by the handle and the angle of the spreader. Its position during sawing should remain vertical (Fig. 10).
Rice. 10. The position of the worker's legs when sawing a board horizontally
The legs of the worker in relation to the material should be located, as shown in fig. 10.
Saw should be free movements, pressing the saw to the bottom of the cut during its working movement down and forward. When idling the saw up, it should be taken back a little. In the case of clamping the saw, a small wedge is inserted into the cut behind it. Sawing long boards is done using bench stands.
Rice. 11. Longitudinal sawing of a horizontal board
When ripping a material located vertically, there can be two types of sawing: perpendicular and parallel to the face. In the first case, the material is fixed in the back vice of the workbench, and in the second case, in the front.
The saw is held with the right hand on the stand during sawing, as close to the handle as possible. With the left hand, support the sawn material. The movement of the saw during operation must be horizontal.
The legs and body of the sawing material, installed vertically, are positioned as shown in fig. 13. Body and left hand during operation must remain motionless.
When the board is in a vertical position, the beginning of the cut should not be placed very high. The saw is first set to the mark and with a short, slow movement of the saw towards itself, a shallow cut is made. Before the formation of washed down, sawing in a sweep is impossible. When sawing, do not press hard on the saw, as this does not speed up the work. You should also not press the sawn bar with your left hand.
Rice. 12. The position of the worker's legs during longitudinal sawing of a board installed vertically
Rice. 13. Sawing across the grain of horizontal material
When sawing across the fibers with a bow saw, the board is placed on the edge of the workbench so that the sawn off part protrudes beyond the rear bar of the cover, and the end rests against the folding stop.
The saw is held with the right hand by the stand near the handle, and the material being cut is supported and pressed against the stop with the left hand. The saw should be held at an angle of no more than 10-15 ° to the upper plane of the material being cut (Fig. 13).
The worker becomes so that his left foot is perpendicular to the board being sawn, and the right foot steps back and to the right with a turn at an angle of about 80 ° (Fig. 14).
The body during sawing is motionless, slightly tilted forward.
Sawing across the grain is the most labor-intensive type of sawing and requires some pressure on the material. In order to make a saw, the saw blade is directed along the nail or along the second joint. thumb left hand.
Rice. 14. The position of the legs of the worker when sawing horizontally located material across the fibers
Rice. 15. Sawing on the knuckle of the thumb
In this case, the joint should be kept above the teeth (Fig. 15). Washed down is done with a smooth movement of the saw towards itself.
At the end of the cut, the sawn off part of the board should be supported with the left hand to avoid splitting the wood.
To cut parts at an angle, the so-called miter box is used (Fig. 16). It is a tray of boards with slots for saws located in the sides at a certain angle. When using a miter box, it is clamped into a workbench.
Rice. 16. Miter box
Marriage when sawing with hand saws can be the result of improper sharpening or divorce of the saw. This results in an uneven, non-straight or rough cut. Due to the skew of the saw blade during operation or the incorrect posture of the worker, the cut may not be perpendicular to the face or edge of the board.
- Sawing by hand
On the Stankoff.RU website you can buy rip saws from leading manufacturers. Available and under the order saw blades for longitudinal sawing along the best prices. Only great deals detailed descriptions and photo. Check prices with managers.
The difference between rip saws is the small number of teeth compared to other types of cutting tools. The tool is used for fast sawing of wood. different breeds providing high performance.
Design feature of circular saws for longitudinal sawing
The main criterion for longitudinal sawing is high productivity, not cut quality, for this reason the cutting blade has the smallest number of teeth (the exact number of cutters depends on the diameter of the disc), because it is when feeding per tooth that the cutting power decreases. The fewer teeth a rip saw has, the faster the feed material is cut.
Another important difference between the discs is a capacious interdental cavity, in which the sawn products fit: chips and sawdust. When performing a longitudinal cut, it is necessary to ensure effective removal waste and prevent them from clogging in small holes, this served as the creation of a special design of the blade with a large cavity. A rip saw provides a rough surface where the cut is made, but this is acceptable for heavy duty sawing.
For heavy cutting operations, carbide rip saw blades are used to maintain blade integrity during use and withstand heavy loads. Carbide cutters are resistant to corrosion and wear.
Discs for work with mechanical feed of workpieces
Some models of blades have special elongated slots with soldered hard alloy plates located at a certain angle. If in the process of wood processing it is not possible to provide automatic feeding of blanks, then a saw is used for longitudinal cutting with plates having a negative angle of inclination (located in through holes).
The plates are not responsible for cutting, but for improved discharge of sawdust, reducing the likelihood of clamping the blade during sawing, reducing friction and heating of the disc. This type of wood rip saw is designed for work with mechanical feed of workpieces, involving a large cutting height.
Discs with limiters and deep notches
There are special blades equipped with limiters - protrusions of the body in front of the saw cutters located on the blade. This design reduces the feed rate, which is especially important for woodworking machines that require manual feed. Another function of the limiters is to protect the edges from damage when knots fall out.
Rip saw blades with a large diameter (600-1500 mm) often have a design that is characterized by the presence of deep cuts under the crown. The cutting tool is called "Hannibal". Cutouts contribute to quick cleaning of the cut and more efficient cooling of the blade in the process.
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