How to correctly put a hacksaw for metal

How to choose a hand hacksaw for metal

Metal hacksaw. a saw capable of cutting high-strength metal workpieces. A distinctive feature of such saws is the use of blades with a fine tooth. The height of the toothing is 1-1,5 (mm). The thickness of the blade is in the range (0.7-1.3 mm), and the width reaches 12-25 (mm). The text will talk about how to choose a hacksaw for metal.

Of course, there are also metal blades with larger gears (2-2.5 mm), but they are already designed for installation on machine tools. Such blades are thick (in the range of 2 mm) and wide (25-55 mm), they are mainly made of durable rapide steel.

Handheld metal saws are used when small amounts of workpieces need to be cut. Of course, the performance of hacksaws is noticeably inferior to their powered counterparts, the same angle grinder or saber saw. But handheld saws are not without weighty advantages:

  • Self-sufficiency and portability
  • Noiseless operation possible
  • Absolute safety

If you choose the right blade for your hacksaw, the serrated blade will provide a quality cut while remaining sharp for a long time.

Sawing requirements

In order to do the wiring correctly, you need to pay attention to the basic requirements. They are as follows:

  • Procedure is carried out with the tool in place.
  • Strict adherence to the angle required, deviations from this angle will reduce the quality of the resulting cut.
  • At the time of work, attention is paid to the fact that the surface has no defects.

It is worth bearing in mind that too high a figure causes an increase in cutting width, resulting in a decrease in performance. That’s why a special device should be used for tooth setting.

How to set up a hacksaw properly

Material and properties of carbide tines

Russian saws use sintered tungsten-cobalt alloys as material for cutting plates (grade 6, 15 etc). figure means the percentage of cobalt). Grade 6 has a hardness of 88.5 HRA, grade 15 has a carbide-tungsten carbide hardness of 88.5 HRA. 86 HRA. Foreign domestic manufacturers use their alloys. Hard alloys consist mainly of tungsten carbide cemented with cobalt. The properties of the alloy depend not only on its chemical composition, but also on the grain size of the carbide phase. The smaller the grain size, the higher the hardness and toughness of the alloy.

Fix the carbide plates to the disk by high-temperature soldering. Soldering material, most likely, is used silver solder (PSr-40, PSr-45), in the worst case. copper-zinc solders (L-63, MNMC-68-4-2).

Carbide tooth geometry

The following types of teeth are distinguished by their shape.

Typically used in saws for quick, longitudinal cuts where quality is of little importance.

With left and right angled back plane. Teeth with different angles of inclination alternate with each other, which is why they are called alternately angled. This is the most common tooth shape. Depending on the angle of sharpening, saws with alternate teeth are used for sawing various materials (wood, chipboard, plastics). Both longitudinally and transversely. Saws with a large angle of inclination of the back plane are used as undercutting saws when cutting double-sided laminated boards. Using them avoids chipping of the coating on the edge of the kerf. Increasing the bevel angle lowers cutting forces and reduces the danger of chipping, but also reduces tooth strength and durability.

Teeth can have not only backward but also forward inclination

The distinctive feature of these teeth is a relatively slow blunting rate of the cutting edges as compared to alternate teeth. They are usually used in conjunction with a straight tooth.

Alternating with and slightly above the latter, the trapezoid tooth performs roughing

, and the straight one following it. finishing. Saws with alternating straight and trapezoidal teeth are used for cutting double-sided laminated panels (chipboard, hardboard, wood-fibre board etc).) and for sawing plastics.

Tapered tooth saws are auxiliary saws and are used to notch the bottom layer of the laminate, protecting it from splintering as the main saw passes through.

In the vast majority of cases the leading edge of the teeth is flat, but there are also saws with a concave leading edge. They are used for finish crosscutting.

Tooth sharpening angles

Sharpening angles are determined by the purpose of the saw. т.е. The front angle is determined by the material to be cut and the direction in which it is to be cut. Saws for longitudinal sawing have a relatively large rake angle (15°-25°). Cross-cutting saws usually have an angle γ of 5-10°. Universal saws intended for cross and longitudinal sawing have an average value of the rake angle. usually 15°.

are not only dictated by the cutting direction but also by the hardness of the material to be sawn. The higher the hardness, the lower the rake angle and posterior angle (less tooth sharpening).

The rake angle can be positive or negative. Saws with such an angle are used for cutting non-ferrous metals and plastics.

Correct blade setting in metal

A metal hacksaw is a hand tool that is used to cut through metal shapes 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 has a groove on one side for inserting and fixing the blade and a screw with a ram which is used for tensioning the blade.

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Metal saw blades differ in width, length, thickness, distance between teeth and their height. Use of one or another blade depends on thickness, hardness and shape of material to be cut. The manufacturers of blades have made sure that you can choose a blade exactly for the material you need to cut, be it aluminum, copper, bronze or even plastic. The dimensions of the blade, namely the length, width, tooth size and steel grade can be found on the hacksaw blade you buy.

How to mount the blade in a metal saw?

As shown in the first picture of the article: with the teeth downward (if the blade is one-sided) and the teeth pointing forward from the handle. When you saw, you apply downward and forward pressure. exactly the same way the teeth of the hacksaw should be pointing, down and forward. To install, release the tensioning screw, take the old blade off the pins, put on the new one and tighten it so much that the blade should snap a finger nail and tinkle like a string. The main thing here is not to overdo it and tear the blade. You find by experience the optimal tensioning.

The tensioning is carried out with the turnbuckle on the adjuster, i.e. turning the turnbuckle tautens the blade. So when tensioning the hacksaw blade you have to find the right tension. Also, make sure the blade is positioned straight and not twisted as twisting will result in an uneven cut during cutting.

How to Saw?

Since you were interested in the question about the installation of the blade, it does not hurt to give some advice about the way to use the metal hacksaw. Grasp the handle of the hacksaw with one hand (right hand if you are right handed or left handed if you are left handed) and take the vertical edge of the hacksaw arc opposite to the handle with the other hand. Place the blade on the cutting line. Guide the blade strictly in the direction of the cut line. Keep 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 line. Cut across the material, at a 90 degree angle, only in emergencies, such as when turning the cut line. The flatter you want the cut line, 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 cutter line. Using smooth, forward movements, press the hacksaw firmly against the material 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 might.

Move as much as possible from blade 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 and do not let it bow in different directions. Cutting direction corresponds to the arc plane of the hacksaw, so chattering is contraindicated here. Also, the blade will break 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 bending.

Cutting with a hacksaw on a curved mower line

The metal hacksaw is also valuable in that it allows you to make a cut along almost any curve of the mowing 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 turn the arc of the hacksaw smoothly, so that the blade follows the intended mowing line. Yes, always be sure to mark the cut line 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 or it will break; turns are an extreme for a hacksaw blade on metal.

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

To cut an inside corner, you must first drill a straight line with a thin drill bit slightly 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 to do it. There is nothing complicated about it.

How to use a hacksaw

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

Metal hacksaw blades

Blade for hacksaw for metal is one of the most undurable elements from the whole range of consumables for tools. Of course, much 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 make the right choice of blade. Today, we will talk about the choice and types, as well as learn how to easily change a hacksaw blade.

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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 ever heard of fortunetools and lathes, my father conducted all the metalwork with an ordinary hacksaw. And with a hand drill.

First of all I would advise to choose a hacksaw like in the second photo. This option is more convenient to work with. It’s just easier to hold it in your hand and it won’t slip in your hand.

When installing the blade, you should pay attention to the correct positioning of the teeth. As you can see in the photo, it should run to the side of the cutter. When cutting, you need to apply force when the saw moves away from you. When bringing the saw back, you need to lift the handle a little and relieve the pressure on the saw itself. This way the teeth stay in service longer.

It’s also worth paying attention to the tension of the blade when you put it in the saw. If the blade is too loose or overtightened, it will break at the slightest sway of the saw.

And you can put a couple of drops of oil in the area of the cut so the blade will not get too hot.

And don’t forget that metal that is cut can be simply broken. That is, sometimes it is enough to saw off half, for example, a pipe or angle, and simply break the remaining part by bending to one side and the other.

I would like to pay your attention to the fact, that it is desirable (if possible) to make a good hold of the part you want to cut, for example in a vice.

There are no secrets. You need to remember a few important points and the metal will scatter like oil on the knife.

It is necessary to choose a saw with a comfortable handle and a strong one. Choose a blade not from the cheap ones, but with the spraying on the teeth of a durable compound. You should place the blade in the saw so that the teeth of the blade would be in the direction from you.

When making the cut you have to use force actively when moving the saw away from yourself and just move it away from yourself without any load. Try to make a 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 to half or little more, as it can break under your little effort. Much depends on the thickness of the pipe and its age.

As many colleagues have already noted, when working with a hacksaw for metal when cutting (sawing) it is necessary to pay attention to the following points:

  • sturdy and with a comfortable handle the saw frame;
  • high-quality and appropriate pitch for a particular metal (depending on the toughness and hardness of the metal) hacksaw blades;
  • You set the direction of the tines from yourself;
  • Arm movements should be smooth and wide amplitude.

As for the nuances, I can say that the hacksaw blades.material with high hardness and brittleness and is afraid of overheating. Therefore, make constant stops in the work and the saw will serve you for a long time.

The secret of your acquaintance is not so much in the way you work with the tool but in the tool itself. Handling with the hacksaw is taught at school (many people made hammers, angles, etc.).д.), that’s why there are no special secrets: Just place the blade correctly and keep it straight when sawing. But here in my practice I met some particular blades for metal (I do not remember exactly where they came from: either from furry or smooth). or from some other machine, but that’s not the point. ) I used to easily cut pipes in the apartment and other metal objects, which were easier to cut with a hacksaw than to unwind an angle grinder for the sake of it.

I can offer you some recommendations that will speed up metal sawing with a hacksaw:

  • use a hacksaw with a sturdy frame made of composite materials.
  • it is better 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 at least 16-18pcs/inch.

For hard metals, the maximum (32 teeth per 25mm).

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

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

  • Not always a high RPM means a fast cut. There is a definite correlation between the number of reciprocating movements 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 is clearly illustrated in this figure.

correctly, hacksaw, metal

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

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The first is that the hacksaw cuts only in the forward direction.

Secondly, for the metal saw to cut metal it is necessary to apply an even force when pushing the hacksaw forward and loosen it completely when pulling it back.

Thirdly, the hand movements must be as sure as possible, uniform, as much as possible in a straight plane (no rocking to the sides, side to side and forward to back, no twisting and jerking).

Fourthly, it is necessary to lubricate the blade of the hacksaw with machine oil on both sides before starting to cut, and with significant cuts to apply lubrication to the blade as it is used.

Fifth, it is necessary to periodically water the cut, so it does not overheat the blade of the hacksaw, which can release the hardening and the blade will simply wipe away.

Sixth definitely matters metal that you are going to saw, because not every metal can be easily sawn with a hacksaw, and there are some that can not be sawn at all, then it is advisable to use a diamond cutting tool.

So here are the nuances. I hope to stop on a choice and installation of the blade is not necessary, and in the previous answers it is already more or less described.

Hand Hacksaw for Metal

Hacksaw for metal is a special saw for cutting metal workpieces. But it can also be used for other materials (Styrofoam, Plexiglas, wood, pasteboard, etc).п.).

    the simple metal hacksaw is the most common and affordable option, which is optimal 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.

Current GOSTs

For manual frames specifications of hacksaw blade GOST 17270-71. The parameters of a metal hacksaw are governed by GOST 6645-86

Hacksaw is used to create through cuts in dense materials made of metal, cutting slots, trimming contour products. A locksmith tool is made of a hacksaw blade and a base machine. One end of the frame is equipped with a static clamping head, a handle to hold the tool, a shank. The counterpart consists of a sliding head and a screw that tightens the cutting plate. Metal hacksaw heads are equipped with slots in which the working blade is mounted and secured by pins.

Frames are made in two forms: sliding, allowing to fix a working blade of any length, and solid.

Number of teeth

Number of teeth per inch is the deciding factor. The following depends on it:

  • The performance depends on it. When the number of cutting edges is increased, the task at hand becomes much more difficult, the chips become finer.
  • A high number allows for a quality cut. This is accomplished by reducing chip production.

In addition, an increase in the number becomes a reason to increase the cost of the product.

Hacksaw blades types

GOST R 53411-2009 “Metal hacksaw blades” specifies two types of such tools. for machine and hand cutting. We will not touch the first ones, and the latter are produced in three basic sizes:

  • Single, with the distance between the fastening holes 250±2 mm, with the total length of the blade not more than 265 mm;
  • Single, with distance between fixing holes of 300±2 mm, with total length of blade not more than 315 mm;
  • Double bars, with 300±2 mm spacing between mounting holes and a total length of no more than 315 mm.

In this case the thickness of single version blade s is 0,63 mm, double version. 0,80 mm. The single tine spacing is 12,5 mm and the double tine spacing 20 mm.

GOST also regulates the pitch P, mm and number z of teeth, which for the first type are respectively 0.80/32, 1.00/24 and 1.25/20. Owners of longer hacksaw blades can also use 1.40/18 and 1.60/16 hacksaw blades in addition to the above.

According to the brand of material used for the production of hacksaw blades for metal, they are made of tool steel:

The assortment of hacksaw blades of domestic production is exhausted by this, but in specialized trade networks the so-called diamond blades, with surface sputtering by titanium nitrides or other refractory metals, are widely distributed. Such blades can be distinguished very easily by their color: ordinary steel blades are dark gray, while the coated blades can have different colors ranging from bright orange to blue (depending on the manufacturer).

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

The high durability of metal saw blades is ensured by an appropriate heat treatment. There are two zones of different hardness values on the surface of the blade: hardness values directly on teeth differ from HRC 6467 for alloy tool steels to HRC 7378. for high-speed steels (for diamond blades this parameter reaches HRC 8284), and in the other zone. HRC 4446. Significant hardness differences confirm the high sensitivity of the product to bending stresses, which is why the standard also limits the maximum force that can be applied to a hand saw. It must not exceed 60 kg for blades with a tooth pitch less than 1.4 mm and 10 kg for blades with a tooth pitch greater than 1.4 mm.