Saws teeth in what direction. How to choose a hacksaw for metal
Hacksaw. Types and work. How to choose and what to use. Teeth
Hacksaw. it is a manual carpentry and metalwork tool, which is a kind of a saw. Depending on the design, it can be used for cutting wood, metal, plastic, aerated concrete and other materials. The tool consists of two parts. the sharp-toothed working blade and the comfort grip handle.
The hacksaw is one of the oldest tools. It appeared much earlier than the modification for working with metals. There are several varieties:
Also known as a broad or regular saw, it is a standard hand-held tool for sawing. Designed for making cross or rip cuts. It can be used to shorten a board or cut a branch. It is a standard carpentry and joinery tool. It makes quick cuts, but the cut is quite coarse and produces coarse chips. Its teeth are triangular and spaced between 1.5 to 6.5 mm.
Corkscrew or narrow
It is a more narrowly focused tool. Due to the small width of the blade, it can be used to cut curvilinear elements. The main purpose of such a tool is not the usual pruning, but the possibility of sawing sheet material, when you need to work on a strictly defined contour. A narrow blade is more maneuverable and allows you to bypass the outlined curves, which cannot be done with wide saws. These saws are considerably lighter and more compact. They can have teeth on both sides that differ in size from each other. This gives the ability to produce clean cuts of varying purity. Smaller saw blades make for smoother cuts.
Also referred to as a cleaver or shovel saw, this is a specific tool, the main purpose of which is to remove protruding studs and grooves. These saws are used by carpenters and joiners for clean and smooth cuts. The blade of this tool is the thinnest, so the kerf is narrow. To keep the blade from twisting, a shim is hooked onto the opposite side of the blade to improve stiffness. Because of the shank, it is not possible to make a cut deeper than the height of the blade. Such a tool has fine teeth in the shape of an isosceles triangle. It is used exclusively for crosscutting. Working part thickness does not exceed 1-1,5 mm.
Types of teeth
Wood is a specialized material that can have sawing complications depending on the direction. In this regard, hacksaws are divided into three categories:
For a longitudinal cut
Hacksaws have special teeth that are angled forward at an acute angle. Their movement causes the wood fibers to cut and sawdust to chip off. This equipment guarantees the fastest possible work in cases where you need to split the board in the direction of the fibers. This produces relatively coarse sawdust, the size of which depends on the height of the tines. The larger the chips, the faster the work is. In case you need to cut even a thin branch, this saw will not be very effective.
For cross-cutting cuts
Straight-toothed sabre saw is used. Such a tool would be an excellent choice for cutting boards or limbing branches in the garden. This is the one suitable for cutting firewood or shortening a shovel cutter. The vast majority of all handheld wood sawing equipment is crosscut.
It is a modification of transversal, but with a special sharpening of the teeth, which allows to compensate for the lack of the received angle of attack to the wood fibers. There are also specialized types of hacksaws in which the teeth are arranged in groups of several. There is a small gap between the groups. This tool is designed for working with raw wood. The indentation between cutters ensures that wet chips are cleared away on their own without the need for manual cleaning.
A special specialized design with pobedite tips was developed especially for working with aerated concrete. This tool ensures a firmer plunge cut into the surface and accelerates the sawing of tough materials. Such a hacksaw is good for both cross and rip cuts.
When choosing a saw it is worth paying attention not only to the direction of the teeth, but also to their size. There are 3 types of cutters:
- 2-2,5 mm. for accurate work with small parts.
- 3-3.5 mm. for medium-sized workpieces.
- 4-6 mm. for rough cuts in logs and firewood.
Metal hacksaw has a special design, which consists of a cutting blade and a frame for its attachment. Blades are replaceable. They have small teeth that are specially hardened. The blade itself is made of high-speed steel, but still as a result of operation rubs off rather quickly, also there are cases of breaking of individual teeth. Dimensions seldom exceed 400 mm in length. The depth of cut is limited by the height of the frame.
How to sharpen a hand wood hacksaw and set the teeth
Sooner or later any cutting tool blade will wear out and become blunt. In this case it is not necessary to change the entire tool. Proper sharpening is enough. You can do this with those devices, which are already available in the house (most often). It goes without saying that nothing will work if you do not have the right technology to perform all the operations. In this article, the master plumber will tell you how to sharpen a hand hacksaw for wood and set the teeth.
To ensure a high quality cut you need to understand the mechanism of the impact of the teeth edges of the hacksaw on the material to be sharpened. Unlike steel and plastic, wood is not a homogeneous material and, precisely because of this quality, several kinds of saws have been developed that differ in tooth profile, sharpening angle and degree of cleavage. All varieties of wood hacksaws, their characteristics and technical data are specified in GOST 26215-84.
Basic types of wood saw teeth: 1 for cross-cutting Type 1; 2 for cross-cutting Type 2; 3 for longitudinal Type 1; 4 for longitudinal Type 2; 5 for universal cutting
There are three types of cross-cutting saws: cross-cutting, longitudinal, and universal. The main difference lies in the cutting principle: when cutting wood across the fiber, the tooth path contains fragments of different density. This is an advantage: the chips generated are smaller and easily removed from the contact area, allowing both sides of the tooth to be resharpened for both forward and reverse sawing. Cross-cutting cuts on the other hand are partially impact cuts, which means that blunter angles of the cutting edges are required.
Sawing wood along the fibers can be characterized as repetitive cycles of micro planing. the force exerted on the tooth is uniform, so the teeth are asymmetrically shaped and point in the direction of cutting. The edge that is formed at the tip of the tooth is perfectly perpendicular to the blade surface. Sawing lengthwise produces elongated chips that are difficult to remove from the contact area. Also, longitudinal cutting produces greater amounts of moisture, resins, and sticky substances, which, when combined with the first factor, prevents sawing in both directions. Chips are removed with a straight cut: the perpendicular cutting edge direction causes swarf to be ejected in the sawing direction. The reverse movement removes residual chips and ensures the self-cleaning of the edges.
Teeth of all hacksaw types are set, they are alternately tilted in different directions from the longitudinal axis of the blade. Due to this in a longitudinal profile of a row of saw teeth a sort of a dovetail is formed. two sets of cutting wedges formed by the tips of the cutting edges of the teeth. Accordingly, two grooves are created in the saw blade at the bottom of the kerf, ensuring evenly stepped removal and efficient chip evacuation.
Professionals know the following signs to look for when a saw is about to malfunction
- When cutting wood, the hacksaw begins to sound different;
- Visually, you can see that the tips of the teeth are rounded and lose their sharpness;
- The color of the teeth changes;
- Sawing force increases;
- The direction of the saw does not hold up well;
- Teeth often get jammed in the wood.
Hacksaw Tooth Setter. HelpLaw
The hand hacksaw is still one of the most commonly used woodworking tools today, despite the variety of electric tools.
It is inexpensive, compact, and ready to use in no time. Hacksaw use is especially urgent when there is no power source.
To be able to saw quickly and correctly, you need to know how to sharpen a wood hacksaw at home, if you do not have a sharpening machine and angle grinder.
Signs that a saw has blunted
Because the hacksaw is subjected to a high degree of stress during use, its teeth dull over time. Dull tools are much less effective. In addition, you should not use such a hacksaw for the following reasons:
- performance is reduced. When sawing wood, more effort of the master and his time is spent;
- worsens the accuracy of the work. Blunt teeth make it nearly impossible to cut wood cleanly and evenly. It is especially difficult to work with such a saw in the garden;
- dangers of using a hacksaw. tools will jam, cut, get out of line, jam, increase risk of injury.
You need to sharpen the hacksaw urgently, if a characteristic blunt sound appeared, the tips of the teeth rounded, you can not make a cut of wood. If the tool has become difficult to work, it is better to stop sawing, inspect it and proceed to address the issue of sharpening.
When sharpening a wood saw with your own hands requires concentration, good eye and skills to work with a file. Despite the apparent complexity of the process, if you follow the recommendations this manipulation can be done quite simply, although not quickly. To sharpen a hacksaw at home, you need to spend an hour or two, you can handle it faster if you have a hand.
Hacksaws are also sharpened with an angle grinder, but many craftsmen treat this method negatively. First, it is not safe, and secondly, you can damage the cutters more than you can sharpen them.
The blade must be securely fixed in a vise. You can sharpen on a lap or on a stool, but it is not comfortable to hold the hacksaw. The place, where sharpening is carried out, should be well illuminated, for safety purposes gloves should be worn. Nothing extraneous, like a TV set, should distract you from your work.
To restore the performance of a joinery tool only a file of good quality should be used. Usually a three-sided file is used, but a special four-sided file is available for small hacksaw tines.
The edges of the cutters should always be cleaned with a file or file with a fine velvet notch. If a used file has to be used, it should be cleaned beforehand with a steel brush.
A small layer of coating is chipped off the cutters. While dressing them, the file should not slip, but should grip them well. If not, it means the file is not suitable for cutting, or the cutters are overhardened. Use a different tool for sharpening. If the second attempt is unsuccessful, it is advisable to change the hacksaw.
To sharpen a wood hacksaw with a file correctly, its handle is clamped with the right hand, and the left hand holds the end. The tool is angled on the teeth of the blade (as it bevels). The pressure should be even, smooth and only in a certain direction (usually away from yourself).
If possible, it is advisable to make sure that the removed metal layers are of the same thickness. To do this, it is recommended to move the tool an equal number of times and with an equal amount of pressure. In this way, the height, pitch and angles of the teeth will be maintained after machining.
Tooth burrs that occur on the tooth should be removed with a wet burr or a file with velvet grit. If left unchecked, they will reduce the sharpness of the teeth and chipping out when cutting wood materials, which will impair the quality of the manipulation performed.
When sharpening is finished, check the sharpness of the teeth by sawing a piece of wood. If when inspecting the saw blade the cutters do not shine, then all actions have been done effectively and the hacksaw is ready for use.
Tooth deburring is necessary to keep the hand saw from getting jammed while cutting so it runs smoothly and easily. After extended use, you may need to set the hacksaw before sharpening it.
The essence of the process is to conduct a uniform bending of the teeth in different directions. After this procedure there should be free gaps on both sides of the blade.
The movement of the sharp-cutting tool in the cut will be much more efficient.
The more the blade is set, the lower the risk of the saw jamming in operation. But do not overdo it, otherwise sawing becomes extremely problematic.
Please note! The standard setting is 2 mm or less. If the hacksaw is intended for sawing dry wood, the tines are bent 0.3-0.5 mm. For sawing raw wood materials, the blade should be diluted by 0.5-1 mm.
For the convenience of bending it is recommended to use razvodki. special devices. The hacksaw is well clamped in a vise, the device is mounted on the work surface. The main thing is that the teeth should not protrude completely, otherwise they will break.
Sharpening crosscut saw teeth
To restore the sharpness of crosscutting tools, it is more effective to use a triangular file with a personal notch and an angle of 60 °.
After clamping a blunt hacksaw in the adjustable lever, proceed to the processing of the left edge of the first cutter. It is recommended to fix the blade at an inclination of 45-50 ° relatively to the working plane.
Install the file parallel to the worktable surface at an inclination of 60-75 °.
Reconstructive manipulation of blunt blade cutters is performed in several steps. Grind left-hand cutting edges of the odd-numbered cutters first, then the right-hand cutting edges.
Sharpen, not blunt a hacksaw: instruction for sharpening a wood hacksaw
Despite the abundance of chainsaws, circular saws, grinders and other automatic cutting tools, the ordinary hand saw is still popular.
If in production and lumbering it has long been superseded by more advanced saws, the good old toothed blade remains in the garages and summer cottages. Wood hacksaw serves for decades if it is timely and properly sharpened.
Even people who regularly work with their hands make mistakes in this process.
The most obvious advantage of sharpness is speed of cutting. When working in the country house this is even more important than in the workshop, since you often have to work in cramped, uncomfortable positions. A badly sharpened blade gets stuck in wood, especially damp wood. And there is a risk that the blade could break and injure the person working with it.
The practical advantages of sharpness include:
- The accuracy of the cuts being made.
- Longer blade life.
- Savings on replacing hacksaws.
- High carpentry productivity.
Identification of the right torque
Without experience, people often go from extreme to extreme and either sharpen the saw every few days or once a year. Determining whether a sharpening is necessary by time is not the right approach.
There are a number of signs that indicate that the teeth are blunt:
- The blade regularly jams in the wood.
- Sawing changes the sound, it becomes duller.
- Teeth change color.
- Material resistance increases significantly.
- The tooth tips are noticeably rounded.
- Blade slips out of line.
The hardened teeth cannot be sharpened. Easy to distinguish: they are blackish with a slight bluish cast.
First you need to prepare the equipment necessary for the work:
Without having a basic set, it is impossible to sharpen the saw in principle.
To make sharpening better, you can prepare additional tools:
Stanley Saw Tooth Set Tool Review
Before the saw sharpness can be restored, the teeth must be set, that is, set apart. Setting is the setting of cutting teeth at a certain angle relative to the blade and to each other.
If you look at the set saw, you can see that the teeth alternate to the right and left of the blade plate itself. This configuration gives the hacksaw freedom in the deep kerf.
It doesn’t jam because it doesn’t touch the walls with its entire plane.
The distance between the bifurcated teeth should be 1.5 or 2 times the thickness of the hacksaw. They are made not thicker than 1,5-2 millimeters, hence the cutting jaws have to be set 0,25-0,5 mm for cutting dry and hard wood; for wet or soft wood it is necessary to bend 0,5-1 mm.
In order to set the right angle to each tooth “by eye”, you need a great experience that not every carpenter has. It comes after many dozens of sharpened saws. For less experienced carpenters, there is a tool called the setting tool. The most primitive version is a flat steel plate with a slit. Insert the hacksaw into this gap with a minimum gap, in tension.
The bending process looks like this:
- Clamp the hacksaw in a vise like this. Make sure the teeth protrude 2 cm over the jaws.
- Clamp the serrations into the slot, then bend back in the middle.
- First you bend all the even teeth to one side, then bend the odd ones in the opposite direction.
- At the end you can separate the jaws of the vice according to the calculated width and try to lead the saw between them.
- An excessively bent tooth will catch in the vise. With the pliers, bend it back a little more.
All cutting protrusions have to be of the same size, so the cutting performance is not impaired. Longer tines are more stressed and wear out faster, while shorter tines don’t even touch the wood.
The pulling of the blade becomes jerky, uneven, more force is spent. The cut will become less precise and the surface of the cut will become rougher.
Adjustment is done before you begin sharpening. To make sure that none of the teeth protrude, press the blade against the sheet of paper placed on the table.
The tips of the teeth will be imprinted on the sheet, and the space in the pattern will allow you to adjust their height. To do this, clamp the saw in a bench vice and file away excessively long teeth.
A block used for sharpening kitchen knives will not help restore the teeth to their former sharpness. You need a special tool: a file with a triangular section or file. It’s a good idea to have several files with different cross sections and notches: this will allow you to work each tooth perfectly.
- Hold the file by the handle with one hand, and place the other hand on the end of the file.
- Determine cutting angle. Usually it’s between 15° and 30°. It can be determined by eye, using a protractor or a simple technique. Cut the wooden block into an isosceles triangle with 90, 60, and 30 degree angles, then use it as a yardstick.
- Sharpen the left-hand cutting edges of the even (farther away from you) teeth. Each require an equal number of file runs to remove the same amount of shavings. The pressure on the tool has to be of the same strength.
- Turn the hacksaw the other way, then sharpen the left edges of the even teeth again.
- Sharpen the tips of the teeth.
- Don’t forget to check the sharpening angle with the bar.
The process seems very simple, though monotonous, but there are a number of nuances:
- Clamp the saw in a vise must be very tight for safety purposes. Do not be afraid of damaging the metal of the blade with strong compression.
- The workplace should be well lit to make it easier to determine angles and sharpness.
- Only remove metal when the file moves away from the carpenter.
- The harder the file is blunted, the coarser the cuts on the file can be, but a file with small cuts should always be used for finishing teeth.
Blade for metal hacksaw. How to choose and how to deliver?
It should not be forgotten that the production of working hacksaw blades is carried out in accordance with established standards in GOST 53411-2009.
The specified information in this normative and technical documentation determines the allocation of two main groups: for machine and manual cutting.
It is worth considering that the machine metal hacksaw blade is purchased very rarely, as such equipment is used very rarely. For manual hacksaw blades the production of the following versions is carried out:
- Single metal hacksaw blade with a distance between the fixing elements of 250 mm. The overall length is 265 mm. This version is suitable for the tool, which is used when there is no need for great productivity.
- Single versions with a distance of 300 mm between two mounting elements. Total length is 315 mm.
- For greater productivity, the installation of a double hacksaw blade is carried out. The length of this version, as well as the previous one.
When choosing, attention is paid to the width, which is 0.63 mm for the single version, and 0.8 mm for the double version. The tooth height in the first case is 12.5 mm, in the second 20 mm.
Regulated value and pitch, as such an indicator determines many performance characteristics.
In the manufacture of such a product may use a variety of alloys, which largely depend on the main performance characteristics. The following alloys are the most common:
Hacksaw blades with tungsten carbide sputtering have recently become quite common, as they are characterized by increased wear resistance. Keep in mind that the lacquering can be of different colors, blue tools are available on the market, and regular steel is dark gray.
The tungsten hacksaw blade under consideration is characterized by the fact that while the hardness of the working surface is high, the structure is characterized by a high sensitivity to bending load. That is why if the metal is cut carelessly, such a product can not last long.
Manufacturers are able to achieve a high degree of toughness through heat treatment. The following should be taken into account:
- The main part of the product is characterized by the hardness of the surface layer of about HRC 44-46.
- Depending on the type of material used in production, the hardness of the tooth varies in the HRC range of 64 to 67. This parameter is characteristic of alloyed alloys. High-speed steel is characterized by a hardness range of 73-78 HRC.
It should not be forgotten that significant variations in hardness make the product sensitive to bending. The tool is designed for different loads, it should not exceed 60 kg at a pitch of 1.4 mm, as well as 10 kg at a pitch of less than 1.4 mm.
Quite a large number of varieties of such a product determines that with the selection of a suitable performance variant does not arise serious problems.
What are they made of
Modern blades for hacksaws on metal are made of the following types of steel:
- Carbon steel. have low strength characteristics, so they can be used for cutting non-ferrous and soft metal. This grade is marked HCS, and the degree of strength does not exceed the values of 44-46 HRC.
- Fast-cutting. have high resistance to abrasion and tooth wear, but their disadvantage is brittleness. High-speed saw blades are marked as HSS and have hardness values up to 73-78 HRC. There are diamond-powdered high-speed steel blades with hardness levels up to 82-84 HRC. per piece
- Bimetal. got this name because of the use of two kinds of steel. Their introduction has created a furor on the market, quickly supplanting their. Bimetal blades are based on carbon steel on which a high speed steel strip is welded. These types of devices are designated by the letters BIM, and their strength is the same as that of fast-cutting steel, but due to the use of carbon steel as a basic material, they have high strength and resistance to deformation
- Alloy tool steels are upgraded versions of their carbon counterparts, and are produced by augmenting carbon with chromium, tungsten, vanadium, silicon, etc.п. Alloying makes it possible to achieve high strength properties and the hardness degree is slightly lower than that of high-speed steel and amounts to 67-67 HRC.
The hardness of the handheld sawing accessories characterizes the sensitivity of the tool to bending stress, so depending on the cutting devices used, you must consider the force exerted on the hacksaw during work.
Generally the blade force should not exceed 60 kg, which is characteristic of tools with a tooth pitch of less than 1.4 mm. If the pitch of the teeth is greater than 1.4 mm, the load should not be more than 10 kg.
Principles of web selection
It is important to choose the most suitable product design for the specific operating conditions. If the surface does not have the required properties, it will not last for a long period of time. The following points can be mentioned as selection criteria:
- The distance between the two fixing holes is the most important selection criterion. With some tools this value can be changed by a special device.
- The next selection criterion is the strength of the metal to be cut. If the work involves cutting of common soft alloys, for example copper or aluminum, choose a product with the lowest hardness of the surface layer. X6VF steel is very common, with imported blades having the HCS designation. It is also possible to work hard metals for which high-speed steel saw blades are suitable, imported marking HSS,
- Also the thicknesses of metal to be cut and the quality to be achieved after machining are taken into account. Abroad, the decisive criterion is PPI, or the number of tooth tips per inch in length. High quality requires PPI over 24, if performance is a priority, then the version with less than 24 is chosen.
- When choosing, attention is paid to the quality of the cutting edge setting. This parameter must comply with the standards, which are set in the above GOST. There are three basic versions: each one, through one tooth or through two adjacent ones.
Blade for metal hacksaw. How to choose and how to apply?
Types of hacksaw blades and their construction
It should not be forgotten that the production of working hacksaw blades is carried out in accordance with the established standards in GOST 53411-2009.
The information in this normative and technical documentation defines the division into two main groups: for machine cutting and for manual cutting.
It is worth considering that the machine metal hacksaw blade is purchased very rarely, as such equipment is used very rarely. For handheld hacksaw blades, the production of the following designs is carried out:
- Single hacksaw blade on metal with the distance between the fixing elements of 250 mm. The overall length is 265 mm. This version is suitable for the tool, which is used when there is no need for high output.
- Single versions with a distance of 300 mm between the two fixing elements. Total length is 315 mm.
- For greater productivity, the installation of a double hacksaw blade is carried out. The length of this version, as well as the previous one.
When choosing, attention is paid to the width, which is 0,63 mm for the single version, and 0,8 mm for the double version. Tooth height in the first case is 12,5 mm, in the second. 20 mm.
Regulated value and the pitch of the location, as such an indicator determines many performance characteristics.
In the manufacture of such a product, a variety of alloys can be used, which largely determines the main performance characteristics. The following alloys are the most widespread:
Hacksaw blades with tungsten carbide sputtering have recently become quite common, as they are characterized by increased wear resistance. It is worth considering that the sputtering can have the most different colors, on sale there are blue variants of execution, the usual steel is dark gray.
The considered tungsten hacksaw blade is characterized by the fact that at high hardness of the working surface the structure is characterized by high sensitivity to bending load. That’s why if the metal is cut carelessly, such a product will not last long.
Manufacturers are able to achieve a high level of durability due to thermal treatment. The following should be taken into account:
- The main part of the product is characterized by the hardness of the surface layer of about HRC 44-46.
- Depending on the type of material used in production, the hardness of the tooth varies in the HRC range of 64 to 67. This is characteristic of alloyed alloys. Rapid-cutting steel is characterized by its HRC hardness in the range of 73-78.
It should not be forgotten that significant variations in hardness make the product sensitive to bending. The tool is designed for different loads, it should not exceed 60 kg at a pitch of 1.4 mm, as well as 10 kg at a tooth pitch of less than 1.4 mm.
Quite a large number of varieties of such a product determines that with the selection of a suitable version of the performance does not have serious problems.
What are they made of?
Modern hacksaw blades for metal are made of the following types of steel:
- Carbon steel. has low hardness values, so it can be used for cutting non-ferrous and soft metal. Blades of such class are marked HCS, and the hardness level does not exceed 44-46 HRC.
- High-speed-cutting. have high indicators of resistance to abrasion and tooth wear, but their disadvantage is brittleness. Fast-cutting saws are labeled HSS and have a hardness rating up to 73-78 HRC. There are blades of high-speed steel with diamond coating, which have hardness level up to 82-84 HRC. each
- Bimetallic. got this name because of the use of two types of steel. Their production created a furor in the market, quickly replacing their analogues. Bimetal blades are based on materials such as carbon steel, onto which a high speed steel strip is welded. These types of devices are designated by the letters BIM, and their strength is the same as that of high-speed steel, only due to the use of carbon steel as the basic material, they have high strength and resistance to deformation
- Alloyed tool steels are modernized models of carbon steel grades, which are produced by augmenting carbon with chromium, tungsten, vanadium, silicon, etc.п. Alloying makes it possible to achieve high strength characteristics, and the hardness degree is a little bit lower than that of high-speed steel, and amounts to 67-67 HRC.
The hardness of the handheld circular saw headset characterizes the sensitivity of the tooling to bending stress, so depending on the cutting devices used, it is necessary to consider the force applied to the hacksaw during work.
Generally, the maximum force is 60 kg, which is characteristic of tools with a tooth pitch of less than 1.4 mm. If the tooth pitch is greater than 1.4 mm, the load should not be more than 10 kg.
Principles of blade selection
It is important to choose the most suitable version of the product for the specific operating conditions. If the surface does not have the required properties, it will not last for a long period of time. The following points can be mentioned as selection criteria:
- The distance between the two mounting holes is the most important selection criterion. With some tools this value can be varied thanks to a special device.
- The next selection criterion is the strength of the metal to be cut. If the work involves cutting common soft alloys, for example copper or aluminum, choose a product with the lowest hardness of the surface layer. X6VF steel is very common, imported blades have the HCS designation. It is also possible to carry out processing of strong metals, for which the hacksaw blade made of high-speed steel, imported marking HSS is suitable,
- Also takes into account the thicknesses of metal being cut and the quality to be achieved after machining. Abroad, the decisive criterion is PPI, which is the number of tooth tips per inch in length. To ensure high quality requires a PPI greater than 24, if the priority is performance, then select a version with an index of less than 24.
- Quality of the cutting edge spread is a deciding factor. This parameter must comply with the standards laid down in the above GOST. There are three basic setups: each one, through one tooth, or through two adjacent teeth.
Metal saw. Hacksaw blade for metal :
Saw (hand hacksaw for metal). a tool designed to cut thick sheets of profiled, round and strip metal and to cut grooves, slots, cut/cut blanks on the contour, as well as other work.
Locksmith hand hacksaw includes a hacksaw blade and frame (machine tool). On one end of the frame is a fixed head with a handle and shank. And the other has a sliding head with a nut for tensioning the blade and a tensioning screw.
the heads of metal hacksaws have slots in them: the hacksaw blade is inserted and fastened with the help of pins.
Hacksaw frames are made as sliding frames, which allow different blade lengths to be clamped, and as solid frames.
To extend the hacksaw, it is necessary to bend the knees until the rivet is removed from the notch, after which it is displaced. The rivet is inserted in the other notch, then the knees are straightened.
A machine with a sliding holder includes an angle piece with a handle. On it you can fix and move the holder in the required direction.
Blade for metal hacksaw: what is it?
Hacksaw blade is a narrow and thin steel plate with 2 holes and teeth on one edge. Blades can be made of such steel grades as Х6ВФ, Р9, У10А with the hardness of HRC 61-64. Depending on their purpose, blades can be machine and manual. They are inserted in the frame with teeth forward.
The length (size) of the handheld hacksaw blade can be determined by the distance available between the centers of the holes set aside for the pins. Practically always the hacksaw blades are used which are designed for handheld hacksaws with thickness h. 0,8 and 0,65 mm, height b. 16 and 13 mm, length L. 250-300 mm.
Work of hacksaw blade differs in conditions of work of the cutter itself, therefore here are other values of corners.
When cutting metal with a large width, it is possible to obtain cuts of considerable length: each tooth of the blade will remove chips, which should fill the chip space until the tip of the tooth comes out of the kerf completely. The size of the chip space will depend on the tooth pitch S, the anterior angle Y and the posterior angle A.
Depending on the hardness of the metal to be cut, the front angle of the teeth of a hacksaw blade can be negative, positive or zero.
Cutting efficiency of a blade with a zero rake angle will be lower compared to one with a rake angle greater than 0°.
To cut harder materials, blades with a larger tooth angle are used. And in order to cut soft materials the blade tip angle should be smaller. Blades with a larger angle of sharpening are more resistant to wear.
Required number of teeth of a hacksaw blade for different metals
For the purpose of metal cutting in most cases hacksaw blades with the pitch of 1.3-1.6 mm are used, and on the length of 25 mm there are 17-20 teeth.
the thicker the workpiece to be cut, the coarser the teeth, and vice versa, the thinner the workpiece, the finer the teeth of the hacksaw blade must be.
For metals of different hardness use blades with the following number of teeth: angle, strip and hard steel. 22, tool steel, cast iron. 22, hardened steel of medium hardness. 19, soft metals. 16.
Hand hacksaw for metal 300mm: working with the tool
In case of cutting with a hand hacksaw at least 2-3 teeth must be used (simultaneous metal cutting). To avoid a jamming effect in the metal of the hacksaw blade, it is necessary to set the teeth.
Setting the teeth is performed so that the width of the cut, which was made with the hacksaw, was somewhat greater than the thickness of the blade itself. This can prevent the blade from jamming in the cut and makes working very easy.
The hacksaw blades having tooth pitch 0,8 mm (also pitch 1 mm is permissible) should have wavy setting of the teeth, that is every 2 adjacent teeth should be bent in the opposite directions for about 0,25-0,6 mm.
Metal hacksaw blades with a tooth pitch greater than 0.8 are set to the tooth (so-called corrugated setting). In this setting take 2-3 teeth to the left and 2-3 to the right. At a medium pitch, one tooth is set to the left, the second tooth is not set, and the third tooth is set to the right. At a coarse pitch, one tooth is set to the right, and the second tooth to the left. The tooth setting is appropriate for blades with a pitch of 1.6 and 1.25 mm.
It is necessary that the setting of the hacksaw blade ended at a distance from the end not more than 30 mm.
Preparing to work
Before you start your work with the hacksaw (hacksaw), you must firmly fix the material to be cut in a vise. The degree of the material in them must match the height of the worker. After that, choose a hacksaw blade according to the size, shape and hardness of the metal to be cut.
If the rafters are long, then take hacksaw blades with a coarse tooth pitch, in the case of short should use a fine tooth pitch.
How to Choose Hand Saws | Ask This Old House
Metal hacksaw (photo above) is installed in the head slots so that the teeth are not pointing toward the handle.
However, initially insert the end of the blade into the fixed head, then secure the position with a pin, and then place the second end of the blade into the slot of the pin, securing the pin.
The blade is tensioned manually without any effort (use of vice, pliers is not allowed) by turning the wing nut. Hacksaw for metal 300 mm at the same time keep away from the face.
With a slight twist a blade that is too taut and with increased pressure a blade that is too weakly taut will cause a kink and breakage. The tension of the blade should be checked by pressing lightly on the side of the blade with your finger: the tension is sufficient if the blade does not sag at all.
Working body position
When cutting metal with a handheld hacksaw, stand firmly, freely and straight in front of the vise, half-turned in relation to the axis of the workpiece or the jaws of the vise.
Before proceeding directly to sharpening, the teeth must be set. This is to avoid clamping the blade in the material when working and to improve the cutting ability of the teeth. If you consider the mechanism of the hacksaw, the setting plays a very important role, because it allows only the teeth to make contact with the material, and the blade itself does not touch the wood. The wider the setting, the wider the kerf and the less likely that the tool will get caught in the thickness of the workpiece.
The dimension of the spread is taken as 1,5-2 thickness of the hacksaw blade and usually does not exceed 2 mm. The smaller the setting for dry wood and the larger the setting for fresh or wet wood. Tooth setting is performed by means of the tool with the same name that looks like a metal plate with a slit, the width of which is comparable to the width of the saw blade itself. Teeth are bent in different directions from the tool’s longitudinal axis. To work comfortably, the saw is clamped in a vice between two wooden blocks, so that only the cutting elements protrude above them. Tooth is not bent at its base, but about in the middle, at the so-called tap line. By bending an element below this line, you can accidentally break it. Check the quality of work by eye. to see if the setting is correct, the blade is looked at lengthwise in the light. If any teeth are protruding from the row, set them right.
Metal hacksaw manual its purpose types and how to choose
The relevance of hand hacksaws on metal remains relevant, as this type of tool has many advantages and only one disadvantage. This is the first tool that was invented by man to cut metal workpieces.
Today, every self-respecting craftsman has at least one option among the different types of this tool in his arsenal.
Handheld metal saw is popular because the tool is always ready to work in the absence of an angle grinder and electricity.
Design parameters of handheld metal saws
Looks like a manual metal hacksaw is quite simple:
- The base or U-shaped frame is predominantly metal
- Handle of different shapes for manual operation
- Metal blades for handheld sabre saws or a cutting unit fixed to the edge of the frame
These are the basic elements that make up handheld metal hacksaws. An important detail is the blade, which has a characteristic kind of teeth. Smaller teeth are designed especially for work with harder materials.
The blade is attached to the frame. Alloy steel is used for the frame. Frames come in different types, shapes and designs. Professional hand tools have a blade angle adjustment feature. There are frame variants that are capable of extending. This feature in the tool allows you to install cutting elements of different lengths.
The handle is also an important node, as it can provide convenience and comfort of using the tool. Handles come in different shapes, as well as made of such materials. wood, metal, plastic. The simplest handle is made of wood, and the most comfortable handle is considered to be of two-component material: metal and rubber insert.
Blade for hand hacksaw for metal. a thin strip, which is made of hard types of steel, and has different lengths. There are wedge-shaped teeth on one or both sides.
Hacksaw blade is the most fragile element of the tool, so when working it is important to control the rigidity of its fastening.
Cutting elements for hand saws are made by the method of heat treatment of teeth, which allows you to extend the life of the product.
Important note! Manual hacksaw blades are not designed for sharpening, so if the teeth are worn out, they need to be replaced. Blades are now available in bimetal and hardened metal (nickel-plated stainless steel). they differ in color: bimetal blade is painted in different colors, and the fully hardened blade has a dark color.
When selecting a blade, attention must be paid to its length. The length of the blade can be from 10 cm up to 70 cm. Classic mechanical manual metal saws allow the use of blades with a length of 30 cm, because this is the size of the tool is the most comfortable and convenient for work.
What are hand hacksaws for metal
Metal hand hacksaws are designed for cutting metal materials. This is not the only purpose of the tool, as it has proven good for materials such as plastic, chipboard, styrofoam, polystyrene, plexiglass, ceramic, laminate.
Considered saw for sawing metal. is a very necessary tool in the economy, because in the absence of angle grinder, it can always help in the situation. to saw off the head of an oxidized bolt or re-saw a steel wire.
The big disadvantage of such a tool is a large expenditure of physical strength and time. The presence of fine teeth is reflected in the time it takes to achieve the result. To get a result from the master requires not only the application of titanic force, but also patience.
The result of long and hard work with the tool is the most precise result, which sometimes surpasses the cut with an angle grinder.
Types of handheld hacksaws on metal
There are the following types of hacksaws for metal:
- Homemade. The simplest variants, which are available in the set of every craftsman. Such devices are considered an obsolete version, but their production continues to this day. The advantage of these tools is their simple design. The handle is made of wood, and is located in the same plane as the blade
- Professional ones are intended for use in case of prolonged work. Such products are equipped with a more convenient handle, which in addition happens to be rubberized. Some higher-priced models have a mechanism for adjusting the angle of the blade during operation
- Mini hacksaw or metal hand saw has a special shape that differs from the first two types. These products are designed to be used only when it is difficult to access the part to be sawed. The device is shaped like a blade with an extra point to hold the blade in place. The handle is made of plastic and metal with rubber
How to properly saw with a handheld metal hacksaw
Manual metal saw requires the master to observe the following rules of operation:
- Adopting the correct stand for the craftsman. You should rest your feet well on the floor, and the device is only operated with two hands, so initially take care that the workpiece is securely clamped in the jaws of the vice
- Securely securing the blade. Hacksaw blades are very fragile, so if the product “wiggles” from side to side if not properly secured, at one point it will simply break
- Proper sawing movements. To cut a part you need not only to hold the tool properly but also work with it. You press the tool against the workpiece you are sawing when you move it forward, and when you move it backward, the pressure is released. The teeth of the blade will dull quickly if the clamping pressure on the return stroke of the tool is not reduced
It is important to pay attention to! The blade on the frame of a hand saw must be locked in position with the teeth facing away from the handle.
Selecting the tool or what to look for
To choose the best handheld metal hacksaw, pay attention to the following parameters: