The technology of locksmith processing contains a number of basic operations, such as marking, cutting, straightening and bending of metals, cutting of metals, filing, drilling, countersinking, countersinking and reaming of holes, threading, riveting, lapping and finishing, soldering and others. Most of these operations relate to the processing of metals by cutting.
markup
markup called the operation of applying lines (risks) to the surface of the workpiece, showing, according to the drawing, the contours of the part or place to be processed. Markup is divided into:
Linear (one-dimensional) - along the length of bars, rolled products, strip steel,
Planar (two-dimensional) - for sheet metal blanks,
Spatial (volumetric, three-dimensional) - for bulk blanks.
Special marking tools include scribers, center punches, marking compasses, thickness gauges. In addition to these tools, hammers, marking plates and auxiliary devices are used: linings, jacks, etc.
| Figure 6 Scribe | Scribers(Figure 6) are used to draw lines on the marked surface of the workpiece. They are made from tool steel U10 or U12 (hardness HRC 58-62). Center punches(Figure 7) is used to apply recesses (cores) on pre- |
 Figure 7 Punch |
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| marked lines so that the lines are clearly visible and not erased during the processing of parts. Kerner- this is a rod made of tool carbon steel U7, U8 (HRC 52-57) with a length of 100-160 mm and a diameter of 8-12 mm. Sharpening angle - usually 60 °, with more accurate markings - 30-45 °, for the centers of future holes - 75 °. Marking (locksmith) compasses the device is similar to drawing compasses. Reismus(Figure 8) is used to apply parallel vertical and horizontal marks. AT recent times more often use a height gage with a sharp tip. Planar and especially 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. Template called a device by which parts are made or checked |
after processing. Template marking is used in the manufacture of large batches of identical parts. It is expedient because the time-consuming and time-consuming markup according to the drawing is carried out only once during the manufacture of the template. All subsequent operations of marking blanks consist in copying the outlines of the template. In addition, the manufactured templates can be used to inspect the part after the workpiece has been machined.
Straightening and bending of metals
edit called the operation to eliminate defects in workpieces and parts in the form of concavity, convexity, waviness, warpage, curvature, etc. Its essence lies in the compression of the convex metal layer and the expansion of the concave one.
The metal is straightened both cold and hot. The choice of one or another method of dressing depends on the amount of deflection, dimensions and material of the workpiece (part).
Dressing can be manual (on a steel or cast iron straightening plate) or machine (on straightening rollers or presses).
Right Stove , as well as marking, should be massive. Its dimensions can be from 400´400 mm to 1500´3000 mm. Plates are installed on metal or wooden supports, which ensure the stability of the plate and the horizontal position of its position.
For straightening hardened parts (straightening) use straightening grandmas. They are made from steel and hardened. The working surface of the headstock can be cylindrical or spherical with a radius of 150-200 mm.
Manual dressing is carried out with special hammers with a round, radius or plug-in soft metal striker. Thin sheet metal rule mallet(with a wooden mallet).
Check the editing "by eye", and when high requirements to the straightness of the strip - with a curved ruler or on a test plate.
Shafts and round blanks of large cross section are corrected using a manual screw or hydraulic press.
bending metal is used to give the workpiece a curved shape according to the drawing. Its essence lies in the fact that one part of the workpiece is bent relative to the other at any given angle. Manual bending is carried out in a vice using a bench hammer and various devices.
Bending of thin sheet metal mallet .
With plastic deformation of the metal during the bending process, the elasticity of the material must be taken into account: after the load is removed, the bending angle slightly increases.
The manufacture of parts with very small bending radii is associated with the risk of rupture of the outer layer of the workpiece at the bend. The size of the minimum allowable bending radius depends on the mechanical properties of the workpiece material, on the bending technology and surface quality.
Pipe bending is carried out with or without filler (usually dry river sand). The filler protects the pipe walls from the formation of folds and wrinkles (corrugations) in the places of bending.
metal cutting
felling is an operation in which, with the help of a chisel and a metal hammer, layers of metal are removed from the workpiece or the workpiece is cut.
The physical basis of cutting is the action of a wedge, the shape of which is the working (cutting) part of the chisel. Cutting is used in cases where the machining of workpieces is difficult or irrational.
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.
Cutting is usually done in a vise. The cutting of the sheet material into pieces can be carried out on the plate.
The main working (cutting) tool during cutting is a chisel, and a hammer is a percussion tool.
Cold chisel (Figure 8) is made of U7A or U8A carbon tool steel. It consists of three parts: shock, middle and working. shock part 1 it is performed tapering upwards, and its top (the striker) is rounded; for the middle part 2 the chisel is held during cutting; working (cutting) part 3 has a wedge shape.
Figure 8 Bench chisel
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 medium hard materials (steel) - 60°;
For soft materials (copper, brass) - 45°;
For aluminum alloys - 35°.
Kreutzmeisel - a chisel with a narrow cutting edge (Figure 10), designed for cutting narrow grooves, keyways of low accuracy and cutting rivet heads. 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 , used in metal cutting are of two types: with round and with square briskly. The main characteristic of a hammer is its mass.
Hammers with a round face are numbered : 1st to 6th . Nominal weight of hammer No. 1 - 200 g; No. 2 - 400 g; No. 3 - 500 g; No. 4 - 600 g; No. 5 - 800 g; No. 6 - 1000 g. Square hammers are numbered from 1 to 8 and weight from 50 to 1000 g.
Hammers material - steel 50 (not lower) or U7 steel.
The working ends of the hammers are heat treated to hardness HRC 49-56 for a length equal to 1/5 of the total length of the hammer from both ends.
For locksmith work, hammers with a round striker No. 2 and 3, with a square striker No. 4 and 5 are used. The length of the hammer handle is approximately 300-350 mm.
metal cutting
Cutting - plumbing operation to separate the whole piece(blanks, parts) into parts. It is carried out without chip removal: with wire cutters, scissors and pipe cutters and with chip removal: with hacksaws, saws, cutters and special methods (gas cutting, anode-mechanical and electric spark cutting, plasma cutting).
The wire is cut with needle nose pliers (nippers), sheet material - with scissors; round, square, hexagonal and strip material of small sections - with hand saws, and large sections on cutting machines with hacksaw blades, circular circular saws, in special ways.
The essence of the operation of cutting metal with needle nose pliers (nippers) and scissors is to separate the wire, sheet or strip metal into parts under pressure of two wedges (cutting knives) moving towards each other.
Pliers cut (bite off) round steel parts and wire. They are made with a length of 125 and 150 mm (for cutting off wire with a diameter of up to 2 mm) and a length of 175 and 200 mm (for diameters up to 3 mm).
The cutting edges of the jaws are straight and sharpened at an angle of 55-60°. Cutters are made from U7, U8 carbon tool steel or steel 60-70. Sponges are thermally processed to hardness HRC 52-60.
Hand scissors designed for cutting sheet mild steel, brass, aluminum and other metals. They are made in lengths of 200 and 250 mm for cutting metal with a thickness of up to 0.5 mm, 320 mm (for a thickness of up to 0.75 mm), 400 mm (for a thickness of up to 1 mm).
The material of the scissors is steel 65, 70. The scissor blades are heat-treated to a hardness of HRC 52-58. The cutting edges of the blades are sharply sharpened at an angle of 70°. The blades of the scissors in the closed state mutually overlap, and the overlap at the ends does not exceed 2 mm.
Chair scissors cut sheet metal up to 3-5 mm thick. One of the handles of the scissors is bent at an angle of 90° and is rigidly attached to a table or other base. The length of the working handle of the scissors is 400-800 mm, the cutting part is 100-300 mm.
Lever scissors used for cutting sheet metal up to 5 mm thick. The scissors are made from U8A tool steel and heat treated to a hardness of HRC 52-58. The angle of sharpening of the cutting edges of the knives is 75-85°.
Pipe cutters Designed for manual cutting of thin-walled (gas) pipes made of mild steel, cutting is performed without removing chips. They are available in two sizes: for cutting pipes from 1/2 to 2" and for pipes - from 1 to 3".
The main parts of the pipe cutter are rollers: one cutting (working) and two guides. The pipe is cut by a working roller; at the same time, it is fixed on guide rollers and tightened with a screw.
Hand saw (Figure 9, a) is 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. They are made from U8-U12 or 9XC steels with the hardness of the cutting part HRC 58-61, the core - HRC 40-45. It consists of a frame 1 , tension screw with wing nut 2, handles 6, hacksaw blade 4, which is inserted into the slots of the heads 3 and fastened with pins 5.
 Figure 9 Hand saw a - device, b - sharpening angles, c - tooth setting "on the tooth", d - tooth setting "on the canvas". | Each tooth of the blade has the shape of a wedge (cutter). On it, as well as on the incisor, a rear angle is distinguished α, taper angle β , rake angle γ and cutting angle δ= α + β (Figure 9, b). When notching the teeth, it is taken into account that the resulting chips must be placed between the teeth before they exit the cut. Depending on the hardness of the materials being cut, the blade tooth angles can be: γ = 0-12°, β = 43-60° and α = 35-40°. In order for the width of the cut made by the hacksaw to be slightly larger than the thickness of the blade, the teeth are set “along the tooth” (Figure 9, in) or “along the canvas” (Figure 9, G). This prevents the blade from jamming and makes work easier. |
filing metal
filing called a locksmith operation, in which layers of material are removed from the surface of the workpiece using a file. It is usually carried out after cutting, peeling or cutting to give the necessary purity and accuracy to the workpiece.
File - This is a multi-blade cutting tool that provides relatively high accuracy and low roughness of the workpiece (part) surface to be machined.
With the help of files, planes, curved surfaces, grooves, grooves, holes of various shapes, surfaces located at different angles, etc. are processed.
A file (Figure 10, a) is a steel bar of a certain profile and length, on the surface of which there is a notch (cutting). The notch forms small and sharpened teeth, having a wedge shape in cross section.
notch can be single (simple), double (cross), rasp (point) or arc (Figure 10, b - e).
Files with single cut remove wide chips along the length of the entire notch. They are used for cutting soft metals.
Files with double notch used when filing steel, cast iron and other hard materials, as the cross notch crushes the chips, which makes it easier to work.
Rasp notch obtained by pressing the metal with special triangular chisels. Rasps work very soft metals and non-metallic materials.
Arc notch obtained by milling. It has an arcuate shape and large cavities between the teeth, which ensures high productivity and good surface quality.
Files are made from steel U10, U12, U13, as well as from alloyed chromium steel ШХ15 and 13Х. After notching the teeth, the files are heat treated to a hardness of at least HRC 54.
By appointment files are divided into the following groups: general purpose, special purpose, needle files, rasps, machine files.
Files are used for general plumbing work general purpose.
By number of notches files are subdivided into 1 cm length for 6 rooms .
Notched files No. 0 and 1 (bastard) have the largest teeth and are used for rough (rough) filing with an error of 0.5-0.2 mm.
Notched files No. 2 and 3 (personal) are used for fine filing of parts with an error of 0.15-0.02 mm.
Files with a notch No. 4 and 5 (velvet) are used for final fine finishing of products. Processing error - 0.01-0.005 mm.
By lenght files can be produced from 100 to 400 mm.
According to the shape of the cross section they are subdivided into flat, square, trihedral, round, semicircular, rhombic and hacksaw. For processing small parts, small-sized files are used - needle files.
Processing of hardened steel and hard alloys produced with special needle files, on the steel rod of which grains of artificial diamond are fixed.
Improving conditions and increasing labor productivity when filing metal is achieved through the use of mechanized (electric and pneumatic) files.
Threading
Threads are single pass formed by one helix (thread), or multiple formed by two or more threads.
In the direction of the helix, the threads are divided into right and left.
According to the shape of the thread profile, they are divided into triangular, rectangular, trapezoidal, stubborn(profile in the form of an unequal trapezoid) and round.
Depending on the sizing system, threads are divided into metric, inch, tubular and etc.
In a metric thread, the angle of the triangular profile α is 60 °, the outer, middle and inner diameters and the thread pitch are expressed in millimeters. Designation example: M20´1.5 (the first number is the outer diameter, the second is the pitch). In an inch thread, the angle of the triangular profile is 55 °, the diameter of the thread is expressed in inches, and the pitch is the number of threads per inch (1 inch \u003d 25.4 mm). Designation example: l ¼" (outside thread diameter in inches).
A pipe thread differs from an inch thread in that its initial size is not the outer diameter of the thread, but the diameter of the hole in the pipe, on the outer surface of which the thread is cut. Designation example: Pipes ¾" (numbers are the inner diameter of the pipe in inches).
Threading is performed on drilling and special thread-cutting machines, as well as manually. In the manual processing of metals, the internal thread is cut with taps, and the external thread is cut with dies.
 Figure 11 Elements and types of thread along the profile a - metric with a triangular profile; b - rectangular; in - trapezoidal symmetrical; g - trapezoidal asymmetric (thrust); d - round. | Taps by appointment divided into manual, machine-manual and machine, and depending on the profile of the thread to be cut- into three types: for metric, inch and pipe threads. Tap(Figure 12) consists of two main parts: the working part and the shank. The working part, in turn, consists of the intake (cutting) and guiding (calibrating) parts. The intaking (cutting) part performs the main work when threading and is usually made in the form of a cone. The calibrating (guide) part, as the name implies, guides the tap and calibrates the hole. Longitudinal grooves serve to form cutting blades with cutting edges and to accommodate chips in the threading process. The shank of the tap serves to secure it in the chuck or in the wrench during operation. |
To cut threads of a certain size, manual (locksmith's) taps are usually made in a set of three pieces.
The first and second taps pre-cut the thread, and the third give it the final size and shape. The number of each tap in the kit is marked by the number of notches on the tail. There are sets of two taps: preliminary (rough) and finishing.
Figure 12 Parts and elements of the tap
Taps are made from carbon steels U10A, U12A, high-speed R9, R18, alloyed 9XC, HVSG, etc. (hardness of the working part HRC 59-65, tail - HRC 30-45).
When cutting threads with a tap, it is important to choose the right drill diameter to obtain a threaded hole. The diameter of the hole should be slightly larger than the inner diameter of the thread, since the material will be partially extruded towards the axis of the hole when cutting. The dimensions of the threaded hole are selected according to the tables.
Dies , employees for cutting external threads, depending on the design, are divided into round and prismatic (sliding).
Figure 13 Round plate
Round die(Figure 13, a) is a whole or cut ring with a thread on the inner surface and grooves that serve to form cutting edges and chip exit. Round dies when cutting threads are fixed in a special wrench-die holder(Figure 14).
Figure 14 Die holder (turn)
Figure 15 Prismatic (sliding) die
a - klupp, b - sliding plate
Prismatic (sliding) dies (Figure 15), unlike round ones, consist of two halves, called half-dice. Each of them shows the dimensions of the thread and the number 1 or 2 for proper fixing in a special fixture (kluppe). The angular grooves (grooves) on the outer sides of the half-dies serve to install them in the corresponding protrusions of the die. Dies are made from the same materials as taps.
When cutting an external thread, it is also important to determine the diameter of the threaded rod, since in this case there is some extrusion of the metal and an increase in the outer diameter of the formed thread compared to the diameter of the rod. The thread diameter is selected according to special tables.
The following questions should be disclosed in the locksmith practice report
1 Locksmith operations
(Define operations and list the tool used.)
2 Characteristics of the main locksmith tools
2.1 Bench chisel
(Give a sketch of the chisel, sharpening angles for cutting different materials, steel grades, hardness.)
2.2 Files
(List the types of files, give a sketch of the file, steel grades, hardness.)
2.3 Taps and dies
(Describe the design of a tap and a round die, give a sketch, material, hardness.)
Markup.
Locksmith's workplace.
Topic. Basics of locksmith processing.
(independent study)
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. 48) - 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. 48 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 vise is rarely used, only for 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 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. 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.
chisel cut metal and cut off burrs. It has a working middle and impact parts. The working part of the chisel is wedge-shaped with a cutting part sharpened at a certain angle depending on the hardness of the metal being processed. The chisel is held for the middle part during cutting, the impact part (head) tapers upward and is rounded to center the blow.
Kreutzmeisel they cut out grooves and narrow grooves, and for cutting profile grooves they use special crosscuts - “grooves”, which differ in the shape of the cutting edge.
Chisels, crosscuts and groovers are made of steel U7, U7A, U8 and U8A. Their working and shock parts are hardened and released.
Locksmith hammers have a square or round shock part - a striker. The end of the hammer opposite the striker, which has the shape of a rounded wedge, is called the toe. It is used for riveting, straightening, etc.
Hammers are made of steel grades 50, 50X, U7 and U8. The working parts of the hammer (striker and toe) are hardened and released.
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.
Rivets are metal cylindrical rods with pre-planted heads. They are made from carbon steels, alloyed steels 09G2 and Kh18N9T, non-ferrous metals and alloys MZ, L62, AD1 and D18P. Several types of rivets are used: with a semicircular high or low head, with a flat head, with a countersunk and semi-secret head, explosive, two-chamber. Rivets with semicircular and countersunk heads are most often used. The second (closing) head of the rivet is planted during riveting.
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.
Files are made with single and double (cross) notch. According to their purpose, files are divided into groups: general purpose, special purpose, needle files, rasps, machine files. Depending on the number of notches per 1 cm of length, the files are divided into the following numbers: 0 and 1 - bastard, 2 and 3 - personal, 4 and 5 - velvet. Bastard files are used for rough filing, when it is necessary to remove a metal layer of more than 0.3 mm, the accuracy of their processing is low. For fine filing with an accuracy of 0.02 and 0.05 mm, personal files are used, the thickness of the metal layer removed by them is not higher than 0.02 and 0.06 mm. Velvet files are designed for final processing of parts with an accuracy of 0.01 ... 0.005 mm, the thickness of the metal layer removed by them is 0.01 ... 0.03 mm.
Files with a notch in the form of individual (point) teeth are called rasps. They are used for filing viscous and soft materials (babbitt, wood, etc.).
For processing small surfaces and finishing work, needle files are used. Files are available in lengths of 100, 125, 150, 200, 250, 300, 350 and 400 mm. According to the shape of the cross section, files are produced in eight types of flat
(pointed and blunt), square, round, semicircular, trihedral, rhombic and hacksaw.
In the process of obtaining and processing holes, drills are used, countersinks, countersinks and reamers.
In locksmithing, in some cases, holes are drilled and machined manually. In this case, the tool is rotated with manual, electric and pneumatic drills, as well as with the help of ratchets. With manual countersinking and reaming, the tool is fixed in the wrench and rotated, and the workpiece (just like when drilling) is clamped in a vice or other devices. It should be remembered that the work of a blunt or incorrectly sharpened tool on faulty equipment and fixtures causes tool breakage and defective parts.
Threaded connection- a reliable type of fastening of machine parts. It allows easy assembly, adjustment, disassembly.
A helical groove cut on the outer or inner cylindrical surface forms an external or internal thread, respectively. A thread profile is a section of its coil by a plane passing through the axis of the cylinder on which the thread is cut. Thread (coil) called the part of the thread formed during one complete revolution of the profile. Profile angle thread is called the angle enclosed between the sides of the thread profile. profile cavity- the section connecting the sides of the groove. thread pitch- the distance between two similar points of adjacent turns, measured parallel to the axis of the thread.
According to the thread profile, there are cylindrical triangular, conical triangular, rectangular, trapezoidal, persistent and round.
In mechanical engineering, three triangular thread systems are common: metric, inch and pipe. Metric thread has a profile angle of 60 °, is characterized by a pitch and a diameter expressed in the metric system of measures - millimeters. Inch thread has a profile angle of 55 °, the outer diameter is measured in inches (1 "is equal to 25.4 mm), the pitch is characterized by the number of threads per 1", rarely used. Pipe thread has an inch thread profile and is characterized by the number of threads 1", used to connect pipes.
Threading tools are taps and dies. They are made from steels U10A, U11A, U12A, 9XC and P18.
For threading holes, a set of two or three taps with different diameters of the working part (rough, medium and finish) is used. To distinguish the tap on its shank, circular risks are applied. The fine tap has three circular risks and is used for fine threading, as it has a full profile of the cutting part.
For cutting external threads, several types of dies are used: round, square, hexagonal and sliding prismatic.
The diameter of the drill to obtain a hole for a thread is determined from the tables or (with sufficient accuracy) by subtracting its pitch from the diameter of the thread. The diameter of the rod should be equal to the outer diameter of the thread being cut, but usually it is taken less by 0.3 ... 0.4 mm to obtain good quality threads.
Emulsion, kerosene, machine oil are used as lubricants.
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.
Scrapers are divided: by design (one-piece and with insert plates); by the number of cutting ends (one-sided and two-sided); according to the shape of the cutting part (flat, three-, four-sided and shaped).
For scraping planes, a flat scraper with a straight or curved cutting edge is used, the cutting part is sharpened for rough processing at an angle of 70 ... 75 °, and for finishing - 90 °. Internal cylindrical surfaces are treated with a trihedral scraper.
Calibration tools for scraping are plates, flat and angled rulers, rollers.
The process of preparation and scraping is carried out in the following sequence. The surfaces of the part are cleaned and wiped. A thin layer of paint (soot, azure, and others mixed with engine oil) is applied to the calibration plate and the part is carefully placed on the plate with the treated surface. Then the part is moved in a circular motion on the plate and carefully removed. On the treated surface, the most protruding places are slightly stained. In the process of scraping, the metal is gradually scraped off the painted areas by moving the scraper forward with slight pressure, each time in different directions so that the strokes cross at an angle of 90 °. With rough scraping, the working stroke of the tool is 10 ... 15 mm, and with finishing - 4 ... 5 mm.
To check the accuracy of scraping the planes, a frame of 25x25 mm in size is applied to them in several places and the number of spots in the area bounded by the frame is counted. Scraping is completed with the following number of spots: rough - 8 ... 10, semi-finish - 12, finish - 15, fine - 20, thin - 25. In addition, the surface should have a small and uniform stroke, without deep scraper marks. The accuracy of scraping curved surfaces is checked with a template - a grid.
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).
To prepare the grinding mixture, finely divided abrasive materials are used: electrocorundum, silicon carbide, boron carbide, synthetic diamonds, chromium oxide, etc. Machine oil, kerosene, stearin and petroleum jelly are used as a binding liquid.
When grinding, GOI pastes are widely used, containing in their composition, in addition to the abrasive and binder, surfactants, as well as diamond pastes.
The lapping material must be softer than the surface of the lapping material. It is usually made of gray cast iron, bronze, copper and wood. The shape and dimensions of the lap must be very precise, as they replicate the surface being machined.
For lapping planes, lapping plates are used, along which the parts are evenly moved in circular motions with slight pressure. By lapping on the plates, a high processing accuracy is obtained.
The inner conical surfaces are rubbed with conical lapping plugs, and the outer ones - in special lappings with a conical hole.
Lapping is carried out until the surface becomes matte or mirror. The quality is checked with paint, which should evenly lay down over the entire surface.
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.
Greetings friends! Let's discuss what types of plumbing operations exist. Let's not forget to understand in detail what they are intended for and how to perform them correctly in order to prevent jambs and injuries.
Locksmith operations. Who performs and what is it.
locksmith operations- this is a set of actions of a toolmaker or repairman performed by a special tool in a certain sequence. During these operations, the metal is subjected to manual processing. Seven sweats can break while you complete these works. This includes various adjustments and adjustments of parts, repair of mechanisms and assemblies.
By the way, I was inspired to write this post by the unexpected (for me) popularity of the post, which I recently published on my blog. I wrote it from my own experience at the factory. Glad you liked it.
Types of plumbing operations. Appointment and application.
To get started, check out this one video lesson about the main types of plumbing operations:
There are actually plenty of such works and we will talk about each operation separately. For some points, we will watch video materials to consolidate information.
1. Metal cutting.
When cutting metal, it is enough to clamp it in a vise and pick up a tool called a chisel. Please note that before you perform this locksmith operation, you must at least theoretically understand what you are doing. From the outside it looks simple and easy, but in fact there are a number of tricks.
For example, the angle of the chisel should be approximately 35 degrees. If more or less work will go very reluctantly. No need to cling to the death grip on the chisel. Hold it with 3-4 fingers with a little effort. Well, how to hit it with a hammer - it already depends only on you. Hit rhythmically and don't beat your fingers.
2. Part marking.
The main types of plumbing operations include such - markup. The locksmith takes tools such as a square, a pattern, a hammer, a chisel and even a special marking compass. He chooses devices depending on the complexity of the operation performed. Perhaps the most popular is a metal scriber, we will shine a separate post on it. Keep for updates.
Putting a sheet of metal in front of him, the locksmith begins to create. To begin with, he uses a regular pencil to apply preliminary markings. When the design of the future part is drawn, we put the pencil aside. Then a rough tool comes into play, which literally tears out (scratches) the contour of the part blank. When all the lines are applied, it is very easy to cut, cut or extrude the necessary part or workpiece along them.
3. Metal cutting.
Then I remembered my school years, and my daughter probably took classes in kindergarten. When you have made the markup, take the scissors and feel free to start cutting. To tell the truth, the process is not very pleasant. From the side it seems even cool to cut metal figures. In life, when metal scissors begin to dig into your fingers and cause unbearable pain, then there is no time for jokes. Out of habit, this type of plumbing operation causes great discomfort to the hands.
The more often you perform these actions, the painless this process will be. If the metal is thick or strong enough, the scissors will not take it. Here you will have to resort to hydraulic shears or a guillotine. The guillotine is not the one that has been used since 1791 for cutting off the head (which was invented by Joseph Guillotin), but a machine for cutting off sheets of metal. Watch the video - how to use metal shears.
4. Editing of metal.
We see in the figure two main options for editing metal. The top two figures show the case when shock loading is needed to correct the curved meanders of the metal. To do this, you need special hammers. The striker of such a metalworking tool is made of wood, brass, duralumin, plastic with a metal core, etc. The main condition for such a tool is that it must be softer than the workpiece that you are going to edit.
The second view shows how a piece of metal is corrected using a special tool (to increase torque) and a conventional metalwork vise. For straightening bars, special machines and devices are used. If you are interested in this topic, read more on the Internet, but rather take a book on plumbing. And we continue study the main types of plumbing operations.
5. Riveting. Creation of permanent connections.
I'll tell you right away. The connection of two sheets of metal with rivets by experienced locksmiths is called a “rivet seam”. The figure on the left shows stretch and support.
On the right is shown swage. The whole riveting process looks something like this.
The riveting process. Step-by-step instruction.
Today, there are already a lot of devices and automated machines for making a riveted seam. But they all work on the same principle. Classic is immortal..
Take a file in your hands and let's go. That's what our locksmith teacher told me. But in the process of filing, it is important not only to remove chips from the part, but also to maintain the size according to the sketch or drawing. Perform this metalworking operation with extreme care - there is a high probability of injury. When the work is completed, it is necessary to check the compliance of the part with the drawing parameters.
Inspection of the part after filing.
Everything is much simpler here. Attach the control square (or template) to the part and look at the clearance. There should be no gaps, or it will be minimal if allowed. Patterns can be varied depending on the detail.
7. Scraping or fitting surfaces.
scraping- This is a locksmith operation for particularly precise fitting of surfaces. Even today, this seemingly outdated method is relevant and mechanization is not acceptable. The process is as follows. Minium type paint is applied to the surface and a mating part is applied. All the irregularities that remain as a result of such an overlay are eliminated using a tool called a scraper.
Shabreni, I tell you, is not for the faint of heart. In terms of accuracy, it can be compared with jewelry. Such operations are used in the manufacture of guides production equipment, sliding bearings of machine carriages, etc. When scraping, it is possible to achieve a roughness of up to 0.32 Ra.
Types of plumbing operations. Conclusion.
And I say goodbye to you! ALL THE GOOD TO YOU!
Andrey was with you!
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 slide, 29 - turning on the longitudinal automatic feeding, 27 - button for turning on and off the main electric 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 feed motion of the tool 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. Toolholders are usually made from 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 trimming 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 vertical positions the planes of the workpiece and the application of 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. The file is a steel bar certain profile and length, on the surface of which there are notches (cuts) that form cavities 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); G - rhombic files are used for filing gears, disks and sprockets; Z - 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 handheld 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 drilled 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 part - 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 serve to form cutting edges and 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 for cutting metric thread in nuts in one working 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, resistance 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 welded metal 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 radiators for cooling valves, 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 of its ends 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 connection, thickness and chemical composition weld metal, as well as the temperature environment. 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 way 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.
The purpose of locksmith work is to give the workpiece the dimensions and surface finish specified by the drawing. These operations include: preparatory planar and spatial marking felling straightening bending metal cutting; dimensional processing operations that allow obtaining the specified geometric parameters and the necessary roughness of the machined surface, filing, drilling, countersinking and reaming of holes, threading; fitting providing high accuracy and low roughness...
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THEME 2
TYPES OF FITCHWORK
locksmith work- processing of metal blanks and products, supplementing machining or completing production. It is carried out with a manual assembly tool using fixtures and machine tools.
The purpose of plumbing work isgiving the workpiece the shape, dimensions and surface finish specified by the drawing.
These operations include:
preparatory- planar and spatial marking, felling, straightening, bending, metal cutting;
sizing operations, allowing to obtain the specified geometric parameters and the necessary roughness of the treated surface - filing, drilling, countersinking and reaming of holes, threading;
fitting , providing high accuracy and low surface roughness of mating parts - scraping, grinding, finishing.
1 Preparatory operations
1.1 Planar and spatial markings
markup - the operation of applying marking lines (marks) to the workpiece to be processed, which determine the contours of the future part or the place to be processed. The marking accuracy can reach 0.05 mm. Before marking, it is necessary to study the drawing of the part to be marked, to find out the features and dimensions of the part, its purpose.
The markup must meet the following basic requirements:
Exactly match the dimensions indicated on the drawing;
Marking lines (risks) should be clearly visible and not be erased during the processing of the workpiece.
To install the parts to be marked out, marking plates, linings, jacks and swivel devices are used. For marking, scribers, center punches, marking calipers and thickness gauges are used.
Depending on the shape of the blanks and parts to be marked, planar or spatial (volumetric) markings are used.
Planar markingsare performed on the surfaces of flat parts, as well as on strip and sheet material. When marking, contour lines (risks) are applied to the workpiece according to specified dimensions or according to templates.
Spatial markupmost common in mechanical engineering and differs significantly from planar. The difficulty of spatial marking is that it is necessary not only to mark the surfaces of the part located in different planes and at different angles to each other, but also to link the marking of these surfaces to each other.
Base - basing surface or base line, from which all dimensions are counted when marking. It is chosen according to the following rules:
If the workpiece has at least one machined surface, it is chosen as the base one;
In the absence of machined surfaces of the workpiece, the outer surface is taken as the base.
Preparation of blanks for markingbegins with its cleaning with a brush from dirt, scale, traces of corrosion. Then the workpiece is cleaned with sanding paper and degreased with white spirit.
Before painting the surface to be marked, it is necessary to make sure that there are no shells, cracks, burrs and other defects on the part.
To paint the surfaces of the workpiece before marking, the following compositions are used:
Chalk diluted in water;
Ordinary dry chalk. Dry chalk is rubbed on the marked untreated surfaces of small irresponsible blanks, since this color is fragile;
A solution of copper sulfate;
Alcohol varnish is used only for precise marking of the surfaces of small products.
The choice of coloring composition for application to the base surface depends on the type of workpiece material and the method of its preparation:
The raw surfaces of blanks made of ferrous and non-ferrous metals, obtained by forging, stamping or rolling, are painted with an aqueous solution of chalk;
The treated surfaces of blanks made of ferrous metals are painted with a solution of copper sulfate, which, when interacting with the material of the blank, forms a thin film of pure copper on its surface and provides a clear selection of marking marks;
The treated surfaces of non-ferrous metal blanks are painted with quick-drying varnishes.
Markup methods
Template markupused in the manufacture of large batches of parts of the same shape and size, sometimes for marking small batches of complex workpieces.
Sample markupused in repair work, when dimensions are taken directly from the failed part and transferred to the marked material. This takes into account wear. A sample differs from a template in that it has a one-time use.
Markup in placeproduced when the parts are mating and one of them is connected to the other in a certain position. In this case, one of the details acts as a template.
Pencil markingproduced in a line on billets of aluminum and duralumin. When marking blanks from these materials, scribers are not used, since when drawing marks, the protective layer is destroyed and conditions are created for the appearance of corrosion.
Marriage at marking, i.e. non-compliance of the dimensions of the marked workpiece with the drawing data, occurs due to the inattention of the marker or the inaccuracy of the marking tool, the dirty surface of the plate or workpiece.
1.2 Cutting metal
metal cutting this is an operation in which excess layers of metal are removed from the surface of the workpiece or the workpiece is cut into pieces. Cutting is carried out using a cutting and impact tool. The cutting tool for cutting is a chisel, a cross-cutting tool and a groover. Percussion tool metalwork hammer.
Destination felling:
Removal of large irregularities from the workpiece, removal of a hard crust, scale;
- cutting out keyways and lubrication grooves;
Cutting the edges of cracks in parts for welding;
Cutting off the heads of rivets when they are removed;
Punching holes in sheet material.
Cutting bar, strip or sheet material.
The cabin can be fair and rough. In the first case, a layer of metal 0.5 mm thick is removed with a chisel in one pass, in the second - up to 2 mm. The processing accuracy achieved during felling is 0.4 mm.
1.3 Editing and straightening
Editing and straightening -operations for straightening metal, blanks and parts with dents, waviness, curvature and other defects.
Dressing can be done manually on a steel straightening plate or cast iron anvil and by machine on straightening rollers, presses and special devices.
Manual dressing is used when processing small batches of parts. Enterprises use machine editing.
1.4 Bending
bending operation, as a result of which the workpiece takes the required shape and dimensions due to the stretching of the outer layers of the metal and the compression of the inner ones. Bending is performed manually with soft-faced hammers on a bending plate or with the help of special devices. Thin sheet metal is bent with mallets, wire products with a diameter of up to 3 mm with pliers or round nose pliers. Only ductile material is subjected to bending.
1.5 Cutting
Cutting (cutting) -separation of bar or sheet metal into parts using a hacksaw blade, scissors or other cutting tool. Cutting can be done with or without chip removal. When cutting metal with a hand saw, on hacksaw and turning-cutting machines, chips are removed. Cutting materials with manual lever and mechanical scissors, press shears, wire cutters and pipe cutters is carried out without removing chips.
2 Dimensional processing
2.1 Sawing metal
Filing an operation to remove a layer of material from the surface of the workpiece using a cutting tool manually or on filing machines.
The main working tools for filing are files, needle files and rasps.
With the help of files, flat and curved surfaces, grooves, grooves, holes of any shape are processed.
Filing accuracy up to 0.05 mm.
2.2 Holemaking
When processing holes, three types of operations are used: drilling, reaming, reaming and their varieties: reaming, countersinking, countersinking.
drilling an operation to form through and blind holes in a solid material. It is carried out using a cutting tool - a drill that performs rotational and translational movements about its axis.
Purpose of drilling:
Obtaining irresponsible holes with a low degree of accuracy and a class of roughness of the machined surface (for example, for fixing bolts, rivets, studs, etc.);
Obtaining holes for threading, reaming and countersinking.
Reaming enlargement of a hole in a solid material obtained by casting, forging or stamping.
If you want to high quality machined surface, then the hole after drilling is additionally reamed and reamed.
Countersinking processing of cylindrical and conical pre-drilled holes in parts with a special cutting tool - a countersink. The purpose of countersinking is to increase the diameter, improve the quality of the machined surface, increase accuracy (reduce taper, ovality). Countersinking can be the final operation of hole processing or an intermediate operation before hole reaming.
countersinking this is the processing of a special tool countersink cylindrical or conical recesses and chamfers of drilled holes for the heads of bolts, screws and rivets.
Spotting produced counterbores for cleaning end surfaces. Counterbores process bosses for washers, thrust rings, nuts.
Deployment is a hole finishing that provides the highest accuracy and surface finish. The reaming of holes is carried out with a special tool reamers on drilling and turning machines or manually
2.3 Finishing threaded surfaces
Threaded Surface Finishing this is an operation carried out by removing a layer of material (chips) from the surface to be machined (threading) or without removing chips, i.e. plastic deformation (thread rolling).
3 Fitting operations
3.1 Scraping
scraping the operation of scraping very thin layers of metal from the surfaces of the workpiece with a cutting tool scraper. With the help of scraping, a snug fit of the mating surfaces and tightness of the connection are ensured. Scraping process rectilinear and curved surfaces manually or on machines.
In one pass, the scraper removes a layer of metal with a thickness of 0.005 ... 0.07 mm, while achieving high accuracy and surface finish.
In tool production, scraping is used as a final treatment of non-hardened surfaces.
The widespread use of scraping is explained by the fact that the scraped surface is very wear-resistant and retains lubricants longer.
Sawing processing holes with a file in order to give them the desired shape. The processing of round holes is carried out with round and semicircular files; triangular holes triangular, hacksaw and rhombic files; square square files.
Preparation for sawing begins with marking and punching the marking marks, then drill holes along the marking marks and cut out the armholes formed by drilling. Before marking the surface of the workpiece, it is desirable to process it with sandpaper.
Fit processing of the workpiece according to the finished part in order to connect two mating parts. Fitting is used in repair work and assembly of single products. For any fitting work, sharp edges and burrs on the parts are smoothed out with a personal file.
fitting precise mutual adjustment by filing mating parts connected without gaps (light gap no more than 0.002 mm).
Fit both closed and semi-closed contours. One of the attached parts (with a hole, an opening) is called an armhole, and the part included in the armhole is called an insert.
Fitting is carried out with files with a fine and very fine notch No. 2; 3; 4 and 5, as well as abrasive powders and pastes.
Lapping processing of blanks of parts working in pairs to ensure tight contact of their working surfaces.
fine-tuning Finishing workpieces in order to obtain accurate dimensions and low surface roughness. Finished surfaces resist wear and corrosion well.
Lapping and finishing is carried out with abrasive powders or pastes applied to a special tool - lapping or to the surfaces to be treated.
Lapping accuracy 0.001 ... 0.002 mm. In mechanical engineering, hydraulic steam, plugs and valve bodies, valves and engine seats, working surfaces of measuring instruments, etc. are subjected to grinding.
Lapping is carried out with a special tool - lapping, the shape of which must correspond to the shape of the surface to be ground. By shape, laps are divided into flat, cylindrical (rods and rings), threaded and special (spherical and irregular shapes).
Polishing (polishing)is the processing (finishing) of materials to obtain a mirror finish of the surface without ensuring accuracy and dimensions. Polishing of metals is carried out on polishing machines with fast-rotating soft circles made of felt or cloth or fast-rotating belts, on the surface of which polishing paste or fine abrasive grains are applied. In some cases, electrolytic polishing is used.
In the process of lapping, it is necessary to clean the surface to be treated not with a hand, but with a rag; use protective devices for suction of abrasive dust; be careful with pastes, as they contain acids; securely and stably install laps; observe safety precautions when working with mechanized tools, as well as on machine tools.
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