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Marking operation as part of the technological process. Spatial layout

markup

markup

1) a locksmith operation, which consists in preparing a part or several parts of a product for processing, manufacturing, assembly. When marking, they use tools and fixtures that are necessary to determine the dimensions, check the relative position of the planes of the part, the axes of the holes, the parallelism of lines, etc. marking plate- a massive steel plate with a well-finished surface. Cylindrical parts for marking are fixed on a special prism with a clamping bolt. Marking consists in drawing lines and dots on the workpiece, indicating the contours of the part to be marked. For this purpose, a scriber is also used. According to the drawing, sample or in place in accordance with the dimensions of the interface (as if fitting), auxiliary and center marks are applied, as well as lines for precise positioning of the workpiece on the machine. Measurements are performed using a square (checking the mutual perpendicularity of the axes and planes), goniometer (location of oblique surfaces and edges), calipers (comparison of hole diameters, length, thickness, etc.), thickness gauge (drawing parallel lines), gauge gauge and others caliper tools, level (determining the horizontalness of the surface), etc.

1 - marking plate; 2 - marking box; 3 - center punch; 4 - scriber; 5 - compass; 6 - prism for fixing cylindrical parts; 7 - square; 8 - goniometer; nine - ; ten - ; 11 - level

2) Road marking- lines and signs on the carriageway of streets and roads, as well as on bridge supports, curbs, etc., establishing the traffic order and helping to navigate the traffic situation.

Encyclopedia "Technology". - M.: Rosman. 2006 .


Synonyms:

See what "markup" is in other dictionaries:

    Label, marking; application, measurement, marking, layout, size Dictionary of Russian synonyms. markup noun, number of synonyms: 10 wiki markup (1) ... Synonym dictionary

    LAYOUT- drawing on the difference to be machined To Art. Marking Tools and devices used for marking: 1 marking plate; 2 marking box; 3 punch; 4 scribers; 5 compasses; 6 prism for fixing cylindrical ... ... Great Polytechnic Encyclopedia

    Dictionary Ushakov

    MARKING, markings, pl. no, female (specialist.). The same as the layout in 1 digit. Explanatory Dictionary of Ushakov. D.N. Ushakov. 1935 1940 ... Explanatory Dictionary of Ushakov

    MARK, sword, mark; curly; owl., what. Arrange icons, labels. R. fonts (for typesetting). Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

    - (Marking) the operation of transferring points and lines from the drawing to the workpiece to indicate the places and size of subsequent processing. Samoilov K.I. Marine Dictionary. M. L .: State Naval Publishing House of the NKVMF of the USSR, 1941 ... Marine Dictionary

    FES elements are linear, flat and three-dimensional figures, which are made both in the form of products and applied to the surface at the location. Note: Lines and figures are used to designate alone or in combination with inscriptions and ... ... Emergencies Dictionary

    markup- Transferring from the drawing to the surface of the workpiece the contour, points and lines of processing the future part in full size [ Terminological dictionary on construction in 12 languages ​​(VNIIIS Gosstroy of the USSR)] EN marking outsetting out DE AnreißenAnzeichnen FR… … Technical Translator's Handbook

    markup- 3.6 markup: FES elements are linear, flat and three-dimensional figures, which are made both in the form of products and applied to surfaces at placements. Note Lines and figures are used to designate alone or in combination with inscriptions ... Dictionary-reference book of terms of normative and technical documentation

    Locksmith operation, which consists in applying recesses (cores) and lines (rises) to the surface of the workpiece, defining the contours of the manufactured part or the place to be processed. According to the risks, the Allowance is removed from the workpiece during processing. R … Great Soviet Encyclopedia

    Markup: Road markings Unified network markings Signal markings Workpiece markings Markup language ... Wikipedia

Books

  • Road signs and road markings (set of 10 posters), Posters of the series are intended for specialists of auto enterprises, students of driving schools, universities, colleges, training centers, vocational schools, the program of which provides for the study ... Category: Driving school teachers. Visual aids. Posters Publisher: Third Rome,
  • New road signs and markings for 2018 , , V recent times cases of complaints and appeals from citizens on the issue of bringing them to administrative responsibility for violating the rules have become more frequent in the Department of Traffic Safety of the Ministry of Internal Affairs of Russia ...

Marking work in plumbing are an auxiliary technological operation that consists in transferring contour constructions according to the dimensions of the drawing to the workpiece.

markup- this is an operation to apply lines (marks) to the surface of the workpiece,

defining the contours of the manufactured part, which is part of some

technological operations.

Planar markings used in the processing of sheet material and profile

rolled products, as well as parts on which marking risks are applied in the same plane.

Planar marking consists in drawing on the material or workpiece contour lines: parallel and perpendicular, circles, arcs, angles, various geometric shapes along given dimensions or contours according to templates. contour lines applied in the form of continuous risks.

In order for traces of risks to be preserved until the end of processing, small depressions are applied to the risks using a center punch, close to one another, or a control risk is applied next to the marking risk. Risks should be subtle and clear.

Spatial markup - this is the application of scratches on the surfaces of the workpiece, interconnected by mutual arrangement.

Planar marking is made on the workpiece with a scriber. Accuracy at

marking is achieved up to 0.5 mm. Marking risks with a scriber are carried out once.

The depth of the core hole is 0.5mm. When performing practical

tasks scriber and marking compasses can be kept on a locksmith's workbench.

At the end of work, it is necessary to remove dust and scale from the marking plate with a sweeping brush. When performing a practical task, it is necessary to press the ruler against the workpiece with three fingers of the left hand so that there is no gap between it and the workpiece. When punching long notches (more than 150mm), the distance between the recesses should be 25..30mm. When punching short marks (less than 150 mm), the distance between the recesses should be 10..15 mm. Before setting the compass to the size of the arc radius, the center of the future arc must be punched. To set the compass to the size, you need to set one leg of the compass with the tip at the tenth division of the ruler, and the second - the endowment, exceeding the specified one by 10 mm. Angles, less

90º, measured with a goniometer using a square. With planar marking

parallel risks are applied using a ruler and a square. When marking on

plate of a circle of a given diameter, you need to set the compass to the size

exceeding the radius of the circle by 8..10mm.

The following tools are used to mark, measure and verify the correctness of manufacturing products: ruler, square, compass, caliper, caliper, inside gauge, scale and pattern ruler, protractor, scriber, center punch, marking plate. As devices that speed up the marking process, templates, patterns, stencils are used.



Scriber should be convenient for drawing clear lines on the surface to be marked and, together

so as not to spoil the working planes of the ruler, square. Scribe material

selected depending on the properties of the marked surfaces. For example,

brass scriber leaves a clearly visible mark on the surface of the steel. At

marking parts made of softer materials, it is advisable to use

pencil. Before marking on a plane, it is better to apply a thin layer of water-based paint.

Center punches are used for drawing the centers of circles and holes on the marked

surfaces. The cores are made from solid steel. The center punch length is from 90

up to 150mm and diameter from 8 to 13mm.

As a percussion tool when making core holes, use

a metalwork hammer, which should be light in weight. Depending on whether

how deep the core hole should be, use hammers weighing from 50 to 200g.

Protractor steel with a goniometer is used for marking and checking corners when

production of mating pipe assemblies, fittings and other parts

Air ducts.

Marking compasses used to draw circles

arcs and various geometric constructions, as well as for transferring

sizes from a ruler to a marking blank or vice versa. There are rack and pinion compasses,

thickness gauges, calipers, calipers, calipers.

Marking plates installed on special stands and cabinets with storage boxes

14

marking tools and fixtures. Small marking plates are placed on the tables. The working surfaces of the marking plate should not have significant deviations from the plane.

Various geometric figures applied on the plane with the same marking tool: ruler, square, compass and protractor. To speed up and

simplify planar markings identical products, sheet steel templates are used.

A template is applied to the workpiece or material and pressed tightly so that it does not budge during marking. Lines are drawn along the contour of the template with a scriber, indicating the contours of the workpiece.

Large parts are marked on the plate, and small parts are marked in a vise. If the product is hollow, for example, a flange, then a wooden cork is driven into the hole and a metal plate is fixed in the center of the cork, on which the center for the leg of the compass is marked with a center punch.

The flange is marked as follows. The surface of the workpiece is painted with chalk, the center is marked and circles are drawn with a compass: the outer contour, the contour of the hole and the center line along the centers of the bolt holes. Often the flanges are marked according to the template, and the holes are drilled along the conductor without marking.

The marking is carried out using various tools and devices, which include a scriber, a compass, a thickness gauge, a gauge gauge, a scale altimeter, squares, center finder squares, punches, a bell, a hammer, a marking plate,

The scriber is used to draw lines (marks) on the surface to be marked using a ruler, square or template. When drawing a scriber, the scriber is held in the hand like a pencil, pressing it tightly against the ruler or template and tilting it slightly in the direction of movement so that it does not tremble. The risk is carried out only once, then it turns out to be clean and correct. The methods of using the scriber are shown in fig. one.

Rice. Fig. 1. Scriber and its application: a - scriber, b - two positions of the scriber when drawing a risk: correct (left) and incorrect (right), c - applying a risk with the curved end of the scriber

The scriber is made of carbon tool steel U10-U12. Its ends are hardened over a length of about 20 mm. The scriber is sharpened for grinding machine, while it is held with the left hand by the middle, and with the right hand by the non-sharpened end. Having attached the tip of the scriber to a rotating stone, they evenly rotate it with the fingers of both hands around the longitudinal axis.

The compass is used to transfer linear dimensions from the scale bar to the workpiece, divide lines into equal parts for constructing angles, mark circles and curves, to measure the distances between two points, followed by determining the size using the scale bar.

There are simple marking compasses (Fig. 2, a) and spring ones (Fig. 2, b). A simple compass consists of two hinged legs, solid or with inserted needles. To fix the open legs in the required position, an arc is attached to one of them

Rice. 2. Compasses: a - simple, b - spring

At the spring compass, the legs are connected by a spring ring. Breeding and convergence of the legs is carried out by rotation in one direction or another of the split nut along the set screw.

The legs of the compass are made of steel grades 45 and 50. The ends of the working parts of the legs are hardened over a length of about 20 mm.

The thickness gauge is used to draw parallel, vertical and horizontal lines, as well as to check the installation of parts on the plate. The thickness gauge consists of a cast-iron base, stand and scriber. The scriber can be fixed anywhere on the rack, rotated around the axis and tilted at any angle. On fig. 3b shows various types of thickness gauges and how to use them.

Rice. 3. Thickness gauge and its application: a - general view of the thickness gauge: 1 - base, 2 - stand, 3 - scriber needle, 4 - set screw for setting the needle to the exact size setting, 5 - thrust pins; b - some methods of using the thicknesser: 1 - drawing parallel risks (thrust pins of the thicknesser are lowered with springs, and the thicknesser rests against the edge of the marked tile), 2 and 3 - drawing risks at different positions of the thicknesser needle, 4 and 5 - drawing circular risks on disks; c - thickness gauges for marking sheet material: 1 - sliding thickness gauge with precise setting on the size, 2 - plate for drawing marks from the edge of the sheet at one certain distance from it, 3 - sliding sliding thickness gauge with setting the size according to the scale bar

Scale altimeter. In addition to the previously described scale ruler, which is used to determine linear dimensions and draw straight lines on the surface of the marked workpieces, a scale altimeter is used to measure distances and lay off vertical dimensions.

The marking caliper is intended for drawing circles of large diameters. It consists of a rod with millimeter divisions and two legs - fixed and movable with nonius. The legs, fixed in the required position with locking screws, have insertion needles that can be placed higher or lower, which is very convenient when describing a circle at different levels.

Rice. 4. Scale altimeter (surface gauge nearby)

Rice. 5. Marking caliper with inserted needles: 1 - fixed leg, 2 - bar, 3 - locking screw for fixing the frame, 4 - frame with vernier, 5 - one hundred. stopper screw for fastening the insertion needle, 6 - movable leg, 7 - insertion needles

On fig. 6 shows another type of marking caliper for more accurate marking of straight lines and centers and shows examples of its use.

Height gauge is used to check the heights and more accurate drawing of center and other marking lines on the treated surfaces.

Squares are used to draw vertical and horizontal lines on the surfaces to be marked, to check the correct installation of parts on the plate, as well as to mark sheet and strip material, center-finder squares are used to apply marks passing through the center to the ends of round products. The center finder square (Fig. 30) consists of two strips connected at an angle; the working edge of the ruler passes through the middle of the corner. The connection bar is used for the rigidity of the instrument. When marking the centers, the part to be marked is placed on the end. A square is applied to the upper end so that the planks connected at an angle touch the part. On the line with a scriber, a risk is drawn. Then the part or square is rotated by about 90 ° and a second risk is drawn. The intersection of the notches defines the center of the end face of the part.

Rice. 6. Caliper for accurate marking of straight lines and centers (a) and its application (b)

Rice. 7. Weight gauge: 1 - rod, 2 - frame clamp, 3 - frame, 4 - base, 5 - leg for measuring trot, 6 - vernier, 7 - micrometric frame feed, 8 - leg for marking

Rice. 8. Marking square and its application. a - a square with a shelf, b - installation of a square when drawing (or checking) vertical lines, c - position of a square when drawing lines in a horizontal plane

The center punch is used to make small indentations on the risks. This tool is a round rod with a knurling in the middle part, at one end of which there is a conical point with an angle at the tip of 45-60 °; the other end of the center punch is drawn to a cone; on this end, when punching, strikes with a hammer.

Rice. 9. Square-centre finder

Rice. 10. Punch

Center punches are made from U7A carbon tool steel. Their working part (point) is hardened at a length of about 20 mm, and the impact part at a length of about 15 mm.

The tip of the center punch is sharpened on a grinding machine, fixing the center punch in the chuck; in no case should you hold the center punch in your hands when sharpening.

When punching, the center punch is taken with three fingers of the left hand - thumb, index and middle, as shown in Fig. 32. The tip of the center punch is set exactly in the middle of the risks or at the point of intersection of the risks. Before the impact, the center punch is slightly tilted away from itself in order to place it more accurately, and at the moment of impact, without moving the center punch from the risks, they place it vertically. Hammer strikes are easy.

The hammer for striking the center punch should be light in weight, approximately 50-100 g.

A bell is a special device that makes it easy and convenient to mark the center and punch center holes at the ends of round parts. The device is placed on the end of the part with a conical hole; in this case, the center punch of the bell is automatically set in the center of the end face of the part. With a light hammer blow on the center punch, the center is marked.

Rice. Fig. 11. Piercing: a - installation of a center punch at risk, b - position of the center punch when struck with a hammer, c - marked and punched part before processing (above) and after processing (below)

Rice. 12. Bell for punching centers

Rice. 13. Spring punch

The spring punch has a body screwed in three parts. Two springs are placed in the body, a rod with a center punch, a striker with a shifting cracker and a flat spring. When punching, i.e. when you press the product with the tip of the center punch, the inner end of the rod rests against the cracker, as a result of which the drummer moves up and compresses the spring. Leaning against the rib of the shoulder, cracker

moves to the side, and its edge comes off the rod. At this moment, the drummer, under the action of the force of a compressed spring, delivers a strong blow to the end of the rod with a center punch. Immediately after this, the initial position of the center punch is restored by the spring.

The electric punch consists of a body, springs, a striker, a coil with a winding of varnished wire, a punch. When you press the point of the center punch installed at risk, the electric circuit closes and the current passing through the coil creates a magnetic field, the drummer is instantly drawn into the coil and strikes the center punch rod. During the transfer of the center punch to another point, the spring opens the circuit, and the spring returns the drummer to its original position.

Rice. 14. Electric punch

Rice. 15. Marking plate on the table

Marking plate - the main device for marking. It is a cast iron plig with a finely machined top surface and sides. On the plane of the plate, the product to be marked is installed and the markup is made. The surface of the marking plate must be protected from damage and impact. At the end of the marking, the plate is wiped with a dry, clean cloth or washed with kerosene and oiled, then covered with a protective wooden shield.

When marking, various devices are used in the form of linings, prisms, cubes.

The main stages of markup

Before marking, the workpiece is carefully examined, checking whether it has defects - shells, bubbles, cracks, captivity, distortions, whether its dimensions are correct, whether the allowances are sufficient. After that, the surface intended for marking is cleaned of scale and molding earth residues and irregularities (nibbles, burrs) are removed from it, then painting is started.

The coloring of the workpiece is carried out so that the marking lines are clearly visible during processing. Black, i.e., untreated, as well as roughly processed surfaces, are painted with chalk, quick-drying paints or varnishes. Chalk (powder) is diluted in water to the density of milk, and a little linseed oil and a desiccant are added to the resulting mass. It is not recommended to rub the surface to be marked with a piece of chalk, as the chalk quickly crumbles and the marking lines disappear.

Copper sulphate is used for painting cleanly treated surfaces - in solution or in pieces. A solution of copper sulfate (two or three teaspoons per glass of water) is applied to the surface with a brush or cloth; lump vitriol rub the surfaces moistened with water. In both cases, the surface is covered with a thin and durable copper layer, on which marking lines are clearly visible.

Before applying marking marks to a painted surface, a base is determined from which risks will be applied. For planar marking, the outer edges of flat parts, strip and sheet material, as well as various lines applied to the surface, for example, center, middle, horizontal, vertical or inclined, can serve as bases. If the base is the outer edge (lower, upper ^ or side), then it must first be aligned.

The risks are usually applied in the following order: first all the horizontal risks are drawn, then the vertical ones, then the inclined ones, and finally the circles, arcs and roundings.

Since the risks during operation are easy to wipe with your hands and then they will become poorly visible, small depressions are filled along the lines of the risks with a center punch. These recesses - cores should be shallow and divided by a risk in half.

Distances between center punches are determined by eye. On long lines of a simple outline, these distances are taken from 20 to 100 mm; on short lines, as well as in corners, bends or roundings - from 5 to 10 mm.

On the machined surfaces of precision products, the marking lines do not kern.

Markup by templates and by product in plumbing

A template (Fig. 1) is the simplest device used to manufacture or check homogeneous parts or products in serial and mass production. Marking templates are used to mark parts that are repeated in production and whose shapes do not often change. Templates are made of sheet steel with a thickness of 1.5 to 4 mm.

Depending on the quantity, accuracy and size of the parts to be marked, the templates can be hardened and non-hardened.

Rice. 1. Templates: 1 - for marking the contour of a flat part. 2 - for marking the keyway, 3 - for marking holes

Marking circles, centers and holes in plumbing

When marking, all geometric constructions are made using two lines - a straight line and a circle (in Fig. 38, elements of a circle are shown with integer repetition).

A straight line is shown as a line drawn with a ruler. A line drawn along a ruler will only be straight if the ruler itself is correct, that is, if its edge represents a straight line. To check the correctness of the ruler, two points are taken arbitrarily and, having attached an edge to them, draw a line; then they shift the ruler on the other side of these points and again draw a line along the same edge. If the ruler is true, then both lines will match, if not true, the lines will not match.

Rice. 1. Circle and its elements

Circle. Finding the center of a circle. On flat parts, where there are already finished holes, the center of which is unknown, the center is found geometrically. At the ends of cylindrical parts, the center is found using a compass, thickness gauge, square, center finder, bell (Fig. 2).

The geometric method for finding the center is as follows (Fig. 2, a). Let a flat metal plate be given with a ready-made hole, the center of which is unknown. Before marking begins, a wide wooden block is inserted into the hole and a tinplate metal plate is stuffed onto it. Then, on the edge of the hole, three points L, B and C are slightly arbitrarily marked, and from each pair of these points AB and BC arcs are described until they intersect at points 1, 2, 3,4; draw two straight lines towards the center until they intersect at point O. The point of intersection of these lines will be the desired center of the hole.

Rice. 2. Finding the center of the circle: a - geometrically, b - marking the center with a compass, c - marking the center with a thickness gauge, d - marking the centers along a square, d - punching with a bell

Marking the center with a compass (Fig. 2b). Clamping the part in a vice, spread the legs of the compass a little more or less than the radius of the part to be marked. After that, by attaching one leg of the compass to the side surface of the part and holding it with your thumb, an arc is outlined with the other leg of the compass. Next, the compass is moved on the circle (by eye) and the second arc is outlined in the same way; then, through each quarter of the circle, the third and fourth arcs are outlined., The center of the circle will be inside the outlined arcs; it is stuffed with a center punch (by eye). This method is used when high accuracy is not required.

Marking the center with a thickness gauge. The part is placed on prisms or parallel pads laid on a marking plate. The sharp end of the thickness gauge needle is set slightly above or below the center of the part to be marked and, holding the part with the left hand, move the thickness gauge along the plate with the right hand, drawing it with a needle at the end of the part at a short risk. After that, the part is rotated on! D circles and the second risk is carried out in the same way. The same is repeated every quarter turn for the third and fourth risks. Inside the risks there will be a center; it is stuffed in the middle with a center punch (by eye).

Marking the center on the square. A square-centre-finder is applied to the end of the cylindrical part. Pressing it with your left hand to the part, draw with your right hand along the ruler of the center finder with the help of a scriber at risk. After that, the part is turned approximately on the ‘/’ circle and the second risk is drawn with a scriber. The intersection point of the marks will be the center of the butt, which is stuffed with a center punch.

Rice. 3. Dividing the circle into parts

Marking the center with a bell (Fig. 2e). The bell is mounted on the end of the cylindrical part. Holding the bell with the left hand in a vertical position, with the right hand strike with a hammer on the center punch located in the bell. The punch will make a recess in the center of the butt.

Division of a circle into equal parts. When marking circles, you often have to divide them into several equal parts - 3, 4, 5, 6 or more. Below are examples of Dividing a circle into equal parts in a geometric way and using a table.

Division of a circle into three equal parts. First draw the diameter AB. From point A, arcs are described with the radius of this circle that intersect points C and D on the circle. Points B, C and D obtained from this construction will be points dividing the circle into three equal parts.

Division of a circle into four equal parts. For such a division, two mutually perpendicular diameters are drawn through the center of the Circle.

Division of a circle into five equal parts. Two mutually perpendicular diameters are drawn on this circle, intersecting the circle at points A and B, C and D. The radius OA is divided in half, and from the resulting point B an arc with a radius BC is described until it intersects at point F at the radius OB. After that, the straight points D and F are connected. Putting aside the length of the straight line DF along the circumference, divide it into five equal parts.

Division of a circle into six equal parts. A diameter is drawn that intersects the circle at points A and B. The radius of this circle describes four arcs from points A and B until they intersect with the circle. The points A, C, D, B, E, F obtained by this construction divide the circle into six equal parts.

Dividing a circle into equal parts using a table. The table has two columns. The numbers in the first column show how many equal parts the given circle should be divided into. The second column contains the numbers by which the radius of the given circle is multiplied. As a result of multiplying the number taken from the second column by the radius of the marked circle, the value of the chord is obtained, that is, the distance along the straight line between divisions of the circle.

Setting aside the resulting distance on the marked circle with a compass, we divide it into 13 equal parts.

Marking holes on parts. The marking of holes for bolts and studs in flat parts, rings and flanges for pipes and cylinders of machines requires special attention. The centers of the holes of bolts and studs must be exactly located (marked) around the circumference so that when two mating parts are superimposed, the corresponding holes fall strictly one under the other.

After the marked circle is divided into parts and the centers of the holes are punched in the appropriate places along this circle, they start marking the holes. When punching the centers, first the recess is punched only slightly and then the equality of the distance between the centers is checked with a compass. Only after making sure that the markup is correct, the centers are finally punched.

The holes are marked with two circles from the same center. The first circle is drawn with a radius according to the size of the hole, and the second, as a control, with a radius 1.5-2 mm larger than the first. This is necessary so that when drilling it can be seen whether the center has shifted and whether drilling is proceeding correctly. The first circle is punched: 4 cores are made for small holes, 6-8 or more for large holes.

Rice. 5. Hole marking: 1 - a marked ring, 2 - a wooden plank hammered into a hole, 3 - drawing a circle, 4 - marking holes, 5 - marked holes, 6 - a circle of hole centers, 7 - a control circle, 8 - cores

Marking corners and slopes in plumbing

When marking, you have to build different angles, more often at 90, 45, 60, 120, 135, 30 °.

To measure angles, special tools are used - a protractor and a goniometer.

The protractor has the shape of a semicircle divided into 180 equal parts. The center of the semicircle is indicated by a small notch O. When measuring an angle with a protractor, it is superimposed on the angle so that the top of the angle coincides with the Center of the protractor and one of the sides of the angle coincides with the base line of the inner semicircle. Then, on the scale of the protractor, the degrees enclosed between it and the second side of the angle are counted from this side of the angle. The goniometer (Fig. 43) consists of two disks sitting on the same axis. The disk with divisions in degrees printed on it is one with a fixed ruler. The second - a rotary disk with a vernier fixed on it is connected to a movable ruler, which can be set to the required length and fixed with a screw. When the disk is rotated, the ruler rotates and as a result, full contact of the edges of both rulers with the sides of the angle being measured is achieved. After that, both rulers are fixed with a screw. When measuring, whole degrees are counted across the disk, starting from zero to the right or left, to the zero division of the vernier; minutes are counted on the vernier also from zero - until the division of the vernier coincides with the division on the disk. The accuracy of measurements with a universal protractor can be increased to 5 minutes.

Rice. 1. Universal goniometer and its application: a - goniometer device: 1 - disk, 2 - rotary disk, 3 - hinged screw, 4 - movable ruler, 5 - fixed goniometer ruler; b - goniometer measurements

Rice. 2. Construction of perpendicular lines: o-line intersecting line AB in the middle, b - perpendicular to line AB at point C on the line, a - perpendicular to line AB from point C, not on this line, d - perpendicular at the end of line AB

The marking of corners is reduced to the construction of perpendicular and inclined lines on the details. In order for students to repeat these already familiar constructions in Fig. 1 gives examples for exercises in constructions.

Marking parallel lines from the edge of the material and from the center lines

The marking of parallel lines on the surface of parts can be performed both geometrically and using marking tools - a scale ruler, square and scriber, compass and thickness gauge.

Let's consider markup with tools using three examples.

Rice. 1. Construction of inclined lines and slopes: a - straight lines, dividing any angle in half, b - straight lines, dividing the right angle into three equal parts, c - with obtaining the size of the slope in the form of a fraction, d - as a percentage

1. Let's take the end and side sides of the strip as a marking base
2. Paint the surface to be marked with diluted chalk.
3. Let's measure the length of the cut piece of metal on the strip. To do this, we impose a scale ruler on the surface to be marked so that the division of the ruler 100 mm coincides with the edge of the end of the strip. Then, without moving the ruler, we make a mark at its beginning with a scriber.
4. To draw a cut line on the strip, put a square on it so that one side of it is firmly pressed against the side of the strip, and the other exactly matches the mark. On this side of the square, without moving it from its place, we draw a transverse risk with a scriber.
5. After that, in order to make the place of the cut more noticeable, we fill the cores at a distance of 8 mm from one another on the drawn risk.

Rice. 2. The geometric method of constructing parallel lines: a - along a straight line and a point outside it, b - at a certain distance from each other, c - along a given straight line, arbitrarily

Rice. 3. Marking lines from the edge of the part: a - notch with a scriber marks on a scale ruler, b - drawing a line along a square

Rice. 4. Marking parallel lines: a - marking, b - drawing marks on the square, c - marked detail

Rice. 5. Marking with a compass: a - setting the legs of the compass to the size on the scale bar, b - transferring the dimensions to the part by drawing scratches with a compass

Example 2
Mark on the machined surface of the steel part parallel lines 10 mm apart from one another using a scale ruler, scriber and square.
1. We take the bottom and sides of the part as the marking base.
2. We paint the marked surface of the part with a solution of copper sulfate.
3 We impose a scale ruler on the part so that its beginning or any selected division exactly coincides with the edge of the part; firmly pressing the ruler with your left hand to the surface to be marked, we make marks on it with a scriber every 10 mm.
4. Through the marked marks, but on the square superimposed on the part, we draw parallel risks with a scriber.

Example 3. On a machined brass strip, mark with a compass at the corners four points for the centers of the holes at a distance of 20 mm from the edges of the strip.
1. We take the sides of the plank as the marking base.
2. We do not paint the surface, since the traced risks are very clearly visible on non-ferrous metal and without painting.
3. With a compass on the scale ruler, we remove the size of 20 mm.
4. Without knocking down the compass, we draw two intersecting lines from the edges of the plank.
5. At the points of intersection of the lines, we core the recesses for the centers of the holes.

Layout of cube, cylinder and cone sweeps

It is often necessary to resort to the construction of a development of a cube, a cylinder and a cone in the manufacture of products from sheet material.

Rice. 1. Development of the cube (a) and development of the cylinder (b)

Unfolding of the cube (Fig. 1, a).

The cube is limited by six square-shaped planes, equal in size to each other. Each plane is called a face. The faces are mutually perpendicular, that is, they are located at right angles to each other. The line along which two faces intersect is called the edge of the cube; there are 12 edges in a cube. The point where three edges of a cube meet is called a vertex; there are 8 vertices in a cube. To connect the edges, a seam allowance is added to the size of the development.

Cylinder reaming. An unfolded cylinder (Fig. 1b) is a rectangle with a height equal to the height H of the cylinder and a length equal to the circumference of the base of the cylinder. To determine the circumference of the cylinder, you need to multiply the diameter of the base of the cylinder by 3.14, i.e. L - l.

In order to get a complete development (on sheet material), an allowance for a connection with a bend (connection to a fold) and a flanging for rolling wire must be added to the dimensions of the development.

Rice. 2. Development of the cone

Development of the cone (Fig. 2a). The unfolded surface of the cone has the form of a sector. Graphical construction of a cone sweep can be performed in two ways.

First way. They mark the point O and from it, as from the center, describe a part of the circle with a radius equal to the length of the generatrix of the cone.

The second way. Draw the profile of the cone and from its apex O with a radius equal to the length of the generatrix, describe a part of the circle - arc A. Then divide the diameter of the base of the cone into seven equal parts and lay off the resulting segment along the arc A from point 1 22 times. Connecting the last point 2 with the center O, we get the development of the cone. If a seam connection or wire rolling is provided, an allowance is given.

A truncated cone is constructed in the same way (Fig. 2b).

Marriage with planar marking, warning measures and rules for safe work

There are times when the parts processed according to the markup turn out to be a marriage. This type of marriage can occur both for reasons beyond the control of the marker, and through his fault. Reasons beyond the control of the marker are work on incorrect drawings, marking on the wrong marking plate and inaccurate devices - prisms, cubes, linings, use of inaccurate or worn out control and measuring tools (if these shortcomings of the tool were not known to the marker).

Size error. Such an error is the result of inattentive reading of the drawing by the markup, who did not understand the dimensions indicated on the drawing. The marker, if he himself is not able to understand the drawing, is obliged to seek clarification from the master.

The inaccuracy of setting the dimensions on the scale bar. Here, the fault can be either the negligence of the marker, or his lack of sufficient skills in using marking and measuring tools.

Incorrect postponing of dimensions, i.e., the use as bases of the wrong surfaces from which the markup should have been made. In such cases, black spots often remain on the surfaces of the part after its processing, i.e., places that the processing has not touched, and the part goes to waste. The marker must remember that marking is not carried out from randomly taken surfaces, but from pre-planned base surfaces to lines.

Careless installation of the part on the marking plate, i.e., its inaccurate alignment with new installations. The displacement of the part during the marking process inevitably gives distortions; the part marked in this position after processing goes to marriage.

All these markup errors are due to the inattention of the markup. The main condition for high-quality marking is a conscientious, attentive attitude of the marker to his work. The marker is obliged to use only serviceable and accurate tools, quite suitable devices. After marking is completed, it is necessary to carefully check the correctness of the work performed.

General concepts of felling in plumbing

Cutting is the processing of metal with a cutting and impact tool, as a result of which excess layers of metal are removed (cut down, cut down) or metal is cut into pieces, intended for further processing and use. A chisel or kreidmeisel is usually used as a cutting tool in plumbing, and simple or pneumatic hammers are used as a percussion tool.

With the help of cutting, you can produce:
- removal (cutting off) of excess metal layers from the surfaces of workpieces;
- leveling uneven and rough surfaces;
- removal of hard crust and scale;
- cutting edges and burrs on forged and cast blanks;
- chopping after assembly of the protruding edges of the sheet material, the ends of the strips and corners;
- cutting into parts of sheet and varietal material;
- punching holes in sheet material according to the outlined contours;
- prirubanie edges in a joint for welding;
- cutting heads of rivets when they are removed;
- cutting out lubrication grooves and keyways.

Cutting is done in a vice, on a plate or on an anvil; bulky parts can be processed by felling at their location. A chair vise is best suited for chopping; it is not recommended to perform cutting on parallel vices, since their main parts - sponges made of gray cast iron, often do not withstand strong impacts and break.

The part to be cut must be stationary. Therefore, small parts are clamped in a vise, and large parts are placed on a workbench, stove or anvil, or placed on the floor and well strengthened. Regardless of where the felling takes place, the installation of parts in height must be done in accordance with the height of the worker.

Starting cutting, the locksmith first of all prepares his workplace. Taking out a chisel and a hammer from the workbench box, he puts the chisel on the workbench on the left side of the vise with the cutting edge towards him, and the hammer on the right side of the vise with the striker pointing towards the vise.

When chopping, one must stand straight and steady at the vise, so that the body is to the left of the axis of the vise.

Rice. 1. Cutting reception: a - elbow swing, b - shoulder swing, c - correct position of the legs of the person working during cutting, d - holding the chisel

The left leg is put half a step forward, and the right one, which serves as the main support, is slightly pushed back, spreading the feet at an angle approximately as shown in Fig. 1, c.

Hold the chisel in your hands as shown in Fig. 1, g, loose, without excessive clamping. During cutting, they look at the working part of the chisel, more precisely, at the place of cutting, and not at the impact part, which is hit with a hammer. It is necessary to chop only with a sharply sharpened chisel; a blunt chisel slips off the surface being chopped off, the hand quickly gets tired of this, as a result, the correctness of the blow is lost.

The depth and width of the metal layer (chips) removed by the chisel depend on the physical strength of the worker, the size of the chisel, the weight of the hammer and the hardness of the metal being processed. The hammer is chosen by weight, the size of the chisel - by the length of its cutting edge. For every millimeter of the length of the cutting edge of the chisel, 40 g of hammer weight is required. For cutting, hammers weighing 600 g are usually used.

Depending on the order of operations, cutting can be rough and finish. During rough cutting, with strong blows of a hammer, a layer of metal with a thickness of 1.5 to 2 mm is removed in one pass. When finishing felling, a layer of metal with a thickness of 0.5 to 1.0 mm is removed per pass, inflicting lighter blows.

To obtain a clean and smooth surface, it is recommended to moisten the chisel with machine oil or soapy water when cutting steel and copper; cast iron should be cut without lubrication. Brittle metals (cast iron, bronze) must be cut from the edge to the middle. In all cases, when approaching the edge of the part, the surface should not be cut to the end, 15-20 mm should be left to continue cutting from the opposite side. This prevents chipping and chipping of the corners and edges of the workpiece. At the end of metal cutting, as a rule, it is necessary to weaken the hammer blow on the chisel.

Cutting in a vice is carried out either according to the level of the vise jaws, or above this level - according to the intended risks. According to the level of the vice, thin strip or sheet metal is most often cut, above the level of the vice (by risks) - wide surfaces of the workpieces.

When chopping wide surfaces to speed up the work, you should use a crosscut and a chisel. First, grooves of the required depth are cut with a crosscut, and the distance between them should be equal to 1D of the length of the cutting edge of the chisel. The resulting protrusions are cut down with a chisel.

In order to properly cut, you need to be good at chisel and hammer: this means holding the chisel and hammer correctly, moving your hand, elbow and shoulder correctly, and hitting the chisel with a hammer accurately, without a miss.

division of metal chips, which is the essence of the cutting process.

The tool used for cutting - a chisel - is the simplest cutting tool in which the wedge is especially pronounced. The wedge, as the basis of any cutting tool, must be strong and regular in shape - have a front and back edges, a cutting edge and a sharpening angle.

The front and back faces of the wedge are two generatrix planes that intersect each other at a certain angle. The edge that faces outward during operation and along which the chips come off is called the front; the edge facing the workpiece is the back.

The cutting edge is the sharp edge of the tool formed by the intersection of the front and back faces. The surface that is formed on the workpiece directly by the cutting edge of the tool is called the cutting surface.

Normal cutting conditions are provided due to the cutting tool front and back corners.

On fig. 2 shows the angles of the cutting tool.

The rake angle is the angle that is between the front face of the wedge and the plane perpendicular to the cutting surface; denoted by the letter g (gamma).

Clearance angle - the angle formed by the rear face of the wedge and the cutting surface; denoted by the letter a (alpha).

Pointing angle - the angle between the front and rear faces of the wedge; denoted by the letter p (beta). the division of the metal layer from the rest of its mass occurs as follows. The wedge-shaped steel body of the cutting tool, under the action of a certain force, presses on the metal and, compressing it, first displaces and then cleaves the metal particles. Previously broken off particles are displaced by new ones and move up the front face of the wedge, forming chips.

Rice. 2. Cutting patterns and cutting tool angles

The shearing of chip particles occurs along the shearing plane MN, located at an angle to the front face of the wedge. The angle between the shearing plane and the direction of tool movement is called the shearing angle.

Let us consider the action of a wedge during the operation of a simple planer (Fig. 3). Let's assume that it is required to remove a certain layer of metal from workpiece A with a cutter. To do this, a cutter is installed on the machine so that it cuts the metal to a given depth, and by the action of a certain force P, it is told to continuously move in the direction indicated by the arrow.

A cutter made of a rectangular bar, devoid of wedge corners, does not separate the chips from the metal. It crumples and crushes the removed layer, tears and porgs the treated surface. It is clear that such a tool cannot work.

On fig. 54 shows a cutter with a working part sharpened in the shape of a wedge. The cutter easily separates the chips from the rest of the metal mass, and the chips slide freely along the cutter, leaving a smooth machined surface.

Chisel. The metalwork chisel is the shock cutting tool applied at the cabin of metals. On fig. 55, and a drawing of a chisel is given. The end of the working part of the chisel has a wedge-shaped shape, which is created by sharpening two symmetrical surfaces at a certain angle. These surfaces of the working part are called the edges of the chisel. The edges at the intersection form a sharp edge, called the cutting edge of the chisel.

The edge along which the chips come off during cutting is called the front, and the edge facing the surface being machined is called the back. The angle a formed by the edges of the chisel is called the angle of sharpening. The angle of sharpening of the chisel is selected depending on the hardness of the metal being processed. For hard and brittle metals, the angle a must be greater than for soft and ductile metals: for cast iron and bronze, the angle a is taken as 70 °, for steel - 60 °, copper and brass - 45 °, aluminum and zinc - 35 °, medium shape part of the chisel is such that it allows you to comfortably and firmly hold it in your hand during cutting. The sides of the chisel should have rounded and deburred ribs.

Rice. 3. Cutter in the process of cutting: L - product, 1 - cutter, 2 - depth of the layer to be removed, P - force acting during cutting

The impact part of the chisel has the form of a truncated cone of irregular shape with a semicircular upper base. With this shape of the impact part, the force of hitting the chisel with a hammer is used with the best result, since the blow always falls in the center of the impact part.

Rice. 4. Chisel (a) and cross-cut (b) Dimensions of chisels in mm

When cutting metal, the chisel is held in the left hand by the middle part, freely clasping it with all fingers so that the thumb rests on the index finger (Fig. 56) or on the middle one, if the index finger is in an extended position. The distance from the hand to the impact part of the chisel must be at least 25 mm.

Rice. 5. The position of the chisel during cutting: a - cutting according to the level of the vice, 6 - cutting according to the risk

Rice. 6. Installing the chisel on the workpiece but in relation to the vise jaws

For cutting, the chisel is installed on the workpiece, as a rule, with the back edge inclined to the workpiece surface at an angle, but not more than 5 °. With such an inclination of the back face, the angle of inclination of the chisel (its axis) will be made up of the sum of the back angle and half the angle of sharpening. For example, with a taper angle of 70 °, the angle of inclination will be 5 + 35 °, i.e. 40 °. With respect to the line of the vise jaws, the chisel is set at an angle of 45 °.

Proper installation of the chisel contributes to the complete transformation of the force of impact with a hammer into cutting work with the least fatigue of the worker. In practice, the angle of the chisel is not measured, but the correctness of the inclination is felt to work, especially with the proper skill. If the angle of inclination is too great, the chisel cuts deep into the metal and slowly moves forward; if the angle of inclination is small, the chisel tends to break out of the metal, slip off its surface.

The inclination of the chisel to the surface being machined and relative to the vise jaws is directed by the movement of the left hand during cutting.

Kreutzmeisel. Kreuzmeisel is essentially a chisel having a narrow blade. It is used for cutting narrow grooves and keyways. The sharpening angles of the crosscut are the same as those of the chisel. Sometimes a cross-mesh is used instead of a chisel, for example, when the chisel is large in terms of the width of the cutting edge or when it is inconvenient to use it due to working conditions.

Rice. 7. Sharpening a chisel (crosscut) on a grinding machine and a template for checking the correctness of sharpening

To cut through semicircular, sharp and other grooves, special-shaped crosscuts, called groovers, are used.

Sharpening chisel and crosscut. During the operation of the chisel and crosscut, their edges are abraded, the cutting edge is slightly broken and the apex of the sharpening angle is rounded off. The cutting edge loses its sharpness, and further work with the tool becomes unproductive, and sometimes impossible. The performance of a dull tool is restored by sharpening.

The chisel is sharpened on a grinding wheel - on a grinding machine. Taking a chisel in hand, as shown in Fig. 7, put it on a rotating circle and with light pressure slowly move it to the left and right over the entire width of the circle. During sharpening, the chisel is turned with one or the other side, sharpening them alternately. It is impossible to press hard on the wheel with a chisel, as this can lead to severe overheating of the tool and loss of its initial hardness by the working part.

At the end of sharpening, burrs are removed from the cutting edge of the chisel, carefully and alternately applying edges to a rotating grinding wheel. The cutting edge of the chisel after sharpening is filled on an abrasive bar.

The chisel can be sharpened with a coolant supply and on a dry wheel. In this case, it is necessary to cool the chisel being sharpened by tearing it off the circle and lowering it into the water.

When sharpening a chisel, you need to carefully monitor that the cutting edge is straight and the edges are flat, with the same angles of inclination; the angle of sharpening must correspond to the hardness of the metal being processed. The angle of sharpening during sharpening is checked by a template.

Kreuzmeisel is sharpened in the same way as a chisel.

Locksmith hammers. It has already been pointed out earlier that two types of hammers are used in plumbing - with round and square heads. The end of the hammer opposite the striker is called the toe. The toe is wedge-shaped and rounded at the end. It is used for riveting, straightening and drawing metal. During cutting, the chisel or kreutz-meisel is struck only with the striker of a hammer.

How to hold a hammer. The hammer is held by the handle in the right hand at a distance of 15-30 mm from the end of the handle. The latter is clasped with four fingers and pressed against the palm of your hand; the thumb is placed on the index finger, all fingers are tightly squeezed. They remain in this position both when swinging and when hitting. This method is called "holding the hammer without unclenching the fingers" (Fig. 9, a).

Rice. 8. Locksmith hammers: a - with a round striker, b - with a square striker, c - hammer jamming on the handle

There is another way, which involves two steps. With this method, at the beginning of the swing, when the hand moves up, the hammer handle is clasped with all fingers. Later, as the hand is raised upwards, the compressed little finger, ring and middle fingers are gradually unclenched and support the hammer leaning back (Fig. 9, b). Then the hammer is given a push. To do this, first squeeze the unclenched fingers, then accelerate the movement of the entire arm and hand. The result is a strong hammer blow.

Rice. 9. Methods of holding the hammer during cutting: a - without unclenching the fingers, b - with unclenching the fingers

Hammer blows. When chopping, hammer blows can be made with a carpal, elbow or shoulder swing.

The wrist swing is carried out by the movement of only the hand.

The elbow swing is made by the elbow movement of the arm - its flexion and subsequent rapid extension. With an elbow swing, the fingers of the hand act, which are unclenched and compressed, the hand (moving it up and then down) and the forearm. To get a strong blow, the extensor movement of the arms must be done quickly enough. With exercises in the elbow swing, the elbow joint develops well along with the hand and fingers.

A shoulder swing is a full swing with the whole arm, which involves the shoulder, forearm and hand.

The use of one or another swing is determined by the nature of the work. The thicker layers of metal are removed from the treated surface, the greater the need to increase the impact force, therefore, to increase the swing; however, by incorrectly applying a wide swing, one can spoil the workpiece and tool and tire quickly without need. You need to learn how to accurately measure the impact force according to the nature of the work performed.

A blow with a hammer on a chisel should be made with an elbow swing with fingers unclenched; with such a blow, you can chop for quite a long time without tiring. Strikes must be measured, well-aimed and strong.

The productivity of cutting depends on the hammer force acting on the chisel and on the number of blows per minute. When cutting in a vise, from 30 to 60 beats per minute are made.

The impact force is determined by the weight of the hammer (the heavier the hammer, the stronger the blow), the length of the hammer handle (the longer the handle, the stronger the blow), the length of the arm of the worker and the magnitude of the hammer swing (the longer the arm and the higher the swing, the stronger the blow).

When cutting, it is necessary to act with both hands in concert. With your right hand, you need to accurately and accurately hit the chisel with a hammer, with your left hand, move the chisel over the metal between blows

Cutting in a vice

In a vice, sheet and strip materials, as well as wide surfaces, are cut.

Cutting of sheet material is carried out only according to the level of the vise jaws. On fig. 1, a, b shows a steel plate with a wedge outline marked on it. Consider how to cut a wedge in a vise.

For this work you need a vise, a chisel, a hammer.

Rice. 1. Detail drawing (a) and marked workpiece (b).

How to do the job:
1) prepare the workplace - take a chisel and a hammer from the box and place them on the workbench;
2) clamp the plate in a vice so that the line of the wedge contour is at the level of the vise jaws;
3) pick up a chisel and a hammer, stand up to the vise and take a working position for cutting; set the chisel at an angle of 35° to the surface of the vise jaws and at an angle of 45° to the workpiece so that the chisel is in contact with the metal in the middle of the cutting edge; striking with a hammer on a chisel, chop off excess metal at risk; at the end of the cabin, it is necessary to weaken the blows;
4) after finishing the stump, put the tool on the workbench;
5) open the vise, rearrange the plate with the opposite risk (opposite side) up and clamp it again so that the risk is at the level of the vise jaws;
6) cut off excess metal at risk from this side;

Rice. 2. Cutting of sheet material

Cutting strip material. Parts made of strip material are cut in a vise according to the level of the jaws or according to the risks located above the vise. A layer of metal up to 1.5 mm thick is chopped off in one pass, 3 mm thick - in two passes. Thicker layers are cut off using a crosscut, which is pre-cut through narrow grooves; the resulting protrusions are cut down with a chisel (Fig. 3).

Cutting wide surfaces. When cutting wide surfaces, a layer of metal is cut down in two stages: first, grooves are cut with a crosscut, then protrusions are cut with a chisel. When cutting with the use of a crosscut, the bevel is first cut with a chisel on the edge of the workpiece. Then, on the upper surface and on the bevel, the distances between the grooves are marked (each gap should be equal to approximately 3D of the length of the cutting edge of the chisel) and risks are applied along the bevel to mark the depth of each pass.

Rice. 4. Cutting wide surfaces: a - cutting grooves with a crosscut, b - cutting protrusions with a chisel

After that, the marked workpiece is clamped in a vice above the level of the jaws by 4-8 mm and proceed to cutting.

The thickness of the c-load at each pass of the crosscut is from 0.5 to 1 mm, and when cutting off the protrusions with a chisel, from 1 to 2 mm. When chopping with both a crosscut and a chisel, a metal layer of 0.5-1 mm is left for finishing with a chisel. If, after cutting, the surface must still be filed with a file, then when finishing cutting, an allowance of 0.5 mm is left for filing.

Rice. 3. Cutting of strip material a - cutting grooves with a cross cutter in a thick steel strip, b - cutting off protrusions with a chisel

On fig. 4 shows a steel tile that needs to be cut off the upper wide surface so that it is parallel to the lower surface.

For this work, a vice, a marking plate, a thickness gauge, a scale ruler, a center punch, a chisel, a hammer, and chalk are needed.

Execution method:
1) prepare a workplace - take a chisel, a hammer, a scale ruler, a center punch and chalk from the workbench; get a thickness gauge in the tool pantry;
2) place the entire tool on the workbench as previously indicated;
3) put risks on the sides of the tile with a thickness gauge, marking the thickness of the cut layer, mark the risks;
4) clamp the tile in a vise so that the risks are 4-8 mm higher than the jaws;
5) pick up a chisel and a hammer and stand in front of the vise in the working position;
6) cut a bevel on the front edge of the tile with a chisel for convenient installation of the cross-cut and chisel at the beginning of cutting, put the chisel on the workbench;
7) take a cross-cutting tool and cut through the first groove from the right edge along the marking, removing chips with a thickness of approximately 1 mm with each pass; leave a metal layer of about 0.5 mm (minimum) for fine cutting;
8) in the same way, cut through the rest of the grooves with a crosscut;
9) put on the workbench kreuzmeysel and take a chisel;
10) chop off the first protrusion on the right side of the tile with a chisel, removing chips 1 mm thick for each pass of the chisel; leave a layer of metal about 0.5 mm for fine trimming;
11) in the same way chop off all the other protrusions of the tile;
12) make a final trimming (leveling) with a chisel of the entire surface of the tile, removing chips 0.5 mm thick;
13) check the straightness of the cut surface of the tile with a ruler.

Cutting through curved grooves with a crosscut or groover (Fig. 5). The direction of the grooves is marked on the surface to be treated, then the part is clamped in a vice with the marked surface up and proceed to cutting. First, with a crosscut or groover, inflicting light blows with a hammer, a trace of grooves is marked along the risks. After that, grooves are cut from one pass with a depth of 1.5-2 mm. Finishing cutting level the irregularities formed in the grooves and give them the same width and depth throughout.

Rice. 5. Cutting curved grooves: 1 - on a flat surface, b - on a curved surface (in the bearing shell)

Cutting grooves and slots (longitudinal or transverse) in gas or other pipes. This work (Fig. 6) is carried out with a special cross-cutting tool, which has four cutting edges, and on the end cutting side, a surface concave in an arc.

Before starting cutting, at the beginning to the end of the groove to be cut, holes are drilled with a diameter equal to the width of the groove.

The tube to be processed is clamped in a vise in special caps.

Cutting iron pipes (Fig. 7). There are cases when you need to shorten a cast-iron pipe or cut off a piece from it for some need. This work is done with a crosscut or chisel. First, a cutting line is marked around the circumference of the pipe, then the pipe is laid on wooden linings or sandbags and cutting is started. It is impossible to cut the pipe on weight, since then longitudinal cracks may appear in the places of cutting. During operation, the pipe must be gradually rotated around its axis and the chisel must be moved along the risk. After several full turns of the pipe, the notched part is easily separated.

Rice. 6. Cutting grooves and slots in the pipe with a special crosscut: 1 - crosscut, 2 - pipe (in cross section) with an embedded crosscut, 3 - shavings

For cutting large-diameter cast-iron pipes, a cutting line is marked along their circumference and holes are drilled on it at equal distances from one another. Wooden wedges are tightly hammered into the holes. After that, the gaps between the holes are cut with a chisel or cross-measure at risk along the entire cutting line, gradually turning the pipe around its axis. So the notch is continued with the pipe turning until the cut off part is separated from the pipe.

Rice. 7. Chopping cast iron pipes


Similar information.


Locksmith marking


To Category:

markup

Locksmith marking

Markup is the process of transferring the shape and dimensions of a part or part of it from a drawing to a workpiece. The main purpose of marking is to mark the places and boundaries of processing on the workpiece. The processing points are indicated by the centers of the holes obtained by subsequent drilling, or by bending lines. Machining boundaries separate the material to be removed from the material that remains and forms the part. In addition, marking is used to check the dimensions of the workpiece and its suitability for the manufacture of this part, as well as to control the correct installation of the workpiece on the machine.

Workpieces can be processed without marking, using conductors, stops and other devices. However, the costs of manufacturing such devices pay off only in the production of serial and mass parts.

Marking (which is essentially close to technical drawing) is performed using special tools and fixtures on the surfaces of workpieces. Marking risks, i.e., lines drawn on the surface of the workpiece, indicate the boundaries of processing, and their intersections indicate the positions of the centers of the holes or the position of the centers of the arcs of circles of the mating surfaces. According to the marking risks, all subsequent processing of the workpiece is carried out.

Marking is mechanized and manual. Mechanized marking, performed on jig boring machines or other devices that provide accurate movement of the workpiece relative to the marking tool, is used for large, complex and expensive workpieces. Manual marking is performed by toolmakers.

Distinguish between surface and spatial markings. Surface marking is performed on one surface of the workpiece, without linking its individual points and lines with points and lines lying on the other surface of this workpiece. In this case, the following methods are used: geometric constructions; according to the template or according to the sample of the part; with the help of devices; on the machine. The most common type of surface marking is planar, used in the manufacture of flat gauges, conductor plates, die parts, etc.

Spatial marking is performed by linking the dimensions between points and lines lying on different surfaces of the workpiece. In this case, the following methods are used: for one installation; with rotation and installation of the workpiece in several positions; combined. Spatial marking is used in the manufacture of parts of complex shape.

Tools and devices for marking. According to its purpose, the marking tool is divided into the following types:
1) for carrying out risks and drawing indentations (scribers, thickness gauges, compasses, center punches);
2) for measuring and controlling linear and angular values ​​(metal rulers, calipers, squares, micrometers, precision squares, goniometers, etc.);
3) combined, which allows you to make measurements and carry out risks (marking calipers, height gauges, etc.).

Scribers are used to apply marks on the surface of the workpieces. Steel scribers are used to mark raw or pre-treated surfaces of workpieces, brass scribers are used to mark ground and polished surfaces, and soft pointed pencils are used to mark precise and finished surfaces of non-ferrous alloy workpieces.

Marking compasses according to the device and purpose correspond to the drawing ones and serve to draw circles and divide them into parts, transfer linear dimensions, etc.

Rice. 1. Marking tool: a - scriber, b - compasses, c - center punch, d - square

The steel legs of scribers and compasses are made from U7 and U8 steels (the working ends are hardened to 52-56 HRC3) and from VK.6 and VK8 hard alloys. The working ends of the scribers and compasses are sharpened sharply. The thinner and harder the tips of these tools, the thinner the risks are and the more accurately the part will be made.

A center punch (Fig. 1, c) is used to apply recesses (cores) on marking risks. This is necessary so that during the processing the marking risks, even when erased, are noticeable. Center punch - a steel round rod made of alloyed (7HF, 8HF) or carbon (U7A, U8A) steel. Its working part is hardened and sharpened at an angle of 609. The center punch head, which is struck with a hammer, is made rounded or chamfered and also hardened.

The thickness gauge used for spatial marking for drawing horizontal marks on the surface to be marked and for checking the position of the workpiece on the marking plate is made in the form of a stand on which the scriber can be moved in height and fixed in the required position. In the simplest design thickness gauge, the scriber is set to the required height using a vertical scale bar or using end measures. In tool production, they mainly use height gauges, and sometimes (if necessary) also special-design thickness gauges (for example, a multi-strip thickness gauge that has several scribers on the rack, independently set in height to a given size). Combined thicknesses are also used, i.e., ordinary thicknesses, additionally equipped with various devices and tools (for example, a thicknesses with a center finder).

A square is used to draw lines, build angles and check them.

A marking caliper is used to measure the dimensions of the outer and inner surfaces and to carry out marking marks. It differs from a conventional caliper by the presence of sharp-edged carbide tips on its jaws.

Devices used in marking and serving to install, align and secure workpieces include adjustable wedges, prisms, linings, jacks, chucks, collets, rectangular magnetic plates, rotary tables, sine tables, dividing heads and many others.

Auxiliary materials are used to prepare the surfaces of the workpiece for marking. Workpieces are cleaned of dust, dirt, rust, scale and oil with steel brushes, files, sandpaper, wiping ends, napkins, brushes, etc. In order for the marking risks to be clearly visible during subsequent processing, the cleaned surface is usually painted even and thin layer. The paint should adhere well to the surface, dry quickly and be removed well. Unfinished or roughly finished surfaces of steel and cast iron blanks are painted with chalk dissolved in water with the addition of wood glue and turpentine (or linseed oil and desiccant). Pre-treated surfaces are coated with a solution of copper sulphate. Treated surfaces of large sizes and aluminum alloys are coated with a special marking varnish. For this purpose, you can use a solution of shellac in alcohol, stained with fuchsin. Coloring of small surfaces is carried out by cross movements of the brush. Large surfaces are spray painted. Dry the painted surface.

The sequence of work during marking. Marking includes three stages: preparation of blanks for marking; markup itself and markup quality control.

The preparation of the workpiece for marking is performed as follows:
1. Carefully study and check the drawing of the part.
2. Preliminarily inspect the workpiece, identify defects (cracks, scratches, shells), control its dimensions (they must be sufficient to manufacture the part of the required quality, but not excessive).
3. Clean the workpiece from dirt, oil, traces of corrosion; paint and dry those surfaces of the workpiece on which the marking will be made.
4. Choose the base surfaces from which the dimensions will be laid off, and prepare them. If the edge of the workpiece is chosen as the base, it is pre-aligned; if two mutually perpendicular surfaces, they are processed at a right angle. The base lines are applied already in the marking process. The location of the bases should ensure that the part fits into the contour of the workpiece with the smallest and uniform allowance.

The markup itself is performed in the sequence determined by the markup method. When marking according to the template, the latter is installed on the workpiece, correctly oriented relative to the bases, and fixed. The template should fit snugly to the workpiece along the entire contour. Then the contour of the template is traced on the workpiece with a scriber and the template is unfastened.

The marking method of geometric constructions is carried out as follows. First, all horizontal, and then all vertical marking risks are carried out (relative to the base); then perform all fillets, circles and connect them with straight or inclined lines.

When marking, the thickness gauge stand is taken by the base and moved along the marking plate relative to the surface of the workpiece, while avoiding distortion. The thickness gauge touches the vertical surface of the workpiece and leaves a horizontal line on it. The scriber should be located at an acute angle to the direction of movement, and the pressure on it should be small and uniform. The risks are carried out parallel to the working surface of the marking plate. In order for the marks to be strictly linear and horizontal, the bearing surfaces of the thickness gauge and marking plate must be machined with great precision. The quality of the markup increases if a flat scriber is used in the thickness gauge.

Marking quality control and core marking is the final stage of marking. The centers of the cores should be located exactly on the marking risks, the cores should not be too deep and differ from each other in size. On direct risks, cores are punched at distances of 10-20 mm, on curvilinear ones - 5-10 mm. The distances between the cores are the same. With an increase in the size of the workpiece, the distance between the cores also increases. The junction points and intersections of the marking marks are necessarily kern. On the machined surfaces of precision products, marking marks do not kern.

Marriage during marking can lead to significant material losses. Its most frequent causes are: wrong choice of bases and their poor preparation; errors when reading a drawing, when postponing dimensions and in calculations; wrong choice of marking tools, fixtures, their malfunction; wrong methods and techniques of markup.

The widespread use of mechanized marking tools and fixtures improves the quality and productivity of marking. Therefore, mechanical, electrical and pneumatic punches, calipers and height gauges with electronic indication, mechanized devices for setting, aligning and fixing workpieces should be widely used. Significantly speeds up work and reduces the number of errors using microcalculators for calculations. It is necessary to create more versatile and easy-to-use marking tools and fixtures. Where it is economically justified, coordinate machines, coordinate measuring machines should be used for marking, or marking should be completely eliminated by processing workpieces on CNC machines.



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Chapter XII

LAYOUT

§ 46. TYPES OF MARKING

A significant part of machine parts is made from blanks supplied in the form of castings, forgings or sectional material.

During the subsequent processing of the workpiece to the size of the part specified in the drawing, a certain layer of metal is removed.

In order to avoid errors in the manufacture of a part during processing, the dimensions of the part are laid out exactly according to the drawing on the workpiece and marked with lines (risks) indicating the processing boundaries to which the metal layer (allowance) should be removed.

The operation of applying risks that define the boundaries of processing is called markup.

There are two types of markup: planar and spatial.

Planar marking It is carried out by drawing scratches on the surface of flat parts, sheet and strip metal, surfaces of cast and forged parts.

Spatial markup significantly different from flat. The difficulty in performing this markup lies in the fact that surfaces and lines lying in different planes and at different angles are interconnected by a certain position in space.

The choice of marking method is determined by the shape of the workpiece, the required accuracy and the number of products to be manufactured. In practice, there are various marking methods: according to the drawing, template, sample and in place.

Marking is carried out with the help of special devices and tools: squares, goniometers, calipers, gage gauges, etc.

Marking risks serve as guidelines for the correct installation of the workpiece on the machine and determining the amount of machining allowance.

The accuracy of the markup significantly affects the quality of processing. The degree of marking accuracy ranges from 0.25-0.5 mm. Errors made during marking usually lead to marriage and damage to valuable material. In order to properly markup, you need to know drawing well, be able to read drawings, and also use marking tools and fixtures correctly.