home Audience 3 Circular saw for longitudinal cutting. Circular saw blades for wood and metal: sizes and types of circles. Shape and inclination of teeth

Circular saw for longitudinal cutting. Circular saw blades for wood and metal: sizes and types of circles. Shape and inclination of teeth

Saw

Wood has to be sawed both along the grain and across, and depending on the purpose, saws are divided into longitudinal (with an oblique tooth) and transverse (with a straight tooth). A crosscut saw has teeth shaped isosceles triangle, sharpened on both sides (Fig. 28).

Teeth rip saw look like a series of narrow chisels located one after another. They have an asymmetrical shape and are slightly tilted forward; the leading edge is almost perpendicular to the longitudinal axis of the saw.

A crosscut saw cuts fibers equally well when moving forward and backward, while a rip saw cuts fibers only when moving forward.

Saws with large teeth are used for rough cutting of workpieces, as well as for sawing mainly soft and raw wood. For fine work and sawing dry and hard wood, you need to use fine-toothed saws. It is difficult to saw a board if the distance between the tips of the saw teeth is almost the same as the thickness of the material. The saw will stick its teeth behind the edge of the board and will not move.

For sawing logs, thick boards, and firewood, a two-handed transverse saw is usually used. Two people operate this saw. The saw is set with its teeth at the mark at which the material needs to be sawed off, and a small cut is made with two or three short movements, after which they begin to saw at full swing. Each of the workers takes turns pulling the saw only towards himself and when reverse stroke does not push it forward, but only supports it by the handle, freely releasing the saw when its partner pulls it towards him.

Bow saws and hacksaws are usually used for carpentry and carpentry work. An amateur can get by with one hacksaw, as it is quite suitable for both longitudinal and cross cutting. In addition, a hacksaw has a number of advantages: it is simple in design, universal, and thanks to the wide blade, it goes straighter in inexperienced hands. A circular saw is used for filing along curved lines. There are also hacksaws for sawing tenons, ends, etc., which will be discussed below.

Clean, accurate work with a handsaw depends mainly on good sharpening, setting and correct handling with a tool.

When sawing, hold the hacksaw firmly right hand, and it is better to direct the index and thumb along the hacksaw blade (Fig. 29, A). This grip contributes to the correct and smooth movement of the tool, since the muscles of the forearm do not tense as much as when fully gripping the handle of the saw (into a fist). This is especially true for small hacksaws.

You should start sawing by moving not forward, but towards yourself. Guide the saw thumb with the left hand along the mark (Fig. 29, B), with a slow movement they pull the saw towards themselves and thus make a cut of sufficient depth. The saw is directed along the marking line so that left-hand side The teeth passed exactly along the marking line, and the allowance for the width of the tooth spread fell on the part being sawn off. If a very clean end is required, then a small allowance is left, which is then removed with a plane.

When starting sawing, you need to ensure that the saw blade forms a right angle with the plane of the object being cut (Fig. 29, B). It is convenient to check the correctness of the cutting plane with a square (Fig. 29, D) or an evenly cut block. The saw can be oriented along the rectangular edge of the workbench on which sawing is being done, making sure that the saw blade moves parallel to the edge. For greater cutting accuracy, the board or block should be marked on all sides.

It is necessary to position the object being sawed so that the sawn part does not narrow the cut with its weight and does not pinch the saw. When longitudinal sawing, it is useful to insert a wedge into the cut from the end (Fig. 29, E). It should not be hammered too hard, otherwise the board may split. In order to expend less force when sawing, the saw is held at an angle to the plane of the board. Typically this angle is 60°, but when cross-cutting soft wood and less than 20 mm thick, an angle of about 40° is more advantageous. We must remember that what large quantity the teeth are in contact with the wood at the same time, the better the cut will be; this should be guided by practical definition saw angle.

When sawing plywood, flakes usually form on the opposite side of the sheet. To avoid them, it is recommended to cut the outer layer of plywood on the bottom side along the markings with a pocket knife.

It is necessary to ensure that the saw is always well sharpened and set apart. Setting and sharpening teeth require some experience, so it is useful to first learn, try to set and sharpen an old, broken saw, and only then start sharpening a new one.

It is more convenient to separate and sharpen the saw if it is fixedly fixed in a bench or bench vice (in the latter case, two narrow wooden spacers must be placed under the jaws) (Fig. 30, A). The saw is clamped so that the protruding cutting part it did not vibrate when working with a file.

If the saw blade is bent, it should not be straightened in a vice or with a metal hammer. First you need to try to straighten it with your hands, and if this fails, then place the saw on a flat wooden surface and straighten it with a mallet (Fig. 30, B).

When sawing, the teeth do not work equally. Sometimes their height is violated as a result of careless sharpening of the saw. To align the teeth at height, they are filed from above along the blade with a flat file. In this case, it is very important not to tip the file to one side, otherwise after setting and sharpening the teeth will have irregular shape. This task is greatly simplified if you make a special block. A hole is drilled in a small block along the axis and a longitudinal cut is made. A triangular file is firmly fixed in the hole (Fig. 30, B). Then the block is placed on the saw and, with reciprocating movements along the blade, the teeth are filed to the desired size, checking them with a long ruler.

The setting of the teeth is done so that the width of the cut is greater than the thickness of the saw, otherwise it will jam, which will significantly complicate the work. The setting consists of alternately bending the teeth through one in opposite directions; a value equal to approximately half the thickness of the canvas (0.25 - 0.7 mm). For sawing soft wood, the tooth set must be larger than for dry and hard wood.

It is not necessary to bend the entire rubber tooth from the base, but only the upper third of it.

It is most convenient to install a saw with a special wiring (Fig. 31, A) but an amateur may not have one and will have to use pliers. Having clamped the saw, as indicated, the teeth are bent one at a time in one direction, then the saw is turned over and the previously missed teeth are bent in the same direction. In a crosscut saw, the teeth are bent outward from the sharpening chamfer.

The distribution uniformity has essential, since a saw with incorrectly bent teeth will make an uneven cut and will be pulled to the side. It is convenient to check the correctness of the setting using a simple template shown in Figure 31, B. When viewed longitudinally, correctly set teeth should have the profile shown in Figure 31, B.

Sharpening is usually done with a triangular or diamond-shaped file with a fine notch. The teeth are sharpened by moving the file away from you; when moving back, it should not touch the saw blade. You need to work with a file without strong pressure.

The teeth of the crosscut saw are sharpened at an angle of approximately 45° (Fig. 32, A). The sharpened teeth of the cross-cut saw should look as shown in Figure 32, B.

The rip saw is sharpened by straight sharpening, moving the file perpendicular to the blade, as in Figure 32, B. In this case, there is no need to turn the saw in the clamp.

After sharpening the teeth, the saw is placed with the blade on a flat board and the burrs formed during the sharpening process are removed. This can be done either with the same file or with a whetstone.

If saws are used exclusively at a work table, then for ease of use you can make a special stand, shown in Figure 33, A.

If you need to keep the saw in a box to protect the teeth from dulling, you can use a bar with a cut groove (Fig. 33, B) or a piece of an old rubber hose. During long-term storage, the saw blade must be lubricated with machine oil to prevent it from rusting.

It is difficult to imagine the arsenal of tools of a home craftsman or mechanic without a hand saw. Another name for it is a hacksaw. With this tool you can cut down branches in the garden, shorten pickets for a fence and do a lot of other work where you need to change the length of a wooden product: laminate flooring, farm boards, etc.

You may not have thought about it, but the correct choice of a hacksaw determines not only its service life, but also the ease of use and quality of the cut. Let's look at the main parameters the right choice This is a necessary tool for farming and carpentry.

How to choose a saw?

A hacksaw for wood is on the market in different options. How products may differ:

Tooth shape and size;
Canvas size;
The grade of steel from which the working part (blade) is made;
Handle shape.

A hacksaw with a change in one of the specified parameters can radically change its characteristics. Also, sitting comfortably in the hand of one master, it will not suit another at all. These factors must be taken into account when choosing a tool for different purposes.

Teeth size

This parameter affects the quality and speed of work. For convenience in determining the size and number of teeth, the designation TPI was introduced, indicating the number of teeth in one inch. This parameter can be seen in the description of a hand saw for wood; the value is often written on the blade.

A carpenter's saw is selected primarily based on the size of the tooth. So, for ordinary wood, small and large are suitable, but for “delicate” materials such as fiberboard, a fine-toothed saw is needed. In stores you can now find similar designations: “for wood”, “for drywall”, etc. Their main difference is the size of the teeth, which is optimal for sawing each of the materials indicated on the label.

The teeth are distinguished by shape, depending on this the tool acquires different purposes:

Steel selection

To make the tool last longer, you should choose high grades of steel for the production of the blade. It's better if it's stainless.

The teeth can be hardened or regular. Regular saws can be sharpened at home, saws with hardened teeth are disposable, and once worn out, nothing can be done with them. They are easy to recognize by their dark color as in the photo.

Blade length

This parameter is determined by the size and pitch of the saw tooth.

A mini-hacksaw is always equipped with small, frequent teeth; the length of its blade does not exceed 350 mm;
A universal hacksaw has an average tooth size and a length of no more than 550 mm;
The wide hacksaw is equipped with large teeth with an increased pitch, the length of its blade is over 600 mm.

In addition to the length, the canvas can vary in shape. A traditional saw has the shape of a rectangle narrowed on one side. This is a universal type of tool that can be used to cut anything.

The rounded blade is adapted for working with branches and other objects at a distance: it is lightweight and easily glides along the wood without much effort.

Handle shape

This part of the saw determines the ease of work. The tool should fit perfectly into your hand and be comfortable. To make handles, various plastics that are pleasant to the body are used. Important Note– the material should not slip if your hand suddenly becomes sweaty. For this purpose, the handle body has recesses and grooves and a rubberized lining.

Varieties

By combining the above factors, manufacturers have developed and are now producing standard products with different blades, handle and tooth shapes. To understand how to choose a hacksaw for wood, you first need to familiarize yourself with existing types drank.

Type 1: Classic

The main type of saw that almost every man has, even those far from construction and carpentry. This hacksaw can have a blade of any length with a different number of teeth; the tool is often equipped with replaceable blades, which are included with the purchase.

Type 2: Narrow

Its other name is a circular hacksaw. It takes its name from its main application - it cuts out lines of different shapes, and it does it neatly and clearly. It is also used for cutting through round and square holes. The saw blade is narrow, the teeth are frequent, and can be located either on one working plane or on both.

When working with a saw, you should be careful: if you move uncertainly, the blade will turn in the other direction, so when choosing a hacksaw for wood with a narrow blade, you should choose a product made of high-quality hard steel that will not bend during the cutting process.

Type 3: With pad

A hacksaw with a backing is equipped with a stiffening rib (the same backing), which prevents the blade from bending during operation. Thus, the tool is not able to make a cut lower than the width of the working part of the saw.

A backed hacksaw is always equipped with a comfortable handle at an angle of 45° to the blade for easy work execution.

Type 4: Bow

For plumbing, a bow saw is indispensable: it is used for cutting rough parts of the trunk, knots, cutting out figures from plywood and other wood materials, cutting wood along and across the grain. The use of a bow saw is so widespread that it alone can replace a small woodworking machine.

The wide range of work carried out is slightly obscured by the main disadvantages:

Bulky. The bow saw is a complex structure, its supporting part is made in the form of a large curved arc, to which a thin, thread-like blade with teeth is attached.
Fragility. You need to work with the tool extremely carefully: the blade can fly off the mounts and tear during operation; it requires frequent replacement.

Type 5: Reward

The award saw requires a lot of effort to master. This is a tool that resembles a plane. It is equipped with two handles. Its main application is cutting grooves and tenons; the depth of holes and recesses can be different sizes, and on rocks of any hardness.

Type 6: Folding tool

A mechanical hacksaw that you can take with you on a hike or on vacation. It is compact, lightweight, and completely safe when folded. A folding hacksaw has fine teeth and a short, pointed blade.

Selection by purpose

In addition to taking into account the main types of saws, the choice of a hacksaw for wood should be made upon request under certain type works:

Swing for longitudinal sawing;
Transverse copes well with wood across the grain;
Tenoning for cutting grooves, tenons and technological recesses in products;
Circular for cutting holes of different shapes;
Folding hacksaw for wood

These types of wood hacksaws generalize the above tool models. The choice should be made according to the main purpose for which the selected type of tool is purchased. For household It is advisable to purchase a saw with replaceable blades or have several hacksaws of different types in your arsenal.

How to decide

This amount of new information is not easy to put into practice, so we will give you some tips on how to consistently choose the right saw.

The first factor to consider is what sawn material will be used and what is the desired quality of the cut. Carpenters working with small wooden products, choose small saws with a short blade. For a carpenter, it is better to use large teeth and a blade - this master does not require high precision work, speed is a priority. A folding garden hacksaw is ideal for summer residents who will only cut through trees and shrubs.
Frequency of application. Determine how often you will need to use the tool. If the need arises rarely, take a saw with hardened teeth; if the need for sharpening often arises, use ordinary steel.
The quality of the steel must be high for a tool with any frequency of use. The higher the class of metal, the better the quality of the product. Before purchasing, take the tool in your hands and carefully bend the blade to 45 0. Good metal elastic and when the end of the saw is released it will restore its shape without displacing the central axis. If you notice a deviation, return the hacksaw to the seller.
In this case, price is a guarantee of quality. Of course, provided that the seller is honest and does not offer you a fake. Good product can't be cheap. Choose in the middle price range, if your wallet allows it - don’t skimp on an expensive saw. Select a manufacturer based on its trust rating and give preference to its products in the store. In most cases, this tactic allows you to avoid buying something unknown instead of a good tool.
Take the hacksaw tool in your hand. You should feel comfortable holding it. The material used can be solid plastic with a rubberized handle.

Sticking to these simple rules You can easily choose the right wood hacksaw for your needs.

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Details Category: Wood processing

Sawing with a carpenter's hacksaw

Sawing is one of the most critical operations in the wood processing process. The quality of manufacturing of parts and wood savings largely depend on the quality of its execution. By correctly performing the sawing, you can reduce the allowances for subsequent planing and the time for manufacturing the part.

Hand saws are divided into tension saws with a thin saw blade and loose saw blades with a loose, thicker blade. Tensioned saws include all bow saws, and for saws with a free blade - hacksaws.

Below you can watch a fragment of a film about making hand saws and hacksaws. Full version the film can be downloaded.

According to the direction of cutting the fibers, they are distinguished transverse, longitudinal and mixed Sawing
At transverse sawing the direction of the cut (cut) is perpendicular to the fibers.
At longitudinal sawing - parallel to the fibers. At mixed sawing - directed at an angle towards them.

Cutting element any saw is tape with teeth cut into it. Each tooth represents cutter. Saw teeth are also characterized step and height: height- the shortest distance between the base and the top of the tooth; step- the distance between the tops of adjacent teeth.
For cross cutting For workpieces, saws are used whose teeth have straight triangular profile, and for rip sawing - saws with inclined profile teeth

Hand saws are available with fine and coarse teeth.

Have saws for transverse sawing, the sharp cutting edges of the tops of the teeth alternately cut the wood fibers and remove the broken wood particles in the form of sawdust.
Have saws for longitudinal sawing, the cutting edges of inclined teeth protruding forward cut off the wood fibers and the cut particles are chipped along the fibers, forming sawdust. The figures below show the shapes of the teeth and the patterns for cutting fibers with longitudinal and transverse saws.

Technical characteristics of saw teeth

Tool	(triangle)	Point angle
*Bow saws*
Transverse	Isosceles
Dissolute	Oblique
	Rectangular
Fine-toothed	Rectangular
Circular	Rectangular	50-60 or 80-85	Straight or small boring
*Hacksaws*
	Isosceles or rectangular	Depends on the shape of the teeth
	Rectangular
Obushkova	Rectangular
Award	Isosceles

Purpose of sawing tools

Types of hacksaws and special saws	Purpose	Appearance and device
Wide	Cross rough sawing
Narrow (trigger)	Through sawing on a plane and curved sawing
Obushkovaya (slotted)	Finishing shallow cuts and adjusting products during assembly
Award (blade made from scraps of old saws)	Shallow sawing of grooves

When sawing, the saw blade rubs against the walls of the separated parts of the wood. And so that it does not get pinched in the cut, the saw teeth must be divorced(set of teeth), i.e., alternately bent in different directions. This makes the cut a little wider and makes sawing easier. Below is the views wiring for spreading the teeth.
There are wiring different forms. In the picture below on the left( A) shows the main types of wiring. On the image b And V- shows correctly set teeth for transverse ( b) and longitudinal sawing ( V).

When sawing workpieces, retreat from the marking line by 2-3 mm.

The hacksaw blade should move at right angles to the workpiece.

Sawing control carried out along the marking line. It should remain to the left of the sawing point on the workpiece.

For more precise sawing of wood or plywood blanks, use saws with fine teeth. The inclination of the saw is shown in the figure.

This is how they work with a hacksaw. The marked workpiece is placed on a board (1) on a carpentry bench that has a stop (2). With your left hand you press the workpiece against the stop, and with your right hand you make a cut. In this case, the hacksaw is pressed against the stop and several short smooth movements are made towards you. After sawing, the hacksaw is moved along its entire length, aligning it with the marking line of the cut.

By moving the saw along the line, an incision is made, then the block is removed and the part is sawed off. At the end of sawing, the pressure on the saw is eased so as not to break off the wood fibers at the exit of the saw. The position of the hands when sawing is shown in the figure.

For precise sawing of bars and boards at angles of 90°, 45°, 60° and others, they are used miter box . Miter box has a grooved shape. It consists of a bottom 1, two sidewalls 2, between which the workpiece to be cut 3 is clamped. The sidewalls have cuts made at the desired angle. Saw blade 4 is inserted into these cuts and sawing is performed at the desired angle.

Application miter box eliminates part marking, increases cutting accuracy, reduces time spent on part marking, thus increasing labor productivity. The use of a miter box is especially effective in mass production details. The miter box may look like the one shown in the photo.

For ease of sawing, they also use tsulagu. Tsulaga very quickly made from a sheet of plywood or board and two bars. Thanks to the lower bar, it is easy to press it to the tabletop, and the upper one serves to support the workpiece. Tsulaga can be made with a movable sawing stop large quantity identical parts.

Sawing techniques using tsulagu, miter box, stops, are shown in the figures.

For sawing different blanks and figured sawing are used different saws and hacksaws. Examples are given in the figure.

Securely secure the workpiece when sawing.
Use stops, miter boxes and other devices.
Sawing only with a serviceable, sharply sharpened saw.
Do not allow the saw to skew when sawing.
Do not make sudden movements with the saw.
Do not keep your left hand close to the saw blade.
Place the saw on the workbench with the teeth facing away from you.
Do not blow away sawdust or sweep it away by hand. Use only a brush.

Classification of types of sawing

Characteristics of the sawing process

Sawing is the process of dividing wood with a saw into volumetric, undeformed parts by turning the volume of wood between these parts into chips.

A saw is a multi-blade cutting tool that works in a closed cut. A kerf is a gap formed in wood when teeth cut narrow shavings (sawdust). The cut has side walls and a bottom with which the blades (teeth) interact.

Sawing wood is classified according to several criteria.

Depending on the position of the saw plane in relation to the wood fibers, longitudinal, transverse and mixed sawing is distinguished.

For longitudinal sawing The plane of the saw is parallel or approximately parallel to the grain of the wood. Sawmill frames, circular saws and band saws, on which logs and beams are sawed into boards, lumber is cut in width or thickness in the longitudinal direction.

When cross cutting the plane of the saw is perpendicular or approximately perpendicular to the grain of the wood. Sawing is performed manually with cross-cut saws, hacksaws or on cross-cutting machines used for cutting logs into round logs, removing wood defects and wane areas from the ends of the lumber, as well as giving the lumber a given length and quality.

For mixed sawing the saw plane is located at an acute angle (10˚...80˚) to the direction of the fibers.

Depending on the type of saws used, there are different the following types sawing:

– longitudinal frame sawing, sawing with band, circular and jigsaws;

– cross-cutting with circular, chain and jigsaws;

– mixed sawing with circular, band and jigsaws.

Depending on the number of simultaneously working saws in the machine, a distinction is made between individual and group cutting methods. Cutting logs and lumber with one saw is called individual cutting, and cutting with several saws is called group cutting.

For individual sawing logs are sawn into lumber with separate cuts on circular saws, band saws, vertical or horizontal machines. The cutting is carried out taking into account individual characteristics quality zones of each log. This cutting method is effective when sawing valuable wood, cutting large-diameter logs and logs with significant defects.

For group sawing sawmill frames, multi-saw circular saws and band saws, as well as milling and sawing machines are used.

Depending on the position of the workpiece relative to the center of the circular saw, sawing with the peripheral zone of the saw, the middle zone and the central zone of the saw, as well as sawing with the upper and lower zone of the saw are distinguished.

When working in the peripheral zone saws, the teeth of the saw protrude above the surface of the workpiece by an amount approximately equal to the height of the tooth.

When working in the middle zone saw teeth protrude above the surface of the workpiece by an amount equal to approximately one third of the radius of the saw.

When working in the central zone The center of the saw is located at the middle of the cutting height. This type of sawing is used in milling and sawing machines.

The peripheral and middle working zones of the saw can be located on the upper or lower sections of the saw, which is observed in circular saws with a lower and upper saw shaft.

At divorce (Fig. 2, A) the tips of the teeth with a length of 0.3...0.5 of the tooth height are bent alternately in different directions. At flattening (Fig. 2, b) the tips of the teeth are flattened and shaped, giving them the shape of blades located symmetrically relative to the saw body.

The sawing rule can be formulated as follows: when inserting a tooth into wood, you first need to cut the fibers, and then, with the least resistance, separate them from the massif and remove the chips from the cut.

K category: Carpentry work

Sawing by hand

Sawing is a type of cutting in which wood is separated to form a cut and separate sawdust. The cut is limited by three faces, of which the bottom is called the bottom, and the other two are called the side surfaces.

Sawing involves cutting boards lengthwise into sections, sawing boards or sections widthwise into bars or slats, trimming parts to length, trimming edges, sawing boards and plywood, as well as curved and openwork sawing.

A saw for hand sawing (is a steel strip, on one edge of which there are teeth-cutters located sequentially one after another (Fig. 38). Between the teeth there are depressions, the so-called sinuses. Each saw tooth 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 edge and the side surface of the tooth.

The dimensions of the saw tooth are determined by the pitch and height. The tooth pitch is the distance between the tips of two adjacent teeth. The height of a tooth is the distance from its top to its base, determined by a perpendicular drawn from the top of the tooth to the base line.

The front edge of the saw tooth for longitudinal sawing is called the breast, the back - the back. Saw teeth have different shapes.

For longitudinal sawing, saws with oblique (oblique) teeth are used. The cutting edge of such a tooth is its front, short edge. The side edges chip away sawdust. Sharpening saw teeth for longitudinal sawing is done at a right angle to the saw blade. This sharpening is called straight. The teeth only work when the saw moves forward, i.e. in the direction in which the teeth are tilted. The sharpening angles of saw teeth for longitudinal sawing of soft rocks are from 40 to 50° and hard rocks 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 cross cutting

For cross cutting, saws with teeth in the form of an isosceles or equilateral triangle are used. The cutting edges of such teeth are the side edges. Sharpening of the teeth is done with an oblique at an acute angle to the saw blade. The top of the tooth is a triangular incisor. Oblique sharpening, often called boring or pointing, is performed through a 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 cross-cutting is 60-70°, and the sharpening angle between the chamfer and the side edge of the saw blade is from 45 to 80°. Cutting angle more than 90°.

For mixed longitudinal-transverse sawing (along curved outlines), saws with a tooth in the form of right triangle. Teeth for mixed sawing are cut with all edges of the breast. These teeth are sharpened at right angles to the saw blade or with a small bore (75-80°). The teeth of such a saw only work when moving forward. The sharpening angle of the saw teeth for mixed sawing is 50-60°; cutting angle 90°.

Rice. 2. Bow saw

Hand saws

Hand-held joinery saws come in tensioned thin blades and loose, thicker blades. Tension saws include all bow saws; for 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 posts, a spacer, two handles, a bowstring made of string or wire and a twist.

According to their purpose, bow saws are divided into transverse, open, tenon, fine-tooth and rotary.

Cross-cut 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 (swing) 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 inclined shape, height 5-6 mm, pitch 5-6 mm, sharpening angle 40-50°, cutting angle up to 80°, straight sharpening. The tooth spread is equal to twice the thickness of the blade. Saws work quickly, produce rough cuts, and require a lot of effort.

Tenon saws are intended for clean cutting 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 right triangle with a height of 3-4 mm, a sharpening angle of 80-85° (to the blade), and a bore. The tooth set is 12/3 of the thickness of the saw blade. Compared to a loose saw, a tenon saw requires significantly less effort when cutting.

Rice. 3. Knife saws: a - wide, b - narrow, c - butt saws, 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 right triangle with a height of 2-3 mm, a pitch of 2-3 mm, a sharpening angle of 60-80°, and a bore. The tooth spread is 1/3 of the thickness of the saw blade. The saw requires little effort when cutting.

Rotary (circular) saws are designed for figure sawing, have a length of 350-500 mm, a width of 4-15 mm, and a thickness of 0.4-1 mm. Their teeth have the shape of a right triangle 2-3 mm high, pitch 2-4 mm, sharpening angle 50-60°, straight sharpening or small boring.

Knife saws (hacksaws) can be wide or narrow.

Wide hacksaws (Fig. 3, a) are used for transverse, straight cutting of boards. The thickness of the canvas 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 sharpening angle of 55°. The teeth 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 internal contour of the workpiece. Narrow hacksaws are usually made smaller than wide ones (300-400 mm). The thickness of the canvas is 1.5 mm. The divorce is done very small; the teeth are shaped like a right triangle.

Back saws (Fig. 3, c) have a thin rectangular blade with a thickness of 0.6-0.8 mm. A steel butt is riveted to the upper edge of the backing saw to give it rigidity. The saw teeth have the shape of a right triangle with a fine pitch and a very slight set. The teeth cut when moving away from you. Backing saws are used for fitting joints, shallow sawing, sawing small parts and mitering corner joints.

Rewards (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 surface being processed. Saw with a reward along a ruler at any angle to the plane with the initial movement of the saw only towards you. The teeth of the teeth are directed towards the worker. The teeth have the shape of a right triangle with a fine pitch and a very small set.

Plywood saw is a special award with fine teeth located along a curved convex line. Used for cutting planed plywood.

To eliminate jamming of the saw in the cut, change the shape of its teeth or set them apart (Fig. 4, a, b, c, d). For the same purpose, the saw blade is made of a trapezoidal cross-section with the teeth located at a wider base.

The amount of set of all teeth must be the same, otherwise the less bent teeth will not participate in sawing, and the most bent teeth will carry heavy load. The saw teeth are set using special sets, 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 of all teeth. In Fig. 6 shows universal wiring. When working with it, the saw blade is clamped in a vice mounted in a workbench.

Rice. 4. Different kinds changes in the shape of the saw teeth: a - setting, b - flattening, a - trapezoidal widening, d - times. vodka with side sharpening for cross cutting

Rice. 5. Saw teeth set

Rice. 6. Vise

After setting, the saw teeth are sharpened. This is done with a triangular file with a fine notch. When sharpening straight, the file is held perpendicular to the blade, and when sharpening - at an angle of 45-80° (Fig. 8, a, b). When sharpening directly, 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 raised 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 apart, but also have the same height. During operation of the saw, the teeth work differently, so before sharpening they should be aligned in height or ground. 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, 3 - adjusting screws, 4 - hinge adjuster. adjuster for the amount of adjustment, 5 - scale for setting the amount of adjustment, 6 - screw with a stop for teeth of different sizes, 7 - spring

Rice. 8. Sharpening saws: a - direction of the file during straight sharpening, b - direction of the file during oblique sharpening, c - position of the file on the saw teeth

Rice. 9. Device for jointing saw teeth

Job hand saws

There are three main types of hand sawing wood:
a) longitudinal at horizontal position material;
b) longitudinal at vertical position material;
c) transverse.

The least labor-intensive is sawing the board longitudinally in a horizontal position. Before starting sawing, cut lines are marked on the selected board using a surface planer. The cutting line is marked in such a way that after sawing there remains a certain supply of material for subsequent processing. Then the board is secured to the workbench along its front edge so that the sawn part protrudes beyond the edge of the workbench. The board is secured with a clamp or a bench blade.

The saw blade is rotated at a certain angle relative to the plane of the beam and tensioned. The opening saw is held by the handle and the angle of the spacer. Its position during the sawing process should remain vertical (Fig. 10).

Rice. 10. The position of the worker’s legs when longitudinally sawing a board installed horizontally

The legs of the worker in relation to the material should be positioned as shown in Fig. 10.

Sawing should be done with free movements, pressing the saw to the bottom of the cut as it moves downward and forward. When the saw is idling upward, it should be moved back slightly. If the saw is clamped, 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 longitudinally sawing material located vertically, there can be two types of sawing: perpendicular and parallel to the face. In the first case, the material is secured in the rear vice of the workbench, and in the second case, in the front.

While sawing, hold the saw with your right hand by the stand, as close to the handle as possible. With the left hand, support the material being cut. The movement of the saw during operation should be horizontal.

The legs and body of the material working when sawing, installed vertically, are positioned as shown in Fig. 13. Body and left hand must remain motionless during operation.

When the board is in a vertical position, the start of the cut should not be placed very high. The saw is first set on the mark and a short, slow movement of the saw towards itself makes a shallow cut. Before the formation of a gash, it is impossible to saw in a sweeping manner. When sawing, do not press the saw too hard, as this will not speed up the work. You should also not press with your left hand on the sawn block.

Rice. 12. The position of the worker’s legs when longitudinally sawing a board installed vertically

Rice. 13. Sawing across the grain of material located horizontally

When sawing across the grain with a bow saw, the board is laid on the edge of the workbench so that the part to be sawn protrudes beyond the back bar of the lid, 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 stands so that his left foot is located perpendicular to the board being cut, and his right foot steps back and to the right with a turn at an angle of about 80° (Fig. 14).

The body is motionless during sawing, 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 cut, the saw blade is directed along the nail or along the second joint thumb left hand.

Rice. 14. The position of the worker’s legs when sawing horizontally located material across the grain

Rice. 15. Sawing along the thumb joint

In this case, the joint should be kept above the teeth (Fig. 15). The cut is made by smoothly moving the saw towards you.

At the end of the cut, the part of the board to be sawn should be supported with your left hand to avoid chipping the wood.

To cut parts at an angle, a so-called miter box is used (Fig. 16). It is a tray made of boards with slots for saws located in the sides at a certain angle. When using a miter box, it is clamped into the workbench.

Rice. 16. Miter box

Defects when sawing with hand saws can be the result of improper sharpening or misalignment of the saw. This results in an uneven, non-straight or rough cut. Due to the skew of the saw blade during operation or incorrect working posture, the cut may not be perpendicular to the face or edge of the board.

- Sawing by hand