The blade for a hacksaw for metal refers to those parts that quickly deteriorate and require frequent replacement. However, knowing the intricacies of choosing a product, you can ensure long and high-quality work!
Universal saw - hacksaws for all occasions
Even an ordinary, at first glance, hacksaw can cause confusion for the average consumer, he will find many different tools on the shelves! To simplify the choice, we list three main types of tools, into which, depending on the purpose, they are divided:
- Hacksaws for metal - a narrow saw with fine teeth. It has a characteristic recognizable appearance, basically it is a C-shaped or U-shaped frame, between the ends of which the canvas is attached tightly. Older hacksaw models often have a handle that runs parallel to the blade, while modern hacksaws are equipped with a much more ergonomic pistol grip.
- - a classic carpentry tool used for sawing wooden building materials, as well as plywood sheets. As a rule, carpentry hacksaws have a wide beveled working part, on the edge of which there are cutting teeth. The teeth are set alternately left and right to facilitate cutting. At the same time, straight teeth on some models help to remove chips from the cutting line.
- A concrete hacksaw looks like a carpentry saw, with the difference that the first tool has larger teeth. Quite often, they have soldered carbide metals, thanks to which this tool can be used to saw foam blocks and sand concrete structures.
The quality of the tool is determined by the following indicators:
- Blade length - depending on the size of the workpiece, the appropriate tool is also selected. On average, the length of the working part ranges from 300-700 mm.
- Tooth pitch - This measure determines the thickness and hardness of the materials that the tool is able to handle. For example, a pitch of 3.5 mm is suitable for sawing wood materials from soft wood, 5 mm hacksaws work with hard wood.
Hacksaw for metal - we cut steel in house slippers!
With the advent of hacksaws for metal, it has become much easier to work with various metal products - even at home, in your garage or workshop, you can saw off the desired piece of reinforcement or thick wire. And even the appearance of mechanical analogues did not affect the popularity of hand tools: firstly, the cost is affordable for almost any craftsman, secondly, in the process of work, high accuracy is achieved, thirdly, the tool is almost impossible to break, and fourthly - the independence of the product from the mains makes it indispensable in the field.
Modern hacksaws differ not only in the "pistol grip" - manufacturers come up with and improve systems for fastening the blade. The threaded clamp, which is present in all old models, is gradually replaced by a lever mechanism, thanks to which the blade installation is many times faster. True, they are more expensive than hacksaws with a "lamb".
However, the design features affect, by and large, only the ease of maintenance of the tool, the quality of the cut and the speed of work depends, first of all, on replaceable hacksaw blades. There are plenty of them on sale, you can find a product for any wallet and any purpose. The cost of blades depends on the alloy from which they are made and the number of teeth per inch. Basically, there are parts made of hardened steel and bimetallic products. The disadvantage of hardened steel is its fragility, therefore, although products are cheaper, they break more often, while bimetallic ones can boast of good flexibility and hardness, and therefore they are more expensive.
Choosing a hacksaw for metal - don't overpay!
Even to the choice of such simple tool like a hacksaw for metal, you should approach the knowledgeable. Remember that the seller's task is to sell the most expensive instrument, the capabilities of which you will use by hardly 10%. Use the rule of the golden mean - avoid completely budgetary models and do not buy the most expensive ones. The tool should be practical, provide for the ability to work at different angles and with different blades.
The popularity of some models is due to the ability to work with canvases of any length, and this is indeed a very successful move. Pay attention also to the possibility to change the blade angle in the frame itself - this function allows you to work with metals even in hard-to-reach places. Take the tool in your hands, grasp the handle with your palm. The palm should completely encircle the handle, while the fingers should not interfere with each other and should not rest on the details. Avoid hollow handles - crushing a little will break the tool. The product should not be loose, all parts are fitted and create a feeling of reliability.
Metal hacksaw blades - knowledge-based choice!
When buying a canvas, pay attention, first of all, to its appearance- even the smallest flaws can affect his work. Avoid canvases with traces of corrosion, cracks, roughness. The ideal blade should be smooth, clean, with even teeth, and when folded, instantly restore its original shape. The more teeth per inch, the faster you can cut the part. So, there are canvases with 18 and 24 teeth per inch, most often they are bought for the home, but 32 teeth per inch is the lot of professionals.
Avoid buying black products - these are enough for several passes, then the crumbling teeth make the job impossible. Although hardened products are not flexible, they are much more convenient to work with. In appearance, they look like a nickel-plated strip of stainless steel with dark teeth - it is by the color of the teeth that it is easiest to guess about their hardening. Bimetallic blades are usually painted in some colors, and although they are more expensive, they will last much longer. After choosing the right material, make sure that the length of the product matches the length of the hacksaw.
Using the tool - patience and work will grind everything!
A hacksaw for metal does not require any special operating skills. You just have to monitor the condition of the canvas and change it in a timely manner. By the way, due to its small teeth, the tool is suitable for working not only with metal, it will show itself perfectly in plastic, chipboard, PVC, laminate and even ceramics and plexiglass. In this case, the edges of the cut will turn out to be quite even.
The biggest difficulty that beginners face when cutting metal and other materials with a metal hacksaw is wobbling the blade from side to side. If this happens, check the condition of the fasteners - wobbling may mean that the wing is not tightened enough. By the way, do not rely on the effort of your hands alone - use at least pliers to increase the pressure. Unlike a carpenter's hacksaw, it will not work to sharpen the canvas after it is dull, you just have to replace it with a new one.
You need to fasten the blade with the teeth down and forward from the handle. It is necessary to stretch the canvas during its change in such a way that from the slightest blow it would ring like a string. See, don't overdo it!
You can only find the optimal tension by experience. When working, the blade of the hacksaw must lie on the part. You need to work at an angle of up to 45 ° - this is how you succeed less vibration and noise, and the cut will be smooth. At the first movements, you should not press on the canvas - there is no need for excess force, the canvas will only begin to slide in different directions. Increase the pressure when moving forward, when you return the saw to its original state, do not use any pressure at all. And already when the blade has cut a good edge, you can work with all your might.
A hacksaw is used to create through cuts on dense materials made of metal, cut slots, trim contour products. The locksmith tool is made of a hacksaw blade and a base machine. One end of the frame is equipped with a static clamping head, a handle for holding the tool, and a shank. The opposite part consists of a movable head and a screw that tightens the cutting insert. The heads of the hacksaws for metal are equipped with slots in which the working blade is installed, which is fixed with pins.
The frames are made in two forms: sliding, allowing you to fix the working blade of any length, and solid.
Peculiarities
Each type of material has its own cutting blade.
- Saw blade for metal is a narrow metal strip with fine teeth placed on it. Frames are made outwardly similar to the letters C, P. Outdated frame models were equipped with wooden or metal handles, placed parallel to the blade. Modern models are made with a pistol grip.
- Saw blade for working with wood- the most common carpentry version of the product. It is used for processing and cutting plywood, wood building materials of various densities. The design of hand saws is specially equipped with a beveled working surface, teeth are located on the side of the blade.
- For working with concrete the blade has larger teeth on the cutting edge. Equipped with carbide taps. Thanks to this, it becomes possible to saw concrete structures, foam blocks, sand concrete.
- For processing metal products Blades with a step width of about 1.6 mm are used, up to 20 teeth are located on a 25 mm file.
The greater the thickness of the workpiece, the larger the cutting teeth should be, and vice versa.
When processing metal products with a different hardness index, files with a certain number of teeth are used:
- angle and other steel - 22 teeth;
- cast iron - 22 teeth;
- hardened material - 19 teeth;
- soft metal - 16 teeth.
In order for the file not to get stuck in the workpiece, it is worthwhile to pre-set the teeth. Let's consider on what principle the wiring is done.
- The width of the cut is greater than the thickness of the working blade.
- Hacksaw saws with a pitch of about 1 mm must be wavy. Each pair of adjacent teeth must be bent in different directions by approximately 0.25-0.5 mm.
- The plate with a pitch of more than 0.8 mm is divorced using the corrugated method. The first few teeth retract to the left, the next few teeth to the right.
- With an average pitch of about 0.5 mm, the first tooth is retracted to the left, the second is left in place, and the third to the right.
- Coarse insert up to 1.6 mm - each tooth retracts in opposite directions. It is necessary that the wiring ends at a distance of no more than 3 cm from the end of the web.
Specifications
GOST 6645-86 is a standard that establishes requirements for the type, size, quality of saw blades for metal.
It is a thin, narrow plate with holes located at opposite ends, on one side there are cutting elements - teeth. Files are made of steel: Х6ВФ, Р9, У10А, with hardness HRC 61-64.
Depending on the type of work, hacksaw files are divided into machine and manual.
The length of the plate is determined by the distance from the center of one hole to the other.The universal hacksaw file for hand tools has the following dimensions: thickness - 0.65-0.8 mm, height - 13-16 mm, length - 25-30 cm.
The standard value for the length of the blade is 30 cm, but there are models with an indicator of 15 cm. Short hacksaws are used when the standard large tool is not suitable for work due to its size, as well as for filigree types of work.
GOST R 53411-2009 establishes the configuration of blades for two types of hacksaws. Saw blades for handheld equipment are produced in three standard sizes.
- Single type 1. The distance between the through holes is 250 ± 2 mm, the length of the file is no more than 265 mm.
- Single 2 types. The distance from one hole to another is 300 ± 2 mm, the length of the plate is up to 315 mm.
- Double, the distance is 300 ± 2 mm, the length of the working surface is up to 315 mm.
Single plate thickness - 0.63 mm, double plate - 0.80 mm. The height of the file with a single set of teeth is 12.5 mm, for a double set - 20 mm.
GOST defines the values of the pitch of the teeth, expressed in millimeters, the number of cutting elements:
- for a single plate of the first type - 0.80 / 32;
- single second type - 1.00 / 24;
- double - 1.25 / 20.
The number of teeth changes for longer tools - 1.40 / 18 and 1.60 / 16.
For each type of work, the value of the cutter angle can be changed. In the process of processing metal with a sufficient width, rather long cuts are achieved: each saw cutter removes the sawdust that fills the chip space until the tip of the tooth comes out completely.
The size of the chip space is determined from the pitch of the tooth, the front corner, the back corner. The rake angle is expressed in negative, positive, zero values. The value depends on the hardness of the workpiece. A saw with a zero rake angle is less efficient than a rake angle greater than 0 degrees.
When cutting the hardest surfaces, saws with teeth are used, which are sharpened at a large angle. For soft products, the indicator may be below average. The hacksaw blades with the sharper teeth are the most wear-resistant.
The saw type is classified into professional and household tools. The first option has a rigid structure and allows work at angles of 55-90 degrees.
A home hacksaw does not allow you to perform a high-quality even cut, even with professional saw blades.
Views
The second criterion for choosing a blade for a hacksaw is the material from which the product is made.
Used steel grades: Х6ВФ, В2Ф, Р6М5, Р12, Р18. Domestic products are made only from these types of material, but diamond-coated products are found in specialized stores. The surface of the file is sprayed from various refractory metals, titanium nitride. These files differ in appearance in color. Standard steel blades are light and dark gray, diamond and other coatings - from orange to dark blue. The tungsten carbide coating is distinguished by the extreme sensitivity of the blade to bending, which affects the short life of the blade.
Diamond-coated tools are used to cut abrasive and brittle materials: ceramics, porcelain and others.
The strength of the file is ensured by the hot heat treatment procedure. The saw blade is divided into two hardening zones - the cutting part is processed at a temperature of 64 to 84 degrees, the free zone is exposed to 46 degrees.
The difference in hardness affects the sensitivity of the product to the bending of the blade during the execution of work or the installation of the file into the tool. To solve this problem, a standard was adopted that regulates the indicators of the forces applied to hand-held equipment. The force on the tool should not exceed 60 kg when using a file with a tooth pitch of less than 14 mm, 10 kg is calculated for a cutting product with a tooth pitch of more than 14 mm.
Saws made of carbon steel, marked with the HCS mark, are used for working with soft materials, do not differ in durability, and quickly become unusable.
Metal cutting tools made of HM alloy steel are more technological, like blades made of alloyed chrome, tungsten, vanadium. In terms of their properties and service life, they occupy an intermediate place between carbon and high-speed steel saws.
High speed products are marked with the letters HSS, are fragile, high price, but more resistant to wear of cutting elements. Today, HSS blades are being replaced by bimetallic saws.
Bimetallic products are designated by the abbreviation BIM. Made of cold-rolled and high-speed steel by electron beam welding. Welding is used to instantly connect two types of metal while maintaining the hardness of the working teeth.
How to choose?
When choosing a cutting product, they are guided, among other things, by the type of tool.
For manual
Hand saws are, on average, equipped with type 1 single blades marked HCS, HM. The length of the file depends on the length of the tool frame, the average is in the region of 250-300 mm.
For mechanical
For a mechanical tool, files with any markings are selected depending on the surface to be treated. The length of the cutting double blade is from 300 mm and more. Mechanical equipment is used when processing a large number of workpieces with a length of 100 mm or more.
For mini hacksaw
Mini hacksaws work with blades no more than 150 mm. They are mainly designed for convenient and quick cutting of wooden materials and metal products of small diameter, work with blanks, in a curve.
Before using the tool, it is worthwhile to properly install the blade into the equipment.
The installation method depends on the design of the fastening system of the tool. If the heads are equipped with slots, then the blade is inserted directly into them, stretched a little if necessary, and fixed with a pin.
To make it easier to insert the file into the clamping head, you can pre-lubricate the element technical oil... If there is a sharp load on the file, you will have to periodically inspect the mount, check the degree of tightness of the pin so that the blade does not fall out of the retainer during the process of cutting the product.
The installation of the cutting product in a lever-type hacksaw is carried out by extending the lever, putting on the blade, returning the tool frame to its original position.
The blade for a hacksaw for metal is one of the most short-lived elements from the entire range of consumables for tools. Of course, a lot depends on the technology of working with metal and the skills of using a hacksaw, but first of all you need to be able to do right choice canvases. Today, we will talk about the choice and types, and also learn how to easily change the hacksaw blade.
Types of hacksaw blades
GOST R 53411-2009 "Hacksaw blades for metal" establishes two types of such tools - for machine and manual cutting. We will not touch on the first ones, but the second ones are produced in three main standard sizes:
- Single, with a distance between the fixing holes 250 ± 2 mm, with a total blade length of no more than 265 mm;
- Single, with a distance between the fixing holes of 300 ± 2 mm, with a total blade length of no more than 315 mm;
- Double, with a distance between the fixing holes of 300 ± 2 mm, with a total blade length of no more than 315 mm.
In this case, the thickness of the leaf s of a single version is 0.63 mm, of a double one - 0.80 mm. The height with a single row of tines is 12.5 mm, and with a double row it is 20 mm.
GOST also regulates the values of the pitch of the teeth P, mm and their number z, which for the first type of blades are 0.80 / 32, 1.00 / 24 and 1.25 / 20, respectively. Owners of longer hacksaws, in addition to those listed above, can also use hacksaw blades with parameters 1.40 / 18 and 1.60 / 16.
According to the brand of material used for the manufacture of hacksaw blades for metal, they are made from tool steels:
- H6VF brands.
- В2Ф brands.
- High-speed, brands P6M5, P12 or P18.
The assortment of domestic hacksaw blades is exhausted by this, however, so-called diamond blades with surface spraying with titanium nitrides or other refractory metals are widespread in specialized retail chains. These canvases can be easily distinguished by their color: ordinary steel canvases are dark gray, and the sprayed ones can have different colors - from bright orange to blue (depending on the manufacturer).
There are also canvases with the so-called tungsten carbide spraying, however, with a very high hardness, they are extremely sensitive to bending stresses. Therefore, when cutting metal, their durability is negligible.
High strength of hacksaw blades for metal is ensured by appropriate heat treatment. On the surface of the blade, two zones with different values of hardness are distinguished: directly at the teeth it ranges from HRC 64 ... 67 for alloyed tool steels to HRC 73 ... 78 - for high-speed steels (for diamond blades this parameter reaches HRA 82 ... 84), and in the rest zone - НRС 44 ... 46. A significant difference in hardness confirms the high sensitivity of the product to bending stresses, therefore the standard also limits the maximum force applied to the hand hacksaw. It should not exceed 60 kg when working with blades with a tooth pitch of less than 1.4 mm, and 10 kg for blades with a tooth pitch of more than 1.4 mm.
Principles for choosing a canvas
The selection criteria are:
- Type, more precisely - the distance between the mounting holes. It is better if it is variable, then a hacksaw blade of any standard size is suitable for work.
- Tensile strength of the cut metal. If the tool is supposed to be used to separate soft, ductile metals - copper, aluminum, etc., then it is advisable to have a hacksaw blade with the lowest hardness. H6VF steel can be adopted as a material; imported canvases have the HCS designation on the lateral plane. For cutting harder metals, blades made of high-speed steels are suitable (corresponding import marking - HSS).
- The thickness of the metal to be cut and the quality of the separation surface. Foreign practice recommends using the PPI parameter - the number of tooth vertices per inch of blade length - as a selection criterion. So, for thin metals, where a very smooth cut surface is required, a PPI value> 24 is considered correct. If for the user the main factor of productivity than quality, then there should be PPI<24. С увеличением числа зубьев полотна для ножовки по металлу параметр PPI увеличивается.
- The quality of the setting of the teeth. GOST R 53411-2009 provides for three options - dilution for each tooth, through a tooth, or two adjacent through one undivided tooth. In the latter case, the extreme plane of the canvas should protrude beyond the main one by a distance of (0.15 ... 0.25) s, and in the rest - by (0.65 ... 0.90) s. Since wiring is done in both directions, the actual distance measured with a caliper should be twice as large as indicated above.
The quality of the coating also affects the durability of the hacksaw blade. For domestic tools, the most common coating is Khim.Oks.Prm., Less often there are tools with nitroenamel coatings such as NTs-25 or NTs-132. It should be remembered that under prolonged loads, when the file heats up, the enamel can crack.
When choosing a high-quality hacksaw blade, you should pay attention to the uniformity of the tooth setting: in high-quality products, this parameter should not exceed 45% of the tooth pitch over a length of 10 mm. Product quality can also be assessed by the parameter of equal height of the teeth: the difference in adjacent vertices should not exceed 0.10 ... 0.15 mm, which is checked using a micrometer or depth gauge.
How to install a blade on a hacksaw for metal?
The installation method is determined by the design of the fastening system on the hacksaw itself. In the case of a threaded clamp, the file is slid onto the corresponding lug, tightened slightly, and then secured with a wing nut. With sharp changes in the load on the hacksaw, such a mount will have to be checked periodically. For hacksaws with a lever-type device, the installation and replacement process is simplified: just pull out the lever located on the side opposite to the handle of the hand-held hacksaw, put on the blade, and return the lever to its original position.
When tightened correctly, the blade should emit a slight ringing and vibrate slightly. During operation, such a blade should not change the direction of its movement under load.
For single sided blades, it is important to correctly position the direction of the tines. Their slope should be directed away from the handle. Most workers make the main working movement away from themselves, when the metal is cut. The reverse movement is only intended to return the hacksaw to its original position. When trying to cut metal and during idling, the geometry of the teeth, not adapted to such loads, will tear the tooth off the base, and as a result, the blade may collapse. This phenomenon is especially true for diamond blades.
Recently, the so-called bimetallic blades (designation - BIM) have become popular, when a high-speed steel strip is welded onto the main strip of hardened structural steel such as steel 45. Here, quality decides everything: for Chinese-made saws, the metal grade is most often not guaranteed (as, indeed, the weld quality), therefore, when working with durable metal, there are often cases of delamination of bimetallic blades.
Blades for metal for a hacksaw are distinguished by size, by material of manufacture, by the type of tooth setting. There are also one-sided and double-sided canvases.
The size of the blade can be from 150 mm (mini-hacksaw) to 300 mm (standard hacksaw). The blade for metal has fine teeth, since it is almost impossible to cut metal products with large teeth.
In blades for cutting metal, there are such main areas as: edge (ends of the blade), back (upper part), cutting part (part of the blade on which the teeth are located).
Useful information:
The teeth must be hardened, because it must be harder than the metal it is intended for cutting. Therefore, quenching or carburizing is carried out on the working part of the web, followed by quenching (this or that process depends on the brand of metal used for production).
Types of paintings
According to the material for making hacksaw blades, there are the following types:
- Carbon steel blades (economical and flexible)
- Partially heat-treated canvases
- Fully hardened blades (used for precise, directional cuts)
- High-strength, semi-flexible steel blades with high kobold content and hardened tooth
- Bimetallic blades (have great flexibility and wear resistance)
Each type of hacksaw blade for metal has its own characteristic features - thickness, width, tooth pitch, number of teeth per inch.
By setting the teeth of the blade for metal there are two types:
- With wiring along the canvas (on the working side it has a wavy shape). This setting is used with a very small tooth pitch (less than 1 mm).
- With streaks on the teeth. In this type of routing, there may be options - for each prong, across a prong, two adjacent prongs across a prong.
Which tooth to choose
The spaces between the teeth are called shaving. It is in them that the metal shavings remain until the teeth leave the cut. The larger the gaps, the less resistance to the blade during long cuts.
Often, the setting of the teeth ends at some distance from the ends of the blade.
Blades for metal are made with different tooth pitch, while the tooth size plays an important role when cutting the material. The number of teeth per linear inch of blade (25 mm) is taken as a standard. This can be 18, 24, or 32 teeth per linear inch of blade.
The larger the number of teeth, the smaller the tooth, and accordingly the blade will cut harder material (metal). But do not use blades with a very fine tooth for working with soft metal, because the working part of the blade will quickly become clogged with chips (this will greatly slow down and complicate the work).
For long-term work, hardened or bimetallic blades are better suited. The hardened blades are nickel-plated steel with dark (hardened teeth), they are used when cutting hard metals. Black canvases are often of poor quality and will not last long.
A hacksaw for metal is designed for cutting sheets of round, profile and strip metal. A hacksaw consists of hacksaw blade for metal and frames (machine tool). At one end of the machine there is a stationary head with a shank and a handle, at the other end there is a tension screw, a movable head and a nut for tensioning the blade. The blade is inserted into the slots in the heads and attached with pins.
The frames are made sliding, which allows you to fix the canvases of different lengths. To extend the hacksaw, bend the knees until the rivet leaves the cutout. The rivet is guided into another cut and the knees are straightened. Machine with movable holder also includes a square with a handle, along which the holder is fixed and moved.
Description of the canvas
Steel narrow thin plate with two holes and teeth on one edge. It can be manual or machine, depending on the purpose. For the manufacture of these elements, the following steels are used:
- U10A;
- P 9;
- X 6VF.
The hardness of the material should be HRC 61-64. They are inserted into the frame, teeth first. Almost always used for hand hacksaws 250-300 mm long, 0.65 and 0.8 mm thick, 13 and 16 mm high. The work of the blade differs depending on the working conditions of the cutter, which explains the difference in angles.
Long cuts can be made when cutting large metal workpieces: each tooth removes chips that must fill the chip space until the tip of the tooth leaves the kerf. The amount of space depends on the pitch S of the tooth, anterior (Y) and posterior (A) angles. Depending on the hardness of the workpiece rake angle canvases can be zero, negative, or positive. The efficiency of cutting with a hacksaw with a blade with a zero angle is lower compared to one whose angle is greater than 0 °. To cut harder materials, elements with a large angle of sharpening of the teeth are used (they are more wear-resistant). For cutting soft materials, this figure should be lower.
Number of teeth
In most cases, blades with a pitch of 1.3-1.6 mm are used for cutting metals, with a length of 25 mm teeth with this will be 17-20. The thicker the material to be processed, the larger the teeth should be, and vice versa. For different metals, canvases with the following number of teeth are required:
- Soft metals - 16;
- Tempered steel of medium hardness - 19 ;,
- Cast iron, tool steel - 22;
- Strip, angle and solid steel - 22.
Hacksaw 300 mm
In the process of work, two or three teeth should be involved. To avoid seizing the blade in the metal, the teeth are bred. The routing is performed so that the width of the cut made with the hacksaw is slightly greater than the thickness of the blade. This prevents jamming in the blade cut and makes work easier.
For blades with a pitch of 0.8 mm (permissible 1 mm), the setting of the teeth should be wavy, that is, every two adjacent teeth are bent in opposite directions approximately 0.25-0.6 mm. The working element with a step of more than 0.8 is divorced along the tooth (corrugated divorce), two or three teeth are retracted to the left and right. With an average step, one tooth is retracted to the left, the second is not retracted, the third is retracted to the right. With a coarse step, one tooth is retracted to the right and the other to the left. The setting on the tooth is appropriate at a pitch of 1.6 and 1.25 mm. The wiring should be completed at a distance from the end of no more than 30 mm.
Preparatory stage
First, the material to be processed is firmly fixed in the vice. And it must be fixed so that it is convenient for the worker to work. Further, in accordance with the hardness, shape and dimensions of the workpiece to be cut, a hacksaw blade is selected. If the rafters are long, it should be with a coarse pitch, if short, with a fine one.
The hacksaw is installed in the slot of the head so that the teeth are not directed towards the handle. The end of the blade is inserted into the stationary head and secured with pin bookmarks, then the second end of the blade is placed in the slot of the pin, which is secured with the pin. The blade is manually tensioned (vise or pliers cannot be used) by rotating the wing nut. Keep the hacksaw away from your face.
With a slight misalignment, the canvas, stretched tight, and with significant pressure, weakly stretched lead to bending, due to which a break is possible. The degree of tension is checked by pressing the finger from the side: if there is no deflection, the tension is sufficient.
Cutting process
During the cutting process, two moves are made:
- Worker - the tool moves forward from the worker.
- Idle - the hacksaw moves to the worker.
When idling, the tool is not pressed, as a result, the teeth only slide. During the working stroke, light pressure is provided with both hands, and the hacksaw moves in a straight line.
Operating rules
During cutting, in front of the vise, you need to stand firmly, straight and freely, half-turned to the axis of the workpiece to be processed or to the jaws of the vise. The left leg protrudes slightly forward approximately along the line of the workpiece, and the body rests on it. The feet must be positioned so that they form 60-70 ° (with a distance between the heels).
The correct posture of the worker can be considered when the right hand with the tool, set in the initial position and bent at the elbow, forms right angle between the elbow and shoulder. The handle is gripped with the right hand so that the handle rests on the palm. It is wrapped with four fingers, and the thumb is placed on top along the handle.
The fingers of the left hand grasp the movable head of the hacksaw and the nut. In the process of cutting, strict coordination of efforts is observed, that is, the correct increase in pressure. The movement of the tool must be horizontal. Press on it with both hands, but a small effort is made with the left hand, and with the right hand, reciprocating movements are carried out mainly.
- Short workpieces are cut along the widest side. When machining corner, channel and T-profiles, it is better to change the position of the workpiece rather than cutting along the narrow side.
- Cutting should be carried out smoothly and slowly, no more than 40-60 double strokes are made within a minute.
- The entire canvas must be involved.
The greatest difficulty for beginners is the wobbling of the work item. If this trouble occurs, you should check the condition of the fasteners - wobbling may indicate insufficient tightening of the "lamb". Unlike carpentry tools, ours cannot be sharpened with a new one, you need to change.
When you need to make a cut in a hard-to-reach place, it is better to use a hacksaw for metal.