Metal hacksaw how to set the blade

Construction of a hand hacksaw with a horizontal handle

Hand hacksaw (fig. 6.3) consists of two main parts. a hacksaw blade and a special frame (holder), in which the hacksaw blade is placed and which is called a frame or machine. There are two types of frames. one-piece and sliding. Sliding frames are more convenient, as they allow you to install a hacksaw blade of different lengths. One end of the frame has a shank with a handle and a fixed head, while the other end has a movable head and a tensioning screw with a wing nut to tension the hacksaw blade. The heads are equipped with slots and holes for fixing the blade of the hacksaw.

Insert the hacksaw blade into the frame as follows. Its ends are placed in the head slots so that the teeth of the blade point away from the handle and so that the holes that are on the ends of the blade and the holes in the heads coincide. Then pins are inserted into the holes and the blade is stretched by tightening the wing nut. Tighten the saw blade neither too tight nor too loose. An overstretched blade can, during operation, break from the slightest tilt or sideways movement. a blade that has been loosely tensioned will bend during use and could therefore also break.

Hacksaw blade, the cutting part of a hacksaw, is a thin, narrow band with teeth on the bottom edge. The teeth are sharply angled, t. е. each tooth is a wedge (cutter) whose sharpening angle for a normal hacksaw blade is 60° with a cutting angle of y=0. Back angle a=30°, fig. 6.4.

Tooth angles of hacksaw blades for cutting of metals of different hardness and tenacity are different: the front angle varies between 0-12°, and the back angle. between 30-35°. Tooth pitch: for soft and ductile metals (copper, brass) t= 1 mm, for hard metals (cast iron) (=1.5 mm, for mild steel t= 2 mm. For metal work mainly hacksaw blades with a pitch of 1,5 mm which have about 17 teeth on a length of 25 mm are used.

When cutting with a hacksaw, make sure that at least 2.5 teeth are involved (touching the metal at the same time). In order to avoid jamming of the hacksaw blade in the metal, the teeth are set apart, t. е. Every two adjacent teeth bend in opposite directions by 0,25-0,6 mm.

Along with simple trailing, there is also corrugated trailing. It is made as follows. Small tooth pitch: 2 to 3 teeth to the right and 2 to 3 teeth to the left. At a medium pitch, one tooth is set to the left, the second to the right, the third is not set. The corrugations in the corrugated part are caused by the fact that together with the bent teeth they grab some metal underneath their base.

Blades for hand saws are produced in length from 150 to 400 mm, width from 10 to 25 mm and thickness from 0,6 to 1,25 mm. As a material for the blades are used:

  • cemented low-carbon steel in the form of cold-rolled strips;
  • carbon tool steel U10A;
  • Х6ВФ steel alloyed steels (increased blade life);
  • high-speed steel. the teeth have the highest cutting ability and resistance, but their main disadvantage is brittleness.

Hacksaw blades are subjected to thermal treatment. hardening to high hardness.

In addition to conventional steel blades there are also produced:

  • Bimetallic blades with carbon basis, on which a strip from high-speed steel is welded with teeth shaped on it; such blades are stronger than high-speed ones and surpass them in durability;
  • Tungsten carbide coated blades that are used for cutting glass, ceramics, faora and other hard materials, including hardened carbon and alloy steel.

Tungsten carbide coated blades come in two varieties:

  • flat. instead of teeth, the metal base is covered (in the form of a strip) with tungsten carbide coating;
  • The “wire ropes” are coated on the steel wire with an eye for fastening, the same as the flat blades, Fig. 6.5.

Figs. 6.5. The blade in the form of a “rope” with a coating of tungsten carbide

How to correctly and quickly saw with a hacksaw on metal?

To be honest, I do not know any special secrets, but there are some nuances that should be observed.

About 30 years ago when nobody has ever heard of fortunetools and metal saws my father used an ordinary hacksaw to do all his metalwork. And with a hand drill.

First of all, I would suggest choosing a hacksaw like the one in the second photo. This variant is more convenient to work with. It’s just easier to hold and the handle won’t slip in your hand.

When installing the blade pay attention to the correct positioning of the teeth. As shown in the photo, they should go away from the cutter. When cutting, you need to apply force when the saw moves away from you. When you bring the saw back, you have to lift the handle a little and loosen the pressure on the saw itself. This way the teeth stay in their working condition for a longer time.

You should also pay attention to the tension of the blade when you insert it into the saw. If the saw blade has too little or too much tension, it will break at the slightest vibration of the saw.

Well, to keep the blade cool, you can drop a couple of drops of oil in the area of the cut.

And you shouldn’t forget that the metal you’re cutting can be broken. So sometimes it is enough to saw off half of e.g. a pipe or angle and simply break the other half by bending to one side and to the other.

I would like to pay your attention to the fact that the part that is supposed to be cut is desirable (if possible) to be fixed firmly, for example in a vice.

There are no secrets. You need to remember a few important points and the metal will disperse like butter against the knife.

You need to choose a saw with a comfortable handle and sturdy. Choose a blade not from the cheap ones, but with the teeth sprayed with a strong composition. Place the blade in the saw so that the teeth of the blade are facing away from you.

When making the split, you need to actively apply force when you move the saw away from yourself and just perform the movement away from yourself without any load. Try to make the cut with the position of the blade with the maximum area of contact of the teeth of the blade with the surface of the object that needs to be sawn or filed. As for splitting a pipe, it is enough to saw a pipe halfway or little more than that and it can break under your slight effort. Much depends on the thickness of the pipe and its age.

As many colleagues have already noted, when carrying out work with a hacksaw on metal when cutting (sawing) it is necessary to pay attention to the following points

  • The saw frame is strong and has a comfortable handle;
  • quality and appropriate pitch for the particular metal (depending on the toughness and hardness of the metal) hacksaw blades;
  • You set the direction of the tines away from yourself;
  • the hand movement have to be smooth and wide amplitude.

As for the details, I can tell you that the hacksaw blades.the material is very hard and brittle and is afraid of overheating. That is why you have to stop the saw constantly and it will serve you well for a long time.

The secret of your acquaintance is not in the way of work with the tool, but in the tool itself. Handling with a hacksaw on metal is taught at school (many people made hammers, corners, etc.).д.), that’s why there are no special secrets: Just set the blade correctly and keep it straight when sawing. But here, in my practice I met special blades on metal (I do not remember exactly from where: either from mech. or from some other machine, but that’s not the point. ), with which the pipes in the apartment and other metal objects, which was easier to cut with a hacksaw than to untwist an angle grinder for the sake of this work, were cut lightly.

I can offer a few recommendations to speed up metal sawing with a hacksaw:

  • use a hacksaw with a sturdy frame made of composite materials.
  • to buy bimetal blades with hardened teeth for work.
  • For metals of different hardness select a blade with the appropriate number of teeth:

for soft metals the number of teeth should be minimum. 16-18 pcs/inch.

for hard metals. maximum (32 teeth per 25mm).

  • It is more reasonable to use new blades for cutting softer and tougher metals (aluminum, brass, bronze, copper). ), and b/w for hard metals (steel, cast iron. )
  • if a blade breaks, it is necessary to clean the kerf from any splinters of the blade and only after that continue working with a new blade.

By the way, if only one or a couple of teeth are broken, the blade can be saved from further destruction by making an arc (notch) with rounded edges in this place with an emery.

  • Not always a high tempo of work means fast cutting of metal. There is a definite correlation between the number of reciprocating motions and the hardness of the metal.

the harder the metal, the less intensity you need to work, otherwise the blade will overheat and quickly shrink.

The position of the hacksaw, arms, body and legs clearly demonstrates this picture.

To learn how to cut metal quickly with a hacksaw, you must understand the following!

First. the hacksaw cuts only in forward direction.

metal, hacksaw, blade

Second. in order to cut metal with a hacksaw you must apply an even force when pushing the hacksaw forward and loosen it completely when pulling it back.

Third. the hand movements should be as confident and steady as possible, in a straight plane (no rocking to the sides, side to side or forward to back, no twisting and jerking).

Fourthly it is a necessity to lubricate the cutter blade with machine oil on both sides before starting to cut, and if you make big cuts it is necessary to apply lubrication to the blade as it is used up.

Hacksaw blades

Metal hacksaw is a hand tool that is used for cutting profile metal and pipes. The simplest metal hacksaw consists of a machine and a hacksaw blade. The machine, in its turn, consists of a frame into which on one side is inserted a handle which has a device for fixation of the blade and on the other side a device for fixation and regulation of the tension of the blade. The tensioning device, on one side, has a groove for the insertion and fixation of the blade and, on the other side, a screw with a ram which is used for tensioning the blade.

Metal hacksaw blades differ in width, length, thickness, distance between teeth and their height. The use of one or another blade depends on the thickness, hardness and shape of the material to be cut. Blade manufacturers made sure you can choose a blade just right for the material you want to cut, whether it’s aluminum, copper, bronze, or even plastic. The dimensions of the blade. specifically the length, width, tooth size and steel grade. can be found on the hacksaw blade you buy.

How to install a blade in a metal hacksaw?

As it is shown in the first picture of the article: with the teeth downward (if the blade is single sided) and the teeth pointing forward from the handle. When you saw, you apply downward and forward pressure. the teeth of the hacksaw should be facing down and forward in exactly the same way. To install, release the tensioning screw, remove the old blade from the pins, put on the new one and tighten it so much that the blade should ring like a string when you snap your finger nail. Here the main thing is not to overdo it and not to break the blade. You find the ideal tension by experimenting.

Tensioning is done by means of the ram on the adjuster, i.e. by tightening the ram you will tighten the webbing. So when tensioning the hacksaw blade, you need to find the golden mean. Also, make sure the blade is set flat with no tilting, as tilting will cause an uneven cut during cutting.

How to saw?

Since you were interested in the question of blade setting, it does not hurt to give you some advice on how to use a hacksaw on metal as well. Hold the handle of the hacksaw with one hand (right hand if you are right-handed, left handed if you are left-handed) and the opposite vertical edge of the arc of the hacksaw with the other hand. Set the blade on the trimmer line. Guide the blade strictly in the direction of the cutting line. Keep the angle of the hacksaw small. The blade should almost lie on the piece, usually at an angle of 30-45 degrees. That way there is less vibration, less noise, and a smoother trimmer blade. Cut across the material, at a 90-degree angle, only in emergencies, such as when turning the cutting line. The flatter you want the trimmer blade to cut, the smaller the angle.

The first movements should be done with a little effort so that the blade cuts into the material and does not slide sideways away from the cutting line. With a smooth, gradual motion, press the hacksaw against the workpiece as you move forward and release pressure as you return to the starting position. When the blade grips the material. you can work with all your strength.

You have the maximum reach from blade edge to edge without the arc of the hacksaw hitting the workpiece. No need to stomp on it. that way you will quickly erase the blade in one area and have to throw it away, because you can’t use a defective blade. Keep the arc of the hacksaw straight, don’t let it bow in different directions. The cutting direction corresponds to the arc plane of the hacksaw, so chattering is contraindicated here. Also, the blade breaks easily if the hacksaw jerks to the side. The material properties of the blade are such that it holds very well under longitudinal tensile stress, but is very brittle in flexure.

Cutting along a curved line with a hacksaw

Metal saws are also valuable because they let you cut almost any curve. In order to cut in an arc without stopping the forward motion of the hacksaw, align it perpendicular to the face of the workpiece material (t.е. angle of 90 degrees) and gradually turn the arc of the hacksaw smoothly so that the blade follows the planned line. Yes, the line for trimmer cut is always sure to mark with anything. pencil, marker, scratch nail. The main thing is that it should be visible when you work. You must make the turn of the blade as gently and smoothly as possible, otherwise it will break; turns are an extreme for a metal saw blade.

If you have to make a sharp turn of, say, 90 degrees, you have to practically stomp in place. while continuing to saw and smoothly turning the arc of the hacksaw, stepping back periodically so as not to get too far out of the way of the turn, using the side of the blade that is external to the workpiece to turn the blade.

To cut the inner corner, you must first drill a straight line for the trimmer with a thin drill bit slightly longer than the width of the blade, pass the blade into this groove and cut further with a hacksaw. Well, practice will show how it’s done. Nothing complicated here.

The picture below shows another way to use a metal hacksaw. For this method, you need to reset the blade by turning it 90 degrees.

Hacksaw blades for metal

Hacksaw blades for metal are one of the most unreliable elements in the whole range of consumables for tools. Of course much depends on the technology of work with metal and skills of using a hacksaw, but first of all you need to be able to make the right choice of blade. Today, we’re going to talk about choices and types, and learn how to easily change a hacksaw blade.

Crab Pens ♋ Almois Jobbing Official

The general theory of sawing with a hacksaw on metal looks something like this:

The theory of sawing with a hacksaw. Introductory course

That’s why we won’t study the theory, but go straight to practice:

In this video the whole story about how to saw is actually presented, but now there will be a postscript, a number of additions and corrections (plus a brief retelling of the video content).

So, let’s start with the fact that you have to saw horizontally with both hands gripping the tool with the hacksaw. For this purpose it would be good to use a hacksaw with a well-defined handle for gripping with the second hand.

It is inconvenient to saw horizontally, because it requires the workpiece to be secured at chest level, and to saw standing up. However, workbenches are usually tables at which you have to sit, and if you saw, you have to stand up and from the top down. That’s why hacksaws are more often made one-handed and cut with them at an angle of 45°.

To regulate pressure on the saw (the harder the metal, the harder you need to load the blade, to press it so that the teeth dig into the flesh; and vice versa. if the teeth cut too hard, for example, into aluminum, then you need to reduce pressure) you can: a) change the angle of inclination while sawing, b) put your hand on top to increase weight, c) turn the blade with teeth backwards.

The saw often gets stuck in the kerf when it reaches the end of the blade. That’s because the blade has a wavy pattern to the teeth (so the kerf is wider than the blade and it doesn’t get stuck in the kerf) but over time the amplitude of this wave decreases in the center of the blade and almost none at the ends.

The teeth are worn down more in the center of the blade

This misalignment is the result of not using the full length of the blade before. It is no longer possible to correct (increase the separation in the center or decrease it on the ends) because the teeth are hardened. So the moral: Always saw the entire length of a new blade right from the start.

Next problem: if I saw a thin sheet of metal with thickness less than the distance between the teeth, the saw jams:

Too thin workpiece gets stuck between the teeth

If the metal is hard (iron). you can’t move it, but if it’s soft (aluminum). a huge piece of metal is torn out, jagged edges are formed, the edge is bent.

Saw a thin part at a steep angle

Saw at an angle to form a kerf of such length that at least two teeth are on it simultaneously (kerf length ≥ two distances between teeth).

Next topic: sawing thin-walled aluminum pipe:

Torsion direction of the pipe

Set the blade with teeth backwards, twist the pipe in the direction of the teeth (otherwise the blade will get stuck on the near edge of the kerf and tear when applying force).

Well, one more thing the metal hacksaw blade can be restored and the teeth sharpened, for example, in this way:

Originally this diamond disc was larger in diameter and this drill with this disc, being thus pressed against the blade was strictly parallel to the tooth line of the blade and the disc was accordingly perpendicular. And that was right. the new hacksaw has the leading edges-surfaces of the teeth orthogonal to the blade. Now a slight negative angle is formed. a little less better, but also okay.

Just for the record: this blade can be drilled with an ordinary metal drill bit (made of HSS steel). Because at production the whole blade is hardened not very much, to elasticity, and hereto teeth are hardened separately by induction heating with fast cooling to hardness, therefore by these teeth it is possible to saw backwards a drill bit without problems.

Crab Hands ♋ Almois Jobbing Official

The general theory of sawing with a metal hacksaw looks something like this:

Hacksaw sawing theory. Introduction course

So we will not go through the theory, we will go straight to the practice:

In this video, the whole story of how to saw is actually presented, but now there will be a postscript, a number of additions and corrections (plus a brief retelling of the video content).

So, let’s start with the fact that it is necessary to saw with a metal hacksaw horizontally gripping the tool with both hands. For which a hacksaw with a well-defined handle for a second hand grip would be a good idea.

It is inconvenient to saw horizontally, because it requires the workpiece to be secured at chest level, and to saw standing up. However, workbenches are usually tables at which one must sit, and if one is sawing, standing and from top to bottom. That’s why hacksaws are more often made one-handed and saw at a 45° angle.

To adjust the pressure on the saw (the harder the metal, the harder you need to load the blade, to press it so that the teeth dig into the flesh; and vice versa. if the teeth cut too hard, for example, into aluminum, you need to reduce the pressure) you can: a) change the angle of the sawing, b) put your hand on top to increase weight, c) turn the blade with the teeth backwards.

The saw often jams in the kerf when it reaches the end of the blade. This is because the blade has an undulating pattern of teeth (so that the kerf is wider than the blade and it does not get stuck in the kerf), but over time the amplitude of this wave decreases in the center of the blade, and almost none at the ends.

Teeth get ground more in the center of the blade

This misalignment is the result of not sawing with the full length of the blade before. It is no longer possible to correct (increase the separation in the center or decrease it at the ends) due to the fact that the teeth are hardened. So the moral: since the beginning of a new blade you should always saw with its full length.

The next problem: If we saw a thin sheet of metal with a thickness less than the distance between the teeth, the saw jams:

Workpiece too thin gets stuck between the teeth

If metal is hard (iron). you can’t move it, and if it is soft (aluminum). a huge piece of metal is torn out, ragged edges are formed, the edge bends.

Sawing a thin piece at a steep angle

Saw at an angle to form a kerf of such length that at least two teeth rest on it at the same time (kerf length ≥ two tooth spacing).

Next topic: sawing thin-walled aluminum pipe:

Torsion direction of tube

We set the blade with teeth backwards, twist the pipe in the direction of the teeth (otherwise the blade will get stuck on the near edge of the kerf and tear when applying force).

Well, one more thing the metal saw blade can be restored, the teeth can be sharpened, for example, in this way:

Originally this diamond disc was bigger in diameter and this drill with this disc, being pressed this way to the blade, was strictly parallel to the teeth line of the blade and the disc, respectively, perpendicular. And that was right. the new hacksaw has the front edge-surfaces of the teeth orthogonal to the blade. Now a slight negative angle is formed. a little less better, but also normal.

One more thing to note: this blade can be drilled with an ordinary metal drill bit (made of HSS steel). Because the whole blade is not hardened very much at production, for elasticity, but the teeth are hardened separately by induction heating with rapid cooling for hardness, so these teeth can safely cut the drill backwards.

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Hand Hacksaw for Metal

Metal hacksaw is a special saw for cutting metal workpieces. But it can also work with other materials (foam plastic, plexiglass, wood, pastmass, etc.).п.).

    a simple hacksaw for metal. the most common and affordable option, which is optimally suited for simple tasks around the house and is particularly comfortable to use. Often such hacksaws are equipped with additional tensioning screw mechanisms, combined with a wooden handle, located longitudinally to the blade.

Design of a hand hacksaw for metal

Hacksaw frames are manufactured according to GOST 17270-71 “Hand Hacksaw Frames. Specifications”

Metal hacksaw handle

Hacksaw handle plays a major role when working, especially when it comes to comfort when held for a long time.

Two-component handles with special rubber inserts are considered the best of all types.

Handle can be placed on the side or on top of the hacksaw. Top-mounted handles (models without a bulky frame) are needed when working in hard-to-reach places or for laborious types of work.

Metal saw frame

The frame can be made of various materials. When cutting hardwood, the frame can be made of high-strength composites.

Altering the angle of the handheld metal saw blade

Frame design depends on working conditions. So when cutting metal in poorly accessible places a saw with adjustable blade angle or a short frame is used.

Frame may be one-piece or sliding. The preference is usually given to the sliding frames, because of the possibility of attachment of hacksaw blades in their design.

The length of handheld hacksaws is characterized by the distance between the holes in the ends. from 6 ” to 14 ” (from 150 to 400 mm).

There are two screws for fastening the blade to the frame: one of them can be part of the handle, and the other is placed on the outside of the arc of the saw frame.

Metal saw blades

HSS blades are made thin and narrow, of high speed steel and H6VF steel. Only a heat treatment of the blade teeth is used to prevent the blade from breaking.

For manual sawing blades 250 mm and 300 mm in width 12,5 and 25 mm and thickness 0,63. 1,25 mm are used.

Wedge-shaped teeth (cutters) are applied to the edges of the blades. The greater the number of teeth on the blade, the faster the product is cut.

Small-toothed blades are good for hard metal materials and coarse-toothed blades for soft materials.

Properly installing the blade in metal

Metal saw blade is a hand tool that is used for cutting profile metal and pipes. The simplest metal hacksaw consists of a machine and a hacksaw blade. The machine, in its turn, consists of a frame into which on one side is inserted a handle which has a device for fixing the blade, and on the other side, a device for fixation and regulation of tension of the blade. The tensioning device, on one side, has a groove for inserting and fixing the blade, and, on the other side, a screw with a rammer which is used for tensioning the blade.

Blades for metal saws differ in width, length, thickness, distance between teeth and their height. Use of one blade or another depends on the thickness, hardness and shape of the material to be cut. Blade manufacturers make sure you have the right blade for the material you need to cut, whether it’s aluminum, copper, bronze, or even plastic. The dimensions of the blade, specifically the length, width, tooth size and steel grade, can be found on the hacksaw blade you buy.

How to set the blade in the metal saw?

As shown in the first diagram in this article, the teeth are facing down (if the blade is single sided) and the teeth are facing forward from the handle. When you are sawing you apply downward and forward pressure. the teeth of the hacksaw should be pointing in the same way, down and forward. To install, loosen the tensioning screw, remove the old blade from its pins, put on the new one, and tighten it enough to make the blade tinkle like a string when you snap your fingernail. The main thing here is not to overdo it and tear the blade. By trial and error you will find the ideal tension.

The tensioning is done with the turnbuckle on the adjuster, that is, by screwing in the turnbuckle you will tighten the blade. So you have to find a happy medium when you’re tensioning the hacksaw blade. Also, make sure the blade is set straight without twisting it, because twisting will cause an uneven cut while you’re cutting.

How to saw?

Since you were wondering about setting up the blade, it doesn’t hurt to have some advice about how to use a metal trimmer blade as well. Grasp the handle of your hacksaw with one hand (right hand if you are right-handed, left handed if you are left-handed) and hold the opposite vertical edge of the arc of the hacksaw with the other hand. Place the blade on the trimmer blade. Aim the blade straight in the direction of the cut line. Make the angle of the hacksaw small. The blade should almost lie on the part, usually at an angle of 30-45 degrees. That way there will be less vibration, less noise, and a smoother cut. Cutting across the material, with a 90 degree angle, is worthwhile only in emergency cases, for example, when turning the cutting line. The flatter you need the trimmer line for the cut, the smaller the angle.

The first movements should be done with little effort so that the blade cuts into the material and does not slide sideways away from the cutting line. Moving smoothly, in a straight forward motion, press the hacksaw against the workpiece as you move forward, and release pressure as you return to the starting position. When the blade grips the material. you can work with all your strength.

Move as far as possible from edge to edge without hitting the workpiece with the arc of the hacksaw. There is no need to “tread on the spot”. you will quickly erase the blade in one area and have to throw it away, because it is impossible to use a defective blade. Keep the arc of the hacksaw straight, do not let it bow in any direction. The cutting direction corresponds to the arc plane of the hacksaw, so chattering is contraindicated here. In addition the blade breaks easily if the saw jerks suddenly to the side. The material properties of the blade are such that it holds very well under longitudinal tensile stress, but is very brittle in bending.

metal, hacksaw, blade

Cutting along a curved line with a hacksaw

A metal saw blade is also valuable in that it allows you to make a cut in almost any curve line. To cut in an arc without stopping the forward motion of the hacksaw, align it perpendicular to the face of the workpiece material (t.е. angle of 90 degrees) and gradually smoothly turn the arc of the hacksaw so that the blade follows the intended line. Yes, the line for the trimmer cut is always sure to mark with anything. pencil, marker, scratch nail. The main thing is to be able to see it when you work. You have to make the turn of the blade as gently and smoothly as possible, otherwise it will break; turns are an extreme for a metal saw blade.

If you need to make a sharp turn, say 90 degrees, you will have to practically “stomp on the spot”, continuing to saw and smoothly turn the arc of the hacksaw, periodically stepping back so as not to go far from the place of turn, while using the side of the blade that is external to the part to turn.

To cut an inside corner, you must first drill a straight line for the trimmer with a thin drill bit longer than the width of the blade, slide the blade into this groove and cut further with the hacksaw. In general, practice will show how it is done. Nothing complicated here.

The figure below shows another method of using a hacksaw for metal. For this method, you need to reset the blade by turning it 90 degrees.

Hacksaw blades for metal

Hacksaw blades for metal. one of the most short-lived elements of the entire range of consumables for tools. Certainly much depends on technology of work with metal and skills of using a hacksaw, but first of all you need to be able to make a correct choice of blade. Today, we will talk about the choice and types, as well as learn how to easily change a hacksaw blade.

Types of hacksaw blades

GOST R 53411-2009 “Hacksaw blades for metal” establishes two types of such tool. for machine and manual cutting. We will not touch the first ones, but the latter are available in three basic sizes:

  • Single, with the distance between the fixing holes 250 ± 2 mm, with a total length of the leaf not more than 265 mm;
  • Single, with the distance between the fixing holes of 300±2 mm, with a total length of the blade not exceeding 315 mm;
  • Double, with the distance between the fixing holes 300±2 mm, with the total length of the blade not more than 315 mm.

In this case, the thickness of the web s single version. 0.63 mm, double. 0.80 mm. The height with a single row of teeth is 12.5 mm, and with a double row is 20 mm.

GOST also regulates values of pitch P, mm and their quantity z, which are 0,80/32, 1,00/24 and 1,25/20 accordingly for the first type of blades. Owners of more “long” hacksaws, in addition to the above mentioned, can also use hacksaw blades with the parameters 1.40/18 and 1.60/16.

According to material grade, used for manufacture of blades for metal hacksaw blades are made of tool steels:

The assortment of Russian-made hacksaw blades is limited to this, but in specialized retail chains the so-called diamond blades with surface spraying of titanium nitrides or other refractory metals are widespread. Such blades can be easily distinguished by their color: ordinary steel blades are dark gray, while sprayed blades can have different coloring. from bright orange to blue (depending on the manufacturer).

There are also blades with the so-called carbide-tungsten dusting, but they are extremely sensitive to bending stresses, though their hardness is very high. Therefore when cutting metal their durability is insignificant.

High durability of metal saw blades is ensured by an appropriate heat treatment. Two zones with different hardness values are distinguished on the surface of the blade: directly at the teeth it ranges from НRС 6467 for alloy tool steels to НRС 7378. for high-speed steels (for diamond blades this parameter reaches НRС 8284) and in the other zone. НRС 4446. Significant hardness difference confirms the high sensitivity of the product to bending stresses, so the standard also limits the maximum force applied to the hand saw. It must not exceed 60 kg when working with blades with tooth pitch less than 1,4 mm and 10 kg for blades with tooth pitch over 1,4 mm.

Work with the hacksaw

When tensioning the blade, the saw blade must be held at a distance from your face because of the danger of blade breakage.

When starting to cut with a hacksaw, stand in front of the vice half-turn (in relation to the jaws of the vice or to the axis of the workpiece). Left leg

Fig. 6.6. Position of the saw blade in relation to the handle of the hacksaw blade

is placed slightly forward, approximately in line with the object to be cut, and the body rests on it. The hacksaw is held in the right hand so that the handle rests in the palm of the hand, and the thumb is on top of the handle. Use the other four fingers to hold the handle from underneath. With the left hand, grasp the front end of the hacksaw frame as shown in Fig. 6.7 and rice. 6.8.

When cutting, the hacksaw blade must be held mostly in a horizontal position. It should be moved smoothly without jerks. Give the hacksaw such a swing that the whole blade works and not just the middle. Normal reach length is 2 1/2 lengths of hacksaw blade tucked in the frame.

Fig. 6.7. How to hold a hacksaw with horizontal handle (difference in position)

Work with the hacksaw at a speed of 30 to 60 strokes per minute (double strokes forward and backward are meant). Hard metals are cut with lower speed, soft metals with higher speed. For example, when cutting hard steel up to 30 double strokes per minute, when cutting medium-hard steel 40 to 50 strokes per minute, when cutting mild steel and cast iron 50 to 60 strokes per minute.

The hacksaw should be pressed while moving forward. No pressure should be applied when making backward strokes. The amount of pressure on the hacksaw depends on the hardness of the metal and the size of the surface to be cut. Hard metals require more pressure on the hacksaw than soft metals. The normal amount of pressure should be about 1 kg per 0,1 mm of thickness of the blade. At the end of the cut, the pressure is released.

A hand held hacksaw is most commonly used without cooling. To reduce the friction of the blade against the walls of the kerf, a thick grease made of lard or graphite ointment is used, which includes lard (2 parts) and graphite (1 part). This grease stays on the hacksaw blade for a long time.

During the cutting process the hacksaw blade sometimes “runs” sideways resulting in teeth chipping or blade breakage. Also, if it retracts, it creates an oblique cut on the object that is to be cut. Cause of misalignment: low blade tension or poor sawmanship.

If the blade slips, start the cut in a new place. the back side of the bad cut. Attempting to straighten an oblique cut “in place” always causes the blade to break. Teeth of a hacksaw blade also break if it is too hard (not properly hardened), if the pressure on the hacksaw blade is too high, especially when cutting narrow workpieces and in cases where foreign solid contaminants are embedded in the metal to be cut.

If the teeth of the blade break. even if only one tooth. you should not continue working with this hacksaw, otherwise adjacent teeth will break and all others will be blunted quickly. To restore the cutting ability of a hacksaw with a chipped tooth, you need to grind two or three neighboring teeth on an emery wheel or grinding wheel, as shown in Fig. 6.9. After removing the remains of the hacksaw tooth stuck there from the started slot, continue working with the restored hacksaw blade.

If the old, worn out hacksaw blade breaks while cutting, you cannot continue working with a new hacksaw blade. it will not enter the

Fig. 6.9. Using a hacksaw blade with broken teeth: а. View of a hacksaw blade with broken teeth; б. The blade with teeth ground down; в. Sawyer line for trimmer sharpening adjacent teeth

the gash. Having turned the product, start cutting in the other place. If, however, it is not possible to turn the workpiece due to working conditions, it is necessary to widen the initial slot by carefully sawing it with a new hacksaw blade.

Blade dimensions, length, width

Saw sizes are determined by the method of attachment.

For such products only 2 sizes are available: 300 and 150 mm.

The first variant is considered standard; products of this size are made of all possible types and materials.

Saws with 150 mm length are made only of carbon steel.

Thickness depends on application.

On professional models the value varies from 0.63 to 1.25 mm.

Power saw blades have greater thickness up to 2.5 mm.

Saw blade height up to 13 mm. Only made of bimetallic alloy, because all other materials are too brittle.

Made of bimetallic alloy only.

Products with fine teeth are suitable for sawing hard metals.

Variant with coarse is designed for processing soft.

Since when sawing soft metals with fine teeth, the saw quickly gets clogged with shavings, and the cut turns out sloppy, jagged.

Metal saw blade is a construction tool that every frugal homeowner has. It is difficult to imagine the performance of any simple household works without the use of this device. Hacksaw can be actively used in work with different types of materials, so it is often called a universal tool.

Now the choice of hacksaws is quite extensive and difficulties in choosing such a device, as a rule, do not arise. The main thing, when buying take into account certain characteristics and parameters of hacksaws.

In construction markets, hacksaws come in two main varieties. manual and electric. The handheld type cutter can be used everywhere because it is very light and mobile. And the main advantage of the tool is its low market price. The only disadvantage is the additional time and great physical effort required.

Number of teeth

The determining factor is how many teeth per inch. It affects the following

  • The number determines the performance. When the number of cutting edges is increased, the task is considerably more difficult, the chips become finer.
  • A large number allows you to get a quality cut. This is achieved by reducing the size of the chips it produces.

Also, an increase in the number raises the cost of the product.