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Details Category: Long products

Cutting metal with a hacksaw

For cutting billets from long products, manual cutting is used. hacksaw.

Canvas hacksaw - a thin strip of solid steel, on one edge of which teeth wedge-shaped. Each tooth represents cutter .

Hacksaw blade must be securely fastened to framed (see picture on the right 5 ) tension screw (1 ), A teeth directed in the opposite direction pen (4 ).

Below you can watch a fragment of a film about making hacksaws. Full version The film can be downloaded and .

Before starting work, you should adjust the tension of the blade in the hacksaw frame. To do this, you need to insert one edge of the canvas into rear head (3 ) and secure with a cotter pin. Insert the second edge of the blade into the cut front head (2 ) and tension the fabric using tension screw . Too much tension on the fabric, as well as too little tension, can lead to its breakage. Using the marking line, make a shallow cut with a triangular file. This will ensure the exact direction of movement of the blade.

While working, you need to take the correct working position (see figure on the left): stand half-turned to the vice, put your left leg forward and place your feet at an angle to each other.

The hacksaw is held with both hands while cutting. The position of the hands is shown in the figure below. The hacksaw can be moved only by hand, and the body remains motionless. This saves energy and provides high quality work.

A hacksaw can cut strip material only if its thickness accommodates three or more teeth of the hacksaw blade.

More thin material secure between wooden blocks (see figure on the right). Thin workpieces are collected in bags, that is, several pieces are folded together and secured in a vice.

When cutting long workpieces It is not always possible to complete the cutting due to the fact that the machine frame rests on their end. Then the canvas is turned 90° relative to the frame (see figure on the left) and work continues.

Shaped profile blanks(angle, channel, etc.) when cutting with a hacksaw, it is recommended to fix it in wooden mouthpieces(see figure on the right).

At the beginning of cutting strip and square products, the hacksaw is tilted slightly forward. The tilt is gradually reduced and after the cut reaches the nearest edge of the workpiece, the hacksaw is returned to the horizontal position.
It is necessary to ensure that the marking line is maintained. If you cut exactly along the marking mark, then after sawing the size of the part will be less than that specified in the drawing, which will lead to irreparable defects.
The forward movement of the hacksaw is working, since at this time the teeth of the blade are cutting metal, and the backward movement is idle. When moving the hacksaw forward, it is slightly pressed down; the reverse movement is performed without pressure.

The hacksaw stroke must be complete so that the blade wears evenly along its entire length. You need to move the hacksaw smoothly, without jerking, rhythmically. The speed of movement of the hacksaw can be from 30 to 60 double strokes per minute. To reduce friction, the hacksaw blade is coated with machine oil or other thick lubricant.

The workpiece must be securely secured in a vice.
You need to work with a hacksaw smoothly, without jerking.
When finishing cutting, it is necessary to release the pressure on the hacksaw and hold the part to be cut from below.
Do not blow away the shavings or sweep them away by hand. You need to use a brush.

The illustration shows different variants hand saws and various devices for sawing metal.

The metal to be cut is firmly fixed in a bench vice. The distance between the vice and the worker’s body should be such that in the initial position of the hacksaw before cutting, the shoulder part of the right hand should be vertical, the worker’s body should be straight. The right shoulder should be against the vice screw, the body is turned to the right at an angle of 45° (Fig. 113, a). The emphasis should be on the left leg, the right leg takes on the entire weight of the body. The feet are placed at an angle of 60-70° to one another (Fig. 113, b).

Rice. 113. Hand hacksaw operation:
a - position of the body, b - position of the legs, c - grip of the handle right hand. d - gripping the handle with the left hand

The handle of the hacksaw is grasped with the fingers of the right hand (the thumb is placed on top of it along the handle, the other fingers support it from below), the end of the handle is pressed into the palm (Fig. 113, c). Should not be pulled forefinger along the handle and turn the brush too far to the right or left. You should not make a deep grip on the handle, in which the end sticks out of the hand and does not rest against the center of the palm. You should hold the hacksaw frame with your left hand, as shown in Fig. 113, city

You need to press on the machine with both hands, but the greatest pressure should be exerted by the left hand, and the right hand carries out mainly the reciprocating movement of the hacksaw.

The cutting process consists of two strokes: the working stroke, when the hacksaw moves forward from the working one, and the idle stroke, when the hacksaw moves back towards the working one.

When idling, do not press on the hacksaw, as a result of which the teeth only slide, but during the working stroke, apply light pressure with both hands so that the hacksaw moves straight. When working with a hacksaw, you must following rules:

1. choose a hacksaw blade based on the material being cut (hardness, size, shape of the material);
2. insert the blade into the slots of the frame so that the tip of the teeth is directed away from the handle. The fabric should not be stretched too tightly or too loosely;
3. for long cuts, you need to choose a hacksaw blade with a large pitch of teeth, and for short cuts - with a fine pitch;
4. short workpieces should be cut along their widest side. When cutting rolled corner, T- and channel profiles, it is better to change the position of the workpiece than to cut along the narrow side;
5. the entire hacksaw blade must be involved in the work;
6. You should work with a hacksaw slowly, smoothly, without jerking, making no more than 30-60 double moves per minute. At faster rates, fatigue sets in more quickly and, in addition, the blade heats up and dulls faster;
7. before reaching the end of the cut, you should ease the pressure on the hacksaw, since with strong pressure the hacksaw blade does not cut, but breaks the metal and may break;
8. When cutting, do not allow the blade to heat up. To reduce friction of the blade against the cut walls of the part, it is recommended to periodically lubricate the blade mineral oil or graphite lubricant, especially when cutting tough metals;
9. brass and bronze should be cut only with new blades, since even slightly worn blades do not cut, but slide;
10. In case of breakage or chipping of at least one tooth, work should be stopped immediately, the remains of the broken teeth should be removed from the cut and the blade replaced with a new one, or another 2-3 adjacent teeth should be ground on a sharpener and only then continue work.

Cutting round metal. A marking line is first made on the workpiece to be cut. Clamp it in a vice in a horizontal position and, to guide the hacksaw, use a triangular file to make a shallow cut along the line.

By installing a hacksaw into the cut, the cut is made without breaking off the part being cut off. Breaking off is allowed if the ends of the workpiece will be processed (filed). In this case, cuts are made in the rod on two to four sides, and then it is broken off either by holding it in a vice or using a hammer, which is used to strike the rod, while the workpiece is placed on pads.

Cutting strip and square metal. The workpiece is secured in a vice and a shallow cut is made at the site of the future cut with a triangular file for better direction of the hacksaw. At the beginning of the operation, the hacksaw is tilted slightly away from you (forward). As cutting progresses, the slope is gradually reduced until the cut reaches the opposite edge of the workpiece. Then the workpiece is cut with the hacksaw in a horizontal position (Fig. 114).

Rice. 114. Techniques for cutting workpieces with wide sides

It is considered more rational to cut strip material not along the wide side, but along the narrow side. This, however, can only be done if the side width is greater than 2.5 blade pitches.

When cutting a strip lengthwise and for deep cuts, the hacksaw blade in the frame is given a lateral position (Fig. 115, a). To do this, the canvas is rearranged into the side slots of the frame heads. With this position of the hacksaw, you need to work very carefully, since if the frame is skewed, the hacksaw blade may break.

Rice. 115. Metal cutting:
a - a hacksaw for deep slits, b - a hacksaw thin sheets, in - jigsaw curved and angular slots

Cutting thin sheet and profile metal. Part blanks made of thin sheet material are clamped between wooden blocks one or several pieces at a time and cut together with the bars (Fig. 115, b).

Cutting along curved contours. When cutting along curved contours, the hacksaw blade is ground down to a width of 8-10 mm and secured in a frame, having first given it the same lateral position as when making deep cuts (Fig. 115, c). Jigsaw files are also used.

To cut a shaped window (hole) in a metal (sheet), holes are drilled or cut out with a diameter equal to the width of the hacksaw or jigsaw blade. Having passed the canvas through such a hole, they fix it in a frame and cut it in a given direction.

Slots of larger sizes are cut with ordinary hacksaws with one or two blades interlocked together (depending on the width of the slots).

>>Technology: Cutting metal with a hacksaw

Billets from long products are cut with a hacksaw (Fig. 67). The main parts of the hacksaw are the one-piece frame 2 (it can also be detachable, as in Fig. 68), the hacksaw blade 4 and the shank with handle 6.
A hacksaw blade is a thin strip of tool steel with two holes at the ends. On one or two edges of the blade, teeth are cut that are inclined in one direction. The hacksaw blade is attached to the frame with pins 7 and tensioned with a tension nut 1. In this case, the teeth should be directed in the direction opposite to the handle. The tension on the hacksaw blade should not be very strong or very weak, as this may cause it to break.

♦ Handsaw, frame, hacksaw blade, shank, mechanical hacksaw.

1. What is the difference between sawing with a carpenter's hacksaw and cutting with a bench saw? What are their similarities?

2. List the safety rules when working with a hacksaw.

3. What are the main parts of a hacksaw?

4. For what purpose is a cut made on the workpiece at the cutting site with a triangular file?

5. Why do you need to release the pressure on the hacksaw at the end of cutting the workpiece?

6. How to cut a long piece?

Simonenko V.D., Samorodsky P.S., Tishchenko A.T., Technology 6th grade

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1. Before starting work, you must check the correct installation and tension of the blade.

2. Marking of the cutting line must be done along the entire perimeter of the rod (strip, part) with an allowance for subsequent processing of 1... 2 mm.

3. The workpiece should be firmly secured in a vice.

4. Strip and corner material should be cut along the widest part.

5. If the length of the cut on a part exceeds the size from the blade to the frame of the hacksaw machine, cutting must be done with a blade fixed perpendicular to the plane of the hacksaw machine (a hacksaw with a rotated blade).

6. Sheet material should be cut directly with a hacksaw if its thickness is greater than the distance between the three teeth of the hacksaw blade. Thinner material to be cut must be clamped in a vice between wooden blocks and cut together with them.

7. Gas or water pipe must be cut, securing it in a pipe clamp. When cutting, thin-walled pipes should be secured in a vice using profile wooden spacers.

8. When cutting, the following requirements must be observed:

At the beginning of cutting, tilt the hacksaw away from you by 10... 15°;

When cutting, keep the hacksaw blade in a horizontal position;

In work, use at least three quarters of the length of the hacksaw blade;

Make working movements smoothly, without jerking, approximately 40...50 double strokes per minute;

At the end of cutting, release the pressure on the hacksaw and support the cut part with your hand.

9. When checking the size of the cut part according to the drawing, the deviation of the cut from the marking mark should not exceed 1 mm upward.

Labor safety rules

1. It is forbidden to cut with the blade tensioned too loosely or too tightly, as this can lead to blade breakage and injury to your hands.

2. To avoid breaking the blade and injuring your hands when cutting, do not press the hacksaw down too hard.

4. When assembling a hacksaw, you should use pins that fit tightly into the holes in the heads without swaying.

5. If the teeth of the hacksaw blade crumble, stop work and replace the blade with a new one.

6. To avoid the handle coming off and injuring your hands during the working movement of the hacksaw, do not hit the front end of the handle on the part being cut.

Basic rules for cutting sheet metal up to 0.7 mm thick with hand scissors

1. When marking the cut part, it is necessary to provide an allowance of up to 0.5 mm for subsequent processing.

2. Cutting should be done with sharpened scissors wearing gloves.

3. Place the sheet to be cut strictly perpendicular to the blades of the scissors.

4. At the end of the cut, the scissors should not be pulled back completely to avoid tearing the metal.

5. It is necessary to monitor the condition of the scissors-screw axis. If the scissors begin to “punch” the metal, you need to slightly tighten the screw.

6. When cutting material with a thickness of more than 0.5 mm (or when it is difficult to press the handles of the scissors), one of the handles must be firmly secured in a vice.

7. When cutting out a part of a curved shape, for example a circle, you must follow the following sequence of actions:

Mark the contour of the part and cut the workpiece with a straight cut with an allowance of 5... 6 mm;

Cut the part according to the markings, turning the workpiece clockwise.

8. Cutting should be done exactly along the marking line (deviations are allowed no more than 0.5 mm). The maximum amount of “overcut” in the corners should not be more than 0.5 mm.

Basic rules for cutting sheet metal and

strip material using lever shears

1. Cutting must be done with gloves to avoid cutting your hands.

2. Cutting sheet material of significant size (more than 0.5 × 0.5 m) should be done by two people (one should support the sheet and move it in the direction “away” along the lower knife, the other should press the scissors lever).

3. During operation, the material to be cut (sheet, strip) must be positioned strictly perpendicular to the plane of the movable knife.

4. At the end of each cut, the knives should not be brought to full compression in order to avoid “tearing” the material being cut.

5. After finishing work, you need to secure the scissor lever with a locking pin in the lower position.

Basic rules for cutting pipes with a pipe cutter

1. The cutting line should be marked with chalk along the entire perimeter of the pipe.

2. The pipe must be firmly secured in a pipe clamp or vice. Fastening the pipe in a vice should be done using profile wooden spacers. The cutting location should be located no further than 80... 100 mm from the clamping jaws or vice.

3. During the cutting process, the following requirements must be observed:

Lubricate the cutting area;

Make sure that the pipe cutter handle is perpendicular to the pipe axis;

Carefully ensure that cutting discs were located exactly, without distortion, along the cutting line;

Do not apply much force when rotating the screw of the pipe cutter handle to feed the cutting discs;

At the end of the cut, support the pipe cutter with both hands; Make sure that the cut piece of pipe does not fall on your feet.

Power tools and cutting equipment

metals

Mechanization of work when cutting materials is carried out in two ways: using a mechanized hand tools and through the use of stationary equipment.

Hand powered tools

Mechanical hacksaw(Fig. 2.62) is effective when cutting materials at the mechanic’s workplace. It consists of housing 2, which houses the electric motor. A drum 7 is installed on the motor shaft, into a spiral groove of which a finger 3 fits, connected to a slider 4. A hacksaw blade 6 is mounted on the slider. When the drum rotates, the hacksaw blade receives a reciprocating motion and cuts the metal. During operation, the hacksaw is supported by bracket 5 and supported by the handle.

Manual electric vibration shears(Fig. 2.63) provide cutting of sheet steel up to 2.7 mm thick. They consist of a housing 3, in which an electric motor is mounted, and a knife head housing 2. The motor drives the eccentric roller 1 through a worm pair. The connecting rod 9 is mounted with its head on the eccentric roller 7, and the lower head is connected to the pin 8 of the upper knife lever b. The lower knife 5 is attached to the bracket 4. During operation, the connecting rod 9, performing a reciprocating movement, causes the knife lever 7 to swing with the upper knife 6, ensuring metal cutting. The gap between the knives is adjusted by moving bracket 4 in the cutter head housing. The size of this gap depends on the thickness of the material being cut.

While working, you need to take the correct working posture and hold the hacksaw with both hands (Fig. 68). When the hacksaw moves forward (working stroke), the teeth cut metal, and when reverse movement (idling) do not cut. Therefore, during the working stroke, you need to move the hacksaw with light pressure on the workpiece, and when idle, without pressure.

The hacksaw should be moved along the workpiece in such a way that the entire length of the hacksaw blade is involved in cutting. In this case, the wear of the blade will be uniform along the entire length and the blade will last longer.

If the workpiece is long and the frame rests against its end, then the hacksaw blade is turned 90° relative to the frame and work continues

At enterprises, long products are cut using mechanical hacksaws, circular saws or band saws.

Safety regulations

• 4. When finishing cutting, it is necessary to ease the pressure on the hacksaw and support the part of the workpiece that we are cutting off.
• 1. Mark the template blanks to control the angles of the device for making rivets and other parts.

Billets from rolled products are cut by a mechanic. The main parts of a hacksaw are a one-piece frame (it can also be detachable).

It is easier to cut strip metal on the narrow side. However, the thickness of the strip should not be less distance between three teeth of the blade, otherwise the teeth will break. If the thickness of the workpiece is less than this distance, then it is secured in a vice between two wooden blocks and then cut.

If the workpiece is long and the frame rests on its end, then the hacksaw blade is turned 90° relative to the frame and work continues.

At enterprises, long products or band saws are cut using mechanical

When cutting hard materials, the pressure on the hacksaw should be strong, when cutting soft materials, strips, pipes - small. Before the end of cutting, the force is reduced in all cases. When cutting, the hacksaw moves horizontally to avoid sliding; when cutting, the hacksaw is tilted away from itself.

Strip metal with a thickness of over 3 mm is cut along a narrow edge, and with a smaller thickness - along a wide edge. When cutting wide surfaces, the hacksaw is successively tilted away from you and towards you.

Thin sheets are clamped between two wooden blocks and cut along with them. When cutting long strips from a sheet, the blade is turned 90° and the hacksaw is held horizontally.

Shaped blanks (parts) and slots are cut out with jigsaws or hacksaw blades ground to a width of 8-10 mm.

Bar material is cut in the same way as strip material. If the cut site is processed, then it is allowed to cut the workpiece from several sides and then break it off.

Manual cutting with a hacksaw is usually done without cooling. To reduce friction, the blade can be lubricated with mineral oil.

When moving the hacksaw blade to the side, you should not try to correct the position by turning the hacksaw, as this will break the blade. In this case, cutting must be started in a new place.

You cannot cut with a blade with broken teeth; it must be replaced or 2-3 teeth adjacent to the broken one must be ground off. When cutting continues with a new blade, it begins in a new place, since the worn blade produces a cut of less width.

Safety regulations

• 1. Securely secure the workpiece in a vice.
• 2. Work smoothly, without jerking.
• 3. The hacksaw handle must be in good working order and fit tightly onto the shank.
• 4. When finishing cutting, it is necessary to ease the pressure on the hacksaw and support the part of the workpiece that we are cutting off
• 5. Do not sweep away shavings by hand. You need to use a special brush.

A hacksaw blade is a thin strip of tool steel with two holes at the ends. On one or two edges of the blade, teeth are cut that are inclined in one direction. The hacksaw blade is attached to the frame with pins 7 and tensioned with a tension nut 1. In this case, the teeth should be directed in the direction opposite to the handle. The tension on the hacksaw blade should not be very strong or very weak, as this may cause it to break.

The workpiece is firmly secured in a vice and a small cut is made at the cutting site with a triangular file so that the blade does not slide over its surface. The cutting site is located at a distance of 10... 15 mm from the edge of the jaws.

During work, you need to take the correct working position and hold the hacksaw with both hands. When the hacksaw moves forward (working stroke), the teeth cut metal, and when moving backwards

Cut sheet metal into separate parts, cut holes in parts, produce parts with a curved contour and perform other similar works Can be done with hand scissors. Depending on location cutting edge The blades of the scissors (to the right or left of the lower blade) are called right (Fig. 47, a) or left (Fig. 47, b). Hand scissors are made with straight (and curved) cutting blades.

Hand scissors with straight cutting blades are used for cutting sheets, strips and strips of steel up to 0.7 mm thick, and non-ferrous metals up to 1.5 mm thick along straight lines. Scissors with curved cutting blades are used when cutting sheets, strips and tapes from steel up to 0.6 mm thick, and from non-ferrous metals up to 1.2 mm thick along curved lines or when cutting out parts with a combination of curves and straight lines.

Hand scissors are manufactured in lengths of 200, 250, 320 and 400 mm; while the width along the outer circumference of the handles is closed position respectively, the total length is 40, 40, 50, 55 mm.

Scissors consist of two halves, which are made in one piece or in parts with welded blades. Solid halves of scissors are made of carbon steel 65, 70. Handles of welded scissors are made of carbon steel not lower than grade St. 2, and the blades are made of tool carbon steel U7 with heat treatment them up to a hardness of HRC 52--58. The cutting edges of the blades are sharpened sharply at an angle of 70-75° and the blades and surfaces of the scissors should be free of blockages, snatches, crumbled places, burrs, shells, caps, hairlines, nicks and cracks.

The blades of the scissors should overlap each other when closed, and the overlap at the ends should not exceed 2 mm. Both halves must be connected using a screw and nut and ensure a tight fit of the halves without distortions or play. Scissors should cut with any part of the cutting edges; in this case, their STROKE should be smooth without jamming.

The lower knife is straight and the upper one is curved towards the cutting edge. The lower knife is equipped with a special flange, thanks to which the part of the sheet being cut is bent and the scissors freely pass along the marking line along the entire sheet to be cut. Thanks to this shape of the knives, cutting with these scissors is carried out with less effort. These scissors have handles located at an angle of 30° to the cutting plane, which eliminates the possibility of cutting your hands. These shears cut sheet metal in half the time than regular hand shears.

Sheet metal is cut with hand scissors, usually according to pre-marked surfaces. sheet metal Marking lines do not cut idle speed. Therefore, during the working stroke, you need to move the hacksaw with light pressure on the workpiece, and when idle, without pressure. The hacksaw should be moved along the workpiece in such a way that the entire length of the hacksaw blade is involved in cutting. In this case, the wear of the blade will be uniform along the entire length and the blade will last longer

It is easier to cut strip metal on the narrow side. However, the thickness of the strip should not be less than the distance between the three teeth of the blade, otherwise the teeth will break. If the thickness of the workpiece is less than this distance, then it is secured in a vice. If the workpiece is long and the frame rests against its end, then the hacksaw blade is turned 90° relative to the frame and work continues between two wooden blocks and then cut

At enterprises, long products are cut using mechanical hacksaws 0), circular saws or band saws.

When cutting metal, you must follow the following safety rules:

• 1) secure firmly and correctly hacksaw blades, since if the fastening is weak, the canvas may jump out of the frame, and if it is tightly stretched, it may burst, as a result of which the worker may be injured;
• 2) firmly and securely fasten the part to be cut in a vice, since if it is not fastened well, it may fall on the worker’s feet;
• 3) you cannot use a hacksaw without a handle or with a cracked handle;
• 4) at the end of cutting, reduce the pressure on the hacksaw and support the part being cut so that it does not fall on your feet;
• 5) do not blow shavings out of the sawn area, as shavings may get into your eyes;
• 6) systematically remove scraps and blanks from the workplace;
• 7) workplace must be clean, there must be no oil on it;
• 8) there should be a box for scraps at the workplace, convenient for transporting it on an electric car;
• 9) the material intended for cutting should be placed on the side of the cutter.

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