Today there are a huge number of hacksaws for metal. They all differ in their appearance, characteristics, etc. These tools are also divided into professional and home ones. Most significant difference Between these two types there will be a metal blade.
Dimensions
Currently, the standard length for canvas is 300 mm. There are also hacksaws for which this figure is 150 mm. Shorter options are used only in cases where a large hacksaw is not suitable precisely because of its size or the master needs to perform very delicate work.
If we talk about the teeth of the metal blade, they are very small. This choice is due to the fact that it is small teeth that best cope with the cutting task. metal products. Masters of working with this tool pay attention to the fact that the canvas is essential element, but it is worth paying due attention to the handle of the tool. For some types, it is made very poorly, and it will be inconvenient to work with such a device, even if the metal blade meets all the qualities.
Tool differences
As mentioned earlier, saws are conventionally divided into professional and home. Main advantage professional tool the fact that its design is more rigid, and also makes it possible to carry out work at an angle of 90 and 55 degrees. Household equipment is often more flimsy, and during work they are constantly subject to storms. In this case, even a high-quality metal blade does not guarantee high-quality cutting. However, here it is necessary to build on the frequency of use of this tool. Home saws are much cheaper and should only be purchased if the hacksaw is rarely used. If you have to use this tool quite often, then it’s not worth saving.
It is worth mentioning a separate thing - a hacksaw-handle. The main difference between this tool and a regular hacksaw is that it is designed to work with a broken hacksaw blade for metal.
Product design
The design of this tool is almost the same for all models. The saw is a C-shaped arc, between the lower edges of which the blade is secured or tensioned. The working and main part of this tool is the same hacksaw blade for metal, having many small teeth.
The handle is one of the three main parts of the device and plays a significant role in terms of ease of use of the tool when long work. Two-component composite handles with rubber inserts are considered the most successful in terms of performance and comfort of use.
The frame of this tool is an element that is designed to attach a blade for a hacksaw for metal. In production, frames can be used different materials, however, they determine what type of work the saw will be used for. For example, if it is necessary to saw high-strength metals, then it is best for the frame to be made of composite materials also high strength.
It is important to note that the frame design largely determines the working conditions. If it is necessary to cut in hard to reach places, then it is best to use a frame with adjustable blade angle or simply purchase a more short version devices.
Canvas
A hacksaw blade for metal is a thin strip made of hard steel. Despite the fact that this is the only metal part in the construction of the saw, it is also the most vulnerable to breakage, since the thickness of the product is very small. For this reason, it is very important to monitor your actions when working with this tool. Careless and careless handling will lead to rapid breakage of the fragile structural element.
Teeth
By itself, the steel blade for metal, the photo of which is presented below, cannot cut other metal parts.
This process is made possible by applying small wedge-shaped teeth to the edge of the blade. It is very important to pay attention to the hardening of these teeth when choosing a tool. Correct selection will lead to a significant increase in service life, as well as cutting efficiency the necessary details. Currently, it is customary to use canvases with fine teeth for cutting hard metal products, and large teeth are intended for working with soft parts. The canvases themselves can be made from different types steel, but it is best to opt for bimetallic ones. If you couldn’t find such ones, then you can pay attention to hardened canvases. These saw elements are made of nickel-plated stainless steel with teeth. It is worth noting that the blade should be attached in such a way that the teeth go in the opposite direction from the handle.
Selecting a canvas
The quality of the blade is determined by its teeth. The first selection criterion is the form cutting elements, which may vary depending on the inclination of the edge piece.
The second criterion for choosing a blade is the pitch of the teeth. Using this parameter, you can determine what hardness material it is suitable for cutting, and also select the maximum possible thickness of the product that can be sawed. This indicator is measured by the number of teeth per inch of fabric. It is also important to note that the thickness of the metal blade plays an important role here. For example, on professional three-hundred-millimeter hacksaws, the thickness will be 0.63 - 1.25 mm. The thickness of the blade for electric saws with a length of 150 mm is from 1.25 to 2.5 mm.
It is also worth saying that the number of teeth per inch of blade depends on the thickness and material of the workpiece that will be sawed. For example, when cutting an aluminum workpiece with a thickness of more than 5 mm, it is necessary that the number of teeth per inch be 18. If the thickness is from 2 to 5 mm, then the number of teeth can vary from 18 to 24. For a workpiece thickness of less than 2 mm, the number of teeth should be between 24 and 32.
GOST sheets for metal
GOST 6645-86 is state standard, which sets requirements for the type, size, quality of metal blades, etc.
This document establishes the rules for the technical production of this product. In particular, this GOST specifies the grades of steel from which the types of blades must be made. For example, type 1 must be made from steel strip that meets all the requirements of GOST 23522-79. Type 2 hacksaw blade must be made of high-speed steel, which is determined according to GOST 19265-73. The document also states that the canvas must be subjected to heat treatment. A canvas is considered acceptable when there are no cracks, film, scale or corrosion on the surface.
A 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 won’t touch on the former, but the latter are available in three main sizes:
- Single, with a distance between fastening holes of 250±2 mm, with a total length of the blade of no more than 265 mm;
- Single, with a distance between fastening holes of 300±2 mm, with a total length of the blade no more than 315 mm;
- Double, with a distance between mounting holes of 300±2 mm, with a total length of the blade of no more than 315 mm.
At the same time, the thickness of the blade s for a single version is 0.63 mm, for a double version – 0.80 mm. The height with a single row of teeth is 12.5 mm, and with a double row it is 20 mm.
GOST also regulates the values of the tooth pitch P, mm and their number z, which for blades of the first type 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 grade of material used for the manufacture of blades for hacksaws for metal, they are made from tool steels:
- Brands X6VF.
- Brands V2F.
- High-speed, grades P6M5, P12 or P18.
Assortment of hacksaw blades domestic production This is all, but in specialized retail chains so-called diamond blades are widely used, with surface coating of titanium nitrides or other refractory metals. Such blades can be easily distinguished by color: regular steel blades are dark gray, while sprayed steel blades can have different colors - from bright orange to blue (depending on the manufacturer).
There are also blades with so-called tungsten carbide coating, however, with very high hardness, they are extremely sensitive to bending stresses. Therefore, when cutting metal, their durability is negligible.
The high strength of blades for hacksaws for metal is ensured by appropriate heat treatment. On the surface of the canvas there are two zones with different meanings hardness: directly at the teeth it ranges from HRC 64...67 for alloy tool steels to HRC 73...78 for high-speed steels (for diamond blades this parameter reaches HRA 82...84), and in the rest of the zone - HRC 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 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 canvas
The selection criteria are:
- Type, or more precisely, the distance between the mounting holes. It is better if it is changeable, then a hacksaw blade of any size will be suitable for the job.
- The tensile strength of the metal being cut. 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 least hardness. The material can be steel Kh6VF; Imported canvases have the designation HCS on the side plane. For cutting stronger metals, blades made of high-speed steels (corresponding import marking - HSS) are suitable.
- The thickness of the metal being cut and the quality of the cutting surface. Foreign practice recommends using the PPI parameter as a selection criterion - the number of tooth vertices per inch of blade length. So, for thin metals, where it is required to obtain very smooth surface cut, PPI>24 is considered correct. If productivity is more important to the user than quality, then PPI should be<24. С увеличением числа зубьев полотна для ножовки по металлу параметр PPI увеличивается.
- Quality of tooth set. GOST R 53411-2009 provides three options - separation for each tooth, through a tooth, or for two adjacent ones through one undone tooth. In the latter case, the outermost 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 the wiring is done in both directions, the actual distance measured with a caliper should be twice as large as that indicated above.
The durability of the hacksaw blade is also affected by the quality of the coating. For domestic instruments, the more common coating is Khim.Oks.Prm., instruments with nitro-enamel coatings such as NTs-25 or NTs-132 are less common. It should be remembered that under prolonged loads, when the file heats up, the enamel may crack.
When choosing a high-quality hacksaw blade, you should also pay attention to the uniformity of the tooth spacing: in high-quality products, this parameter should not exceed 45% of the tooth pitch over a length of 10 mm. The quality of the product 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 placed on the corresponding protrusion, slightly tensioned, and then secured with a wing nut. If there are sudden changes in the load on the hacksaw, this fastening will have to be checked periodically. For hacksaws with a lever-type device, the installation and replacement process is simplified: simply pull out the lever located on the side opposite the handle of the manual hacksaw, put on the blade, and return the lever to its original position.
When tightened correctly, the blade should make a slight ringing sound and vibrate a little. During operation, such a blade should not change the direction of its movement under load.
For single-sided blades, it is important to position the direction of the teeth correctly. Their tilt should be directed away from the handle. Most workers make the main working movement in the direction away from themselves, when the metal is cut. The reverse movement is intended only to return the hacksaw to its original position. When trying to cut metal and during idling, the geometry of the teeth, unsuited to such loads, will tear the tooth away from the base, and as a result, the blade may collapse. This phenomenon is especially typical for diamond blades.
Recently, so-called bimetallic blades (designation BIM) have become popular, when a high-speed steel strip is welded onto a main strip of hardened structural steel type 45 steel. Quality is everything here: for Chinese-made files, the grade of metal is most often not guaranteed (as is the quality of welding), therefore, when working with durable metal, cases of delamination of bimetallic blades are not uncommon.
Metal blades for hacksaws are distinguished by size, material of manufacture, and type of tooth set. There are also single-sided and double-sided canvases.
The blade size can be from 150 mm (mini hacksaw) to 300 mm (standard hacksaw). The metal blade has fine teeth, since it is almost impossible to saw metal products with large teeth.
In blades for cutting metal, the following main areas are distinguished: edge (ends of the blade), back (top part), cutting part (part of the blade on which the teeth are located).
Helpful information:
The teeth must be hardened, because it must be harder than the metal it is intended for cutting. Therefore, hardening or carburization is carried out on the working part of the blade, followed by hardening (this or that process depends on the brand of metal used for production).
Types of paintings
Depending on the material used to make metal blades for hacksaws, there are the following types:
- Carbon steel blades (economical and flexible)
- Fabrics with partial heat treatment
- Fully hardened blades (used for precise, targeted cuts)
- High-strength, semi-flexible steel blades with a high proportion of kobold and hardened teeth
- Bimetallic blades (have greater flexibility and wear resistance)
Each type of metal blade for a hacksaw has its own characteristic features - thickness, width, tooth pitch, number of teeth per inch.
There are two types of blade tooth alignment for metal:
- With routing along the canvas (on the working side it has a wave-like shape). This setting is used for very fine tooth pitches (less than 1 mm).
- With streaks of teeth. In this type of wiring there can be options - for each tooth, through a tooth, two adjacent teeth through a tooth.
Which tooth to choose
The spaces between the teeth are called chips. It is in them that the metal shavings remain until the teeth leave the cut. The larger the gaps, the less resistance there is to the blade during long cuts.
Often the routing of the teeth ends at some distance from the ends of the blade.
Metal blades are made with different tooth pitches, and the tooth size plays a big 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 greater the number of teeth, the smaller the tooth, and accordingly the blade will cut harder material (metal). But you should not use blades with very fine teeth 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. Hardened blades have the appearance of 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.
We provide answers to questions about what types of hacksaw blades are used for metal, how to choose and install them correctly, and how to extend the service life of the consumable.
Electric and manual hacksaws have a removable working element - a file, also known as a hacksaw blade. As a rule, it has a length of up to 300 mm, a width of 12-15 mm and a thickness of less than 1 mm. This material provides answers to questions about what a hacksaw blade is, how to choose and install it correctly, and also describes some products that are in demand by consumers.
Hacksaw blades are a narrow strip, at the ends of which there are two holes for attaching to the tool. There are three main criteria for their classification:
The division into groups according to the first criterion occurs like with hacksaws - blades for manual (mechanical) and electric (sometimes called machine) tools are distinguished. The dimensions of the working elements vary. So, for manual ones, canvases with a length of 250-300 mm, a width of 12-25 mm, and a thickness of 0.63-1.25 mm are used. An example is a domestically produced blade made of Kh6VF steel with parameters 1.25x12x300, which will cost the buyer 30 rubles per piece.
The parameters of files for power tools vary from 150 mm in length, to 55 mm in width, from 1.25 to 2.5 mm in thickness. An example is a blade for a reciprocating saw HAMMER RS BL 001, the parameters of which are 150x19x1.25 mm, and the cost is 100 rubles per piece.
Another difference between saw blades for hand and reciprocating saws is the number of holes for fastening. The first ones have two, the second ones have one.
The second classification criterion is the material used to make the canvas. Steel products are distinguished:
- carbon(the least durable, suitable for non-ferrous or soft metal; marked as HCS); for example, Bosch HCS TF 350 M 408 mm GFZ for 1400 rubles;
- high-speed(they have the most wear-resistant teeth, but are fragile and high in price; HSS marking); Gross HSS 18TPI 300 mm - 160 rubles per pair;
- bimetallic blades(innovation on the market, displacing analogues; the base is carbon steel, on top of which a high-speed strip is welded, serving as the basis for the teeth; designated BIM); Gross Variozahn 300 mm BIM from 300 rubles per pair.
There are also canvases from alloy steel(designation HM), but more often they are used for cutting brick, concrete or stone.
The size of the teeth for hacksaws for metal is 2-2.5 mm. This parameter is considered “small”, since there are products with larger teeth (for example, for wood saws it is 4-6 mm).
International standardization provides for a different principle of dividing the canvases. So, the number of teeth per 1 inch of file is taken into account. This figure is given in the marking before the letters PPI (points per inch) or TPI (formula “PPI - 1”). The higher the number, the smaller the tooth represented on this canvas.
When choosing products for a hacksaw, the user does not have to guess for a long time - most well-known files have a tooth pitch of 18 or 24. This is how branded products for construction are designated (for example, Standart 24 TPI 300 mm, Kraft-Flex 18 TPI blade from the manufacturer Kraftool).
The main classification of blades for metal hacksaws is based on the given criteria. It is important to know that the presence of set teeth is welcome if the user expects comfortable work without pauses or tool breakdowns. Now let’s talk about how to properly install a hacksaw blade in a manual or electric tool.
Methods for installing the canvas
There are two types of fastening systems on hand hacksaws:- threaded clamp;
- lever mechanism.
In the first case, the canvas is stretched between the mounting holes and secured with a wing nut. In the second, the actions are performed similarly, only the file is put on and removed using a special lever, usually located at the edge farthest from the handle.
The blade is installed in such a way that the teeth tilt in the direction opposite to the handle. When using a hacksaw, the metal layer will be cut while moving away from you. The reverse direction - “towards you” - is idle, in which the workpiece is not cut. Therefore, efforts during the reverse movement are in vain. In addition, it is so easy to dull the teeth of the blade.
For electric hacksaws, the working part is attached differently. For example, below is the process of replacing the blade on a Makita JR 3070 CT reciprocating saw. To do this you need:
- turn the holder head counterclockwise at a slight angle so that the internal slot allows you to remove the product;
- remove the canvas;
- Place the end of the new file into the slot of the holder until you hear a characteristic click.
By the way, the blades are also divided by the type of shank (the section that connects to the holder). There are shanks with one stop, two-jaw, universal 1/4, clamping 1/2 and special for Makita saws, which have two holes at the end.
The principle of attaching hacksaw blades to reciprocating saws is the same for all devices; The manufacturers thought through the design, made inserting the cutting element convenient and made the user’s work easier.
Rules for choosing equipment
Buying something as insignificant as a hacksaw file is a responsible task. To ensure that the user does not make a mistake with his choice, he should listen to some recommendations from experienced craftsmen. The tips are discussed in more detail below.- There should be no cracks or signs of corrosion on top of the canvases.
- Make sure the file is elastic. To do this, you need to bend it slightly and release it. A high-quality product will instantly restore its original shape.
- The cutting speed directly depends on the number of teeth per inch. The more there are, the less time the operation will take.
- Among all the files, the one suitable for sawing a particular metal is selected. Preference should be given to red-hot iron or bimetallic products. The first ones look like stainless steel coated with a layer of nickel, but have dark teeth. The latter are painted in a certain color (red, yellow) or several shades. The listed canvases are much more durable than their black counterparts.
- The length of the blade corresponds to the length of the hacksaw, whether we are talking about a manual or electric tool. In order not to make a mistake, it is important to study the markings that are on both the saw and the hacksaw blade.
- You should not consider the price of a product as a key selection factor. A dozen cheap black files (like the Russian Kh6VF 1.25x12x300 mm, 77707 for 30 rubles) will become dull and fail while a more expensive analogue works (for example, Stanley 1-20-437 300 mm long for 120 rubles).
Having made your choice and purchased a metal unit for a hacksaw, all you have to do is secure the equipment and start working. It is also recommended to adhere to the rules for storing and using hacksaw files. Timely replacement of used equipment will extend the service life of hand or electric tools. If you have experience using certain files, share your opinion in the comments.
A hacksaw blade for metal is one of those parts that quickly deteriorates and requires frequent replacement. However, knowing the subtleties of choosing a product, you can ensure long and high-quality work!
Universal saw – hacksaws for all occasions
Even a seemingly ordinary hacksaw can cause confusion in 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 their purpose, they are divided:
- Hacksaws are a narrow saw with thin teeth. It has a characteristic, recognizable appearance, mainly a C-shaped or U-shaped frame, between the ends of which the canvas is tensioned. Older models of hacksaws often have a handle that runs parallel to the blade; modern products are equipped with a much more ergonomic “pistol” handle.
- – a classic carpentry tool used for sawing wooden building materials, as well as sheets of plywood. 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 make cutting easier. At the same time, straight teeth in some models help remove chips from the cutting line.
- A hacksaw for concrete is similar in appearance to a joiner's saw, with the difference that the first tool has larger teeth. Quite often they are tipped with carbide metals, which makes it possible to saw foam blocks and sand-concrete structures with this tool.
The quality of the tool is determined by the following indicators:
- Blade length - depending on the size of the workpiece, the appropriate tool is selected. On average, the length of the working part ranges from 300-700 mm.
- Tooth pitch - this indicator determines the thickness and hardness of materials that the tool can handle. For example, a pitch of 3.5 mm is suitable for sawing soft wood materials, while five-millimeter hacksaws work with hard wood.
Hacksaw - cutting steel in slippers!
With the advent of hacksaws for metal, working with various metal products has become much easier - even at home, in your garage or workshop, you can cut off the required 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, high precision is achieved in the process of work, thirdly, the tool is almost impossible to break, and fourthly, the independence of the product from the mains makes it indispensable in field working conditions.
Modern hacksaws are distinguished not only by their “pistol handle” - manufacturers come up with and improve systems for fastening the blade. The threaded clamp, which is present in all older models, is gradually being replaced by a lever mechanism, thanks to which installation of the blade is many times faster. True, they are also more expensive than hacksaws with a “lamb”.
However, design features by and large only affect the ease of maintenance of the tool, The quality of the cut and the speed of work depend, first of all, on the replaceable hacksaw blades. There are plenty of them on sale; you can find a product for any budget and any purpose. The cost of the blades depends on the alloy from which they are made and the number of teeth per inch. Mainly, there are parts made of hardened steel and bimetallic products. The disadvantage of hardened steel is its fragility, so although the products are cheaper, they also break more often, while bimetallic steel can boast good flexibility and hardness, which is why they cost more.
Choosing a hacksaw for metal – don’t overpay!
Even the choice of such a simple tool as a hacksaw should be approached with knowledge. Remember that the seller’s task is to sell the most expensive tool possible, the capabilities of which you will use barely 10%. Use the rule of the golden mean - avoid very budget models and do not buy the most expensive ones. The tool must be practical, allow for the ability to work at different angles and with different surfaces.
The popularity of some models is due to the ability to work with canvases of any length, and this is indeed a very good move. Also pay attention to the ability to change the angle of the blade in the frame itself - this function allows you to work with metals even in hard-to-reach places. Take the tool in your hands, wrap your palm around the handle. The palm should completely cover the handle, while the fingers should not interfere with each other and should not rest against the parts. Avoid hollow handles - if you squeeze a little, you will break the tool. The product should not be loose, all parts are adjusted and create a feeling of reliability.
Hacksaw blade for metal – a choice based on knowledge!
When purchasing a canvas, pay attention, first of all, to its appearance - even the smallest flaws can affect its performance. Avoid canvases with traces of corrosion, cracks, or roughness. An ideal blade should be smooth, clean, with even teeth, and when bent it should instantly restore its original shape. The more teeth per inch, the faster you can saw the part. So, there are blades with 18 and 24 teeth per inch, most often these are bought for home use, but 32 teeth per inch are for professionals.
Avoid buying black products - these are enough for several passes, then the teeth fall off and 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 metal with dark teeth - it is by the color of the teeth that it is easiest to guess about their hardening. Bimetallic sheets are usually painted in some color, and although they are more expensive, they will last much longer. Having chosen the appropriate material, make sure that the length of the product matches the length of the hacksaw.
Using a tool - patience and work will grind everything down!
A hacksaw for metal does not require any special skills to operate. You just have to monitor the condition of the canvas and change it in a timely manner. By the way, the tool, due to its small teeth, is suitable for working not only with metal, it will also perform well in plastic, chipboard, PVC, laminate and even ceramics and plexiglass. In this case, the edges of the cut will be quite smooth.
The biggest difficulty that beginners face when cutting metal and other materials with a hacksaw is the blade wobbling 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, you shouldn’t rely on the force of your hands alone - at least use pliers to increase the pressure. Unlike a carpenter's hacksaw, you won't be able to sharpen the blade once it's dull; all you have to do is replace it with a new one.
The blade must be fastened with the teeth down and forward from the handle. When changing it, you need to tension the canvas in such a way that at the slightest blow it rings like a string. Be careful not to overdo it!
You can only find the optimal tension through experience. The hacksaw blade should lie on the part when working. You need to work at an angle of up to 45° - this way you will get less vibration and noise, and the cut will be smooth. During the first movements, you should not put pressure on the canvas - there is no need for extra force here, the canvas will only begin to slide in different directions. Increase the pressure as you move forward; when you return the saw to its original state, do not use any pressure at all. And once the blade has cut a good edge, you can work with all your might.
