The main types of plumbing operations. Purpose and application Carrying out particularly complex metalwork operations

Markup.

Locksmith's workplace.

Topic 25. Basics of plumbing.

Questions:

1. locksmith work - this is the manual processing of materials, the fitting of parts, the assembly and repair of various mechanisms and machines.

workplace they call a part of the production area with all the equipment, tools and materials located on it, which are used by a worker or a team of workers to complete a production task.

The workplace should occupy the area necessary for the rational placement of equipment on it and the free movement of the locksmith during work. The distance from the workbench and racks to the locksmith should be such that he can use mainly the movement of his hands and, if possible, avoid turning and bending the body. The workplace should have good individual lighting.

locksmith workbench(Fig. 36) - the main equipment of the workplace. It is a stable metal or wooden table, the lid (tabletop) of which is made of boards 50 ... 60 mm thick of hardwood and covered with sheet iron. Single workbenches are the most convenient and common, since on multi-seat workbenches, when several people work at the same time, the quality of precision work is reduced.

Rice. 36 Single locksmith workbench:

1 - frame; 2 - countertop; 3 - vice; 4 - protective screen; 5 - tablet for drawings; 6 - lamp; 7 - shelf for tools; 8 - tablet for a working tool; 9 - boxes; 10 - shelves; 11 - seat

The workbench contains the tools necessary to complete the task. The drawings are placed on the tablet, and the measuring tools are placed on the shelves.

Under the tabletop of the workbench are drawers, divided into a number of cells for storing tools and documentation.

To fix the workpieces, a vise is installed on the workbench. Depending on the nature of the work, parallel, chair and hand vices are used. The most widespread are parallel swivel and non-swivel vices, in which the jaws remain parallel during divorce. The rotary part of the vise is connected to the base with a center bolt, around which it can be rotated at any angle and fixed in the required position with the help of a handle. To increase the service life of the vise, steel overhead sponges are attached to the working parts of the jaws. Chair vices are rarely used, only to perform work related to shock loading (when cutting, riveting, etc.). When processing small parts, use a hand vise.

The choice of the height of the vice according to the height of the worker and the rational placement of the tool on the workbench contribute to a better formation of skills, an increase in labor productivity and reduce fatigue.

When choosing the height of the installation of the vice, the left hand bent at the elbow is placed on the vise jaws so that the ends of the straightened fingers of the hand touch the chin. Tools and devices are arranged so that it is convenient to take them with the appropriate hand: what is taken with the right hand - hold on the right, what is taken with the left - on the left.

A protective screen made of metal mesh or durable plexiglass is installed on the workbench to retain pieces of metal that fly off during cutting.

Blanks, finished parts and fixtures are placed on racks installed in the area allotted for them.

2. markup - the operation of applying lines (rises) to the workpiece, defining (according to the drawing) the contours of the part and the places to be processed. Marking is used for individual and small-scale production.

Marking is carried out on marking plates cast from gray cast iron, aged and precisely machined.

Lines (risks) with a planar marking are applied with a scriber, with a spatial marking, with a scriber fixed in the thickness gauge collar. Scribers are made of steel grades U10 and U12, their working ends are hardened and sharpened sharply.

Kerner is intended for drawing recesses (cores) on previously marked lines. It is made from steel grades U7, U7A, U8 and U8A.

Marking compass is used to draw circles, divide angles and apply linear dimensions to the workpiece.

3. The main types of plumbing operations.

felling- a locksmith operation, during which excess metal layers are removed from the workpiece with a cutting and impact tool, grooves and grooves are cut out, or the workpiece is divided into parts. The cutting tool is a chisel, a cross-cutting tool, and a hammer is a percussion tool.

cutting is the operation of separating metals and other materials into parts. Depending on the shape and size of the blanks, cutting is carried out with a hand saw, hand or lever scissors.

Hand saw consists of a steel solid or sliding frame and a hacksaw blade, which is inserted into the slots of the heads and secured with pins. A handle is fixed on the shank of the fixed head. A movable head with a screw and a wing nut is used to tension the hacksaw blade. The cutting part of the hacksaw is a hacksaw blade (a narrow and thin plate with teeth on one of the ribs) made of steel grades U10A, 9XC, P9, P18 and hardened. Hacksaw blades are used with a length (distance between holes) of 250-300 mm. The teeth of the blade are spread (bend) so that the width of the cut is slightly greater than the thickness of the blade.

Metal dressing- an operation in which irregularities, dents, curvature, warpage, waviness and other defects in materials, workpieces and parts are eliminated. Editing in most cases is a preparatory operation. Straightening has the same purpose as straightening, but defects are corrected in hardened parts.

bending widely used to give blanks a certain shape in the manufacture of parts. For manual straightening and bending, correct plates, straightening headstocks, anvils, vices, mandrels, sledgehammers, metal and wooden hammers (mallets) and special devices are used.

Klepka- locksmith operation of joining two or more parts with rivets. Rivet connections are one-piece and are used in the manufacture of various metal structures.

The riveting is performed in a cold or hot (if the rivet diameter is more than 10 mm) state. The advantage of hot riveting is that the rod fills the holes in the parts to be joined better, and when cooled, the rivet pulls them together better. When riveting in a hot state, the diameter of the rivet should be 0.5 ... 1 mm smaller than the hole, and in a cold state, by 0.1 mm.

Manual riveting is performed with a hammer, its mass is chosen depending on the diameter of the rivet, for example, for rivets with a diameter of 3 ... 3.5 mm, a hammer weighing 200 g is required.

filing- a locksmith operation in which a layer of metal is cut from the surface of a part with files to obtain the required shape, size and surface roughness, to fit parts during assembly and prepare edges for welding.

Files are steel (steel grades U13, U13A; ShKh13 and 13Kh) hardened bars of various profiles with teeth cut on the working surfaces. The teeth of the file, having the shape of a sharpened wedge in cross section, cut off layers of metal in the form of chips (sawdust) from the workpiece.

Shabreniy the operation of scraping thin layers of metal from the surface of a part with a cutting tool is called - scraper. This is the final processing of precision surfaces (machine guides, control plates, plain bearings, etc.) to ensure tight mating. Scrapers are made of U10 and U12A steels, their cutting ends are hardened without tempering to a hardness of HRC 64...66.

Lapping and polishing– surface treatment operations with especially fine-grained abrasive materials using lapping.

These operations achieve not only the required shape, but also the highest accuracy (5 ... 6th grade), as well as the lowest surface roughness (up to 0.05 microns).

Fitting and assembly work- these are assembly and dismantling works performed during the assembly and repair of machines. Various connections of parts performed during the assembly of machines are divided into two main types: movable and fixed. When performing locksmith and assembly work, a variety of tools and devices are used: wrenches (simple, socket, sliding, etc.), screwdrivers, punches, pullers, devices for pressing and pressing out.

Many defects of machines entering repair enterprises are well studied and systematized in a typical repair technology. This technology has been developed for most tractors, combines and agricultural machines. It indicates the methods of restoring parts, the tool used for this, the specifications for the repaired parts. However, it is simply impossible to foresee all the cases that may occur in the practice of repair. Sometimes the necessary tool or material may not be available, sometimes it becomes possible to apply a simpler and more reliable repair method.

The repairman must be a generalist. In addition to the ability to perform all general plumbing operations, he must know the rules for the production of dismantling and assembly work, be well versed in the drawings of machine parts and assemblies, designations of tolerances and landings, know the basic mechanical properties of metals and other repair materials, have an idea about the repair process.

1.Technological repair process

The technological process of repairing a machine consists of a series of sequential operations that differ from one another in the nature of the work performed and the equipment used. However, many repair operations are similar to each other. For the production of the same type of technological operations at repair enterprises, special jobs are organized. They are equipped with machine tools, stands, fixtures, instruments and other equipment for disassembling, restoring parts and assembling machines and their components.

The main element of the technological process is an operation performed at one workplace and covering all the actions of the working (or working) and used equipment on one or more jointly processed, disassembled or assembled products. In addition to technological, in the repair industry there are also auxiliary operations: transport, washing, quality control, marking, etc. Technological operations are divided into transitions, passages and receptions.

The transition is a part of the operation, characterized by the invariance of the machined surface (or mating surfaces during assembly), the tool used and the operating modes of the equipment.

Pass - part of the transition, in which one layer of material is removed.

Reception is a complete set of individual movements of a person working in the process of performing an operation (for example, when drilling a hole in a product, the methods will be: fixing the product on the machine table, turning on cr.li ;, approaching the drill to the product, turning on the feed, turning off the feed, retracting the spindle, turning off machine, release of the product). The quality of repair operations is directly related to the qualifications of workers and the equipment of repair enterprises with equipment, fixtures and tools. A novice repairman must first of all study the tool that he will have to use and master the techniques for performing general locksmith operations.

1.1. Basic plumbing operations

The main general plumbing operations include: marking, cutting and cutting, straightening and bending, filing, drilling and reaming holes. Some of them, for example, marking products and drilling holes, the locksmith performs at specially equipped general workplaces for this purpose, and the rest at his individual workplace, where he also cuts threads, scrapes, and solders.

The rational organization of the locksmith's workplace allows to ensure the highest productivity, good quality and safe working conditions with the least expenditure of effort, time and money. It is important to properly equip the workplace and observe the established order on it once and for all.

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Basic plumbing operations - Other

Basic plumbing operations

EAT. Muravyov, Plumbing, Moscow, "Prosveshchenie" 1990, pp. 43-94

Basic plumbing operations

marking, cutting, straightening and bending of metals, cutting of metals, filing, drilling, countersinking, countersinking and reaming of holes, threading, riveting, lapping and finishing, soldering

Workplace - locksmith workbench

It is customary to call a workplace a certain section of the workshop, designed to perform certain work.

Rybins - removable wooden gratings installed on top of the deck.

A clamp is also called a screw clamp.

Chair vise.

Advantages - simplicity of a design and high durability. The disadvantage is that the working surfaces of the jaws are not parallel in all positions.

Rotary parallel vise.

The advantage is the possibility of a tighter clamping of the workpiece. In addition, you can fix at a certain angle.

A hand vise is used to secure small parts or workpieces that are inconvenient or dangerous to hold with your hands.

Marking tool

The operation of drawing small dots-depressions on the surface of a part is called. The point, axis of symmetry or plane from which all dimensions on the part are measured is called the marking base.

markup

The operation of drawing lines and dots on a workpiece intended for processing is called marking. The marking consists in drawing lines (rises) on the surface of the workpiece, which, according to the drawing, determine the contours of the part or the places to be processed.

Scribers are used to draw lines (marks) on the marked surface of the workpiece.

A center punch is used to apply recesses (cores) on pre-marked lines.

Marking (locksmith's) compasses are used for marking circles and arcs, dividing circles and segments into parts, and other geometric constructions when marking a workpiece.

Calipers

Caliper - a measuring (measuring) tool used in plumbing to remove and transfer the dimensions of a part to a scale

Goniometers

Used to measure angular values

Measuring tool

The measuring ruler is used for rough measurements

Straightening and bending

Editing - the operation of returning curved or bent metal products to their original straight or other shape. Giving the metal a certain configuration without changing its cross section and processing the metal by cutting is called flexible Bending of thin sheet metal is done with a mallet. For parts that are bent at right angles without rounding on the inside, the bending allowance of the workpiece should be 0.6 ... 0.8 of the metal thickness.

metal cutting

A percussion instrument consisting of a metal head, a handle and a wedge is called a hammer.

metal cutting

With the help of cutting, metal irregularities are removed (cut down) from the workpiece, hard crust, scale, sharp edges of the part are removed, grooves and grooves are cut, and sheet metal is cut into pieces.

For cutting profile (cutting) grooves (semicircular, dihedral, etc.), special crosscuts are used - groovers, which differ from each other in the shape of the cutting edge.

metal cutting

Hand shears - the simplest tool for cutting metal

Punches (notches)

Locksmith's tool, which is used for punching holes in sheet or strip metal or non-metal materials with a thickness of not more than 4 mm

Pipe cutters

Cutting steel pipes of relatively large diameters is a laborious operation, therefore special pipe cutters are used to perform it.

filing metal

Sawing - the process of removing the allowance with files, needle files and rasps

sharpening machine

Drilling, countersinking, countersinking and reaming

Drilling consists in obtaining and processing holes by cutting with the help of a special tool - a drill.

3e, the upper surfaces of the hole are machined in order to obtain chamfers or cylindrical recesses, for example, under a countersunk head of a screw or rivet.

Countersinking processes holes obtained by casting, stamping or drilling to give them a strict cylindrical shape, improve accuracy and surface quality.

scraping

The process of obtaining the accuracy of shapes, sizes and relative position of surfaces required by the working conditions to ensure their tight fit or tightness of the connection

Lapping

The removal of the thinnest layers of metal by means of fine-grained abrasive powders in a lubricating medium or diamond pastes applied to the surface of the tool is called.

To make accurate measurements, calipers are used. The caliper tools include a caliper, a caliper gauge, a caliper depth gauge, a caliper gauge.

There are three types of calipers: SC-I, SC-II, SC-III. The divisions marked on the bottom of the caliper slider are called vernier.

Linear measurements

Micrometers

Micrometer

A universal tool (device) designed for measuring linear dimensions by the absolute or relative contact method in the area of small sizes with a low error (from 2 microns to 50 microns, depending on the measured ranges and accuracy class), the converting mechanism of which is a screw-nut micropair.

Micrometer scale

Micrometer instruments allow measurements with an error of up to

0.01 mm (6.035)

Diametric expansion of the ends of the pipes to the outside in order to obtain a tight and strong press connection of the ends of the pipes with holes.

Soldering - the process of creating a permanent connection of metals using a filler binder

Tinning - coating the surface of metal products with a thin layer of tin or a tin-based alloy

Threading

Thread types

Metric thread - with a pitch and basic thread parameters in millimeters and a profile angle at the top of 60 °.

Inch thread - with basic thread parameters in inches, pitch in the number of threads per inch and a profile angle at the top of 55 °.

Pipe thread - with the main thread parameters in inches, a pitch in the number of threads per inch and a profile angle at the top of 55 °, designed to connect pipes, fittings and structural elements with pipe threads.

Dial indicator

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Basic plumbing operations.

Locksmith profession.

Locksmithing is commonly understood as work performed by hand and mechanized tools and completing the manufacture of most products through fitting and finishing work, connecting various parts into assembly units, kits and complexes and adjusting them.

Assembly fitters assemble various machines and mechanisms. Their maintenance and repair during operation is performed by repairmen. Locksmiths - toolmakers provide production with the necessary tools, facilitate and improve machining. Locksmiths for the installation of equipment, instruments, communications securely install them and the proper place, supply various types of energy and the main and auxiliary materials necessary for production. All these workers are united by the ability to perform various plumbing operations. This is what they learn in the general locksmith course.

The degree and type of professional training, the availability of knowledge, skills and abilities and the suitability to perform work of a certain content and complexity determine the qualifications of the worker. It is estimated by the tariff category, which is assigned to the worker by the qualification commission. The basis for this is the qualification characteristic given in special, tariff-qualification reference books. It states that the worker ʼʼshould be ableʼʼ and what ʼʼshould knowʼʼ in order to receive the appropriate wage category in his specialty.

Basic plumbing operations.

Consider the basic plumbing operations using the example of processing simple parts - a guide key (Fig. 1). Like wine from the drawing, the entire surface of the key is processed, it has three holes: two stepped mounting screws and one with a thread.

The key is made of keyed steel - a bar of rectangular section. To obtain a workpiece of the desired length, markings are made - lines are applied to the surface of the circle with a scriber that determine the shape and dimensions of the part. Next, a chisel (the operation is commonly called cutting) or a hacksaw (cutting) separates the workpiece. During the cutting process, the workpiece must be bent. She needs to be corrected. Often it is required to perform the opposite work: to bend a workpiece that has a complex shape. Then perform bending.

It is impossible to obtain the correct shape of the surfaces of the part and the specified dimensions with the listed operations. Οʜᴎ are preliminary, procurement. Their goal is to prepare the workpiece for further processing, to ensure and accelerate it by removing large layers of metal. To give the key the desired shape and size, the workpiece is cast. A hole ø 11 mm and for M10 thread is obtained by drilling, and a local expansion of the hole size up to ø 17 mm is drilled. The thread in the drilled hole is cut with a tap. When the hole must have exact dimensions, it is deployed. Except

considered, there are other operations: sawing and fitting - obtaining holes of complex shape and very precise processing of two parts to be joined; scraping and lapping - precise final operations that ensure high accuracy, tightness of joints; riveting, soldering and gluing are operations that allow you to connect parts together to form permanent joints.

As can be seen from the foregoing, all operations for the manufacture of any product must be performed in a certain

sequences. Together they make up the technological process of processing the part.

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Basic plumbing operations.

Locksmith department.

the date	watch	The content of the classes.	Material support.
		Theoretical part: General information: the importance of metalwork and metalwork and assembly work in the national economy. The concept of surface roughness and surface treatment. Sketches of products and blanks. Organization of the locksmith's workplace - typical equipment, working and measuring tools. Locksmith operations: marking, bending, cutting, cutting material. Practical part: Safety briefing. Preparation and equipment of the locksmith's workplace for this cycle of operations. Requirements for the working tool. The study of the elements of working drawings of products and blanks. Preparation of blanks for marking, straightening, straightening, bending, cutting, cutting blanks. Making hooks for hangers.	Locksmith's workplace. Journal of safety briefing. Files, calipers.
		Making a chisel.	Files, calipers.

Report in practice.

Locksmith's workplace equipment.

In metalwork workshops and on sites the equipment of individual and general use is located. Equipment for individual use are workbenches with vise. General use equipment includes: drilling and grinding machines, marking and checking plates, dressing plate, screw press, lever shears.

A vice is used to install and secure workpieces in a position convenient for processing.

The locksmith's working tool is divided into:

· Manual.

· Mechanized.

A typical set of hand tools for metalwork is divided into four groups:

1) cutting tool - files, hacksaws, chisels, drills, taps, dies, scrapers, reamers, abrasive tools;

2) auxiliary tool - hammers, cores, barbs, scribers, compasses, knobs, die holders;

3) fitting and assembly tools - wrenches, screwdrivers, pliers, hand vise, clamps, pullers;

4) measuring and control tools - rulers, calipers, calipers, calipers, micrometers, squares, goniometers.

Basic plumbing operations.

There are the following main plumbing operations:

Marking - drawing on the workpiece to be processed or the surface of the material, intended for the day the workpiece was received, marking lines.

Editing - irregularities, curvature, curvature, defects in the shape of blanks are eliminated.

Straightening - elimination of irregularities in the sheet or warping of the workpiece that has undergone hardening.

Bending - a workpiece or part of it is given a curved shape.

Cutting - removing an excess layer of metal or cutting a workpiece into pieces using a cutting tool.

Cutting.

Sawing - processing holes, grooves and grooves.

Fitting is the processing of one part according to the existing one in order to connect them.

Fitting - the exact mutual fit of parts.

Lapping - finishing of parts working in pairs to ensure the best contact of working surfaces,

Riveting - a type of assembly for the formation of an integral connection of two or more parts using rivets.

Soldering - a type of metalwork for the formation of a permanent connection using a molten intermediate material or alloy, called solder.

Tinning - coating the surface of metal parts with a thin layer of molten tin.

Thread cutting.

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Topic 1.1. The main operations of locksmith processing and their characteristics.

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Correlate the image with the type of processing and tool

Write your answer in the following form: 1-3-5

Topic 1.5. Tolerances and fits and technical measurements

Task 1 Name the main parts of the caliper

Fill the table

Task 2 Name the main parts of a micrometer

Fill the table

Task 3 Read the readings of the micrometer.

Task 4 Consider the schemes of tolerance fields. Determine the shaft tolerance, holes, type of fit.

	Tolerance field scheme		Hole tolerance		Shaft tolerance		fit type
1		1	0,052	1	0,040	1	with gap
2		2	0,046	2	0,019	2
3		3	0,030	3	0,032	3	Transitional
4		4	0,040	4	0,025	4	with interference

Topic 1.2. The main operations of locksmith processing and their characteristics.

Plumbing Test

Choose the correct answer

What is markup:

1. The operation of drawing lines and dots on the workpiece intended for processing

2. Operation to remove a layer of metal from the workpiece

3. The operation of applying a protective layer to the part. The operation of removing burrs from the part.

Choose the correct answer

Name the types of markup:

1. There are two types: straight and angled

2. There are two types: planar and spatial

3. There is one type: basic

4. There are three types: circular, square and parallel

Choose the correct answer

Name the tool used for marking:

1.File, needle file, rasp

2.Drill, countersink, countersink, countersink

3.Pipe cutter, hacksaw, scissors

4. Scriber, hammer, rectangle, center punch, marking compasses

Choose the correct answer

Name the measuring instruments used for marking:

1.Scale ruler, caliper, square, height gauge

2. Micrometer, indicator, thread template, probe

3. Scriber, hammer, rectangle, center punch, marking compasses

4. Mallet, trowel, sledgehammer, hammer with a round head

Choose the correct answer

On the basis of which the markup of the part is made:

1. Produced based on personal experience

2. Produce based on drawing

3. Produced based on the advice of a colleague

4. Produced on the basis of a defective part

Choose the correct answer

What is pinching:

1. This is an operation for applying points-recesses on the surface of the part

2.This is an operation to remove burrs from the surface of the part

3.This is a square hole sawing operation

4. This is an operation to straighten warped metal

Choose the correct answer

Tool used for cutting metal:

1.Applicable: tap, die, klupp

2.Applicable: center punch, scraper, countersink, mallet, trowel

3.Applicable: hacksaw, pipe cutter, metal shears

4.Applicable: metalwork chisel, chisel, groover, hammer

Choose the correct answer

What is metal straightening:

1. Operation to straighten bent or warped metal, only ductile materials are exposed

2. Operation to form a cylindrical hole in a solid material

3. Operation to form a threaded surface on the rod

4. Operation to remove a layer of metal from the workpiece in order to give the desired shape and size

Choose the correct answer

Name the methods of metal straightening:

1. Editing by twisting, breaking and extruding

2. Straightening by pressing, bending and crimping

3. Straightening by tightening, twisting and flaring

4.Editing by bending, pulling and smoothing

Choose the correct answer

Name the tools and fixtures used in editing:

1.Applicable: Parallel Vice, Chair Vice, Clamps

2.Applicable: stretching, crimping, support, chasing

3.Applicable: straightening plate, headstock, mallet, hammer, trowel.

4. Applicable: center punch, scraper, countersink, mallet, trowel

Choose the correct answer

What is metal cutting:

1. This is an operation related to the separation of materials into parts using a cutting tool

2. This is an operation, drawing marking lines on the surface of the workpiece

3. This is an operation to form a threaded surface inside the hole

4. This is an operation to form a thread on the surface of a metal rod

Choose the correct answer

Name a hand tool for metal cutting:

1. Chisel, cutter, groover

2.Hacksaw, hand shears, pipe cutter

3. Smoother, mallet, sledgehammer,

4. Reamer, countersink, countersink

Choose the correct answer

What is filing:

1. Operation to remove the broken saw from the cut on the surface of the workpiece

2. The operation of sawing the workpiece or part into pieces

3. Operation to remove a layer of metal from the surface of the workpiece using a cutting tool - a file

4. Operation to remove metal filings from the surface of the workpiece or part

Choose the correct answer

What tools are used for sawing?

1.Applicable: pliers, round nose pliers, wire cutters

2.Applicable to: round-faced hammer, square-headed hammer

3.Applicable: flat scraper, chisel, mallet

4.Applicable: files, needle files, rasps

Choose the correct answer

What are the types of file notches:

1. Triangular, pitted, square, oval

2.Linear, parallel, perpendicular, angular

3.Broach, shock, planed, persistent

4. Single, double cross, arc, rasp

Choose the correct answer

How many classes are files divided into depending on the number of notches per 10 mm of length:

1. Divided into 7 classes

2. Divided into 6 classes

3. Divided into 5 classes

4. Divided into 8 classes

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Name the cross-sectional shapes of the file:

1. Flat, square, trihedral, round, semicircular, rhombic, hacksaw

2. Oval, triangular, square, fork, straight, hexagon

3. Double-sided, three-sided, universal, specialized

4. Ordinary, professional, semi-professional

Choose the correct answer

What is drilling:

1. This is an operation for the formation of through or blind square holes in a solid material, using a cutting tool - a drill

2. This is an operation to form through or blind oval holes in a solid material, using a cutting tool - a drill

3. This is an operation to form through or blind triangular holes in a solid material, using a cutting tool - a drill

4. This is an operation for the formation of through or blind cylindrical holes in a solid material, using a cutting tool - a drill

Choose the correct answer

Name the types of drills:

1. Triangular, square, straight, angled

2. Hacksaw, manual, machine, machine-hand

3. Spiral, feather, centering, ring, rifle

4. Self-sharpening, basic, trapezoidal, thrust

Choose the correct answer

Name the types of shanks for a twist drill:

1. Oval and parallel

2. Cylindrical and conical

3. Semi-circular and outer

4. Special and regular

Choose the correct answer

What is a drill:

1. A cutting tool that cuts the workpiece into pieces

2. Cutting tool that forms cylindrical holes

3. Cutting tool used in soldering

4. Cutting tool for threading

Choose the correct answer

Name a manual drilling tool:

1. Drill, reamer, countersink, countersink

2. Bench drill, vertical drill, radial drill

3. Hand drill, brace, ratchet, electric and pneumatic drills

4. Lapping, scraper, frame, holder

Choose the correct answer

What is called stationary drilling equipment:

1. Such equipment is called equipment that is transferred from one workpiece or part to another.

2. Such equipment is called - equipment operating on electric current

3. Such equipment is called - equipment located in one place, while the workpiece being processed is delivered to it

4. Such equipment is called - equipment operating on compressed air

Choose the correct answer

Name the types of drilling machines:

1. Suspended, floor and diagonal

2. Desktop, vertical and radial

3. Screw-cutting, boring and slotting

4. Manual, machine and machine

Choose the correct answer

What is reaming:

1. This is an operation related to the processing of a previously drilled, stamped, cast and other hole in order to give it a more regular square shape, higher accuracy

2. This is an operation related to the processing of a previously drilled, stamped, cast and other hole in order to give it a more regular triangular shape, higher accuracy and higher roughness.

3. This is an operation related to the processing of a previously drilled, stamped, cast and other hole in order to give it a more regular oval shape, lower accuracy and lower roughness

4. This is an operation associated with the processing of a previously drilled, stamped, cast and other hole in order to give it a more regular geometric shape, higher accuracy and lower roughness

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Name the types of countersinks:

1. Pointed and blunt-nosed

2. Machine and manual

3. Stone and concrete

4. Solid and mounted

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What is deployed:

1. This is a threaded hole processing operation

2. It is an early-drilled hole processing operation with a high degree of accuracy.

3. It is a square hole machining operation with a high degree of precision

4. It is a taper hole machining operation with a high degree of precision

Choose the correct answer

Name the types of sweeps according to the method of use:

1. Main and auxiliary

2. Manual and machine

3. Machine and locksmith

4. Straight and tapered

Choose the correct answer

Name the types of sweeps according to the shape of the working part:

2. Rhombic and semicircular

3. Tetrahedral and trihedral

4. Straight and tapered

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Name the types of reamers according to processing accuracy:

1. Cylindrical and conical

2. Rough and finish

3. High-quality and low-quality

4. Manual and machine

Choose the correct answer

Name the thread profiles:

1. Triangular, rectangular, trapezoidal, thrust, round

2. Oval, parabolic, three-dimensional, overlap, scalloped

3. Semi-circular, mortise, heavy duty, anti-friction

4. Modular, segmented, tubular, countersunk

Choose the correct answer

Name the thread systems:

1. Centimeter, foot, battery

2. Gas, decimeter, calibrated

3. Metric, inch, pipe

4. Millimeter, water, gas

Choose the correct answer

Name the thread elements:

1. Tooth profile, outside corner, middle corner, inside corner

2. Profile angle, thread pitch, outer diameter, diameter, inner diameter

3. Tooth, modulus, outer radius, middle radius, inner radius

4. Tooth pitch, module angle, outer profile, middle profile, inner profile

Choose the correct answer

Name the tool for cutting internal threads:

1. Kreuzmeysel

Choose the correct answer

Name the external threading tool:

1. Countersink

2. Counterbore

Choose the correct answer

Name the types of plates:

1. Round, square (sliding), thread rolling

2. Hexagonal, spherical, face

3. Resistant, alloyed, hardened

4. Modular segment, profile

Choose the correct answer

What is sawing:

1. Variety of filing

2. Variety of lapping

3. Variety of scraping

4. Variety of fitting

Choose the correct answer

What is an attachment:

1. This is a locksmith operation for mutual adjustment of cutting methods for two mating parts

2. This is a locksmith operation for mutual adjustment by scraping two mating parts

3. This is a locksmith operation for mutual adjustment by grinding in two mating parts

4. This is a locksmith operation for mutual fitting by means of filing two mating parts

Choose the correct answer

What is scraping:

1. This is the final locksmith operation, which consists in scraping very thin layers of metal from the surface of the workpiece using a cutting tool - a lap

2. This is the final locksmith operation, which consists in scraping very thin layers of metal from the surface of the workpiece using a cutting tool - a scraper

3. This is the final locksmith operation, which consists in scraping very thin layers of metal from the surface of the workpiece using a cutting tool - a needle file

4. This is the final locksmith operation, which consists in scraping very thin layers of metal from the surface of the workpiece using a cutting tool - a rasp

Choose the correct answer

Name the types of scrapers according to the shape of the cutting edge:

1. One-sided, double-sided, three-sided

2. Flat, trihedral, shaped

3. Modular, profile, segment

4. Steel, cast iron, brass

Choose the right carrier

Name the types of scrapers by design:

1. Riveted and welded

2. Pin and wedge

3. Whole and composite

4. Keyed and splinted

1	2	3	4	5	6	7	8	9	10

11	12	13	14	15	16	17	18	19	20

21	22	23	24	25	26	27	28	29	30

31	32	33	34	35	36	37	38	39	40

Practical work.

Practice #33

studopedia.net

Markup.

Locksmith's workplace.

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The main types of plumbing operations

Markup.

Locksmith's workplace.

Topic 25. Basics of plumbing.

1. Locksmith work is the manual processing of materials, fitting parts, assembly and repair of various mechanisms and machines.

A workplace is a part of the production area with all the equipment, tools and materials located on it, which are used by a worker or a team of workers to complete a production task.

Locksmith workbench (Fig. 36) - the main equipment of the workplace. It is a stable metal or wooden table, the lid (tabletop) of which is made of boards 50 ... 60 mm thick of hardwood and covered with sheet iron. Single workbenches are the most convenient and common, since on multi-seat workbenches, when several people work at the same time, the quality of precision work is reduced.

Rice. 36 Single locksmith workbench:

1 - frame; 2 - countertop; 3 - vice; 4 - protective screen; 5 - tablet for drawings; 6 - lamp; 7 - shelf for tools; 8 - tablet for a working tool; 9 - boxes; 10 - shelves; 11 - seat

The workbench contains the tools necessary to complete the task. The drawings are placed on the tablet, and the measuring tools are placed on the shelves.

Under the tabletop of the workbench are drawers, divided into a number of cells for storing tools and documentation.

When choosing the height of the vise installation, the left hand bent at the elbow is placed on the vise jaws so that the ends of the straightened fingers of the hand touch the chin. Tools and devices are arranged so that it is convenient to take them with the appropriate hand: what is taken with the right hand - hold on the right, what is taken with the left - on the left.

A protective screen made of metal mesh or durable plexiglass is installed on the workbench to retain pieces of metal that fly off during cutting.

Blanks, finished parts and fixtures are placed on racks installed in the area allotted for them.

2. Marking - the operation of drawing lines (rises) on the workpiece that determine (according to the drawing) the contours of the part and the places to be processed. Marking is used for individual and small-scale production.

Marking is carried out on marking plates cast from gray cast iron, aged and precisely machined.

Lines (risks) with a planar marking are applied with a scriber, with a spatial marking, with a scriber fixed in the thickness gauge collar. Scribers are made from steel grades U10 and U12, their working ends are hardened and sharpened sharply.

The center punch is intended for drawing indentations (cores) on pre-marked lines. It is made from steel grades U7, U7A, U8 and U8A.

The marking compass is used to draw circles, divide angles and apply linear dimensions to the workpiece.

3. The main types of plumbing operations.

Cutting is a locksmith operation, during which excess metal layers are removed from the workpiece with a cutting and impact tool, grooves and grooves are cut out, or the workpiece is divided into parts. The cutting tool is a chisel, a cross-cutting tool, and a hammer is a percussion tool.

Cutting is the operation of separating metals and other materials into pieces. Depending on the shape and size of the blanks, cutting is carried out with a hand saw, hand or lever scissors.

A hand saw consists of a steel solid or sliding frame and a hacksaw blade, which is inserted into the slots of the heads and secured with pins. A handle is fixed on the shank of the fixed head. A movable head with a screw and a wing nut is used to tension the hacksaw blade. The cutting part of the hacksaw is a hacksaw blade (a narrow and thin plate with teeth on one of the ribs) made of steel grades U10A, 9XC, P9, P18 and hardened. Hacksaw blades are used with a length (distance between holes) of 250-300 mm. The teeth of the blade are spread (bend) so that the width of the cut is slightly greater than the thickness of the blade.

Metal dressing is an operation in which irregularities, dents, curvature, warpage, waviness and other defects in materials, workpieces and parts are eliminated. Editing in most cases is a preparatory operation. Straightening has the same purpose as straightening, but defects are corrected in hardened parts.

Bending is widely used to give blanks a certain shape in the manufacture of parts. For manual straightening and bending, correct plates, straightening headstocks, anvils, vices, mandrels, sledgehammers, metal and wooden hammers (mallets) and special devices are used.

Riveting is a metalwork operation of joining two or more parts with rivets. Rivet connections are one-piece and are used in the manufacture of various metal structures.

Manual riveting is performed with a hammer, its mass is chosen depending on the diameter of the rivet, for example, for rivets with a diameter of 3 ... 3.5 mm, a hammer weighing 200 g is required.

Sawing is a locksmith operation in which a layer of metal is cut off from the surface of a part with files to obtain the required shape, size and surface roughness, to fit parts during assembly and prepare edges for welding.

Scraping is the operation of scraping thin layers of metal from the surface of a part with a cutting tool - a scraper. This is the final processing of precision surfaces (machine guides, control plates, plain bearings, etc.) to ensure tight mating. Scrapers are made of U10 and U12A steels, their cutting ends are hardened without tempering to a hardness of HRC 64...66.

Lapping and finishing - operations of surface treatment with especially fine-grained abrasive materials using lapping.

These operations achieve not only the required shape, but also the highest accuracy (5 ... 6th grade), as well as the lowest surface roughness (up to 0.05 microns).

Fitting and assembly work is the installation and dismantling work performed during the assembly and repair of machines. Various connections of parts performed during the assembly of machines are divided into two main types: movable and fixed. When performing locksmith and assembly work, a variety of tools and devices are used: wrenches (simple, socket, sliding, etc.), screwdrivers, punches, pullers, devices for pressing and pressing out.

Edit

Edit- an operation by means of which irregularities, curvature or other defects in the shape of blanks are eliminated.

The main equipment for manual straightening of metals are steel or cast iron straightening plates. As a tool for manual dressing, steel hammers with a round head are used; hammers made of soft materials are used for straightening finished surfaces, as well as for straightening workpieces and parts made of non-ferrous metals and alloys.

felling

Cutting is an operation of cold working of metals by cutting. Locksmith and pneumatic hammers serve as percussion tools for cutting, and chisels, crosscutters and groovers serve as cutting tools.

Chisel. The metalwork chisel is made of tool carbonaceous steel. It consists of three parts: shock, middle and working.

The impact part is made tapering upwards, and its top (striker) is rounded; for the middle part of the chisel is held during cutting; the working part has a wedge-shaped shape. The angle of sharpening is selected depending on the hardness of the material being processed.

For the most common materials, the following taper angles are recommended: for hard materials (solid steel, cast iron) - 70 °;

for materials of medium hardness (steel) - 60 °;

for soft materials (copper, brass) – 45°;

for aluminum alloys - 35 °.

Kreutzmeisel. To cut out narrow grooves and grooves, a chisel with a narrow cutting edge is used - a crosscut. Such a chisel can also be used to remove wide layers of metal: first, grooves are cut with a narrow chisel, and the remaining protrusions are cut down with a wide chisel.

Locksmith hammers. Locksmith hammers used in cutting metals and are of two types: with round and square heads. The main characteristic of a hammer is its mass. For cutting metals, hammers weighing 400 ... 600 g are used.

To facilitate labor and increase its productivity, mechanized tools are used. Among them, the most common is pneumatic chipping hammer.

metal cutting

For cutting metal, a hacksaw is used, the cutting part of which is a blade. The choice of blade depends on the material of the workpiece, its shape and size. Pipe cutters are used to cut pipes manually. For cutting sheet metal with a thickness of up to 1.5 mm, straight-cutting or curly cutting scissors are used. The wire is cut with needle nose pliers or power scissors.

filing

filing- an operation in which a layer of metal is removed from the surface of the workpiece using a cutting tool - file.

Purpose of filing- giving parts the required shape, size and specified surface roughness.

Files differ in the number of notches, section profile and length.

By number of teeth, notched to 10 mm in length, the files are divided into 6 classes (0, 1, 2, 3, 4.5).

Depending on the work performed, files are divided into the following types: metalwork - general purpose and for special work, machine, needle files and rasps.

1)General purpose locksmith's files according to GOST 1465-69, eight types are made: flat, square, trihedral, semicircular, rhombic and hacksaw, from 100 to 400 mm long with a notch No. 0-5.

Locksmith's files for special jobs are intended for removing very large allowances when filing grooves, shaped and curved surfaces; for processing non-ferrous metals, non-metallic materials, etc. Depending on the work performed, files of this type are divided into grooved, flat with oval ribs, bars, double-ended, etc.

2)Machine files according to their design, they are divided into rod, disk, shaped heads and lamellar ones. In the process of work, the rod files are reciprocated, the disk files and shaped heads are rotated, and the lamellar files are in continuous motion along with a continuously moving metal tape.

3)Files according to GOST 1513-67, ten types are manufactured: flat, trihedral, square, semicircular oval, hacksaw, etc. 40, 60 and 80 mm long with a notch of 5 numbers. The length of the file is determined by the length of the working part. Ribs of flat files have a single or double notch. The sides and upper edge of the hacksaw files have a double notch.

Files are used for filing small surfaces and narrow places that are inaccessible for machining with metalwork files.

4)Rasps according to GOST 6876-54, several types are made: general purpose, shoe and ungulate.

Depending on the profile, general-purpose rasps are divided into flat, round and semi-circular with a notch No. 1-2 and a length of 259 to 350 mm.

Holemaking

Drilling is carried out on drilling machines or using manual devices. The main cutting part is the drill, which has two cutting edges. When drilling holes with a diameter of more than 20 mm, pre-drilling the holes with a drill of a smaller diameter is used, then it is reamed to size with a drill of a larger diameter.

After drilling, stamping, cast to obtain a more accurate hole, they are reamed. Depending on the accuracy and purpose of the holes for their processing, countersinks of two numbers are made: No. 1 - for pre-treatment of holes and No. 2 - for final processing. Structurally, countersinks are of two types: solid hole processing from 10 to 40 mm and mounted - from 32 to 80 mm.

Reaming is used to obtain holes with a more precise shape and low roughness. The operation is carried out using a multi-blade tool - a reamer. Depending on the shape, cylindrical and conical reamers are distinguished. According to the method of application - manual and machine, according to the design - one-piece, mounted, sliding (adjustable) and combined, right and left.

Made part:

Lamb

Detail sketch:

Progress:

1. Processing sharp corners of the workpiece with a bastard file.

2. Marking with a caliper and gauge.

3. Punching along the marking contour for drilling.

4. Drilling.

5. Beating off excess material with a chisel.

6. Processing with files until the required dimensions are obtained.

7. Reaming the central hole with one thread. thread cutting,

8. Polishing with sandpaper.

welding area

Turning section

Lathe - a machine for processing bodies of revolution by removing chips from the workpiece during turning. All machines of the turning group have a typical device. We will consider the device of these machines using the example of a screw-cutting lathe model 16K20.

Fig (1). Control handles: 2 - interlocked control, 3,5,6 - setting the feed or pitch of the thread being cut, 7, 12 - controlling the spindle speed, 10 - setting the normal and increased thread pitch and for cutting multi-start threads, 11 - changing the direction of threading (left or right), 17 - moving the upper slide, 18 - fixing the quill, 20 - fixing the tailstock, 21 - the steering wheel for moving the quill, 23 - turning on the accelerated movements of the caliper, 24 - turning on and off the lead screw nut , 25 - control of changing the direction of rotation of the spindle and stopping it, 26 - turning the feed on and off, 28 - transverse movement of the sled, 29 - turning on the longitudinal automatic feed, 27 - button on and off the main motor, 31 - longitudinal movement of the sled; Machine components: 1 - bed, 4 - feed box, 8 - main drive belt drive housing, 9 - headstock with main drive, 13 - electrical cabinet, 14 - screen, 15 - protective shield, 16 - top slide, 19 - tailstock , 22 - longitudinal movement support, 30 - apron, 32 - lead screw, 33 - bed guides.

Main drive, feed mechanism, feed box of a 16K20 screw-cutting lathe.

The main drive of the machine 16K20. In the headstock there is a gearbox and a spindle, which rotate the workpiece at the selected depth of cut and feed. Figure 3 shows the device of the gearbox, which works as follows. The workpiece is clamped in a cam chuck, which is attached to the spindle flange 13. The rotation from the electric motor 1 through the belt drive 2 and the clutch 3 is transmitted to the shaft 5.

· Bed - a massive cast-iron base on which all the main parts of the machine are mounted. It has guides along which the moving parts of the machine can move. The headstock is a cast-iron box, inside of which the main working body of the machine is located - the spindle.

Spindle is a hollow shaft, on the right end of which a cartridge is mounted. It receives rotation from an electric motor through a V-belt transmission and a system of gears and couplings located inside the headstock. The gearbox is a system of gears and clutches that allows you to change the speed of the spindle. .

Caliper - a device for fixing and moving the cutter in different directions. Feed movements can be carried out manually and mechanically (from the lead screw and the lead shaft). .

· Apron - a system of mechanisms that convert the rotational movement of the lead screw and the drive shaft into the rectilinear movement of the caliper.

· Feed box - a mechanism that transmits rotation to the lead screw and the lead shaft and changes the amount of feed. The rotational movement in the feed box is transmitted from the spindle using a reversing mechanism and a guitar with interchangeable gears.

· The guitar is designed to adjust the machine to the required feed by selecting the appropriate replacement gears. The tailstock is designed to support the right end of long workpieces during processing, as well as to secure drills, countersinks, countersinks, reamers, taps, etc. .

Main types of turning works: turning cylindrical surfaces, trimming ends, turning external grooves, cutting off metal, drilling, reaming, countersinking, boring holes, turning internal grooves, centering, surface treatment with shaped cutters, threading with dies, taps, cutters, thread rolling heads, processing of conical surfaces.

The main tools in turning are cutters.. The cutter consists of a working part, called the head, and a body - a holder. The main elements of the working part are the main cutting edge, the auxiliary cutting edge and the top - the point of intersection of the two edges. The cutting of the metal layer is carried out by the main edge, which has a straight or shaped shape. The chips formed during operation descend along the front surface of the cutter.

In the direction of feed movement, the cutters are divided into right and left. For right incisors, the main cutting edge is located on the side of the thumb of the right hand, if you put it on the incisor from above. In the working movement, such incisors move from right to left (from the tailstock to the front). In the left incisors, with a similar imposition of the left hand, the main cutting edge is also located on the side of the thumb. Such cutters in the feed move move from left to right.

By purpose, turning tools are divided into through, boring, cutting, cutting, shaped, threaded and grooving.

Passage straight and bent cutters are used for processing external surfaces

For simultaneous processing of a cylindrical surface and an end plane, through-thrust cutters are used. The cutter works with a longitudinal feed motion.

Scoring cutters are used for cutting the ends of workpieces. They work with a lateral movement of the tool feed towards or away from the center of the workpiece.

Boring cutters are used for boring holes that have been pre-drilled or obtained by punching or drinking. Two types of boring cutters are used: through - for through boring, persistent - for blind boring.

Cut-off cutters are used for cutting workpieces into pieces, cutting off a machined workpiece, and for grooving. Cut-off cutters work with a transverse feed motion.

Threaded cutters are used for cutting external and internal threads of any profile: rectangular, triangular, trapezoidal. The shape of the cutting blades of the threaded cutters corresponds to the profile and cross-sectional dimensions of the threads being cut.

Fig. 2. Turning cutters: a) straight line; b) through passage bent; c) through passage persistent; d) undercut; e) cutting; e) shaped; g) threaded; h) through boring.

By design, cutters are single-piece, made from one workpiece; composite, with one-piece connection. Tool holders are usually made of structural steels 40, 45, 50 and 40X with different sections: square, rectangular, round, special. Cutters with mechanical fastening of carbide inserts have significant advantages over brazed cutters.

Fig. 3. Types of turning tools by design: solid (a, b) composite with soldered (c) or mechanically fastened (d) plates

Installing the cutter. The threaded cutter is set exactly in the center of the workpiece: setting below the center leads to a distortion of the profile, and setting it above the center leads to “rubbing” of the cutter. To obtain the correct thread profile, the cutter is set according to the template.

In turning, measuring tools are used to determine the dimensions, shape and relative position of individual surfaces of parts both during their manufacture and after final processing. In single and small-scale production, universal measuring instruments are used - calipers, micrometers, inside gauges, etc., and in large-scale and mass production - limit gauges.

A task: make a screw(all sizes are below)

Progress:

1) We fix the workpiece in a chuck with a 40mm overhang.

2) We install cutters made of high-speed steel (P18) in the tool holder of the machine, orienting the cutting edge of the cutter along the center of rotation of the workpiece, by placing the required thickness of the plate under the cutter and cutting the end.

3) With the help of a through cutter, removing 3 mm, we grind 14mm on L30mm. turn the tool holder, and set the workpiece up to 5.8-1 * 45 °.

4) We install the Æthrust-through cutter, we grind it up to 5.8 -1 * 45 °.

5) Set the rotation speed to 40 rpm.

6) We cut the M6 thread with a die.

7) Set the previous speed to 400 rpm. 14, at a distance of 4 mmÆ

8) With the help of a cut-off cutter, we cut a groove of 10 mm, with the help of a through cutter we remove the disks 0.5 * 45 ° and 2 * 45 °.

9) Install the cutting tool and cut off the screw.

locksmith shop

The main equipment of a locksmith at the workplace is a workbench with a parallel vice attached to it. The workbench is equipped with a safety net. Additional equipment is installed depending on the nature of the work performed.

Locksmith operations are divided into preparatory, basic and assembly. Preparatory locksmith work includes marking, cutting, straightening, bending. Operations in which the workpiece is given the shape and dimensions specified by the drawing are the main ones. These include cutting, filing, grinding, finishing, scraping. During assembly work, drilling, reaming, reaming, thread cutting, riveting and laika are used.

markup- the operation of applying marks to the workpiece that determine the boundaries of processing. Distinguish between flat and spatial markings.

The marking tool is scribers, center punches, marking compasses, thickness gauges, vernier calipers, scale rulers, caliper gauges, squares, goniometers, center finders.

Scribers are used to draw lines (marks) on the marked surface of the workpiece. Scribers are usually made from U10 or U12 tool steel.

· Center punches are used for drawing recesses. Punches are made from tool carbon steel. The working and shock parts are subjected to heat treatment on pre-marked lines. This is done so that the markings are clearly visible and not erased during the processing of parts.

Marking (locksmith's) compasses are used for marking circles and arcs, dividing circles and segments into parts and other geometric constructions when marking a workpiece.

The height gauge is used like a thickness gauge, but for a more accurate measurement of dimensions:

The scriber is used for drawing marks on a ruler, a square, a template;

· the square is designed to check the vertical positions of the planes of the workpiece and apply perpendicular marks with a scriber;

Protractor is used to apply inclined marks and check the installation of the workpiece on the marking plate;

A center-detector square is needed to apply diametrical marks on the end of the shafts and find the center;

Spatial marking of workpieces is carried out on marking plates.

Marking plate is a cast iron casting, the horizontal working surface and the side edges of which are very accurately machined. On the working surface of large plates, longitudinal and transverse grooves are made with a depth of 2-3 mm and a width of 1-2 mm, which form squares with a side of 200 or 250 mm. This facilitates the installation of various devices on the stove.

Basic plumbing operations

metal cutting. Cutting is an operation in which, with the help of a chisel and a metalwork hammer, layers of metal are removed from the workpiece or the workpiece is cut.

Cold chisel is a steel rod made of tool carbon or alloy steel.

Kreutzmeisel differs from a chisel in a narrower cutting edge and is designed for cutting narrow grooves, keyways, etc. For cutting profile grooves - semicircular, dihedral and others - special crosscuts are used, called groovers.

Locksmith hammers, used in cutting metals and are of two types: with a round and with a square striker. The main characteristic of a hammer is its mass. For cutting metals, hammers weighing 400 ... 600 g are used.

When manually cutting metals, the following safety rules should be observed: the handle of a manual metalwork hammer must be well fixed and not cracked; when cutting with a chisel and a cross-cutting tool, it is necessary to use goggles; when cutting hard and brittle metal, it is imperative to use a fence: mesh, shield

metal cutting. Depending on the shape and dimensions of the material of the blanks or parts, cutting during manual metal processing is carried out using a manual or mechanized tool.

Hand saw used for cutting relatively thick sheets of metal and round or shaped rolled products. A hacksaw can also be used to cut slots, grooves, trim and cut blanks along the contour, and other work. It consists of a frame, a tension screw with a wing lock, a hacksaw blade handle, which is inserted into the slots of the heads and fastened with pins.

Hacksaw frames two types are made: solid (for a hacksaw blade of one specific length) and sliding (hacksaw blades of different lengths can be fixed).

hacksaw blade(the cutting part of a hacksaw) is a thin and narrow steel plate with teeth on one of the ribs. It is made from tool or high speed steel. The length of the most common hacksaw blades is 250-300 mm.

Edit. Editing is an operation to eliminate defects in workpieces and parts in the form of concavity, convexity, waviness, warping, curvature, etc. Its essence lies in compressing the convex metal layer and expanding the concave one.

The most difficult is the editing of sheet metal. The sheet is placed on the plate with a release upwards. Blows are applied with a hammer from the edge of the sheet towards the bulge. Under the action of blows, the flat part of the sheet will be stretched, and the convex part will straighten.

Right Stove, as well as marking, should be massive. Its dimensions can be from 400x400 mm to 1500x3000 mm. Plates are installed on metal or wooden supports, which ensure the stability of the plate and the horizontal position of its position.

Manual dressing is carried out with special hammers with a round, radius or plug-in soft metal striker. Thin sheet metal is ruled by a mallet.

Round metal can be straightened on a plate or on an anvil. 1-x-li-bar has several bends, then the extreme ones are corrected first, and then those located in the middle.

filing. Filing is an operation for processing metals and other materials by removing a small layer with files manually or on filing machines.

With the help of files, planes, curved surfaces, grooves, grooves, holes of any shape, surfaces located at different angles, etc. are processed. Sawing allowances are left small - from 0.5 to 0.25 mm. The accuracy of processing by filing is 0.2 ... 0.05 mm (in some cases - up to 0.001 mm).

Files. A file is a steel bar of a certain profile and length, on the surface of which there are notches (cuts) that form depressions and sharpened teeth (teeth) that have a wedge shape in cross section. Files are made of steel U10A, U13A, ShKh15, 13Kh, after notching they are subjected to heat treatment.

By appointment, files are divided into the following groups: general purpose; special purpose; needle files; rasps; machine. General purpose files are designed for general plumbing work. Files are divided into the following types:

A - flat, B - flat sharp-nosed files are used for filing external or internal flat surfaces; C - square files are used for sawing square, rectangular and polygonal holes; D - trihedral files are used for filing sharp angles equal to 60 degrees or more, as with the outer side of the part, and in grooves, holes and grooves; D - round files are used for sawing round or oval holes and concave surfaces of small radius; E - semicircular files with a segmented cross section are used for processing concave curved surfaces of a significant radius and large holes (convex side); F - rhombic files are used for filing gears, disks and sprockets; H - hacksaw files are used for filing internal corners, wedge-shaped grooves, narrow grooves, planes in trihedral, square and rectangular holes.

Special-purpose files for processing non-ferrous alloys, unlike general-purpose metalwork files, have other, more rational notch angles for this particular alloy, and a deeper and sharper notch, which ensures high productivity and file durability.

Files- these are small files, used for curved, engraving, jewelry work, as well as for cleaning in hard-to-reach places (holes, corners, short sections of the profile, etc.).

Rasps designed for processing soft metals (lead, tin, copper, etc.) and non-metallic materials (leather, rubber, wood, plastics), when ordinary files are unsuitable.

Control of curvilinear machined surfaces is carried out along marking lines or using special templates.

drilling. Drilling is carried out on drilling machines or using manual devices. The main cutting part is the drill, which has two cutting edges. When drilling holes with a diameter of more than 20 mm, pre-drilling the holes with a drill of a smaller diameter is used, then it is reamed to size with a drill of a larger diameter.
After drilling, stamping, cast to obtain a more accurate hole, they are reamed. Depending on the accuracy and purpose of the holes for their processing, countersinks of two numbers are made: No. 1 - for pre-treatment of holes and No. 2 - for final processing. Structurally, countersinks are of two types: solid hole processing from 10 to 40 mm and mounted - from 32 to 80 mm.
Reaming is used to obtain holes with a more precise shape and low roughness. The operation is carried out using a multi-blade tool - a reamer. Depending on the shape, cylindrical and conical reamers are distinguished. According to the method of application - manual and machine, according to the design - one-piece, mounted, sliding (adjustable) and combined, right and left.
Threading. Thread cutting is its formation by removing chips (as well as plastic deformation) on the outer or inner surfaces of workpieces.

The thread is external and internal. A part (rod) with an external thread is called a screw, and with an internal one - a nut. These threads are made on machines or by hand.

Threads on parts are obtained on drilling, threading and turning machines, as well as by rolling, that is, by the method of plastic deformation. Thread rolling tools are knurling dies, knurling rollers and knurling heads. Sometimes the thread is cut by hand.

The internal thread is cut with taps, the external thread is cut with dies, runs and other tools.

Tool for cutting internal threads. Taps. Taps are divided: by purpose - into manual, machine-hand and machine; depending on the profile of the thread being cut - for metric, inch and pipe threads; by design - into solid, prefabricated (adjustable and self-switching off) and special.

Set of three taps includes rough, medium and fine taps

Tap consists of the following parts: working part - a screw with longitudinal grooves is used for threading. The working part consists of the intake (or cutting) part - it performs the main work when cutting and the calibrating (guide) part - the threaded part of the tap adjacent to the intake - it directs the tap into the hole and calibrates the hole being cut; the shank-rod serves to secure the tap in the chuck or collar.

The threaded parts of the tap, limited by grooves, are called wedge-shaped cutting feathers.

Cutting edges are the edges on the cutting feathers of the tap, formed by the intersection of the front surfaces of the groove with the joined surfaces of the working part.

The core is the inner part of the body of the tap. Taps for cutting threads in stainless steels have a more massive (thick) core.

Grooves are recesses between the cutting teeth (feathers), obtained by removing part of the metal. These grooves are used to form cutting edges and to accommodate chips in threading.

Taps have a different design, depending on which they are cylindrical and conical. The set, consisting of three taps, includes rough, medium and finishing taps, which have different diameters and remove different amounts of metal (chips). Draft - up to 60% of metal; medium tap up to 30% metal; the finishing tap is still up to 10%, after which the thread has a full profile.

According to the accuracy of the thread being cut, taps are divided into four groups - C, D, E and H. Group C taps are the most accurate, groups E and H are less accurate with a non-ground tooth profile. Group C and D - with a ground tooth profile; they cut high quality threads.

Machine-manual taps are used for cutting metric, inch and pipe cylindrical and conical threads in through and blind holes of all sizes.

Machine taps are used for cutting machine threads in through and blind holes. They are cylindrical and conical.

Nut taps are used to cut metric threads in nuts in one stroke by hand or machine. They are made in one set, have a long cutting part and shank.

There are also die taps, master taps, special taps, grooveless taps, combined taps, screw-fluted taps, they all differ from each other in shape and place of application.

collars. When cutting threads by hand, the cutting tool is rotated with the help of knobs mounted on the squares of the shanks.

Non-adjustable collars have one or three holes; in adjustable knobs there is an adjustable hole for turning the tap when cutting threads in hard-to-reach places.

The calibrated wrench consists of a body, a spring and a bushing and is used for threading in deep and blind places.

The universal wrench is designed for fixing dies with an outer diameter of 20 mm, all types of taps and reamers with square shanks with sides up to 8 mm. To fix the dies in the body of the universal wrench there is a socket. The plate is fixed with screws.

Exercise. Manufacture of the "Wing Nut" part.

Progress:

Detail sketch:

1) Mark the workpiece with a caliper and
height gauge.

2) Let's do a punching along the contour of the marking for drilling.

3) In place of the received marks, we will make holes using drilling.

4) Beat off excess material with a chisel.

5) Using a file, we will process the part to the desired size
6) For threading, drill a hole in the center of the part.

7) Using a wrench, cut the thread.
8) Polish the part with sandpaper.

welding area

Welding is the process of creating a strong connection using interatomic bonds established between the parts to be welded during their general or local heating, or plastic deformation, or the use of both actions. Nowadays, many different welding methods have been created. All welding methods are classified according to technical, technological and physical characteristics. Physical classification depends on the form of energy used. Welding types such as mechanical welding, thermal welding and thermomechanical welding are envisaged.

Thermal welding includes methods using thermal energy (gas welding, arc welding, plasma welding, etc.).

Thermomechanical method combines all types of welding using thermal energy and pressure (diffusion welding, contact welding)

mechanical view welding combines a welding method that uses mechanical energy (friction welding, cold welding, explosion welding, ultrasonic welding).

Classification of welding methods according to technical characteristics is carried out:

According to the principle of metal protection at the welding site (in air, in a protective gas environment, under a flux layer, in a vacuum, with combined protection);

According to the composition of protective gases (in inert gases, in active gases);

By the nature of metal protection (in a controlled atmosphere, with jet protection);

By the degree of mechanization of the process (manual, automatic, automated, mechanized).

During electric welding, heating is carried out by an electric arc formed between the welding electrode and the metal part.

Electric arc is an electric discharge in gases, characterized by a high current density and a small cathode voltage drop (between the electrode and the parts to be welded), high temperature and gas pressure.

The arc burns between the electrode rod and the metal. When the electrode and metal melt, a metal weld pool 4 is formed. Liquid metal from the electrode is transferred to the weld pool through the arc gap. Together with the electrode rod, its coating 2 melts, forming a gas shield 3 around the arc and a liquid slag pool on the surface of the molten metal. Metal and slag pools together form a weld pool. As the arc moves and the metal solidifies, a welding seam 6 is formed, and the liquid slag forms a solid slag crust 5 on the surface of the seam, which is removed after cooling.

Welding rectifiers are devices for converting AC voltage into DC voltage to produce a welding arc.

DC welding has advantages over alternating current welding: the stability of arc burning increases due to the absence of zero values of the welding current, the depth of penetration of the metal being welded increases, metal spatter decreases, the strength of the weld metal increases and the number of weld defects decreases. Therefore, welding of critical joints is best done at direct current.

The elements of a welding rectifier are a power transformer, a rectifier unit based on semiconductor devices, devices for starting, regulating, protecting, measuring, and cooling.

Important elements of the welding rectifier are valve cooling radiators, a fan that turns on before starting the rectifier, elements of protection against current overloads and overheating.

Regulation of welding current in rectifiers is carried out by electromechanical methods. With electromechanical regulation, a change in current occurs before the rectifier unit, and an alternating current with specified parameters is supplied to the rectifying valves. In this case, transformers with increased magnetic scattering or with a controlled magnetic shunt are used.

Electrode- a rod made of a special metal with a coating of a certain composition applied to it (the length of the electrode depends on its diameter). One end is free from coating for a length of about 3 cm to be captured by the electrode holder and contact with the welding current circuit, the other end is slightly released from the coating for contact with the workpiece when the arc is ignited.

Types of welded joints:

Depending on the relative position in space of the parts to be connected, connections are distinguished:

Butt welded joints (Fig. 6, a) - the elements to be welded are located in the same plane or on the same surface. 32 types of butt joints are installed. Designated O, C2, C3, C4, etc.

Lap welded joints (Fig. 6, b). The elements to be welded are arranged in parallel and overlap each other. The amount of overlap should be in the range of 3-420 mm. Designated H1, H2.

Tee welded joints (Fig. 6, c). A distinctive feature of these joints is that one of the parts to be joined is installed on the surface of the other end and welded, forming, as it were, the letter T in the section (hence the name - tee). Designated TK, 16, etc.

corner welded joints(Fig. 6, d) welded joint of two elements located at a right angle and welded at the junction of their edges.

The strength of the welding current is selected depending on the brand and diameter of the electrode, while taking into account the position of the seam in space, the type of joint, the thickness and chemical composition of the metal being welded, as well as the ambient temperature. When all these factors are taken into account, it is necessary to strive to work at the maximum possible current strength.

The strength of the welding current is determined by the formula

I St \u003d πd e 2 * j / 4,

where d e is the diameter of the electrode (electrode rod), mm;
j - permissible current density, A / mm 2.

Arc welding

Electric arc welding is a melting process that occurs due to the heating of the welded edges with the heat of an electric arc. Currently, four methods of electric arc welding are used.

Manual arc welding

Produced in two ways: consumable and non-consumable electrode.

The specifics of welding work in manual arc welding with a non-consumable electrode. The edges to be welded are brought into contact. When a non-consumable (carbon, tungsten or graphite) electrode and a product are brought in, an electric arc is excited. The injected filler material and the edges of the product are heated to a state of melting. A pool of molten metal forms in the arc zone. When the metal solidifies in the bath, a weld is formed. This method is used when welding stainless steel, aluminium, copper and their alloys, as well as for surfacing hard alloys.

The specifics of welding work in manual arc welding with a consumable electrode. The so-called piece electrodes with coating-coating are used. This is the main method for manual welding. The method of excitation of an electric arc is similar to the first method, but both the electrode and the edge of the product are melted. We get a common bath of liquid metal, which, when cooled, forms a seam.

Semi-automatic and automatic submerged arc welding of metals

Semi-automatic and automatic submerged arc welding of metals is carried out by mechanization of the main movement performed by the welder during manual welding of metals - the supply of the electrode to the arc region and its movement along the welded edge of the product. The supply of the electrode into the arc zone during semi-automatic welding is mechanized, and the movement of the electrode along the edges to be welded is carried out by the welder manually. Automatic metal welding is a fully mechanized process. The bath of liquid metal is protected from the effects of oxygen and nitrogen in the air by the molten slag formed as a result of the melting of the flux supplied automatically to the arc zone. This metal welding provides excellent weld quality and high productivity.

Figure 8. Submerged arc welding: 1 - welding wire, 2 - formed drop, 3 - gas bubble, 4 - arc, 5 - weld pool, 6 - molten flux, 7 - unmelted flux, B - product

Shielded arc welding

Figure 9. Arc welding in shielding gases: 1-electrode, 2-filler wire, 3-product, 4-seam, 5-arc, 6-shielding gas flow, 7-torch.

Arc welding in shielding gases is carried out with non-consumable (tungsten) or consumable electrodes. In the first case, the welding seam is formed from the molten metal of the edges of the product and the filler material supplied to the arc zone if necessary. In the second version, an electrode wire is fed into the arc zone, which, when melted, forms a weld. In this case, the molten metal bath is protected from nitriding and oxidation by a shielding gas jet that displaces atmospheric air from the arc zone.

Electroslag welding

Electroslag welding of metal is carried out by melting the electrode and welded edges located at an angle of 45 degrees. or vertically, due to the heat released by the current when passing through the molten slag. In this case, the slag is the protection of the molten metal from exposure to air. From the bottom, a pallet is welded to the product to be welded. On both sides of the gap between the edges, copper sliders are pressed, forming a seam, with water cooling. A special flux is poured into the tray, one or two electrode wires are placed above it. An arc is initiated under the flux between the tray and the electrodes. The electrode wire is fed into the arc burning zone by a special mechanism. Flux and electrode wire are melted due to the heat of the arc, a pool of molten metal is formed, and above it a pool of slag. In the future, the heat necessary for melting is produced due to the current passing through the molten slag and having a high resistance (Lenz-Joule law). As slag and liquid metal accumulate in the bath, copper sliders with a flux and electrode wire supply mechanism move automatically from bottom to top with the speed of liquid metal rising.

Classification of welds:

By type of welded joint - butt and corner.

According to the position of the welded joint in which the welds are made, there are: “into the boat” lower, semi-horizontal, horizontal, semi-vertical, vertical, semi-ceiling and ceiling.

According to the configuration of the welded joint, the seams are rectilinear annular and curved.

By the length of the welded joint - continuous and intermittent.

According to the type of welding used, they are divided into seams of manual arc welding, automatic and mechanized submerged arc welding, gas-shielded arc welding seams, electroslag welding seams, electric riveting, contact, gas, solder joints.

According to the method of holding the weld pool: on seams made without gaskets and pillows, on removable and remaining steel gaskets, on copper, copper flux, ceramic and asbestos linings.

By the number of sutures, there are one-sided, two-sided, multi-layer and multi-pass.

According to the material used for welding, the seams of welded joints are divided into seams made of carbon and alloy steels, seams of non-ferrous metals, bimetal, vinyl plastic and polyethylene.

According to the location of the parts to be welded relative to each other, the seams can be at an acute, obtuse, right angle, and also located in the same plane.

According to the force acting on the seam, the seams are flank, frontal, combined and oblique.

By volume of deposited metal, normal, weakened and strengthened

According to the shape of the welded structure on the product, longitudinal and transverse.

Exercise. Butt joint welding

Progress:

1) An MP3 electrode with an arc diameter of 4 mm was used.

2) Set the strength of the welding current as 160A, based on the calculations.

3) Cleaned the surfaces to be welded from rust, dirt with a steel score

4) She clamped the electrode between the current-carrying sponge and the lever of the electrode holder.

markup called the operation of drawing lines on the workpiece that define the contours of the part or the place of processing. Marking on the workpiece is carried out in accordance with the drawing of the finished part.

Depending on the marking operations performed, various marking tools and devices are used.

Blanks are installed on the marking plate for drawing contour lines and places to be processed on them. Marking plates are cast from cast iron and have a carefully finished surface. The installation of blanks on the plate is carried out using special jacks and linings. For the convenience of using the stove and protecting its treated surface from damage, the stove is periodically wiped with graphite powder, and after work is completed, it is covered with a wooden case.

In FIG. 415 shows a marking plate mounted on a stable wooden stand.

A scriber is a tool used to draw lines on a marked workpiece. The scriber is made of hardened steel wire in the form of a thick needle, in which one end is bent at an angle of 90 °; both ends of the needle are pointed. For ease of use, a thickening is made in the middle of the needle (Fig. 416, a).

The center punch is used to make recesses on the workpiece in places to be drilled, and on marking lines for better visibility. The center punch is made from hardened carbon steel; its shape is cylindrical, one end is pointed at an angle of 60°, the other end is blunt (Fig. 416, b). During operation, the punch is set with a sharp end normal to the surface of the workpiece; the blunt end is struck with a hammer.

A thickness gauge is used to draw lines on the workpiece to be marked. The thickness gauge consists of a stand with a vertical stand; a clamp with a scriber fixed in it moves along the rack (Fig. 416, b). For the convenience of installing the scriber at a certain height, divisions can be applied on the thickness gauge stand. Thickness gauges with racks with divisions applied to them are called gauge gauges (Fig. 416, d).

A marking square is used to draw a vertical line; its short side has a tee section, which ensures the stability of the square on the marking plate (Fig. 417, a).

Malka is used to draw lines at the required angle; the malka consists of two steel rulers connected by a hinge (Fig. 417, b).

A marking compass is used to draw circles on the marked workpieces; its device is shown in Fig. 417, c.

The center finder is used to find the center on cylindrical blanks (Fig. 417, d). The center finder is a square, to which a ruler is attached, one of the sides of which divides the corner of the square in half. The square is brought into contact with its sides with a cylindrical workpiece; with this installation of the center finder, its ruler divides the circumference of the end face of the workpiece in half. After shifting the ruler to an arbitrary angle, a second line is drawn along the ruler. The intersection point of the lines drawn at the first and second positions of the ruler determines the position of the center of the workpiece circle.

felling produced using a chisel or cross-cutting tool. In FIG. 418, and a drawing of a chisel is given, and in Fig. 418, b - drawing of a cross-cut. As can be seen from these drawings, the crosscut differs from the chisel in the shape of the working head. The angle a of sharpening the chisel and crosscut decreases with a decrease in the hardness of the metal being processed; its value is within 70-45 °.

The chisel is used in all trimming operations, with the exception of cutting nests, keyways, etc., which are performed with a cross cutter.

Chisels and crosscuts are made of carbon steel.

Cutting with a chisel or kreysmeysel is carried out by striking them with a metalwork hammer.

The product to be chopped is clamped in a bench vise. There are vices

chair (Fig. 419, a) and parallel (Fig. 419, b).

cutting metal during metalworking is produced with a hacksaw or scissors. The hacksaw consists of a hacksaw blade and a machine.

Hacksaw blades are made from steel strips 200-300 mm long, 11-16 mm wide and 0.5-0.8 mm thick: 5-12 teeth are cut at a length of 1 cm. A hand saw is used for cutting materials of small diameters, when cutting workpieces of large diameters, powered hacksaws are used. Scissors are used to cut sheet material up to 5 mm thick.

filing called a locksmith operation used to obtain a smooth surface of a part after cutting or cutting. Filing is done with files. Files are made from steel strips with teeth cut on them (manually with a chisel or on a special gear-cutting machine). After notching, the files are subjected to hardening or carburizing followed by heat treatment. Files are made in various profiles and sizes.

According to OST 320-325, the length of the files is 100-450 mm with a width of 4-45 mm. In FIG. 420 shows the main types of files. Depending on the nature of the filing operation and the material being processed, various types of files are used.

For processing babbitt, lead, leather, wood, etc., rasps are used (Fig. 420, 9), which have 2-6 notches per 1 lin. cm.

For rough peeling of metals, bars are used (Fig. 420, 1), having 4-6 notches per 1 linear meter. cm.

For rough filing, bastard files are used (Fig. 420, 2); number of notches 5-12 per 1 cm.

For fine filing, semi-finished (Fig. 420, 3 and 4) and personal (Fig. 420, 5) files are used with the number of notches for the first 12-18 and for the second 18-26 per 1 lin. cm.

For final finishing and for precision work, velvet files (Fig. 420, 6 and 7) with a number of notches of 26-40 are used.

For sawing shaped holes and for small work, needle files are used (Fig. 420, 8) with a number of notches of 50-80 per 1 cm in length.

The quality of filing work depends on the correct use of the file. One of the main requirements for working with a file is to ensure that the movement of the file is parallel to the surface to be treated. The position of the locksmith's hands during the correct work with files is shown in Fig. 421, where a is the work with a bastard file, b is a velvet file.

Manual drilling. Drilling is the operation of obtaining holes in the workpiece material. The tool by which this operation is performed is called a drill. Drills are divided into feather (Fig. 422, a) and spiral (Fig. 422, b).

The cutting edges of the feather drill form an angle of 90° or more. The angle between the rear face of the drill and the machined plane, i.e., the clearance angle, is 10-25 °. To reduce the cutting angle to 70-80°, a groove is sawn out on the front face.

Spade drills are simple and cheap to manufacture: the end of the rod is pulled and forged in the form of a blade, then hardened and sharpened.

Their disadvantage is the inaccuracy of processing, in particular, due to the deviation of the drill axis from the axis of rotation. In addition, when working with a spade drill, the chips clog the resulting hole and spoil it, which makes it necessary to periodically interrupt work to remove the chips.

The twist drill is a round shank with two helical grooves. The grooves are used for chip removal. The angle of inclination of the helical groove to the axis in normal drills is 30°. On the cylindrical surface of the drill along the helical grooves, narrow strips are made, called ribbons or chamfers.

The twist drill consists of a working part 1 (Fig. 422, b, c) and a shank 4. The shank serves to fix the drill and has a cylindrical or conical shape; foot 5 is made at the end of it.

The working part of the drill has helical grooves and cutting part 2, which is a cone with two cutting edges.

Along the helical grooves of the drill there are ribbons 3. The cutting part of the drill (Fig. 422, c) has a back surface 1, a jumper 2, a cutting edge 3, a groove 4, a chamfer 5.

When working with twist drills, the holes are more regular and clean than when working with a spade drill. Chips when working with twist drills are picked up and removed automatically by helical grooves. Twist drills can be reground without changing their diameter.

The disadvantage of twist drills is the complexity of their manufacture. Sharpening twist drills should be done using templates.

The operation of processing holes available in cast and forged blanks or obtained by drilling is called countersinking. Countersinking is carried out in order to increase the diameter of the hole and is carried out with a countersink. A countersink of small sizes (up to 35 mm) is made integral (Fig. 423, a) and differs from an ordinary drill in a large number of grooves (usually four) and a blunt end. Large-sized drills are made mounted (Fig. 423, b), for work they are mounted on a mandrel made of machine-made steel. To process the outlet part of the holes, countersinks of a special shape are used - countersinks; in fig. 423, a countersink is shown, which serves to countersink holes for the conical head of the bolt.

Bringing the drilled holes to the exact size is carried out by reamers (Fig. 423, d). Reamers differ from countersinks in a large number of grooves.

When working with drills, various kinds of devices are used: ratchets, manual and mechanical drills (Fig. 424, a, b and c).

When processing steel parts, the drill is cooled with oil or soapy water; bronze and gray cast iron are drilled without the use of coolants, since when processing these materials, small chips are formed, which, together with the liquid, turns into a very viscous mass, which greatly increases friction.

Thread cutting. A tool used in plumbing to cut threads in holes is called a tap.

The tap is a screw with several grooves along the axis that form cutting edges. Taps can have a cylindrical and conical shape. The tap device is shown in Fig. 425; the thread formed by the tap is determined by the thread profile of the tap, the angle a of this profile, the pitch S, the outer diameter D, the inner diameter D 1. Locksmith taps are used in sets of 3 pieces: peeling, semi-finishing and chi

stovoy. The first serves for the preliminary formation of the thread, the second deepens the thread made by the peeling tap, the third finishes the thread.

A peeling tap has a thread with cut tops, a semi-finishing tap has a less cut thread, a finishing tap has a full thread. Tapping is done in a pre-drilled hole. The diameter of this hole should be slightly smaller than the inner diameter of the thread. During operation, the tap is screwed in one turn, after which it is given half a turn in the opposite direction; this technique achieves chip crushing and facilitates the work as a whole.

To obtain a cleaner thread surface in steel products, taps are lubricated with oil (sulfurized or vegetable); when cutting threads in cast iron and bronze products, lubrication is not used.

Dies are used to cut threads on rods.

Dies are called round or square plates with a central threaded hole; slots are made in the cutting to form cutting edges. The device of round dies is shown in Fig. 426, a, dies for oblique screw plugs, consisting of two halves, - in Fig. 426b. When threading, the dies are fixed in a special device called a klupp (Fig. 426, c).

Klupp consists of a frame in which the dies are fixed with a screw clamp. Klupp has two handles, which produce its rotation.

For threading on rods of small diameter, screw boards are used, which are hardened steel tiles with threaded holes cut in it (Fig. 426, d), it has a handle to rotate the screw board.

Shabreniy called oneation of obtaining very clean surfaces by removing a thin layer of metal from them by scraping; the tool used for this purpose is called a scraper. Scrapers can be straight and curved, and flat, trihedral and rounded in cross section. In FIG. 427a shows various scrapers, and FIG. 427, b - the position of the scraper in the process.

The scraping process is carried out as follows: 1) before scraping, a thin layer of paint (red lead, soot, whitewash) is applied to the calibration plate; 2) the surface to be treated is placed on the plate and slightly moved along it, as a result, a layer of paint adheres to the elevations of the surface to be treated, while other places remain clean; 3) painted places are treated with a scraper. This operation is repeated until the paint covers evenly the entire surface to be treated. Then the paint is removed from the calibration plate, the plate is wiped dry and the product is moved along the calibration plate; at the same time, elevated places of products are indicated by light spots. The quality of scraping is judged by the number of such spots per 1 cm 2 of the treated surface; processing is considered good if the number of spots is 5-6 per 1 cm 2.

The scraping process is very labor intensive. For its mechanization, special devices are used that significantly increase productivity and facilitate the work of the worker. In FIG. 428 shows a scraping machine.