How to install a blade on a hacksaw • CIMFLOK.COM

How to put a blade on a hacksaw for metal

Sawing process

Metal cutting with a hacksaw is carried out as follows:

hold the handle with one hand, the vertical part of the arc with the other;
the blade is aligned according to the cut line of the cut (the saw should be tilted at an acute angle and move, almost adhering to the sheet, which will help to avoid unnecessary noise);
the first movements are done with little effort; this will help the teeth to cut into the metal and prevent the tool from slipping;
with smooth translational movements, the file is moved forward (when the blade returns to its previous position, the pressing force is reduced);
after the appearance of the slot, they begin to work at full strength.

The range of motion should be large. Do not touch the part with the arc of a hacksaw and stay in place for a long time. This will cause the tool to fail, which will require you to purchase a new replacement part. The hacksaw must be held in one position, not allowing it to deviate to the sides. With sudden movements of the tool, the file becomes unusable.

Hacksaw blade for metal – its types and principles of use

A hacksaw blade for metal is a consumable that quickly breaks down. The service life of the file depends on the way the metal is processed with a hacksaw and the skill of using the tool. Correct selection of replacement part plays an important role.

Hacksaw blade for metal. How to choose and install?

The blade for a hacksaw for metal is one of the most short-lived elements from the entire range of consumables for tools. Of course, a lot depends on the technology of working with metal and the skills of using a hacksaw, but first of all you need to be able to make the right choice of the blade. Today, we will talk about the choice and types, and also learn how to easily change the hacksaw blade..

Mowing line curved cut

Compact and full-size hacksaws can cut any type of mowing line. If it is necessary to produce round cuts, the saw is aligned so that it makes a right angle with the part. Turn the bow slowly so that the tool follows the selected line. Marking can be done with a marker or sharp object. It is impossible to make sharp turns, this contributes to a deterioration in cut quality and tool breakage.

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Types of hacksaw blades

GOST R 53411-2009 “Hacksaw blades for metal” establishes two types of such tools – for machine and manual cutting. We will not touch on the first ones, but the second ones are produced in three main standard sizes:

Single, with a distance between the fixing holes 250 ± 2 mm, with a total blade length of no more than 265 mm;
Single, with a distance between the fixing holes of 300 ± 2 mm, with a total blade length of no more than 315 mm;
Double, with a distance between the fixing holes of 300 ± 2 mm, with a total blade length not exceeding 315 mm.

In this case, the thickness of the leaf s of a single version is 0.63 mm, of a double one – 0.80 mm. Height with a single row of tines is 12.5 mm, and with a double row is 20 mm.

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

According to the brand of material used for the manufacture of hacksaw blades for metal, they are made from tool steels:

H6VF brands.
В2Ф brands.
High speed, grades P6M5, P12 or P18.

How to change a blade on a hacksaw

The assortment of domestic hacksaw blades is exhausted by this, however, so-called diamond blades with surface spraying with titanium nitrides or other refractory metals are widespread in specialized retail chains. These canvases can be easily distinguished by their color: ordinary steel canvases are dark gray, and the sprayed ones can have different colors – from bright orange to blue (depending on the manufacturer).

How to replace metal saw blade

There are also canvases with the so-called tungsten carbide spraying, however, with a very high hardness, they are extremely sensitive to bending stresses. Therefore, when cutting metal, their durability is negligible..

High strength of hacksaw blades for metal is ensured by appropriate heat treatment. On the surface of the blade, two zones with different values of hardness are distinguished: directly at the teeth it ranges from HRC 64 … 67 for alloyed tool steels to HRC 73 … 78 – for high-speed steels (for diamond blades this parameter reaches HRA 82 … 84), and in the rest zone – НRС 44 … 46. A significant difference in hardness confirms the high sensitivity of the product to bending stresses, therefore, the standard also limits the maximum force applied to the hand hacksaw. It should not exceed 60 kg when working with blades with a tooth pitch of less than 1.4 mm, and 10 kg for blades with a tooth pitch of more than 1.4 mm.

Sawing process

Metal cutting with a hacksaw is carried out as follows:

hold the handle with one hand, the vertical part of the arc with the other;
the blade is aligned according to the cut line of the cut (the saw should be tilted at an acute angle and move, almost adhering to the sheet, which will help to avoid unnecessary noise);
the first movements are done with little effort; this will help the teeth to cut into the metal and prevent the tool from slipping;
with smooth translational movements, the file is moved forward (when the blade returns to its previous position, the pressing force is reduced);
after the appearance of the slot, they begin to work at full strength.

Choosing a hacksaw blade

When choosing a hacksaw blade, the characteristics that need to be given special attention are the size of the part and the material. The size of the part determines the ability to use a canvas of a certain length and width. The hardness and toughness of the material affect the choice of blade pitch and tooth size

There are the following recommendations:

The hardness and toughness of the material affect the choice of blade pitch and tooth size. There are the following recommendations:

Tin, roofing iron, etc. materials of similar thickness – pitch 0.8 mm.
Thin-walled pipes, thin steel profile – about 1 mm.
Thick-walled pipes and other similar materials – not less than 1.25 mm.
Cast iron, plastic – 1.2 – 1.5 mm.

Classic

The classic hacksaw is also called standard, wide. It is a traditional sawing tool and is used for longitudinal as well as cross cuts. With the help of a classic hacksaw, you can cut down tree branches or shorten boards. Such saws are used in joinery and carpentry, it provides a fairly quick and easy cutting, and the cut itself turns out to be deep and very rough, while large chips are formed..

Thorn

A spiked hacksaw is often called a butt saw or a hacksaw. This is a rather peculiar tool, the basic task of which is to remove all protruding grooves or spikes. Such saws are traditionally used by locksmiths and carpenters to form a perfectly smooth cut..

The finger saw blade is rather thin, so the sawing channel comes out rather narrow.

So that the canvas does not begin to bend, a small back is attached to the side opposite to the teeth (it is necessary to give sufficient rigidity).

The incisors of the tool are made in the form of an isosceles triangle.

Suitable only for cross-cutting, while the thickness of the functional part is not more than 1.5 mm.

Product classification

Hacksaw blades are a narrow strip, at the ends of which there are two holes for attaching to the tool. There are three main criteria for their classification:

purpose (for hand / electric hacksaws);
material of manufacture;

Manual hacksaw blade for metal

The division into groups according to the first criterion occurs as with hacksaws – they distinguish canvases for hand (mechanical) and electrical (sometimes called machine) tools. The sizes of the work items vary. So, for hand-held canvases are used with a length of 250-300 mm, a width of 12-25 mm, a thickness of 0.63-1.25 mm. An example is a domestic-made canvas made of X6VF steel with parameters 1.25x12x300, which will cost the buyer 30 rubles per piece.

Parameters of files for power tools vary from 150 mm in length, to 55 mm in width, from 1.25 to 2.5 mm in thickness. Example – a blade for a reciprocating saw HAMMER RS BL 001, the parameters of which are 150x19x1.25 mm, and per piece.

Another difference between saws for hand and saber saws is the number of holes for fasteners. The first have two, the second have one.

Electric hawk cloth

The second criterion for classification is the material of the fabric. Allocate steel products:

carbon (the least durable, suitable for non-ferrous or soft metal; marked as HCS); for example, Bosch HCS TF 350 M 408 mm GFZ for 1400 rubles;
high-speed (they have the most wear-resistant teeth, but are fragile and costly; HSS marking); Gross HSS 18TPI 300 mm – 160 rubles per pair;
bimetallic blades (an innovation on the market, displacing analogs; the base is carbon steel, on top of which a high-speed strip is welded, serving as the basis for the teeth; denoted by BIM); Gross Variozahn 300 mm BIM from 300 rubles per pair.

There are also blades made of alloy steel (designation HM), but more often they are used for cutting brick, concrete or stone.

The size of the teeth for metal hacksaws is 2-2.5 mm. This parameter is considered “small”, since there are products with a larger tooth (for example, for wood saws it is 4-6 mm).

International standardization provides for a different principle of dividing canvases. So, the number of teeth per 1 inch of the file is taken into account. This number is shown in the marking before the letters PPI (points per inch – “point per inch”) or TPI (formula “PPI – 1”). The higher the number, the smaller the tooth is represented on this blade..

When choosing products for a hacksaw, the user does not have to guess for a long time – most of the famous files have a tooth pitch. This is the designation of branded products for construction (for example, Standart 24 TPI 300 mm, Kraft-Flex 18 TPI canvas from the manufacturer Kraftool).

The main classification of hacksaw blades for metal is compiled on the basis of the above criteria

It is important to know that the presence of set teeth is welcomed if the user expects comfortable work without pauses and tool breakages. Now about how to correctly install a hacksaw blade in a hand or power tool

Band saw teeth: basic parameters

The first point to pay attention to is the number of teeth. When determining this parameter, consider:

the more teeth, the smoother the cut of thick-walled workpieces;
with a low density of teeth, the load on the workpiece area decreases;
with a large number of cutting edges, the stress during operations is distributed over the entire surface of the saw.

The size of the teeth. Consider the following guidelines when sizing teeth.

Standard prongs are suitable for cutting thin material and shape cutting.
Large teeth for deep cuts.
Low cutting edges – the best choice for cutting thin-walled sheets.

The pitch of the teeth of the band saw blade must match the parameters of the counterpart on the machine. It is most rational to use the following recommendations when choosing a tool:

coarse constant pitch is suitable for cutting thin-walled sheets of small sizes;
frequent, evenly spaced teeth are successful when cutting large webs of the material being processed;
Variable tooth belts are suitable for processing soft materials (plastic, non-ferrous metal, wood).

Image # 1: Determining the pitch of the saw band teeth

Manufacturers develop special guidelines for the selection of the pitch of the teeth for various types of rolled products (solid blanks, profiles, sheets, pipes) for the product range. The setting of the teeth determines the quality of the preparation of the material, the level of vibration during the operation and the speed of grinding the tool.

Image: saw band teeth wiring diagrams

According to this parameter, all canvases are divided into 3 groups.

Wavy profile. The teeth are located in the form of a wave along the entire length of the band saw blade, have a different angle of inclination. The corrugated profile is used for cutting thin materials and small workpieces.
Standard wiring. The edge elements are placed alternately on both sides, one tooth in the center. The standard set is suitable for sawing large metal sections on horizontal machines, contour cuts and material handling on vertical feed equipment.
Group wiring. The notches on the edge are located in pairs on the left and right sides. These tools provide maximum speed and clean cuts with a low load on the cutting part..

The quality of sharpening is determined by eye, focusing on the following criteria:

sharpness of teeth;
uniformity of the cutting edge material;
evenness of the mowing line of the edge.

Important! Check when buying whether the blade can be sharpened and how many cutting edge renewal cycles are allowed

Design features of a hacksaw for metal

The widespread use is largely determined by the device of the hacksaw for metal. It is presented in a C-shape, between the two edges of which there is a special canvas. When considering what the tool consists of, note the following:

Lever. Today the handle of a hacksaw for metal in most cases is made of two different components, which ensure a long service life. The shape should be comfortable enough, and the element itself should be placed at the top of the structure or on the side. In most cases, the top location is used when it is necessary to process hard-to-reach places..
Frame. It is designed to take the load, as well as damp vibration at the time of operation. Today, various materials are used in the manufacture of such tool elements. In order to carry out the processing of hard-to-reach places, the structure often has an element due to which the tilt of the web is adjusted. The frame is made in one piece or sliding, the second version of the design allows the installation of the product with different lengths.
The canvas is represented by a hard alloy tape. This element is considered the thinnest and most fragile, represented by a combination of small teeth located relative to each other at a certain distance and angle. At the time of work, you should be careful, as even minor mistakes can lead to damage

When choosing, attention is paid to the fact that the surface must be hardened, since otherwise the required level of wear resistance cannot be ensured. To increase productivity, a blade with a rare tooth is selected, to increase the quality of a cut with a frequent

Recently, bimetallic blade has become widespread..

The design features of the hacksaw for metal determine the very widespread use of the tool. The main part determines the duration of use and other points, the cutting speed and cut quality depends on the installed blade.

Choosing a hacksaw for metal

When buying a hacksaw, pay attention to the frame of the tool, since the blade can be replaced at any convenient time, but the frame cannot. A high-quality frame is made of sufficiently durable composite materials, or metal. A useful feature is the ability to change the angle of inclination for the hacksaw blade, which allows you to work even in the most inaccessible places

A useful feature is the ability to change the angle of inclination for the hacksaw blade, which allows you to work even in the most inaccessible places.

It is also necessary to pay attention to the tool handle. After all, it is for this part that you will hold the hacksaw, so it, in turn, should be very comfortable, sit well in your hand, and, if possible, have special finger stops. The handle of the tool must be solid, and not have hollow parts, since in this case it may simply break

In general, it should also be noted that the hacksaw must be tightly assembled, not have any backlash or other defects – this will guarantee its high quality.

The handle of the tool should be solid, and not have hollow parts, as in this case it may simply break. In general, it should also be noted that the hacksaw must be firmly assembled, not have any backlash or other defects – this will guarantee its high quality..

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