Presentation description for individual slides:
1 slide
Description of the slide:
Technology for the processing of structural materials METAL CUTTING BY HANDMADE KNIVES 6th grade Compiled by technology teacher GBOU SOSH №323 ZOU TO Moscow Seliverstov Yu.I. Honored Teacher of the Russian Federation Moscow 2014
2 slide
Description of the slide:
Theme of employment. Metal cutting with a manual bench saw. Goal. Teaching: - introduce students to the device hacksaw and the technological process of metal cutting; - teach techniques for assembling a hacksaw machine. Developing: - the formation of working skills with a manual hacksaw when cutting long products (square and round bars, pipes); - development of the “ability to learn,” to use knowledge, skills and abilities in the educational process. Educational: - to educate students hard work, respect for the instrument, materials; accuracy and attentiveness in work; responsibility for the results of their activities; vigilance in compliance with labor safety requirements. The task of the lesson: to teach the initial (primary) skills of working with a manual bench saw, the ability to install a hacksaw blade in the frame of a hacksaw. Equipment: bench work bench, vise, bench saws, square billets, trihedral files, benchmark, scriber, oiler, hacksaw, drawing of a marking hammer. Reference knowledge: wood cutting with a joiner's hacksaw, metal marking. Object of work: blank for a marking hammer.
3 slide
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4 slide
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High-quality rolled metal products are called rolling mills in the form of semi-finished products to be further processed to obtain finished products
5 slide
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How are sections of long products divided? Where is the rental of various profiles used?
6 slide
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The following sections of long products are distinguished: simple (circle, square, hexagon, strip, sheet), shaped (rail. Beam, channel, Tauri, etc.), special (reinforcing steel, wheels, etc.). Long products are used as blanks in the manufacture of various parts in the machine-building and machine-tool industry, in construction, etc.
7 slide
Description of the slide:
What is the basis of any cutting tool? What is the name of a saw blade? Why do they set the teeth on hacksaw blades?
8 slide
Description of the slide:
At the heart of any cutting tool is the WEDGE. The cutter of a joiner's hacksaw is called a TOOTH. The wiring of the teeth on the hacksaw blade is made so that the blade does not jam in the cut, to reduce friction when sawing against the walls of the cut.
9 slide
Description of the slide:
For cutting thick sheet metal, strip, round and profile metal, as well as for cutting grooves, slots in the screw heads, cutting the workpiece along the contour (with machining allowance), a manual bench saw is used. Cutting metal with a manual bench saw is the most common locksmith operation. A manual bench saw consists of two main parts: a hacksaw machine (frame) and a hacksaw blade. a b Manual bench saws: a - with a one-piece machine; b - a universal bench saw with a sliding machine: 1 - a shank with a handle; 2 - frame (machine); 3 - a device for lengthening the frame (clip); 4 - a tightening screw; 5 - wing nut; 6 - hacksaw blade; 7 -
10 slide
Description of the slide:
Hacksaw blade - a thin narrow steel plate with teeth on one or two ribs is made of tool alloy steel P9, P18, X6VF. Web thickness is 0.65 and 0.8 mm. To reduce friction, the teeth of the blade (during manufacture) are bred by 0.25-0.5 mm. When sawing, the blade is lubricated with machine oil to reduce friction. The hacksaw blade is attached to the frame with pins. They pull the canvas, without much effort, screw the wing nut on the tension screw without resorting to pliers, a vise and other tools. The teeth of the hacksaw should be directed towards the tensioning screw, i.e. to the side opposite the handle. The web tension should not be very strong or very weak, as this can lead to breakage.
11 slide
Description of the slide:
When cutting workpieces, they are firmly fixed in a vice, a small cut is made in the place of cutting with a three-sided file so that the blade does not slip on its surface. Place the cutting position as close as possible to the vise, approximately 10 ... 15 mm from the edge of the jaws of the vise. Standing near the vise when cutting with a hacksaw should be straight, free and stable, half-turn with respect to the jaws of the vise. The left (supporting) leg must be put forward. The correct working position and grip of the tool helps to achieve high performance with less fatigue.
12 slide
Description of the slide:
During operation, the hacksaw must be kept level, holding it with both hands, i.e. perpendicular to the jaws of the vise, so that an oblique incision is not obtained. The hacksaw is moved only by hand, and the body remains stationary. This saves energy and ensures high quality work. Move the hacksaw smoothly, without jerking and in such a way that all the teeth of the blade participate in the cutting. In this case, the wear of the blade will be uniform over the entire length, and the blade will last longer .. They only press the workpiece forward, that is, during the working stroke. During the return stroke (idle), the hacksaw is slightly raised so that the teeth of the blade do not blunt. The pace of movement when cutting with a hacksaw should be 30-60 double (working plus idle) strokes per minute (0.5-1.0 strokes per second).
13 slide
Description of the slide:
The inclination of the blade is allowed from the plane to the edge of the workpiece. You cannot start sawing with a sharp rib. At the beginning of cutting strip and square rolled hacksaw tilt slightly forward. Gradually, the inclination is reduced and after the cut has reached the nearest edge of the workpiece, the hacksaw is returned to the horizontal position. Strip material can only be cut if three or more teeth of a hacksaw blade are laid on its thickness.
14 slide
Description of the slide:
● When cutting long workpieces, it is not always possible to finish cutting due to the fact that the frame of the machine abuts against their end. Then the canvas is rotated in relation to the frame by 90⁰ and continue to work. ● Finer material is fastened between the wooden blocks. Such preforms are collected in a bag, i.e. put a few pieces together and fasten in a vice.
15 slide
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Methods of cutting blanks of circular cross section: a - the beginning of cutting; b - cutting process. Cutting square and hexagonal workpieces.
16 slide
Description of the slide:
For cutting pipes choose a canvas with a small tooth. To avoid crushing, it is clamped in gaskets. They make a cut with a triangular file at risk and start cutting. The pace of movement should be 35-45 strokes per minute with a small pressure on the hacksaw. Having cut the pipe to the wall thickness, it is turned off by 45-60 ° and continue cutting, combining the rotation of the pipe with cutting along the entire length of the pipe circumference. Pipe cutting Slots and grooves slotted
17 slide
Description of the slide:
Possible rejection when sawing with a bench saw 1. If improperly fixed, poor tension on the blade and strong pressure on the blade during sawing, an oblique incision is obtained and the blade may break. 2. If the layout is incorrect or inattentive, the specified dimensions are not obtained after cutting the workpiece. 3. If the workpiece is not properly secured in a vice (without mouthpieces or gaskets), its surface is damaged.
18 slide
Description of the slide:
Observe safety precautions when sawing 1. The blade should be well tensioned. 2. The workpiece must be well secured. 3. You need to cut evenly without jerking. 4. It is necessary to very carefully continue sawing with a new blade in the unfinished cut (jamming and breakage of the blade is possible). 5. When sawing, use the entire length of the blade. 6. When cutting workpieces with edges and sharp edges, observe the following rule: cutting should go from the plane to the edge so as not to crush the teeth of the blade. 7. In order not to damage the workpiece with the hardened jaws of the vice, you need to use the mouthpiece.
19 slide
Description of the slide:
General safety rules when cutting metal with a hacksaw. 1. Work only with a serviceable hacksaw, firmly fixed and properly stretched cloth. 2. The hacksaw handle must be firmly set in place, have a protective ring and not have cracks. 3. Instead of pins, do not fix the hacksaw blade with nails and screws. 4. You can’t work with a hacksaw, in the canvas of which there are painted teeth. 5. Support the cut-off part of the workpiece so that it does not fall and does not damage the legs. 6. Protect hands from injury by the teeth of the blade and the sharp edges of the workpieces. Put the hacksaw on the workbench with the canvas away from you or insert it vertically with the canvas down. 7. Sawdust at the end of work is removed with a brush-brush in a scoop. It is forbidden to blow away sawdust (they can get into the eye) and remove it with bare hands. REMEMBER! VIOLATIONS OF LABOR SAFETY RULES RESULT IN INJURY AND ACCIDENT.
20 slide
Description of the slide:
Test questions 1. What are the main parts of a bench saw? 2. Why make a hacksaw machine extendable? 3. What is a hacksaw blade? 4. How is the hacksaw blade fixed in the hacksaw? 5. for what and how is the wiring of the teeth of the hacksaw blade done? 6. How to install a hacksaw blade in a hacksaw? 7. Why is it necessary to tightly tighten the hacksaw blade in the machine? 8. Why is the hacksaw blade set with teeth pointing in the direction opposite to the handle? 9. How to fix the workpiece when cutting with a hacksaw? 10. How to hold a hacksaw when cutting? 11. What is the hacksaw stroke called a worker? 12. In what cases does the hacksaw blade turn at right angles to the hacksaw? 13. How to cut workpieces with edges or sharp edges?
21 slide
Description of the slide:
Test your knowledge of the topic “Locksmith Hacksaw” 1. The hacksaw is made extendable in order to: a - make it convenient to store; b - it was convenient to store and transport; c - it was convenient to assemble and disassemble; g - in a hacksaw it was possible to fix the blade of different lengths. 2. The canvas in the machine can be rotated: a - 90 degrees; b - 180 degrees; in - by 45 degrees; reversed. 3. The teeth of the canvas (during manufacture) are bred on: a - 0.65 mm; b -1-2 web thickness; in - 0.25 - 0.5 mm; g - 0.25 - 0.5 cm. 4. Lubricate the canvas with machine oil: a - so as not to rust; b - to make it convenient to store; in - to reduce friction; g - they are covered with paper. 5. The teeth of the blade are painted: a - if the saw is not the full length of the blade; b - if sawing from an edge to a plane; c - if sawing is not even; g - if you saw with a poorly stretched blade. 6. When sawing, an oblique incision is obtained if: a - strongly press the blade; b - incorrectly fix the workpiece in a vice; c - incorrectly mark the workpiece; g - to be inattentive.
22 slide
Description of the slide:
To be continued. 7. The specified dimensions are not obtained after cutting the workpiece with: a - strong pressure on the canvas; b - improper fastening of the workpiece in a vise; in - improper fastening of the canvas; g - inattention or incorrect markup. 8. The surface of the workpiece is damaged when: a - with strong pressure on the canvas; b - improper fastening of the workpiece in a vise; in - carelessness and improper fixing of the canvas; g - inattention or incorrect markup. 9. Normal sawing speed: a - 30-60 double (working plus idle) hacksaw strokes per hour; b - 10-20 double (working plus idle) hacksaw strokes per minute; in - 0.5 - 1 double (working plus idle) hacksaw moves per second; g - 80 - 100 double (working plus idle) hacksaw strokes per minute. 10. During idling, the hacksaw is slightly raised so that: a - the teeth of the blade do not break; b - the teeth of the canvas were not blunted; c - increase the sawing speed; g - less tired.
23 slide
Description of the slide:
Practical work Metal cutting with a bench hacksaw. Object of work: the manufacture of blanks for prism collar for taps. 1. Read the drawing. 2. Prepare a hacksaw for work. 3. Clamp the workpiece (square steel with a cross section of 14 mm) in a vice. 4 Mark the workpiece in accordance with the drawing. 5. Give a processing allowance of 2 mm. 6. At the allowance distance, identify the risk with a three-sided file. 7. Take the correct stand and saw off the workpiece (number of 2 units). 8. Check the dimensions of the workpiece according to the drawing. In the course of work, observe the safety rules.
Metal cutting- the operation of dividing the metal into parts. Depending on the shape and size of the workpieces and parts, the cutting is carried out:
- - manually - with manual scissors, hacksaws, lever scissors and pipe cutters;
- - mechanically - using mechanical hacksaws, circular saws, abrasive wheels, etc.
The essence of the cutting process with scissors is the separation of metal parts under the pressure of a pair of cutting knives. The cut sheet is placed between the upper and lower knives. The upper knife, lowering, presses on the metal and cuts it. The great pressure experienced by the blades during cutting requires a large angle of sharpening of the cutting edge. The harder the metal, the greater the angle of sharpness of the blades: for soft metals it is 65 °, for metals of medium hardness - 70-75 ° and for hard - 80-85 °.
Cutting tools
Manual scissors used for cutting steel sheets with a thickness of 0.5-1.0 mm and non-ferrous metals - up to 1.5 mm.
Depending on the location of the cutting edges of the blade, the right and left scissors are distinguished. For the right scissors, the bevel of the cutting part of each half is on the right side, and for the left - on the left. Use the right scissors to cut along the left edge of the sheet in a clockwise direction so that the marking risk is always visible. Left-handed scissors are cut counterclockwise and the observation of the marking risk is complicated by the cut-off part of the metal. Left scissors are used to cut curved parts.
Manual lever scissors used for cutting sheet steel up to 4 mm thick, aluminum and brass up to 6 mm. The upper articulated knife is driven by a lever. The lower knife is motionless. Scissors provide a cut without dents, cuts along the edge and sufficient accuracy.
Hacksaw It is used for cutting thick sheets of strip, round and profile metal, as well as for cutting slots, grooves, trimming and cutting blanks along the contour and other works.
Hacksaw consists of a steel frame (machine) and a hacksaw blade fixed in shanks. One shank with a handle and a fixed head, the other has a movable head and a tension screw with a wing nut for tensioning the cutting blade.
Hacksaw blade (the cutting part of the hacksaw) is a thin and narrow steel plate with teeth on one of the ribs (sometimes on both). Each tooth of a hacksaw cloth has the form of a wedge (cutter). The chips should be placed in the space between two adjacent teeth (in the chip space) until the tip of the tooth comes out of the cut.
The tooth pitch is adopted, mm:
- - for soft and viscous metals (copper, brass) - 0.8-1;
- - for solid metals (steel, cast iron) - 1.25;
- - for mild steel - 1.6.
For locksmith work, they mainly use hacksaw blades with a pitch of 1.25 mm, in which there are about 20 teeth on the length of the blade.
Hacksaw cutting techniques.Marking is preliminarily applied to the workpiece at risk, then the workpiece is clamped in a bench vise in a horizontal position and a shallow cut is made with a triangular file on the marking risk for a better direction of the hacksaw blade. Pre-grease the canvas with oil.
Hacksaw cutting process consists of two moves:
- - the worker, when the hacksaw moves forward from the worker;
- - idle when the hacksaw moves back towards the working one.
When idling, the hacksaw is not pressed, as a result of which the teeth only slide, and when working, both hands create a slight pressure so that the hacksaw moves in a straight line.
At hacksaw The following rules must be followed:
- - for long cuts use a hacksaw blade with a large tooth pitch, and for short cuts - with a small pitch;
- - hacksaw blade should participate in the work along its entire length;
- - work with a hacksaw slowly, smoothly, without jerking, making no more than 30-60 double strokes per minute. At a faster pace, the web heats up and dulls faster;
- - before the end of the cut, weaken the pressure on the hacksaw to avoid damage to the blade;
- - when cutting, do not let the blade heat up, periodically lubricating it with mineral oil or graphite grease, especially when cutting viscous metals;
- - brass and bronze are cut only with new canvases, since even little-worn teeth do not cut these metals, but glide along their surface.
To start the cut correctly, place the thumb of the left hand with the fingernail at the place of the cut and place the hacksaw blade close to the nail, hold the hacksaw only with the right hand. The index finger of this hand is pulled along the hacksaw handle on the side. This ensures a stable position of the hacksaw during cutting.
The cut is made without breaking off the cut part. Breaking off is allowed if the ends of the workpiece will be subjected to further machining, for example filing.
SECTION: "Manual metal processing."
Subject: "Metal cutting with a bench saw".
Schoolchildren needed to make a large batch “Fixing Square”
for repairing window frames in an educational institution in a short time. At
in doing this work, students made each part individually, which
was a waste of time. Naturally, this did not suit them, since
labor productivity was very small, and accordingly by the deadline
they will not succeed. Children needed to solve this problem. Little
upon reflection, the guys realized how to avoid this problem and developed their plan
action.
Objective: to find out the causes of low labor productivity and its methods
increase.
Specification of the task:
What methods of work and fixtures on time sawing
use to increase labor productivity.
is necessary
Task context:
Select and study information on sawing methods, types of hacksaw
blades and sawing tools, as well as working techniques for
sawing various materials.
Additional Information.
For cutting sheet metal with a cross section over 3
5 mm, and also high-quality metal (round,
strip, corner, box, etc.)
apply hacksaws.
Manual pipe cutting
produced by hacksaw or pipe cutter. Varietal
larger metal is cut into
driven hacksaws
circular saws and
special machines.
A hacksaw consists of a frame called
sometimes with a machine tool (or beam) in which a hacksaw blade thin steel is fixed
stripe with teeth. Frames are solid and sliding. Sliding frames are more convenient
since they allow you to install hacksaw blades of various lengths.
At one end, the frame has a handle and
fixed rod with slot for
fastening hacksaw blade, and on
another slotted screw and nut
lamb for tension
hacksaw
Tension
hacksaw blade should not be
too tight or weak, as both
canvases.
another may damage the web.
Hacksaw blade - thin narrow steel plate with teeth on one or spirit
ribs. The teeth on the blade are bent to reduce friction during sawing. From properties
processed
material
envy the number and size of teeth
canvases.
Hacksaw blade length
i.e. distance between
hole centers, it’s 250,
300 and 350 mm, tape width from
12 to 25 mm with a thickness of from
0.5 to 1.6 mm
canvases
made with small and large teeth, used depending on the hardness and
viscosity of cut metals. The tooth pitch in hacksaw blades is about 0.8 to 1.6 mm,
the number of teeth per 25 mm length ranges from 14 to 32.
Hacksaw
Each of the teeth is a cutter, which for a normal hacksaw
the blade has a sharpening angle of 60 °, the rear angle of 30 °. Cloths clamped in the machine
so that the front surface of the tooth is directed forward from the worker.
To reduce the friction of the side walls of the hacksaw blade on the processed
the surface of the teeth is “bred,” that is, they bend every two teeth in different directions.
As a result, the groove (cut) formed during sawing is made wider than the hacksaw
canvas 0.25 0.6 mm. Hacksaw blades with a large tooth are bred through the tooth, i.e.
one tooth to the right, and the other to the left, in turn. On canvases with a small tooth do
wavy (corrugated) stain, in which 2 3 teeth are deflected to the right, 2 3 teeth
left, etc.
Hacksaw blades are made of tool carbon steel
U8, U10, U12 or alloy steels of tungsten and chromium. After manufacturing
the canvases they are thermally processed are hardened and tempered. Lower apiary
part of the fabric is quenched for high hardness, the upper for a minor, which
gives the canvas the necessary viscosity and strength, reducing the possibility of breakage in
work.
Sometimes hacksaws are made of mild steel (0.1 0.2% carbon) with
subsequent carburization (cementation) of the teeth for greater resistance against
abrasion of teeth.
Depending on the quality of the metal being cut, the shape and size of the product is selected
one or another number of teeth of a hacksaw blade. The harder the metal being cut, the harder
the shape of the product and its smaller size, the canvas is selected with a large number of teeth. AT
in these cases there is less risk of breaking small teeth.
The number of teeth per 25 mm of blade length should be as follows:
a) for soft metals (aluminum, brass, copper) 14 18 teeth,
b) for hard metals (bronze, cast iron, steel) 18 20 teeth,
c) for strip metal 22 24 teeth,
d) for thin sheet metal 24 32 teeth.
The thicker the cut product, that is, the longer the cut line, the larger should
be the teeth of a hacksaw blade.
Cutting metal with a hacksaw must be done in the following order.
Hold clamped material firmly in a vice so that it cannot
move,
swing or
springy. (a) right,
b) wrong).
To choose
hacksaw
the tooth’s largest canvas
according to cut
the material
(hardness,
size, shape).
Monitor the correct position of the body and legs of the worker; this position
is the same as during the operation of metal cutting. Keep a hacksaw while working
with both hands parallel to the cutting plane, move the hacksaw
smoothly, without jerking and without swinging. Normally, the hacksaw should be given such a swing that
at least 2/3 of the length of the hacksaw blade worked.
Marking risks are applied to the workpiece.
The edge of the file makes a recess.
When cutting metal, make sure that
marking lines remained unharmed. At work
the hacksaw is held with two hands. To reduce friction on
material to be cut the web is periodically lubricated
oil. The inclination of the web is allowed from plane to rib
blanks.
You cannot start sawing with a sharp rib.
It is necessary to maintain the cutting part at the end of sawing,
so that she does not fall to her feet. Possible marriage - not sawing
along the line of marking, due to carelessness or poorly
stretched fabric
To reduce the blunting of the teeth of the hacksaw blade,
you need to move the hacksaw forward from the worker (working stroke) with pressure and loosen
pressure during reverse (idle) stroke. To withstand the speed during manual cutting with a hacksaw
30 to 60 double strokes per minute.
Make sure that at least two three are in contact with the metal at the same time.
teeth. It is not recommended to start a metal cut with a sharp rib, it is so easy to break
the teeth. Before reaching the end of the cut, the pressure on the hacksaw should be reduced.
In case of breakage on the blade of one of two teeth, the following two should be ground on the sharpener
three teeth, align the defective place and use this blade further. it
protects the remaining teeth from breakage.
To cut using a hacksaw should be dry, without lubrication. When
the need to reduce the friction of the blade on the metal, you can apply grease,
consisting of fat or graphite ointment (two parts of fat and one part of graphite).
When cutting long narrow strips, put the hacksaw blade perpendicularly
hacksaw planes. Work carefully, without distorting the frame, but
therefore, and hacksaw blade.
When cutting metal for marking, the hacksaw should be guided along the risks. Line
the cut should be approximately 0.5 mm from the risks.
When dragging the canvas to the side (if it is skewed), work should be stopped and started
cut in a new place or on the other hand to prevent damage to the blade.
When cutting thin metal sheets or small tubes, it is recommended to clamp them
in a vice between wooden blocks (thin sheets of several pieces at once) and cut
metal with wooden blocks (fig. a).
When cutting pipes manually, they should be clamped horizontally between
wooden bibs (Fig. b).
Safety when cutting metals with a hacksaw
1. In order to avoid damage to the canvas and life injuries, it is necessary to correctly and
firmly fix the hacksaw blades in the frame of the hacksaw (not tight and not weak).
2. Correctly and reliably secure the cut material in a vice. At the end of cutting
keep the cut-off part of the product on weight, otherwise the workpiece may fall on its feet
working.
3. Correctly insert and fasten the blade into the frame (front surface of the tooth
should be directed forward) and monitors the health of the tool (do not work
hacksaw without a handle or with a cracked handle).
4. Do not blow off chips with your mouth, as it may get into your eyes. Clean chips
with a brush.
The task
1. Familiarize yourself with the hacksaw, its structure and the name of the individual parts.
2. Indicate the dependence of the size of the tooth (the number of teeth per 25 mm) on the hardness of the metal and
blank shapes.
3. Practically familiarize yourself with the correct installation and fastening of the hacksaw
blades in a frame of a hacksaw and fastening "* preparations in a vice. Almost familiar with
hacksaw metal cutting techniques.
4. Cut with a hacksaw according to the previously made marking of sheet, strip,
bar material, with allowances of 0.5-1.0 mm for further processing by filing.
Questions for self-control
1. How is a bench saw made?
2. What material is the hacksaw blade made of?
3. Why is the canvas oiled?
4. How will the sawing accurately match the marking risk?
5. What are the rules for working with a bench saw?
6. Why make a tooth teeth divorce?
7. What are the possible types of marriage when sawing and what are their causes?
8. What safety rules should be observed when sawing metals?
Literature:
1. Antonov L. P., Muravyov E. M. Processing structural materials. - M., 1982.
2. Handbook of labor training: A manual for students 5 - 7 cells. / Ed.
I. A. Karabanova
3. Technology. Textbook for students in grade 6 / Ed. V. D. Simonenko - M., 2002.
I Option
1. What does the woodworking industry do?
but). Forest protection
at). Lumber production
from). Felling a forest.
2. Details of rotation are usually shown in the drawings.
but). One main view
at). Main view and top view
from). The main view and the left view.
3. Each technological machine consists of at least three parts
but). Motor, spindle, feed
at). Engine, gear, actuator
from). Mechanisms of supply, management and control.
4. rental profile depends on
but). Roll diameter
at). Ingot temperatures
from). Roll Forms
5. With increasing humidity, hardness of wood
but). Is increasing
at). Decreases
from). Does not change
6. That the saw blade does not jam in the cut, produce
but). Tooth divorce
at). Tooth bend
from). Tooth extraction
7. A product made with the least cost of funds, material, time and
labor called
but). Strong
at). Technological
from). Economical
8. Cutting from workpieces of a small layer of metal with a file is
but). File cutting
at). Grinding
from). Filing
9. Annealing the workpiece reduces
but). Fragility
at). Hardness
from). Elasticity
10. the hole in the part into which the spike enters is called
but). Nest
at). Eye
from). Hollow
11. The main inscription of the assembly drawing, is located in
but). Top right
at). Bottom right
from). Bottom left
12. The angle of sharpening of the chisel when cutting steel should be equal
but). 60
at). 45
from). thirty
13. According to the chemical composition of the steel are divided into
but). Carbon and heat resistant
at). Carbon and structural
from). Carbon and alloy
14. The details of the gears that transmit the movement are called
but). Leading
at). Transmitting
from). Led
15. The property of wood to withstand certain loads without collapsing
but). Hardness
at). Strength
from). Elasticity
Presentation description for individual slides:
1 slide
Description of the slide:
2 slide
Description of the slide:
Plan Cutting metal Types of scissors Cutting pipes with a pipe cutter Cutting metal with a hacksaw Cutting techniques Safety rules Test questions
3 slide
Description of the slide:
Cutting is the separation of parts (billets) from high-quality or sheet metal. Metal cutting with scissors and pipe cutting
4 slide
Description of the slide:
Cutting is carried out both with chip removal and without it. Cutting with chip removal is carried out with a hacksaw, on hacksaw, large saws, turning and cutting machines. Without chip removal, materials are cut with manual lever and mechanical scissors, wire cutters, pipe cutters, and press shears.
5 slide
Description of the slide:
6 slide
Description of the slide:
Ordinary manual scissors are used for cutting steel sheets with a thickness of 0.5 ... 1 mm and sheets of non-ferrous metals with a thickness of up to 1.5 mm. Manual scissors are made with straight and curved cutting blades. The length of the scissors is 200, 250, 320, 360 and 400 mm, and the cutting part is 55 ... 65, 70 ... 82, 90 ... 105, 100 ... 120 and 110 ... 130 mm, respectively. Well-sharpened and adjusted scissors should cut the paper. Manual scissors
7 slide
Description of the slide:
Scissors with straight blades The essence of the scissors cutting process is to separate the metal parts under the action of a pair of cutting knives. The cut sheet is placed between the upper and lower knives. The upper knife, lowering, presses on the metal and cuts it.
8 slide
Description of the slide:
Scissors with curved blades Holding the sheet with your left hand, feed it between the cutting edges, directing the upper blade exactly in the middle of the marking line, which should be visible when cutting. Then, squeezing the handle with all the fingers of the right hand, except for the little finger, carry out the cutting.
9 slide
Description of the slide:
Chair scissors Chair scissors differ from ordinary ones in large sizes and are used when cutting sheet metal up to 3 mm thick. The lower handle is rigidly clamped in a bench vise or mounted (driven) on a table or other rigid base. For cutting sheet steel up to 3 mm thick, scissors with stationary fastening are used
10 slide
Description of the slide:
Types of scissors Manual small-sized power scissors are used for cutting sheet steel up to 2.5 mm thick and rods up to 8 mm in diameter. Lever shears are used to cut sheet steel up to 4 mm thick, aluminum and brass up to 6 mm. Fly scissors are widely used for cutting sheet metal 1.5 ... 2.5 mm thick Scissors with inclined knives (guillotine) allow you to cut sheet metal up to 32 mm thick
11 slide
Description of the slide:
Pipe cutting with a pipe cutter Cutting with a pipe cutter is much more productive. Pipe Handle Screw Movable roller Pipe cutter handle Pipe cutter Clamp Cutting is carried out as follows. At the pipe cutter installed on the pipe, turn the handle by ¼ turn, pressing the movable roller to the pipe surface so that the marking line coincides with the sharp edges of the rollers. Lubricate the cut point with oil to cool the cutting edges of the rollers. The pipe cutter is rotated around the pipe, moving the movable roller until the pipe walls are completely cut through.
12 slide
Description of the slide:
Electric shears Electric motor handle Switch Reducer Bracket Upper knife Eccentric Lower knife
13 slide
Description of the slide:
Manual hacksaw (saw) - a tool designed for cutting thick sheets of strip, round and profile metal, as well as for cutting slots, grooves, trimming and cutting workpieces along the contour and other works. Hacksaw metal cutting
14 slide
Description of the slide:
Elements of a hacksaw blade A hacksaw blade is a thin and narrow steel plate with two holes and with teeth on one of the edges. Back surface Front surface Positive Equal to zero Negative
15 slide
Description of the slide:
Manual hacksaw 1. shank with handle 2. Frame (machine) 3. Fixed head 4. Hacksaw blade 5. Movable head 6. Nut - knob 7. Device for lengthening the frame
16 slide
Description of the slide:
Reception of cutting Do not extend the index finger along the handle and grasp the handle deeply, as the end of it will come out of the brush, which can lead to injury to the hand when working. Hold the hacksaw frame with your left hand. With four fingers to cover the lamb and the tension bolt, and on one frame, if done differently, it will be difficult to eliminate the swaying of the hacksaw during operation. The hacksaw handle is captured with the fingers of the right hand (the thumb is laid on top, the remaining fingers support the handle from the bottom), the end of the handle rests on the palm of the hand.
17 slide
Description of the slide:
Thin sheet cutting. Sheet metal cutting is carried out in the following sequence. Prepare wooden blocks (flat). Clamp one or more pieces of blanks between flat wooden blocks. Set the bars together with the workpieces in a bench vise. Cut the workpieces with the bars
18 slide
Description of the slide:
Setting the blade with a shallow cut When cutting soft metal, hacksaw blades with a large pitch (16-18 teeth per 1 inch are used; for cutting thin strip metal - hacksaw blades with small teeth (22-23 teeth per 1 inch), and for cutting the thinnest sheet metal - 24-32 teeth per 1 inch. For locksmith work, they mainly use a hacksaw blade with a pitch of 1.5 mm, at which there are approximately 17 teeth on a length of 25 mm.
19 slide
Description of the slide:
The position of the blade with a deep cut The hacksaw with the blade rotated through an angle of 90 ° is cut when the depth of the cut exceeds the distance from the blade to the frame of the hacksaw, i.e. with deep breakthroughs. The blade is inserted into the slots of the shank so that in the working position the frame of the hacksaw blade is horizontal. The slot is located on the side or top of the jaws of the vice, depending on the configuration of the part.
20 slide
Description of the slide:
Work safety rules It is forbidden to perform cutting with a weakly or strongly tightened blade, as this can lead to damage to the canvas and injury to the hands; To avoid damage to the blade and injuring the hands when cutting, do not press the hacksaw down hard; Do not use a hacksaw with a chopped or loosely mounted handle; When assembling a hacksaw, pins should be used; When crushing the teeth of a hacksaw blade, stop work and replace the blade with a new one; In order to prevent the handle from slipping off and injuring the hands during the working movement of the hacksaw, do not strike the cutting part with the front end of the handle
21 slide
Description of the slide:
Test questions What methods of cutting metal do you know? What is the purpose of metal cutting? What rules must be followed when cutting metals with a bench saw? When is metal cutting necessary to turn the blade of a bench saw by 90 °? Why, when using a hand saw, is it necessary to ensure that at least two or three teeth participate in the cutting process? For what reasons can a breakage of a bench hacksaw blade occur and how can this be avoided? Why is it preferable to use a pipe cutter rather than a hacksaw when cutting pipes? What safety rules must be followed when cutting a pipe with a bench saw and a pipe cutter? What is the maximum thickness of the material can be cut with scissors: a - manual; 5-lever?
22 slide
Description of the slide:
Test questions What safety rules must be followed when cutting materials with hand scissors? Why, when cutting large sheets with vibrating scissors, should they be fed by moving the scissors? What role does the lubricant introduced into the cutting zone play when cutting pipes with a pipe cutter? What is the reason for the need to use mittens when cutting metal with scissors? What are the advantages of a sliding hacksaw over one-piece? Describe the assembly sequence of the hacksaw with a blade. Choose from the tools listed below those that can be used for cutting: a - sheet metal with a thickness of 1 ... 3 mm; b - steel wire; in - sheet metal with a thickness of 3 ... 5 mm; g - long products; d - steel sheets with a thickness of 25 ... 32 mm. Tools for cutting: 1 - manual scissors; 2 - chair scissors; 3 - lever scissors; 4 - guillotine shears; 5 - wire cutters Suggest a method of cutting sheet material with a thickness of 0.5 mm with a hacksaw and justify your choice Describe the sequence of work when cutting pipes with a pipe cutter
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Metal cutting with a bench saw
To cut blanks from long products, use manual bench saw.
Canvas bench hacksaw - a thin tape of solid steel, on one edge of which are applied teeth wedge-shaped. Each tooth represents cutter .
Hacksaw blade must be firmly secured in framed (see the figure on the right 5 ) tensioning screw (1 ), but teeth directed in the opposite direction pen (4 ).
Below you can watch a fragment of the film about the manufacture of locksmiths. The full version of the film can be downloaded and.
Getting started, you should adjust the tension of the blade in the hacksaw frame. To do this, insert one edge of the canvas into back head
(3
) and secure with a cotter pin. Insert the second edge of the blade into the cut. front head
(2
) and pull the canvas with wing screw
. Too much tension on the web, as well as too weak, can break it. According to the marking risk, a shallow cut is made with a trihedral file. This will ensure the exact direction of movement of the web. 
During work, you need to take the correct working position (see the figure on the left): stand half-turn to the vise, put your left foot forward and place your feet at an angle to each other.
The hacksaw is held with two hands during cutting. The position of the hands is shown in the figure below. The hacksaw is moved only by hand, and the body remains motionless. This saves energy and ensures high quality work.
A hacksaw can cut strip material only if three or more teeth of a hacksaw blade are laid on its thickness. 
More thin material is fastened between wooden blocks (see figure on the right). Thin workpieces are collected in bags, that is, they stack several pieces together and are fixed in a vice.
When cutting long workpieces it is not always possible to finish cutting due to the fact that the frame of the machine abuts against their end. Then the canvas is rotated in relation to the frame by 90 ° (see figure on the left) and continue to work.
Shaped blanks (corner, channel, etc.) when cutting with a hacksaw, it is recommended to fix in wooden bibs (see figure on the right).
At the beginning of cutting strip and square rolled hacksaw tilt slightly forward. Gradually, the inclination is reduced and after the cut has reached the nearest edge of the workpiece, the hacksaw is returned to the horizontal position.
Care must be taken to ensure that the risk marking is maintained. If you saw exactly according to the marking risk, then after sawing the size of the part will be less than that specified in the drawing, which will lead to irreparable marriage.
The hacksaw’s forward movement is working, since at this time the teeth of the blade cut metal, and the backward movement is idle. When the hacksaw moves 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 over the entire length. You need to move the hacksaw smoothly, without jerking, rhythmically. The speed 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 fixed in a vice.
Work with a hacksaw must be smooth, without jerking.
When finishing cutting, it is necessary to loosen the pressure on the hacksaw and hold the cut part from below.
Do not blow off chips and sweep it away with your hand. It is necessary to use a sweeping brush.
The illustration shows different versions of bench saws and various devices for sawing metal.