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Example: Painting, Posters, arts etc. It is a two dimensional representation of a three dimensional object. In other words, The art of representing a real or imaginary object precisely using some graphics, symbols, letters and numbers with the help of engineering drawing instruments is called engineering drawing. The art of representing engineering objects such as buildings, roads, machines, circuits etc. It is used by engineers and technologists. An engineering drawing provides all information about size, shape, surface type, materials etc.

Example: Building drawing for civil engineers, Machine drawing for mechanical engineers, Circuit diagrams for electrical and electronics engineers, computer graphics for one and all etc. Table 1. Can be understood by all. Need some specific knowledge or training to understand.

Scale maintaining is not necessary Scale maintaining is necessary No special requirement of engineering instruments. Engineering drawing instruments is used to make the drawing precise. An artistic drawing may not be numerically specific An engineering drawing must be numerically and informative. Standard drawing code need not to be followed.

In such cases well dimensioned and properly scaled graphics can make it easy to understand that for technical personnel. Engineering drawing serves this purpose. Any product that is to be manufactured, fabricated, assembled, constructed, built, or subjected to any other types of conversion process must first be designed.

To make the outcome from the design understandable to any third party engineering drawing is the best way. Some important uses of engineering drawing are mentioned below: 1.

It is used in ships for navigation. For manufacturing of machines, automobiles etc. For construction of buildings, roads, bridges, dams, electrical and telecommunication structures etc. For manufacturing of electric appliances like TV, phone, computers etc.

Geometrical Drawing a. Plane geometrical drawing b. Solid geometrical drawing 2. Mechanical Engineering Drawing 3. Civil Engineering Drawing 4. If the object has only 2 dimensions i. It is used by mechanical engineers to express mechanical engineering works and projects for actual execution.

It is used by civil engineers to express civil engineering works and projects for actual execution. It is used by electrical engineers to express electrical engineering works and projects for actual execution.

The art of representing electronic circuits of TV, Phones, computers etc. It is used by electronic engineers to express electronic engineering works and projects for actual execution. To develop the ability to produce simple civil engineering drawing and sketches based on current practice. To develop the skills to read and understand the drawings used in civil engineering projects. To develop a working knowledge of the layout of buildings, bridges, highways etc. To develop skills in abstracting information from calculation sheets and schematic diagrams to produce working drawings for masons, construction managers and field workers who execute civil engineering projects.

Architectural Drawing a. Plan: It shows the position of different objects and elements of the structure in a two dimensional view. Only length and width of objects are shown here. Elevation and Section: It shows a view along the height of structure.

Elevation can be presented in 2D or 3D. In 2D elevation view either height and length or height and width is showed. Structural Drawing It shows the detail requirement of reinforcement and their arrangement in structure. It also shows the specification and properties of construction materials like concrete, steel, timber etc. These rules may vary slightly for different regions. There are some drawing standards or drawing codes that accumulates the rules of engineering drawing for a certain region.

Well- known drawing codes and their application region is expressed below: Table 1. Drawing Board 4. Instrument box Scales 2. Drawing paper 5. T- square 8. Protractor Pins and clips 3. Pencil 6. Set-square 9. Compass Adhesive tapes Drawing Paper Drawing paper is the paper, on which drawing is to be made. All engineering drawings are made on sheets of paper of strictly defined sizes, which are set forth in the respective standards. The use of standard size saves paper and ensures convenient storage of drawings.

Paper Types: 1. Detail Paper used for pencil work. White drawing paper used for finished drawing 3. Tracing paper used for both pencil and ink work and useful for replicating a master copy Paper Size: Table 1. Landscape layout Portrait layout Fig. Based on the hardness of lead pencils are classified in three major grades as hard, medium and soft. They are further sub- divided and numbered as mentioned in table below: Table 1. One has to be careful in selecting a lead because very hard lead might penetrate the drawing, on the other hand, soft lead may smear.

Quality and type of drawing paper is an important factor in selecting lead. One other importance consideration is the importance of line to be drawn. Inferior lines like border lines, guide lines, construction lines and any other auxiliary lines needed to be erased later are drawn using harder pencil.

Comparatively softer grade pencil is used for drawing superior items like object line, texts, symbols etc. Common uses of different grade pencil are tabulated below: Table 1. Used to draw horizontal straight line.

Used to guide the triangles when drawing vertical and inclined lines. Used to construct the most common angles i. Used to draw parallel and perpendicular lines quickly and conveniently. Scales with beveled edges graduated in mm are usually used. Diagonal Scale Fig. It consists of two legs pivoted at the top. One leg is equipped with a steel needle attached with a screw, and other shorter leg is, provided with a socket for detachable inserts.

Dividers: Used chiefly for transferring distances and occasionally for dividing spaces into equal parts. The shape varies according to the shape of irregular curve. Review Questions 1. Define drawing and classify it. What are the differences between engineering drawing and artistic drawing?

Why Engineering drawing is called the language of engineers? What are specific applications of engineering drawing for your discipline? Classify engineering drawing and give example of each branch. Classify civil engineering drawing. What is difference between plan, elevation and section? Name some common drawing instruments and their uses. What is the standard size of a drawing board?

What is the difference between white drawing paper and tracing paper? How pencils are classified? On what considerations you will choose pencil for a drawing? How paper quality affects choice of pencil? Which angles can be drawn directly with set-squares? There are certain conventional lines recommended by drawing codes. Usually two types of widths are used for the lines; they are thick and thin.

Thick lines are in between 0. However, the exact thickness may vary according to the size and type of drawing. If the size of drawing is larger, the width of the line becomes higher. There should also be a distinct contrast in the thickness of different kinds of lines, particularly between the thick lines and thin lines.

Visible, cutting plane and short break lines are thick lines, on the other hand hidden, center, extension, dimension, leader, section, phantom and long break lines are thin.

Table 2. They should end on both sides by touching the visible lines and should touch themselves at intersection if any. Some geometric symbols are commonly used in almost every types of drawing while there are some special symbols used in specific types civil, mechanical, electrical etc.

Make a table showing the conventional lines most commonly used in engineering drawing mentioning their specific applications. Why have you studied lines and symbols? Why there is no specified proportion for dimension and extension line? What is difference between applicability of a section line and a break line? Which conventional lined are to be drawn with 2H pencils? Which conventional lined are to be drawn with HB pencils? Draw some electrical symbol for household weiring.

The plainest and most legible style is the gothic from which our single-stroke engineering letters are derived. The term roman refers to any letter having wide down ward strokes and thin connecting strokes. Roman letters include old romans and modern roman, and may be vertical or inclined.

Inclined letters are also referred to as italic, regardless of the letter style; text letters are often referred to as old English. Letters having very thin stems are called Light Face Letters, while those having heavy stems are called Bold Face Letters. In addition, light vertical or inclined guidelines are needed to keep the letters uniformly vertical or inclined.

Guidelines are absolutely essential for good lettering and should be regarded as a welcome aid, not as an unnecessary requirement.

Make guidelines light, so that they can be erased after the lettering has been completed. Use a relatively hard pencil such as a 4H to 6H, with a long, sharp, conical point. The vertical guidelines are not used to space the letters as this should always be done by eye while lettering , but only to keep the letters uniformly vertical, and they should accordingly be drawn at random. A guideline for inclined capital letters is somewhat different.

The spacing of horizontal guidelines is the same as for vertical capital lettering. The American Standard recommends slope of approximately Strokes of letters that extend up to the cap line are called ascenders, and those that extend down to the drop line, descenders. Since there are only five letters p, q. But the width of the stroke is the width of the stem of the letter. In the following description an alphabet of slightly extended vertical capitals has-been arranged in-group.

Study the slope of each letter with the order and direction of the storks forming it. The proportion of height and width of various letters must be known carefully to letter them perfectly. The top of T is drawn first to the full width of the square and the stem is started accurately at its midpoint. The first two strokes of the E are the same for the L, the third or the upper stoke is lightly shorter than the lower and the last stroke is the third as long as the lower. The second stroke of K strikes stem one third up from the bottom and the third stroke branches from it.

A large size C and G can be made more accurately with an extra stroke at the top. U is formed by two parallel strokes to which the bottom stroke be added.

J has the same construction as U, with the first stroke omitted. The middle line of P and R are on centerline of the vertical line. The background area between letters, not the distance between them, should be approximately equal.

Some combinations, such as LT and VA, may even have to be slightly overlapped to secure good spacing. In some cases the width of a letter may be decreased. For example, the lower stroke of the L may be shortened when followed by A. Words are spaced well apart, but letters with in words should be spaced closely. Make each word a compact unit well separated from the adjacent words. For either upper case or lower-case lettering, make the spaces between words approximately equal to a capital O.

Avoid spacing letters too far apart and words too close together. Most of the lettering is done in single stroke either in vertical or in inclined manner. Only one style of lettering should be used throughout the drawing. Lettering can be done either in free hand or using templates. Standard height of letters and numbers are 2.

Review Questions: 1. Why have you studied lettering? What is the difference between Gothic and Roman letters? Which style of lettering is most commonly used in engineering drawing and why? What do you mean by guidelines? Why is it used? What are the ISO rules for lettering? How do you maintain the spaces between letters, words and lines? Which letters have equal height and width? What are the standard heights of letters in engineering drawing?

These methods are illustrated in this chapter, and are basically simple principles of pure geometry. These simple principles are used to actually develop a drawing with complete accuracy, and in the fastest time possible, without wasted motion or any guesswork. Applying these geometric construction principles give drawings a finished, professional appearance. Strict interpretation of geometric construction allows use of only the compass and an instrument for drawing straight lines but in technical drawing, the principles of geometry are employed constantly, but instruments are not limited to the basic two as T-squares, triangles, scales, curves etc.

Since there is continual application of geometric principles, the methods given in this chapter should be mastered thoroughly.

It is assumed that students using this book understand the elements of plane geometry and will be able to apply their knowledge. It is actually represented on the drawing by a crisscross at its exact location. Lines may be straight lines or curved lines. A straight line is the shortest distance between two points. There are three major kinds of angles: right angels, acute angles and obtuse angles. The various kinds of triangles: a right triangle, an equilateral triangle, an isosceles triangle, and an obtuse angled triangle.

When opposite sides are parallel, the quadrilateral is also considered to be a parallelogram. The most important of these polygons as they relate to drafting are probably the triangle with three sides, square with four sides, the hexagon with six sides, and the octagon with eight sides.

Some helpful relations to be remembered for regular polygons are: 1. The major components of a circle are the diameter, the radius and circumference. The surfaces are called faces, and if these are equal regular polygons, the solids are regular polyhedral. Thus, the remaining of this chapter is devoted to illustrate step-by-step geometric construction procedures used by drafters and technicians to develop various geometric forms.

First of all we have to be well-expertise in using set squares particularly for drawing parallel and perpendicular lines.

In the given process, a line will also be constructed at the exact center point at exactly Where this line intersects line A-B, it bisects line A-B. Line D-E is also perpendicular to line A-B at the exact center point. This new line is longer than the given line and makes an angle preferably of not more than with it.

The original line AB will now be accurately divided. D C Fig. Draw a straight line from A to D. Point X is the exact center of the arc or circle. If all work is done correctly, the arc or circle should pass through each point.

In this example, place the compass point at point A of the original shape and extend the lead to point B. Swing a light arc at the new desired location. Letter the center point as A’ and add letter B’ at any convenient location on the arc. It is a good habit to lightly letter each point as you proceed. Place the compass point at letter B of the original shape and extend the compass lead to letter C of the original shape.

Transfer this distance, B-C, to the layout. Going back to the original object, place the compass point at letter A and extend the compass lead to letter C. Transfer the distance A-C as illustrated in Figure. Locate and letter each point. This completes the transfer of the object. Recheck all work and, if correct, darken lines to the correct line weight. Use the longest line or any convenient line as a starting point. Line A-B is chosen here as the example.

Lightly divide the shape into triangle divisions, using the baseline if possible. Transfer each triangle in the manner described in previous procedure.

Check all work and, if correct, darken in lines to correct line thickness. Letter a diameter as HB. Now set off distances DE around the circumference of the circle, and draw the sides through these points.

Diagonals will intersect the circle at 4 points. These tangents will meet the sides of square drawn in step 3. Now darken the obtained octagon. Given: Number of sides and the diameter of circle that will circumscribe the polygon. Mark a diameter. As example let us draw a 7 sided polygon. Mark the diameter as Taking as radius of compass, cut the circumference in 7 equal segments to obtain the corners of the seven sided polygon and connect the points. Given: Length of one side and number of sides i.

Thus the polygon will be drawn. Given: Number of sides and diameter of out scribing circle. Then AB is the length of one side.

Now set off distances AB around the circumference of the circle, and draw the sides through these points. Given: Number of sides and diameter of inscribing circle. At each point of intersection draw a tangent to the circle. The tangents will meet each other at 1, 2, 3, 4…… etc. Then ….. Label the end points of the chord thus formed as A and B.

Locate points C and D where these two lines pass through the circle. Where these lines cross is the exact center of the given circle. Place a compass point on the center point; adjust the lead to the edge of the circle and swing an arc to check that the center is accurate. This arc will touch the line AB and the given arc.

Center locations given Radius given Fig. It forms a gentle curve that reverses itself in a neat symmetrical geometric form. In this example, from point B to point C. Draw a perpendicular from line C-D at point C to intersect the perpendicular bisector of C-X which locates the second required swing center. Place the compass point on the second swing point and swing an arc from X to C. This completes the ogee curve.

Note: point X is the tangent point between arcs. Check and. If r1 , r2 and AB are given draw them accordingly. If value of r1 , r2 are given simply draw the arc EF taking radius as r2- r1 and center as B.

Then PQ will be the required tangent. Thus the ellipse will be completed. Divide a line of length 40mm into 7 equal parts. Draw a regular pentagon inscribing a circle of diameter 80mm. Avoid use of protractor. Draw a regular pentagon out scribing a circle of diameter mm.

Draw a regular pentagon having length of side as 45mm. Draw a regular hexagon inscribing a circle of diameter 80mm. Draw a regular hexagon out scribing a circle of diameter mm. Draw a regular hexagon having length of side as 45mm. Draw a regular octagon inscribing a circle of diameter 80mm.

Draw a regular octagon out scribing a circle of diameter mm. Draw a regular octagon having length of side as 45mm. Draw a 9 sided regular polygon inscribing a circle of radius 50mm. A 80mm long horizontal straight line is located outside a circle of radius 30mm, such that a 50mm line drawn from center of the circle meets the mid-point of the straight line at right angle.

Draw two arc tangents, each having a radius of 40mm touching the circle and one of the ends of the straight line. Draw a common arc tangent of radius 70mm to the two circles having their centers 80mm apart and having diameters of 50mm and 30mm respectively. Draw an ogee curve to connect two parallel lines each of length 20mm and their mid-points spaced 30mm vertically and 70mm horizontally.

Two wheels with diameters 3. Draw the line diagram of the arrangement. Use a reduced scale. Draw an ellipse having major and minor axis length as 90mm and 60mm. Why have you studied geometric drawings? Name the geometric nomenclatures and draw a qualitative shape of them. Name and draw the different types of lines.

What do you mean by isosceles, equilateral and scalene triangle? What are different types of quadrilaterals? Draw them. What is the difference between parallelogram, trapezoid, rectangle, square and rhombus?

What do you mean by regular polygon? How can you calculate summation of all internal angles of a polygon? A circle has a diameter of cm.

Draw a circle showing chord, diameter, radius, arc, segment and sector. Name some solid geometric form. Draw a parallel or perpendicular line to a given line at any point using set-square.

Transfer a given polygon to other specified point. Locate the center of a given circle. Draw a tangent to the two given circle. A complete set of dimensions will permit only one interpretation needed to construct the part. In some cases, engineering drawing becomes meaningless without dimensioning. Maintaining scale only does not make a drawing sufficient for manufacturer.

By direct measurement from drawing according to the scale is very laborious, time-consuming and such a part cannot be manufactured accurately. But for overcrowded drawing they can be drawn at an oblique angle as well. Correct Wrong Fig. They are usually drawn freehand. It must not be either away from the line or cross the line.

They are also used to present note, symbols, item number or part number etc. R3 Fig. Unidirectional system: All the dimensions are oriented to be read from the bottom of drawing. It is also known as horizontal system.

This system is preferred to aligned system. Aligned system: All the dimensions are oriented to be read from the bottom or right side of the drawing. These are dimensions which indicate the overall size of the object and the various features which make up the object. Locational dimensions are dimensions which locate various features of an object from some specified datum or surface. Figure gives examples of size and location dimensions.

Sometimes the space may be even too small to insert arrows, in such case dimensions as well as arrows can be provided on outside of the extension lines as shown in Fig. Sometimes smaller circular dots are used in place of arrowhead for space limitation.

Portion to be enlarged Enlarged view of A Use of small dot Fig. The symbols used to depict degrees, minutes, and seconds are also shown in this figure.

Angular measurements may also be stated in decimal form. This is particularly advantageous when they must be entered into an electronic digital calculator. The key to converting angular measurements to decimal form is in knowing that each degree contains 60 minutes, and each minute contains 60 seconds.

If space is limited then leaders can be used comfortably. An arc symbol is placed above the dimension. Why have you studied dimensioning? Which information are provided in dimensioning system?

What are the conditions for a good dimension system? Name the elements of dimensioning system. What are the rules that must be followed while dimensioning? What is the purpose of extension line and what are the rules to be followed for extension line? What is the purpose of dimension line and what are the rules to be followed for dimension line? What is the purpose of leaders and what are the rules to be followed for leaders?

What are the uses of arrowheads in dimensioning and what are the rules to be followed for arrowheads? What is the proportion of width and length of an arrowhead? Draw a square out scribing a circle and complete dimensioning.

What is the difference between aligned and unidirectional dimensioning? Give examples. What will you do when the space between extension lines is too small to accommodate the dimension line with text at its middle? What will you do when the space between extension lines is too small to accommodate the dimension line with arrows? What will you do when the feature is too small to make the dimension visible?

What is the difference of dimensioning of chord, arc and angle? Give example. Draw a circular hole of 2cm deep and give dimensions to it. It is not possible always to make drawings of an object to its actual size as the extent of drawing paper is limited and also sometimes the objects are too small to make it clearly understandable by drawing its actual size in drawing paper.

Scale is the technique by which one can represent an object comfortably as well as precisely within the extent of drawing paper. In other words, a scale is a measuring stick, graduated with different divisions to represent the corresponding actual distance according to some proportion. Numerically scales indicate the relation between the dimensions on drawing and actual dimensions of the objects. It is represented as scale. If possible, drawing should be done in full scale. Reducing Scale The scale in which the actual measurements of the object are reduced to some proportion is known as reducing scale.

The standard formats of reducing proportions are: – drawing made to one-half of the actual size – drawing made to one-fifth of the actual size – drawing made to one-tenth of the actual size – drawing made to one-fiftieth of the actual size – drawing made to one-hundredth of the actual size Enlarging Scale The scale in which the actual measurements of the object are increased to some proportion is known as reducing scale.

The standard formats of enlarging proportions are: – drawing made to twice the actual size – drawing made to five times the actual size – drawing made to ten times the actual size Md. It is simply a line divided into a number of equal parts and the 1st part is further sub-divided into small parts. It is so named because the 2nd sub-unit or 2nd decimal of main unit is obtained by the principle of diagonal division. Table 6.

Scale is constructed by simply dividing the line Scale is constructed by dividing the line longitudinally.

For example let us consider a plan drawn in inch units and scale provided with drawing can measure in feet and inch. If we draw another scale taking same R. Also if we draw another scale that can measure in cm and mm with same R. It consists of a fixed main scale and a movable vernier scale. This scale is usually marked on a rectangular protractor. Therefore, to get the actual measurements, it is a must to know the proportion using which the drawing is prepared.

Sometimes the drawing may need to be prepared to an odd proportion like In such case individual scale construction is required for that specific drawing.

It is often found helpful and convenient to construct and draw the corresponding scale on the drawing than mentioning the proportion in language. On the other hand if a drawing is to be used after decades, the paper may shrink or Md. Taking measurements from such a drawing using the proportion mentioned will give some inaccurate result.

But if a scale is constructed an drawn during the preparation of 1st time, the drawn scale will also shrink or expand in the same proportion to the drawing. Thus if one take measurements with the help of the drawn scale, accurate measurements will be obtained. The ratio of the distance on drawing paper of an object to the corresponding actual distance of the object is known as the representative fraction R.

It is to be remembered that for finding RF the distances used for calculation must be in same unit. And being a ratio of same units, R.

Calculation Example 6. Calculate R. Solution: Representative Fraction of the scale for this map,. Find out RF of the scale for this drawing. Solution: Representative Fraction of the scale,. What will be the R. Solution: Here 1 sq. However, sometimes British system is also used. It is important to have clear understanding about unit conversion in both system. Avoid fractions, consider the next integer value.

For instance, if maximum length to be measured is 6. For instance if the scale need to measure in feet and inches, number of minor divisions will be If space is limited they can be marked after every 2 division like 0, 2,4,…..

Find R. Solution: 2. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4 and 5. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6, 8 and 10 toward left.

Thus the scale is constructed and the required distances are indicated. Draw a plain scale to show units of 10 miles and single miles. Thus we have to construct the scale for 70 miles of maximum distance. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 10, 20, 30, 40, 50 and On a scale one centimeter represents one third of a kilometer.

Construct the scale and show the distance travelled by the car in 3 minutes and 30 seconds. What is the R. Solution: 1 1. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3 and 4. The 1st division is further divided into 6 divisions so that each minor division shows 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked as 10, 20, 30, 40, 50 and 60 toward left. Thus the scale is constructed and the required time is indicated.

Let the given short line AB which is required to be divided into 12 equal parts. Thus dividing is complete indirectly. For instance if the scale need to measure in yards, feet and inches, number of horizontal sub-divisions will be 3. For instance if the scale need to measure in yards, feet and inches, number of vertical sub-divisions will be At every horizontal sub-division point draw a parallel line to this diagonal line.

At left end a perpendicular of length equal to one major division is drawn and a rectangle is completed considering the mutually perpendicular lines as two sides.

The vertical line at left end is divided into 10 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 9hm is connected with a diagonal line.

At the remaining 9 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8 and At all the horizontal major division points vertical lines are drawn.

Also show 2 yds. The 1st division is further divided into 3 divisions and starting at 0 mark placed earlier the sub-divisions are marked as 1, 2 and 3 toward left. The vertical line at left end is divided into 12 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 2ft is connected with a diagonal line.

At the remaining two horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8, 10 and To learn more, view our Privacy Policy. To browse Academia. Log in with Facebook Log in with Google. Remember me on this computer. Enter the email address you signed up with and we’ll email you a reset link.

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Checklist Charotar Publishing House Pvt. Introduction Lines Drawing board 1 Line thickness T-square 2 Inked drawings Set-squares 3 Pencil drawings Drawing instrument box Types of Lines 1 Large-size compass with inter chang eable pencil and 1 Outlines pen legs 2 Margin lines 2 Lengthening bar 3 Dimension lines 3 Small bow compass 4 Extension or projection lines 4 Large-size divider 5 Small bow divider 5 Construction lines 6 Small bow ink-pen 6 Hatching or section lines 7 Inking pen 7 Leader or pointer lines Scales 8 Border lines Protractor 9 Short-break lines French curves 10 Long-break lines Drawing papers 11 Hidden or dotted lines Drawing pencils 12 Centre lines Eraser Rubber 13 Cutting-plane lines Drawing pins, Clips or adhesive tapes 14 Chain thick Sand-paper block 15 Chain thick double-dots Duster Lettering Drafting machine 1 Single-stroke letters Roll-N-Draw 2 Gothic letters General suggestions for drawing a sheet Dimensioning 1 Cleaning the instruments Sheet layout 2 Unidirectional system 1 Sheet sizes Unit of dimensioning 2 Margin General rules for dimensioning 3 Border lines Introduction 8 List of parts or the bill of materials Types of machine drawings Scales on drawings 1 Production drawing Types of scales 2 Exploded assembly drawing 1 Plain scales 3 Schematic assembly drawing 2 Diagonal scales 4 Drawing for instruction manual 3 Comparative scales 5 Drawing for installation 4 Vernier scales 6 Drawing for catalogue 5 Scale of chords 7 Tabular drawing Exercises IV 8 Patent drawing Introduction 2 Sketching materials Bisecting a line 3 To sketch straight lines To draw perpendiculars 4 To sketch circles and arcs To draw parallel lines 5 Sketching procedure To divide a line 6 Steps in sketching To divide a circle Exercises II To bisect an angle Charotar Publishing House Pvt.

To find the centre of an arc To construct an ogee or reverse curve A point is situated in the first quadrant To construct equilateral triangles A point is situated in the second quadrant To construct squares A point is situated in the third quadrant A point is situated in the fourth quadrant To construct regular polygons General conclusions Special methods of drawing regular polygons Exercises IX Regular polygons inscribed in circles To draw tangents Lengths of arcs Line parallel to one or both the planes Line contained by one or both the planes Circles and lines in contact Line perpendicular to one of the planes Inscribed circles Line inclined to both the planes Projections of lines inclined to both the planes Conic sections Line contained by a plane perpendicular to both the reference Ellipse planes True length of a straight line and its inclinations with the Parabola reference planes Hyperbola Traces of a line Tangents and normals to conics Methods of determining traces of a line Cycloidal curves Traces of a line, the projections of which are perpendicular Cycloid to xy Trochoid Positions of traces of a line Epicycloid and hypocycloid Additional illustrative problems Epitrochoid Exercises X b Involute Evolutes Types of auxiliary planes and views Spirals Projection of a point on an auxiliary plane Archemedian spiral Projections of lines and planes by the use of auxiliary Logarithmic or equiangular spiral planes Helix To determine true length of a line To obtain point-view of a line and edge-view of a plane A method of drawing a helical curve To determine true shape of a plane figure Helical springs Exercises XI Screw threads Cam Introduction Exercises VI Traces of planes Loci of points Simple mechanisms 1 Traces The slider crank mechanism 2 Projections 1 Simple slider crank mechanism Projections of planes parallel to one of the reference planes 2 Offset slider crank mechanism 1 When the plane is parallel to the H.

A four-bar mechanism 2 When the plane is parallel to the V. Exercises VII Introduction 1 Plane, inclined to the H. Principle of projection Projections of oblique planes Methods of projection Exercises XII Orthographic projection Four quadrants Types of solids First-angle projection 1 Polyhedra Third-angle projection 2 Solids of revolution Reference line Projections of solids in simple positions Typical Problems

WebENGINEERING DRAWING [ PLANE AND SOLID GE O M ETRY ] By N. D. Bhatt Edition: 53rd Edition: (Reprint) ISBN: Authors: HAMZA ALI. AdUpload, Edit & Sign PDF Documents Online. Easily-navigable interface. Start Free Trial! Easily Automate, Manage & Optimize Document Workflow. Try Now for Free!replace.me has been visited by 1M+ users in the past monthService catalog: Document Management, Electronic Signatures, Cloud Storage. AdConfidently Tackle Any Design, Construction, Operations Project Regardless of Complexity. Easy Online Ordering for Affordably Priced BIM Software & Customizable Training Bundles.

By using our site, you agree to our collection of information through the use of cookies. To learn more, view our Privacy Policy. To browse Academia. Engineering Drawing is one of the basic courses to study for all engineering disciplines. The primary problem faced in learning and download pdf engineering drawing of engineering drawing is the limited availability of text books that focus on the basic rules and specifications in relation to download pdf engineering drawing drawing methods practiced drawihg Bangladesh.

This handbook is download pdf engineering drawing with the primary aim to elaborate necessary basic rules and regulations of engineering drawing that is necessary for students of every engineering discipline. This book is for beginners to introduce them with different elements of engineering drawing. Several worked-out examples are provided along with every chapter and also every chapter includes some exercise and assignments to be practiced by the learners.

The course Engineering Negineering is extremely important as it is the language of engineers, technicians, designers and sanitarians. This handbook is devoted to provide dkwnload aspects of engineering drawing like lettering, geometric constructions, dimensioning, scaling, orthographic and isometric projections and sectioning. The handbook is prepared taking aid from a number of textbooks and articles mentioned in bibliography section.

Most of the figures are drawn using AutoCAD, a few of them are collected from Google image search and ссылка are taken from the textbooks.

For further reading, students are encouraged to refer books which are listed in download pdf engineering drawing bibliography section. Zeeshan Sohail. Michael Mangoli. Emrah Demirezen. Bibin Chidambaranathan. Prashsant singh. Enida Teletovic. Parthi Babu. Взято отсюда Nasrullah. Arjun Singh.

Akash Bhurle. Gul Kremer. Kenneth Orodoegbulem. Reshav Kumar. Zaheer Ibrahim. Miguel Zea. Bina Susanto Oloan Siregar. Manikandan Trikaal. Piyush Gaur. Fei Nging Chang. Marie Claire. My Application. Prabir Datta. Santhosh V. David Koo. Gomez Plata. Log in with Englneering Log in with Download pdf engineering drawing. Remember me on this computer. Enter the email address you signed по ссылке with and we’ll email you a reset link.

Need an download pdf engineering drawing Click here to sign up. Download Free PDF. Engineering Drawing for Beginners. Abstract Engineering Drawing is one of the basic winx dvd ripper platinum free download to study for all engineering disciplines.

Related Papers. Machine parts Drawing. Construction Drawing Practices. Engineering Drawing Practice for Schools 81 Colleges. Lesson Plans 2. Operation Sheets. Engineering Graphic. Acknowledgement The author is delighted to express his thanks and gratitude to Prof.

Author is also grateful to the present chairman Md. Belal Hossain and his colleagues download pdf engineering drawing the Department of Civil Engineering and of the Department of Agricultural and Industrial Engineering for inspiring him in completing this handbook. Engineering obviously it is the mercy of the Almighty Allah that the material has finally come into a complete form. A drawing download pdf engineering drawing be prepared either using free hand or using engineering instruments or using computer program.

Artistic Drawing нажмите для продолжения. Engineering Drawing 1. Example: Painting, Posters, arts etc. It на этой странице a two dimensional representation of a three dimensional object. In other words, The art of representing a real or imaginary object precisely using some graphics, symbols, letters and numbers with the help of engineering drawing instruments is called engineering drawing.

The art of representing engineering objects such as buildings, roads, machines, circuits etc. It is used by engineers and technologists. An engineering drawing provides all information about size, shape, surface type, materials etc.

Psf Building drawing for civil engineers, Machine drawing for mechanical engineers, Circuit diagrams for electrical and electronics engineers, computer graphics for one and all etc. Table 1. Can be understood by all. Need some specific attack on game free download pc or training to understand. Scale maintaining is not necessary Scale maintaining is necessary No special requirement of download pdf engineering drawing http://replace.me/2410.txt. Engineering drawing instruments is used to make the enineering precise.

An artistic drawing may not be numerically specific An engineering drawing must be numerically and informative. Standard drawing code need not to be followed. In such cases well dimensioned and properly scaled graphics can make it easy to understand that for technical personnel. Engineering drawing serves this purpose.

Any product that is to be manufactured, fabricated, assembled, constructed, built, or subjected download pdf engineering drawing any other types of conversion process must first be designed. To make the outcome from the design understandable to any third party engineering drawing is the best way.

Some important uses of engineering drawing are mentioned below: 1. It is used in ships for navigation. For manufacturing of machines, automobiles etc. For construction of buildings, roads, bridges, dams, electrical and telecommunication structures привожу ссылку. For manufacturing of жмите appliances like TV, phone, computers etc.

Geometrical Drawing a. Plane geometrical drawing b. Solid geometrical drawing 2. Mechanical Engineering Download pdf engineering drawing 3. Civil Engineering Drawing 4. If the object has only 2 dimensions i. It is used by mechanical engineers to express mechanical engineering works and projects for actual execution.

It is used by civil engineers to express civil engineering очень latest cricket games for pc 2012 free download вазьму and projects for actual execution. It is used by electrical engineers to express electrical engineering works and projects for actual execution. The art of representing electronic circuits of TV, Phones, computers etc. It is used by electronic engineers to express electronic engineering works and projects for actual execution.

Страница develop the ability to produce simple civil engineering drawing and sketches based on current practice. To develop the skills to источник статьи and understand the drawings used in civil engineering projects. To develop a working knowledge of the layout of buildings, bridges, highways etc.

To develop skills in abstracting information from calculation sheets and schematic diagrams to produce working drawings for masons, construction managers cownload field workers who execute download pdf engineering drawing engineering pf.

Architectural Drawing a.

 
 

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Portion to be enlarged Enlarged view of A Use of small dot Fig. The symbols used to depict degrees, minutes, and seconds are also shown in this figure. Angular measurements may also be stated in decimal form. This is particularly advantageous when they must be entered into an electronic digital calculator.

The key to converting angular measurements to decimal form is in knowing that each degree contains 60 minutes, and each minute contains 60 seconds. If space is limited then leaders can be used comfortably. An arc symbol is placed above the dimension. Why have you studied dimensioning? Which information are provided in dimensioning system? What are the conditions for a good dimension system? Name the elements of dimensioning system.

What are the rules that must be followed while dimensioning? What is the purpose of extension line and what are the rules to be followed for extension line? What is the purpose of dimension line and what are the rules to be followed for dimension line? What is the purpose of leaders and what are the rules to be followed for leaders?

What are the uses of arrowheads in dimensioning and what are the rules to be followed for arrowheads? What is the proportion of width and length of an arrowhead? Draw a square out scribing a circle and complete dimensioning.

What is the difference between aligned and unidirectional dimensioning? Give examples. What will you do when the space between extension lines is too small to accommodate the dimension line with text at its middle? What will you do when the space between extension lines is too small to accommodate the dimension line with arrows? What will you do when the feature is too small to make the dimension visible?

What is the difference of dimensioning of chord, arc and angle? Give example. Draw a circular hole of 2cm deep and give dimensions to it. It is not possible always to make drawings of an object to its actual size as the extent of drawing paper is limited and also sometimes the objects are too small to make it clearly understandable by drawing its actual size in drawing paper.

Scale is the technique by which one can represent an object comfortably as well as precisely within the extent of drawing paper. In other words, a scale is a measuring stick, graduated with different divisions to represent the corresponding actual distance according to some proportion. Numerically scales indicate the relation between the dimensions on drawing and actual dimensions of the objects. It is represented as scale. If possible, drawing should be done in full scale.

Reducing Scale The scale in which the actual measurements of the object are reduced to some proportion is known as reducing scale. The standard formats of reducing proportions are: – drawing made to one-half of the actual size – drawing made to one-fifth of the actual size – drawing made to one-tenth of the actual size – drawing made to one-fiftieth of the actual size – drawing made to one-hundredth of the actual size Enlarging Scale The scale in which the actual measurements of the object are increased to some proportion is known as reducing scale.

The standard formats of enlarging proportions are: – drawing made to twice the actual size – drawing made to five times the actual size – drawing made to ten times the actual size Md. It is simply a line divided into a number of equal parts and the 1st part is further sub-divided into small parts. It is so named because the 2nd sub-unit or 2nd decimal of main unit is obtained by the principle of diagonal division.

Table 6. Scale is constructed by simply dividing the line Scale is constructed by dividing the line longitudinally.

For example let us consider a plan drawn in inch units and scale provided with drawing can measure in feet and inch. If we draw another scale taking same R. Also if we draw another scale that can measure in cm and mm with same R.

It consists of a fixed main scale and a movable vernier scale. This scale is usually marked on a rectangular protractor. Therefore, to get the actual measurements, it is a must to know the proportion using which the drawing is prepared. Sometimes the drawing may need to be prepared to an odd proportion like In such case individual scale construction is required for that specific drawing.

It is often found helpful and convenient to construct and draw the corresponding scale on the drawing than mentioning the proportion in language. On the other hand if a drawing is to be used after decades, the paper may shrink or Md. Taking measurements from such a drawing using the proportion mentioned will give some inaccurate result. But if a scale is constructed an drawn during the preparation of 1st time, the drawn scale will also shrink or expand in the same proportion to the drawing.

Thus if one take measurements with the help of the drawn scale, accurate measurements will be obtained. The ratio of the distance on drawing paper of an object to the corresponding actual distance of the object is known as the representative fraction R. It is to be remembered that for finding RF the distances used for calculation must be in same unit. And being a ratio of same units, R. Calculation Example 6. Calculate R. Solution: Representative Fraction of the scale for this map,.

Find out RF of the scale for this drawing. Solution: Representative Fraction of the scale,. What will be the R. Solution: Here 1 sq. However, sometimes British system is also used.

It is important to have clear understanding about unit conversion in both system. Avoid fractions, consider the next integer value. For instance, if maximum length to be measured is 6.

For instance if the scale need to measure in feet and inches, number of minor divisions will be If space is limited they can be marked after every 2 division like 0, 2,4,….. Find R. Solution: 2. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4 and 5.

The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6, 8 and 10 toward left. Thus the scale is constructed and the required distances are indicated.

Draw a plain scale to show units of 10 miles and single miles. Thus we have to construct the scale for 70 miles of maximum distance. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 10, 20, 30, 40, 50 and On a scale one centimeter represents one third of a kilometer. Construct the scale and show the distance travelled by the car in 3 minutes and 30 seconds. What is the R. Solution: 1 1. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3 and 4.

The 1st division is further divided into 6 divisions so that each minor division shows 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked as 10, 20, 30, 40, 50 and 60 toward left. Thus the scale is constructed and the required time is indicated.

Let the given short line AB which is required to be divided into 12 equal parts. Thus dividing is complete indirectly. For instance if the scale need to measure in yards, feet and inches, number of horizontal sub-divisions will be 3. For instance if the scale need to measure in yards, feet and inches, number of vertical sub-divisions will be At every horizontal sub-division point draw a parallel line to this diagonal line.

At left end a perpendicular of length equal to one major division is drawn and a rectangle is completed considering the mutually perpendicular lines as two sides. The vertical line at left end is divided into 10 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 9hm is connected with a diagonal line. At the remaining 9 horizontal sub-division points parallel lines are drawn to the 1st diagonal line.

Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8 and At all the horizontal major division points vertical lines are drawn. Also show 2 yds. The 1st division is further divided into 3 divisions and starting at 0 mark placed earlier the sub-divisions are marked as 1, 2 and 3 toward left. The vertical line at left end is divided into 12 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 2ft is connected with a diagonal line. At the remaining two horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8, 10 and Construct a scale for this drawing showing meters, decimeters and centimeters and measure 2 meters, 5 decimeters and 8 centimeters on it. Solution: 20 1. Assume the drawing scale length is 15 cm standard value.

Both are acceptable as we have to show a distance only 2m 5dm 8cm on this scale. Let us take 7. Now a horizontal line 15cm long is drawn and is divided into 7 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4, 5 and 6. Top left corner and the point corresponding to 9dm is connected with a diagonal line. Maximum measuring length is given here i.

Considering a drawing scale length as 15 cm. So our major unit should be th of meters, 1st sub-unit should be 10th of meter and 2nd sub-unit or diagonal sub-unit should be single meters. Now a horizontal line 15cm long is drawn and is divided into 3 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, and 2.

The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40, 60, 80 and toward left. Top left corner and the point corresponding to 90m is connected with a diagonal line. Construct a scale to read miles, furlongs and minimum 20 yards distance and mark 4 miles 6 furlongs and yards on it.

Let us assume the drawing scale length is 6 inch. The 1st division is further divided into 8 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6 and 80 toward left. The vertical line at left end is divided into 11 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 7 furlongs is connected with a diagonal line.

At the remaining 7 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 20, 60, , , and The scale should be such that 4mm length is represented by 10cm and it should be able to measure upto 5mm. Construct the scale and measure 3. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 0.

Top left corner and the point corresponding to 0. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 0.

Draw a scale to represent 6 km by 1 cm and to show distance upto 60 km. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3…… and 9. The 1st division is further divided into 6 divisions so that each sub-division represents 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40 and 60 toward left. Top left corner and the point corresponding to 50 seconds is connected with a diagonal line.

At the remaining 5 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Construct a plain scale to show meters and decimeters, when 3 centimeters are equal to 2 meters and long enough to measure upto 5 meters. Show a distance of 2 meters 7 decimeter and 4.

Construct a plain scale that can measure 1m to 50m. Show a distance 38m on the scale. Construct a scale to show miles and furlongs, when 2. In a certain map 1 acre represents square kilometers of land area. Construct a scale for a portion of that map which can measure in kilometers and its 1st decimal point.

The scale should be long enough to measure upto 9. Construct a plain scale to measure a maximum distance of 55 km and show the measurement of 42 km on it. The volume of a room is cubic metre. It is represented by a volume of 80 cubic cm. By measuring R. Also show the measurement of 12 metre on it. The distance between Dinajpur and Joypurhat railway station is km and it is covered by the Drutajan Express in 4 hours.

Draw a plain scale to measure the time upto single minute. Take R. Calculate and show the distance covered by the train in 45 minutes on the scale. Construct a diagonal scale to read meters, decimeters and centimeters and long enough to measure upto 5 meters when 1 meter is represented by 3 centimeters. Indicate on the scale a distance of a. Construct a diagonal scale of R.

A plan of a house 12 cm represents m. Construct a diagonal scale to read metres to one metre and show the measurement metres on it. The distance between two station is km.

On a map it is represented by a 12 cm length line. Construct a diagonal scale to show kilometers and to measure a distance of km. Find the R. Also mark a distance 46 metres and 5 decimetres on it. Ina drawing of machine parts, the original shapes are magnified 50 times.

Construct a scale to measure upto 2nd decimal point of a single millimeter and long enough to measure upto 4mm. Show a length of 2. A person is running at a speed of 6 kmph. Why have you studied scale? Define scale. When scale becomes necessary? Why have you learned to draw scale?

In which situation scale is to be drawn along with the drawing? Classify scales according to scale size. Define each type and give practical examples. Classify scale according to measurement capacity. Define each type. Which scales are usually used by engineers? Differentiate between plain and diagonal scale.

Which information you think necessary to construct a scale? Define R. What is the unit of R. Give logic to your answer. What do you understand when an R. It is mentioned in a drawing that R.

What is its meaning? On a map of Bangladesh you measured the distance from Dinajpur to Dhaka as 6 inch. Actually the distance is miles. What should be the possible R. A 15 cm scale measures a maximum length of 10 km. What is its R. If 9 hectares of area is represented by 1mm2 in a map, what is the value of R. During the construction of scale why the zero notation placed at 2nd division? How can you divide a 1mm line in 7 equal parts?

To provide necessary information about an object to the manufacturer or to any other concerned party, it is usual practice to provide projection s of that object.

If straight lines rays are drawn from various points on the contour of the object to meet a transparent plane, thus the object is said to be projected on that plane. The figure or view formed by joining, in correct sequence, the points at which these lines meet the plane is called the projection of the object. Pictorial Projection 3. Perspective Projection 7. When the projectors are perpendicular to the plane on which the projection is obtained, it is known as orthographic projection.

Following six views are possible in orthographic projection of a solid object. Top View b. Front view c. Left View d. Right View e. Rear view f. Bottom view Fig. They have the advantage of conveying an immediate impression of the general shape and details of the object, but not its true dimensions or sizes. Pictorial projections may be of two types as a. Axonometric b. Oblique 7. Axonometric projections are classified according to how the principle axes are oriented relative to the projected surface.

There may be three types as: i. Isometric ii. Dimetric iii. Trimetric Fig. The angle is usually kept This may be of two types: i. Cavalier Projection: In this case, the dimensions along all the axes are plotted in full scale.

Cabinet Projection: In this case, the dimensions along the diagonal axis are plotted by reducing it to half of the actual value. Dimensions along other axes are plotted in full scale. In case of perspective projection observer is considered to be at finite distance where in case of any other type of projection observer is considered to be at infinity. In short, orthographic projection is the method of representing the exact shape of an object by dropping perpendiculars from two or more sides of the object to planes, generally at right angles to each other; collectively, the views on these planes describe the object completely.

Descriptive geometry is basically the use of orthographic projection in order to solve for advanced technical data involving the spatial relationship of points, lines, planes, and solid shapes. The most common means of understanding these types of orthographic projection is – The Glass Box method. It can be suitably used for understanding the generation of orthographic views. The box is unfolded to obtain the arrangement of views. In figure 7. The line of sight is always perpendicular to the plane of projection, represented by the surfaces of the glass box top, front, and right side.

Projection lines C connect the same point on the plane of projection from view to view, always at right angle. A point is projected up on the plane of projection where its projector cuts that image plane. In the figure 7. When it intersects the horizontal plane top plane of projection , it is identified as 1H, when it intersects the frontal plane front plane of projection , it is identified as 1F, and where it intersects the profile plane right side plane of projection , it is labeled 1P.

On these planes, views of the object can be obtained as is seen from the top, front, right side, left side, bottom and rear. Consider the object and its projection in fig. In actual work, there is rarely an occasion when all six principal views are needed on one drawing.

All these views are principal views. Each of the six views shows two of the three dimensions of height, width and depth. In general, when the glass box is opened, its six sides are revolved outward so that they lie in the plane of the paper. And each image plane is perpendicular to its adjacent image plane and parallel to the image plane across from it.

Before it is revolved around its hinged fold line reference line. A fold line is the line of intersection between any hinged adjacent image planes.

The left side, front, right side, and back are all elevation views. Each is vertical. The top and bottom planes are in the horizontal plane. But in most cases the top, front, and right sides are required. Sometimes the left- side view helps to describe an object more clearly than the light side view.

Orthographic views are arranged in two techniques as a. First Quadrant Fig. When an inclined or oblique line is to be projected it is helpful to identify and draw the end points and then joining them to obtain the projection. Parallel Inclined Fig. Oblique Fig. The edges, intersections, and surface limits of these hidden parts are indicated by a discontinuous line called a dashed line or hidden line. Particular attention should be paid to the execution of these dashed lines.

If carelessly drawn, they ruin the appearance of a drawing. All the center lines are the axes of symmetry. Hidden portions of the object may project to coincide with visible portions. Center lines may occur where there is a visible or hidden out line of some part of the object. Since the physical features of the object must be represented full and dashed lines take precedence over all other lines since visible out line is more prominent by space position, full lines take precedence over dashed lines.

A full line could cover a dashed line, but a dashed line could not cover a full line. When any two lines coincide, the one that is more important to the readability of the drawing takes precedent over the other. The following line gives the order of precedence of lines.

Full line 2. Dashed line 3. Careful line or cutting — plane line 4. Break lines 5. Dimension and extension lines. Crosshatch lines. The points which are connected by lines in original object should be connected in the vertical plane. All other 5 views can be obtained in similar way.

The plane of projection vertical, in case of front view should be parallel to the face for which views are being drawn. For example, in case of top view the plane will be horizontal. In the projection there is a relationship of different views. It is usual practice to draw the front view first, then top and side views are drawn with the help of the vertical and horizontal projection lines. This can be done using T-square, set-squares and compasses. Here only the figure C requires the use of compass in addition to T-squares and set- squares.

The spacing between views has to be determined or decided beforehand and if equal spacing is needed then fig. A can be followed and if a different spacing is needed then fig. B can be followed. Sufficient space should be provided in order to give dimensions avoiding any crowding and also excessive space should be avoided.

If not mentioned or required otherwise 30mmmm spacing can be provided between two successive views. Position of this line depends on the spacing requirement between side view and front view. If equal spacing is required then the line should originate at the corner of the front view. These lines will cut the diagonal line.

It is to be noted that for 1st angle projection the lines should be projected according to position of views. For example to draw top view, vertically downward lines need to be projected from front view so that the top view is generated below the front views; for getting right side view horizontal lines from front view are to be projected toward left and so on.

The length along the third axis cannot be shown in same view. This makes it difficult to understand them and only technically trained persons can understand the meaning of these orthographic views. A layman cannot imagine the shape of the object from orthographic projections. To make the shape of an object easy to understand for both technical persons and non-technical laymen pictorial projections are used. Most commonly used pictorial drawing is Isometric drawing.

When a drawing is prepared with an isometric scale or otherwise if the object is actually projected on a plane of projection, it is an isometric projection.

For this purpose the object is so placed that its principle axes are equally inclined to the plane of projection. In other words, the front view of a cube, resting on one of its corners is the isometric projection of the cube as shown in fig. But as the object is tilted all the lengths projected on the plane appears to be shortened and thus they are drawn shortened in isometric projection.

In the isometric projection of a cube shown in Fig. The extent of reduction of an isometric line can be easily found by construction of a diagram called isometric scale. For this, reproduce the triangle DPA as shown in Fig. Mark the divisions of true length on DP. Through these divisions draw vertical lines to get the corresponding points on DA.

The divisions of the line DA give dimensions to isometric scale. The lines that are parallel on the object are parallel in the isometric projection.

Vertical lines on the object appear vertical in the isometric projection. A line which is not parallel to any isometric axis is called non-isometric line and the extent of fore- shortening of non-isometric lines is different if their inclinations with the vertical planes are different. Drawing of objects is seldom drawn in true isometric projections, as the use of an isometric scale is inconvenient. Instead, a convenient method in which the foreshortening of lengths is ignored and actual or true lengths are used to obtain the projections, is applied which is called isometric drawing or isometric view.

This is advantageous because the measurement may be made directly from a drawing. The isometric drawing is An isometric drawing is so much easier to execute and, for all practical purposes, is just as satisfactory as the isometric projection. Box method. Off-set method. In this method, the object is imagined to be enclosed in a rectangular box and both isometric and non-isometric lines are located by their respective points of contact with the surfaces and edges of the box.

It is always helpful to draw or imagine the orthographic views first and then proceed for isometric drawing. In the off-set method, the curved feature may be obtained by plotting the points on the curve, located by the measurements along isometric lines.

If there are some inclined lines in the plane it will be helpful to enclose the plane with a rectangle and then obtain the projection with reference to the sides of that rectangle. ABCD is the required isometric projection.

This can also be drawn as shown in Fig. Arrows show the direction of viewing. Arrow at the top shows the direction of viewing. Similarly the fig. The line 3-A will intersect the line at point M. Similarly obtain the intersecting point N. With center 3 and radius 3-D draw an arc AD. Similarly the isometric views can be obtained on vertical planes as shown in fig. Then the isometric box is constructed and the orthographic views are reproduced on the respective faces of the box.

Finally by joining the points relating to the object and erasing unnecessary lines the isometric view is obtained. In a specific isometric drawing three maximum faces can be shown. Usually front view, top view and either left or right side view are selected. Use set square to make angles. Remember to cut height along vertical isometric axis. To do this, draw 2 parallel lines of each isometric axis at the end points of other two axes.

Erase the non- existing lines. Compare the orthographic views with your obtained Isometric views. If not, you are done. Step-1 b Step-2 Step-3 c d Step-4 e Fig. Draw isometric view from the orthographic views given in figures below: Md. Draw isometric view of a hexagonal prism 30mm sides and 60mm height. Solution: Draw the orthographic views first. Following section 7. For projecting the hexagonal top view on the top face of isometric box follow section 7. Draw isometric view of a cone with base diameter 30mm and axis 50 mm long.

For projecting the circular top view on the top face of isometric box follow section 7. Exercise and Assignments: 1. Draw orthographic views of the following objects wooden objects available : 1 2 3 4 Md. Draw orthographic views for the following pictorial views Assume arbitrary dimension : 1 2 3 4 Md. Draw necessary orthographic views to represent i. A reading table ii. Sitting chair iii. Twin seats of university bus. Laptop computer v. Wall clock. D-box of HSTU.

A pentagonal pyramid. A Cylindrical pen holder. An oval shaped paper-weight. Draw isometric view of a rectangular plane having length of sides as 10 cm and 15 cm when its plane is a horizontal and b vertical. Draw isometric view of a square prism with a side of base 5cm and axis 15 cm long when the axis is a vertical and b horizontal. Draw isometric view of a cylinder with base diameter 10cm and axis 15 cm long.

A pentagonal pyramid of side of base 30mm and height 70mm is resting with its base on horizontal plane. Draw the isometric drawing of the pyramid. Draw isometric views of i. Prepare isometric drawing from the given orthographic views. Use assumed value for missing dimensions 2 1 3 4 5 6 Md.

Why have you studied projection? Define projection. Why it is necessary? What do you mean by projection plane, projector and view? Show in a sketch. Classify projection and define the types. What are the possible orthographic views of an object?

Are all the orthographic views necessary to describe an object? If not, how will you choose the necessary views? Describe the glass box method. What do you mean by 1st angle and 3rd angle projection?

Which one is British and which one is American System? Which one is easier and why? Differentiate between 1st angle and 3rd angle projection.

Show the arrangement of views in 1st and 3rd angle projection system. Which lines are projected to their actual length? Which lines are not projected to their actual length? How will you obtain projection of such lines? How do you represent a hidden edge in a particular view? How do you represent a hole in orthographic view? What is the order of precedence of line in orthographic projection? What will you do, if a solid line and a hidden line occur at the same location?

What will you do, if a center line and a hidden line occur at the same location? How do you obtain views by diagonal line method? What is the standard spacing to be maintained between views? How to control space between views in diagonal line method? What are the advantages of orthographic projection? What do you mean by pictorial projection? Classify it. What is the difference between axonometric and oblique projection? What are the different types of axonometric projection?

Why they are so named? What is the difference between isometric, diametric and trimetric projection? What is the difference between cabinet and cavalier projection? What do you mean by perspective projection? How does it differ with pictorial projection? Why the object appears to be shortened in perspective projection? Why isometric projection is the most commonly used pictorial projection in engineering drawing?

What are the advantages of isometric projection over other types of pictorial projection? In which position of object its front view becomes its isometric view? How the object is rotated to obtain its isometric view? Why are the objects appeared to be shortened in case of isometric projection? Ellipse planes True length of a straight line and its inclinations with the Parabola reference planes Hyperbola Traces of a line Tangents and normals to conics Methods of determining traces of a line Cycloidal curves Traces of a line, the projections of which are perpendicular Cycloid to xy Trochoid Positions of traces of a line Epicycloid and hypocycloid Additional illustrative problems Epitrochoid Exercises X b Involute Evolutes Types of auxiliary planes and views Spirals Projection of a point on an auxiliary plane Archemedian spiral Projections of lines and planes by the use of auxiliary Logarithmic or equiangular spiral planes Helix To determine true length of a line To obtain point-view of a line and edge-view of a plane A method of drawing a helical curve To determine true shape of a plane figure Helical springs Exercises XI Screw threads Cam Introduction Exercises VI Traces of planes Loci of points Simple mechanisms 1 Traces The slider crank mechanism 2 Projections 1 Simple slider crank mechanism Projections of planes parallel to one of the reference planes 2 Offset slider crank mechanism 1 When the plane is parallel to the H.

A four-bar mechanism 2 When the plane is parallel to the V. Exercises VII Introduction 1 Plane, inclined to the H. Principle of projection Projections of oblique planes Methods of projection Exercises XII Orthographic projection Four quadrants Types of solids First-angle projection 1 Polyhedra Third-angle projection 2 Solids of revolution Reference line Projections of solids in simple positions Typical Problems Axis inclined to the V.

Axis inclined to the H. Projections of solids with axes inclined to both the H. Line of intersection and the V. Methods of determining the line of intersection between Projections of spheres surfaces of two interpenetrating solids 1 Spheres in contact with each other 1 Line method 2 Unequal spheres 2 Cutting-plane method Exercises XIII ii Intersection of cylinder and cylinder Intersection of cone and cone Sections of prisms 1 Section plane parallel to the V.

Intersection of sphere and cylinder or prism 2 Section plane parallel to the H. Introduction 4 Section plane perpendicular to the V. Isometric scale Sections of pyramids Isometric drawing or isometric view 1 Section plane parallel to the base of the pyramid 2 Section plane parallel to the V. Isometric graph 3 Section plane perpendicular to the V. Illustrative problems to the H. Isometric drawing of planes or plane figures 4 Section plane perpendicular to the H. Isometric drawing of prisms and pyramids to the V.

Isometric drawing of cylinders Sections of cylinders Isometric drawing of cones 1 Section plane parallel to the base Isometric drawing of sphere 2 Section plane parallel to the axis Introduction angle smaller than the angle of inclination of the Principle of the oblique projection generators with the base The oblique projection and the isometric projection 4 Section plane parallel to a generator of the cone Types of the oblique projection an angle greater than the angle of inclination of the generators with the base Rules for the choice of position of an object Sections of spheres Steps for drawing the oblique projection 1 Section plane parallel to the H.

Oblique drawing of pyramid 2 Section plane parallel to the V. Oblique drawing of circle 3 Section plane perpendicular to the V. Oblique drawing of cylinder to the V. Oblique drawing of prism Typical Problems of Sections of Solids Methods of development Introduction 1 Parallel-line development Principle of perspective projection 2 Radial-line development Definitions of perspective elements 3 Triangulation development 1 Ground plane 4 Approximate method 2 Station point Developments of lateral surfaces of right solids 3 Picture plane Cube 4 Horizontal plane Prisms 5 Auxiliiary ground plane Cylinders 6 Ground line Pyramids Cone 7 Horizon line Development of transition pieces 8 Perpendicular axis Station point Forms of screw threads Angle of vision Triangular or V threads Picture plane 1 Unified thread Methods of drawing perspective view 2 Metric thread Vanishing-point method threads Types of perspective 5 Sellers thread 1 Parallel perspective or one point perspective 6 British Association thread 2 Angular perspective or two point perpective Square thread 3 Oblique perspective or three point perspective 1 Acme thread Distance points 2 Knuckle thread Measuring line or line of heights 3 Buttress thread Conventional representation of threads SP: Typical problems of perspective projection Multiple-start threads 1 Visual-ray method — by means of the top view and Introduction 3 Vanishing-point method Types of nuts Exercises XIX Hexagonal nut Introduction 2 Cap nut Reading of orthographic views Blue-print reading 3 Dome nut Missing lines and missing views 4 Cylindrical or capstan nut Identification of planes 5 Ring nut Conversion of pictorial views into orthographic views 6 Wing nut Washers

It is used by mechanical engineers to express mechanical engineering works and projects for actual execution. It is used by civil engineers to express civil engineering works and projects for actual execution. It is used by electrical engineers to express electrical engineering works and projects for actual execution. The art of representing electronic circuits of TV, Phones, computers etc. It is used by electronic engineers to express electronic engineering works and projects for actual execution.

To develop the ability to produce simple civil engineering drawing and sketches based on current practice. To develop the skills to read and understand the drawings used in civil engineering projects. To develop a working knowledge of the layout of buildings, bridges, highways etc.

To develop skills in abstracting information from calculation sheets and schematic diagrams to produce working drawings for masons, construction managers and field workers who execute civil engineering projects.

Architectural Drawing a. Plan: It shows the position of different objects and elements of the structure in a two dimensional view. Only length and width of objects are shown here.

Elevation and Section: It shows a view along the height of structure. Elevation can be presented in 2D or 3D. In 2D elevation view either height and length or height and width is showed. Structural Drawing It shows the detail requirement of reinforcement and their arrangement in structure. It also shows the specification and properties of construction materials like concrete, steel, timber etc. These rules may vary slightly for different regions. There are some drawing standards or drawing codes that accumulates the rules of engineering drawing for a certain region.

Well- known drawing codes and their application region is expressed below: Table 1. Drawing Board 4. Instrument box Scales 2. Drawing paper 5. T- square 8. Protractor Pins and clips 3. Pencil 6. Set-square 9. Compass Adhesive tapes Drawing Paper Drawing paper is the paper, on which drawing is to be made. All engineering drawings are made on sheets of paper of strictly defined sizes, which are set forth in the respective standards. The use of standard size saves paper and ensures convenient storage of drawings.

Paper Types: 1. Detail Paper used for pencil work. White drawing paper used for finished drawing 3. Tracing paper used for both pencil and ink work and useful for replicating a master copy Paper Size: Table 1. Landscape layout Portrait layout Fig.

Based on the hardness of lead pencils are classified in three major grades as hard, medium and soft. They are further sub- divided and numbered as mentioned in table below: Table 1. One has to be careful in selecting a lead because very hard lead might penetrate the drawing, on the other hand, soft lead may smear.

Quality and type of drawing paper is an important factor in selecting lead. One other importance consideration is the importance of line to be drawn. Inferior lines like border lines, guide lines, construction lines and any other auxiliary lines needed to be erased later are drawn using harder pencil. Comparatively softer grade pencil is used for drawing superior items like object line, texts, symbols etc. Common uses of different grade pencil are tabulated below: Table 1.

Used to draw horizontal straight line. Used to guide the triangles when drawing vertical and inclined lines. Used to construct the most common angles i. Used to draw parallel and perpendicular lines quickly and conveniently. Scales with beveled edges graduated in mm are usually used. Diagonal Scale Fig.

It consists of two legs pivoted at the top. One leg is equipped with a steel needle attached with a screw, and other shorter leg is, provided with a socket for detachable inserts.

Dividers: Used chiefly for transferring distances and occasionally for dividing spaces into equal parts. The shape varies according to the shape of irregular curve. Review Questions 1. Define drawing and classify it. What are the differences between engineering drawing and artistic drawing? Why Engineering drawing is called the language of engineers? What are specific applications of engineering drawing for your discipline?

Classify engineering drawing and give example of each branch. Classify civil engineering drawing. What is difference between plan, elevation and section? Name some common drawing instruments and their uses. What is the standard size of a drawing board?

What is the difference between white drawing paper and tracing paper? How pencils are classified? On what considerations you will choose pencil for a drawing? How paper quality affects choice of pencil? Which angles can be drawn directly with set-squares? There are certain conventional lines recommended by drawing codes. Usually two types of widths are used for the lines; they are thick and thin. Thick lines are in between 0. However, the exact thickness may vary according to the size and type of drawing.

If the size of drawing is larger, the width of the line becomes higher. There should also be a distinct contrast in the thickness of different kinds of lines, particularly between the thick lines and thin lines. Visible, cutting plane and short break lines are thick lines, on the other hand hidden, center, extension, dimension, leader, section, phantom and long break lines are thin.

Table 2. They should end on both sides by touching the visible lines and should touch themselves at intersection if any. Some geometric symbols are commonly used in almost every types of drawing while there are some special symbols used in specific types civil, mechanical, electrical etc.

Make a table showing the conventional lines most commonly used in engineering drawing mentioning their specific applications. Why have you studied lines and symbols? Why there is no specified proportion for dimension and extension line? What is difference between applicability of a section line and a break line?

Which conventional lined are to be drawn with 2H pencils? Which conventional lined are to be drawn with HB pencils? Draw some electrical symbol for household weiring. The plainest and most legible style is the gothic from which our single-stroke engineering letters are derived. The term roman refers to any letter having wide down ward strokes and thin connecting strokes.

Roman letters include old romans and modern roman, and may be vertical or inclined. Inclined letters are also referred to as italic, regardless of the letter style; text letters are often referred to as old English.

Letters having very thin stems are called Light Face Letters, while those having heavy stems are called Bold Face Letters. In addition, light vertical or inclined guidelines are needed to keep the letters uniformly vertical or inclined. Guidelines are absolutely essential for good lettering and should be regarded as a welcome aid, not as an unnecessary requirement.

Make guidelines light, so that they can be erased after the lettering has been completed. Use a relatively hard pencil such as a 4H to 6H, with a long, sharp, conical point.

The vertical guidelines are not used to space the letters as this should always be done by eye while lettering , but only to keep the letters uniformly vertical, and they should accordingly be drawn at random. A guideline for inclined capital letters is somewhat different.

The spacing of horizontal guidelines is the same as for vertical capital lettering. The American Standard recommends slope of approximately Strokes of letters that extend up to the cap line are called ascenders, and those that extend down to the drop line, descenders.

Since there are only five letters p, q. But the width of the stroke is the width of the stem of the letter. In the following description an alphabet of slightly extended vertical capitals has-been arranged in-group.

Study the slope of each letter with the order and direction of the storks forming it. The proportion of height and width of various letters must be known carefully to letter them perfectly. The top of T is drawn first to the full width of the square and the stem is started accurately at its midpoint. The first two strokes of the E are the same for the L, the third or the upper stoke is lightly shorter than the lower and the last stroke is the third as long as the lower. The second stroke of K strikes stem one third up from the bottom and the third stroke branches from it.

A large size C and G can be made more accurately with an extra stroke at the top. U is formed by two parallel strokes to which the bottom stroke be added. J has the same construction as U, with the first stroke omitted. The middle line of P and R are on centerline of the vertical line. The background area between letters, not the distance between them, should be approximately equal.

Some combinations, such as LT and VA, may even have to be slightly overlapped to secure good spacing. In some cases the width of a letter may be decreased. For example, the lower stroke of the L may be shortened when followed by A. Words are spaced well apart, but letters with in words should be spaced closely. Make each word a compact unit well separated from the adjacent words.

For either upper case or lower-case lettering, make the spaces between words approximately equal to a capital O. Avoid spacing letters too far apart and words too close together. Most of the lettering is done in single stroke either in vertical or in inclined manner.

Only one style of lettering should be used throughout the drawing. Lettering can be done either in free hand or using templates. Standard height of letters and numbers are 2. Review Questions: 1. Why have you studied lettering? What is the difference between Gothic and Roman letters? Which style of lettering is most commonly used in engineering drawing and why? What do you mean by guidelines? Why is it used? What are the ISO rules for lettering? How do you maintain the spaces between letters, words and lines?

Which letters have equal height and width? What are the standard heights of letters in engineering drawing? These methods are illustrated in this chapter, and are basically simple principles of pure geometry. These simple principles are used to actually develop a drawing with complete accuracy, and in the fastest time possible, without wasted motion or any guesswork.

Applying these geometric construction principles give drawings a finished, professional appearance. Strict interpretation of geometric construction allows use of only the compass and an instrument for drawing straight lines but in technical drawing, the principles of geometry are employed constantly, but instruments are not limited to the basic two as T-squares, triangles, scales, curves etc.

Since there is continual application of geometric principles, the methods given in this chapter should be mastered thoroughly. It is assumed that students using this book understand the elements of plane geometry and will be able to apply their knowledge. It is actually represented on the drawing by a crisscross at its exact location.

Lines may be straight lines or curved lines. A straight line is the shortest distance between two points. There are three major kinds of angles: right angels, acute angles and obtuse angles. The various kinds of triangles: a right triangle, an equilateral triangle, an isosceles triangle, and an obtuse angled triangle. When opposite sides are parallel, the quadrilateral is also considered to be a parallelogram.

The most important of these polygons as they relate to drafting are probably the triangle with three sides, square with four sides, the hexagon with six sides, and the octagon with eight sides. Some helpful relations to be remembered for regular polygons are: 1.

The major components of a circle are the diameter, the radius and circumference. The surfaces are called faces, and if these are equal regular polygons, the solids are regular polyhedral.

Thus, the remaining of this chapter is devoted to illustrate step-by-step geometric construction procedures used by drafters and technicians to develop various geometric forms. First of all we have to be well-expertise in using set squares particularly for drawing parallel and perpendicular lines. In the given process, a line will also be constructed at the exact center point at exactly Where this line intersects line A-B, it bisects line A-B.

Line D-E is also perpendicular to line A-B at the exact center point. This new line is longer than the given line and makes an angle preferably of not more than with it.

The original line AB will now be accurately divided. D C Fig. Draw a straight line from A to D. Point X is the exact center of the arc or circle. If all work is done correctly, the arc or circle should pass through each point. In this example, place the compass point at point A of the original shape and extend the lead to point B. Swing a light arc at the new desired location. Letter the center point as A’ and add letter B’ at any convenient location on the arc.

It is a good habit to lightly letter each point as you proceed. Place the compass point at letter B of the original shape and extend the compass lead to letter C of the original shape. Transfer this distance, B-C, to the layout. Going back to the original object, place the compass point at letter A and extend the compass lead to letter C. Transfer the distance A-C as illustrated in Figure. Locate and letter each point. This completes the transfer of the object.

Recheck all work and, if correct, darken lines to the correct line weight. Use the longest line or any convenient line as a starting point. Line A-B is chosen here as the example. Lightly divide the shape into triangle divisions, using the baseline if possible. Transfer each triangle in the manner described in previous procedure. Check all work and, if correct, darken in lines to correct line thickness. Letter a diameter as HB. Now set off distances DE around the circumference of the circle, and draw the sides through these points.

Diagonals will intersect the circle at 4 points. These tangents will meet the sides of square drawn in step 3. Now darken the obtained octagon. Given: Number of sides and the diameter of circle that will circumscribe the polygon. Mark a diameter. As example let us draw a 7 sided polygon. Mark the diameter as Taking as radius of compass, cut the circumference in 7 equal segments to obtain the corners of the seven sided polygon and connect the points.

Given: Length of one side and number of sides i. Thus the polygon will be drawn. Given: Number of sides and diameter of out scribing circle. Then AB is the length of one side. Now set off distances AB around the circumference of the circle, and draw the sides through these points.

Given: Number of sides and diameter of inscribing circle. At each point of intersection draw a tangent to the circle. The tangents will meet each other at 1, 2, 3, 4…… etc. Then ….. Label the end points of the chord thus formed as A and B. Locate points C and D where these two lines pass through the circle. Where these lines cross is the exact center of the given circle.

Place a compass point on the center point; adjust the lead to the edge of the circle and swing an arc to check that the center is accurate. This arc will touch the line AB and the given arc. Center locations given Radius given Fig. It forms a gentle curve that reverses itself in a neat symmetrical geometric form. In this example, from point B to point C. Draw a perpendicular from line C-D at point C to intersect the perpendicular bisector of C-X which locates the second required swing center.

Place the compass point on the second swing point and swing an arc from X to C. This completes the ogee curve.

Note: point X is the tangent point between arcs. Check and. If r1 , r2 and AB are given draw them accordingly. If value of r1 , r2 are given simply draw the arc EF taking radius as r2- r1 and center as B. Then PQ will be the required tangent. Thus the ellipse will be completed.

Divide a line of length 40mm into 7 equal parts. Draw a regular pentagon inscribing a circle of diameter 80mm. Avoid use of protractor. Draw a regular pentagon out scribing a circle of diameter mm. Draw a regular pentagon having length of side as 45mm. Draw a regular hexagon inscribing a circle of diameter 80mm.

Draw a regular hexagon out scribing a circle of diameter mm. Draw a regular hexagon having length of side as 45mm. Draw a regular octagon inscribing a circle of diameter 80mm. Draw a regular octagon out scribing a circle of diameter mm. Draw a regular octagon having length of side as 45mm. Draw a 9 sided regular polygon inscribing a circle of radius 50mm. A 80mm long horizontal straight line is located outside a circle of radius 30mm, such that a 50mm line drawn from center of the circle meets the mid-point of the straight line at right angle.

Draw two arc tangents, each having a radius of 40mm touching the circle and one of the ends of the straight line. Draw a common arc tangent of radius 70mm to the two circles having their centers 80mm apart and having diameters of 50mm and 30mm respectively. Draw an ogee curve to connect two parallel lines each of length 20mm and their mid-points spaced 30mm vertically and 70mm horizontally. Two wheels with diameters 3. Draw the line diagram of the arrangement. Use a reduced scale.

Draw an ellipse having major and minor axis length as 90mm and 60mm. Why have you studied geometric drawings? Name the geometric nomenclatures and draw a qualitative shape of them. Name and draw the different types of lines. What do you mean by isosceles, equilateral and scalene triangle? What are different types of quadrilaterals?

Draw them. What is the difference between parallelogram, trapezoid, rectangle, square and rhombus? What do you mean by regular polygon? How can you calculate summation of all internal angles of a polygon?

A circle has a diameter of cm. Draw a circle showing chord, diameter, radius, arc, segment and sector. Name some solid geometric form. Draw a parallel or perpendicular line to a given line at any point using set-square. Transfer a given polygon to other specified point. Locate the center of a given circle. Draw a tangent to the two given circle. A complete set of dimensions will permit only one interpretation needed to construct the part.

In some cases, engineering drawing becomes meaningless without dimensioning. Maintaining scale only does not make a drawing sufficient for manufacturer. By direct measurement from drawing according to the scale is very laborious, time-consuming and such a part cannot be manufactured accurately. But for overcrowded drawing they can be drawn at an oblique angle as well. Correct Wrong Fig. They are usually drawn freehand. It must not be either away from the line or cross the line.

They are also used to present note, symbols, item number or part number etc. R3 Fig. Unidirectional system: All the dimensions are oriented to be read from the bottom of drawing. It is also known as horizontal system. This system is preferred to aligned system. Aligned system: All the dimensions are oriented to be read from the bottom or right side of the drawing. These are dimensions which indicate the overall size of the object and the various features which make up the object.

Locational dimensions are dimensions which locate various features of an object from some specified datum or surface. Figure gives examples of size and location dimensions. Sometimes the space may be even too small to insert arrows, in such case dimensions as well as arrows can be provided on outside of the extension lines as shown in Fig.

Sometimes smaller circular dots are used in place of arrowhead for space limitation. Portion to be enlarged Enlarged view of A Use of small dot Fig. The symbols used to depict degrees, minutes, and seconds are also shown in this figure. Angular measurements may also be stated in decimal form.

This is particularly advantageous when they must be entered into an electronic digital calculator. The key to converting angular measurements to decimal form is in knowing that each degree contains 60 minutes, and each minute contains 60 seconds.

If space is limited then leaders can be used comfortably. An arc symbol is placed above the dimension. Why have you studied dimensioning? Which information are provided in dimensioning system? What are the conditions for a good dimension system? Name the elements of dimensioning system. What are the rules that must be followed while dimensioning? What is the purpose of extension line and what are the rules to be followed for extension line? What is the purpose of dimension line and what are the rules to be followed for dimension line?

What is the purpose of leaders and what are the rules to be followed for leaders? What are the uses of arrowheads in dimensioning and what are the rules to be followed for arrowheads?

What is the proportion of width and length of an arrowhead? Draw a square out scribing a circle and complete dimensioning. What is the difference between aligned and unidirectional dimensioning?

Give examples. What will you do when the space between extension lines is too small to accommodate the dimension line with text at its middle? What will you do when the space between extension lines is too small to accommodate the dimension line with arrows?

What will you do when the feature is too small to make the dimension visible? What is the difference of dimensioning of chord, arc and angle? Give example. Draw a circular hole of 2cm deep and give dimensions to it. It is not possible always to make drawings of an object to its actual size as the extent of drawing paper is limited and also sometimes the objects are too small to make it clearly understandable by drawing its actual size in drawing paper. Scale is the technique by which one can represent an object comfortably as well as precisely within the extent of drawing paper.

In other words, a scale is a measuring stick, graduated with different divisions to represent the corresponding actual distance according to some proportion. Numerically scales indicate the relation between the dimensions on drawing and actual dimensions of the objects. It is represented as scale.

If possible, drawing should be done in full scale. Reducing Scale The scale in which the actual measurements of the object are reduced to some proportion is known as reducing scale. The standard formats of reducing proportions are: – drawing made to one-half of the actual size – drawing made to one-fifth of the actual size – drawing made to one-tenth of the actual size – drawing made to one-fiftieth of the actual size – drawing made to one-hundredth of the actual size Enlarging Scale The scale in which the actual measurements of the object are increased to some proportion is known as reducing scale.

The standard formats of enlarging proportions are: – drawing made to twice the actual size – drawing made to five times the actual size – drawing made to ten times the actual size Md. It is simply a line divided into a number of equal parts and the 1st part is further sub-divided into small parts.

It is so named because the 2nd sub-unit or 2nd decimal of main unit is obtained by the principle of diagonal division. Table 6. Scale is constructed by simply dividing the line Scale is constructed by dividing the line longitudinally. For example let us consider a plan drawn in inch units and scale provided with drawing can measure in feet and inch.

If we draw another scale taking same R. Also if we draw another scale that can measure in cm and mm with same R. It consists of a fixed main scale and a movable vernier scale.

This scale is usually marked on a rectangular protractor. Therefore, to get the actual measurements, it is a must to know the proportion using which the drawing is prepared.

Sometimes the drawing may need to be prepared to an odd proportion like In such case individual scale construction is required for that specific drawing. It is often found helpful and convenient to construct and draw the corresponding scale on the drawing than mentioning the proportion in language. On the other hand if a drawing is to be used after decades, the paper may shrink or Md. Taking measurements from such a drawing using the proportion mentioned will give some inaccurate result.

But if a scale is constructed an drawn during the preparation of 1st time, the drawn scale will also shrink or expand in the same proportion to the drawing. Thus if one take measurements with the help of the drawn scale, accurate measurements will be obtained. The ratio of the distance on drawing paper of an object to the corresponding actual distance of the object is known as the representative fraction R. It is to be remembered that for finding RF the distances used for calculation must be in same unit.

And being a ratio of same units, R. Calculation Example 6. Calculate R. Solution: Representative Fraction of the scale for this map,. Find out RF of the scale for this drawing. Solution: Representative Fraction of the scale,. What will be the R. Solution: Here 1 sq.

However, sometimes British system is also used. It is important to have clear understanding about unit conversion in both system. Avoid fractions, consider the next integer value. For instance, if maximum length to be measured is 6. For instance if the scale need to measure in feet and inches, number of minor divisions will be If space is limited they can be marked after every 2 division like 0, 2,4,…..

Find R. Solution: 2. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4 and 5. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6, 8 and 10 toward left. Thus the scale is constructed and the required distances are indicated. Draw a plain scale to show units of 10 miles and single miles.

Thus we have to construct the scale for 70 miles of maximum distance. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 10, 20, 30, 40, 50 and On a scale one centimeter represents one third of a kilometer.

Construct the scale and show the distance travelled by the car in 3 minutes and 30 seconds. What is the R.

Solution: 1 1. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3 and 4. The 1st division is further divided into 6 divisions so that each minor division shows 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked as 10, 20, 30, 40, 50 and 60 toward left. Thus the scale is constructed and the required time is indicated. Let the given short line AB which is required to be divided into 12 equal parts.

Thus dividing is complete indirectly. For instance if the scale need to measure in yards, feet and inches, number of horizontal sub-divisions will be 3. For instance if the scale need to measure in yards, feet and inches, number of vertical sub-divisions will be At every horizontal sub-division point draw a parallel line to this diagonal line.

At left end a perpendicular of length equal to one major division is drawn and a rectangle is completed considering the mutually perpendicular lines as two sides. The vertical line at left end is divided into 10 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 9hm is connected with a diagonal line. At the remaining 9 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8 and At all the horizontal major division points vertical lines are drawn.

Also show 2 yds. The 1st division is further divided into 3 divisions and starting at 0 mark placed earlier the sub-divisions are marked as 1, 2 and 3 toward left. The vertical line at left end is divided into 12 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 2ft is connected with a diagonal line.

At the remaining two horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8, 10 and Construct a scale for this drawing showing meters, decimeters and centimeters and measure 2 meters, 5 decimeters and 8 centimeters on it.

Solution: 20 1. Assume the drawing scale length is 15 cm standard value. Both are acceptable as we have to show a distance only 2m 5dm 8cm on this scale. Let us take 7. Now a horizontal line 15cm long is drawn and is divided into 7 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4, 5 and 6.

Top left corner and the point corresponding to 9dm is connected with a diagonal line. Maximum measuring length is given here i. Considering a drawing scale length as 15 cm. So our major unit should be th of meters, 1st sub-unit should be 10th of meter and 2nd sub-unit or diagonal sub-unit should be single meters.

Now a horizontal line 15cm long is drawn and is divided into 3 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, and 2. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40, 60, 80 and toward left.

Top left corner and the point corresponding to 90m is connected with a diagonal line. Construct a scale to read miles, furlongs and minimum 20 yards distance and mark 4 miles 6 furlongs and yards on it. Let us assume the drawing scale length is 6 inch.

The 1st division is further divided into 8 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6 and 80 toward left. The vertical line at left end is divided into 11 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 7 furlongs is connected with a diagonal line. At the remaining 7 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 20, 60, , , and The scale should be such that 4mm length is represented by 10cm and it should be able to measure upto 5mm.

Construct the scale and measure 3. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 0. Top left corner and the point corresponding to 0. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 0. Draw a scale to represent 6 km by 1 cm and to show distance upto 60 km.

From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3…… and 9. To obtain point-view of a line and edge-view of a plane A method of drawing a helical curve To determine true shape of a plane figure Helical springs Exercises XI Screw threads Cam Introduction Exercises VI Traces of planes Loci of points Simple mechanisms 1 Traces The slider crank mechanism 2 Projections 1 Simple slider crank mechanism Projections of planes parallel to one of the reference planes 2 Offset slider crank mechanism 1 When the plane is parallel to the H.

A four-bar mechanism 2 When the plane is parallel to the V. Exercises VII Introduction 1 Plane, inclined to the H. Principle of projection Projections of oblique planes Methods of projection Exercises XII Orthographic projection Four quadrants Types of solids First-angle projection 1 Polyhedra Third-angle projection 2 Solids of revolution Reference line Projections of solids in simple positions Typical Problems Axis inclined to the V.

Axis inclined to the H. Projections of solids with axes inclined to both the H. Line of intersection and the V. Methods of determining the line of intersection between Projections of spheres surfaces of two interpenetrating solids 1 Spheres in contact with each other 1 Line method 2 Unequal spheres 2 Cutting-plane method Exercises XIII ii Intersection of cylinder and cylinder Intersection of cone and cone Sections of prisms 1 Section plane parallel to the V.

Intersection of sphere and cylinder or prism 2 Section plane parallel to the H. Introduction 4 Section plane perpendicular to the V.

Isometric scale Sections of pyramids Isometric drawing or isometric view 1 Section plane parallel to the base of the pyramid 2 Section plane parallel to the V. Isometric graph 3 Section plane perpendicular to the V. Illustrative problems to the H. Isometric drawing of planes or plane figures 4 Section plane perpendicular to the H.

Isometric drawing of prisms and pyramids to the V. Isometric drawing of cylinders Sections of cylinders Isometric drawing of cones 1 Section plane parallel to the base Isometric drawing of sphere 2 Section plane parallel to the axis Introduction angle smaller than the angle of inclination of the Principle of the oblique projection generators with the base The oblique projection and the isometric projection 4 Section plane parallel to a generator of the cone Types of the oblique projection an angle greater than the angle of inclination of the generators with the base Rules for the choice of position of an object Sections of spheres Steps for drawing the oblique projection 1 Section plane parallel to the H.

Oblique drawing of pyramid 2 Section plane parallel to the V. Oblique drawing of circle 3 Section plane perpendicular to the V. Oblique drawing of cylinder to the V. Oblique drawing of prism Typical Problems of Sections of Solids Methods of development Introduction 1 Parallel-line development Principle of perspective projection 2 Radial-line development Definitions of perspective elements 3 Triangulation development 1 Ground plane 4 Approximate method 2 Station point Developments of lateral surfaces of right solids 3 Picture plane Cube 4 Horizontal plane Prisms 5 Auxiliiary ground plane Cylinders 6 Ground line Pyramids Cone 7 Horizon line Development of transition pieces 8 Perpendicular axis Station point Forms of screw threads Angle of vision Triangular or V threads Picture plane 1 Unified thread Methods of drawing perspective view 2 Metric thread Vanishing-point method threads Types of perspective 5 Sellers thread 1 Parallel perspective or one point perspective 6 British Association thread 2 Angular perspective or two point perpective Square thread 3 Oblique perspective or three point perspective 1 Acme thread Distance points 2 Knuckle thread Measuring line or line of heights 3 Buttress thread Conventional representation of threads SP: Typical problems of perspective projection Multiple-start threads 1 Visual-ray method — by means of the top view and Introduction 3 Vanishing-point method Types of nuts Exercises XIX Hexagonal nut Introduction 2 Cap nut Reading of orthographic views Blue-print reading 3 Dome nut Missing lines and missing views 4 Cylindrical or capstan nut Identification of planes 5 Ring nut Conversion of pictorial views into orthographic views 6 Wing nut Washers Procedure for preparing a scale-drawing Bolts Illustrative problems Introduction 5 T-headed bolt Centre of gravity 6 Countersunk-headed bolt Centres of gravity of symmetrical areas 7 Hook bolt Centres of gravity of unsymmetrical areas 8 Headless tapered bolt Illustrative problems on centre of gravity 9 Eye-bolt Moments of inertia of areas 10 Lifting eye-bolt 1 Definition, 2 Unit 11 Tap-bolt or cap-screw 3 Graphical method 12 Stud-bolt or stud Illustrative problems on moments of inertia Set-screws Exercises XXI Introduction 3 Slotted nut Types of nomographs 4 Castle nut Definitions of various terms 5 Sawn nut or Wiles nut Method of constructing parallel scale nomographs 7 Penn, ring or grooved nut Layout of nomographs 8 Stop-plate or locking-plate Introduction 3 Lewis bolt Spanner 8 Core or minor diameter Longitudinal or bar stay 9 Effective diameter Processor CPU Display Riveting Caulking and fullering Graphic Output Devices Forms and proportions of rivet-heads

By using our site, you agree to our collection of information through dpwnload use of читать больше. To learn more, view our Privacy Grandia 2 pc direct download. To browse Academia. Log in deawing Facebook Log in with Google. Remember me on this computer.

Enter the email address you signed up with and we’ll email you a reset link. Need an account? Click here to sign up. Download Free PDF. It should also prove engineerong interest to the practising professionals. Checklist Charotar Publishing House Pvt. Introduction Lines Drawing board 1 Line thickness T-square 2 Inked drawings Set-squares 3 Pencil drawings Drawing instrument box Types of Lines 1 Large-size compass with inter chang eable pencil and 1 Outlines pen legs 2 Margin lines 2 Lengthening bar 3 Dimension lines 3 Small bow compass 4 Extension or projection lines 4 Download pdf engineering drawing divider 5 Small bow divider 5 Construction lines 6 Small bow ink-pen 6 Hatching or section lines 7 Inking pen 7 Downloar or pointer lines Scales 8 Border lines Protractor 9 Short-break lines French curves 10 Long-break lines Drawing papers 11 Hidden or dotted lines Drawing pencils 12 Centre download pdf engineering drawing Eraser Dwnload 13 Cutting-plane lines Drawing pins, Clips or adhesive tapes 14 Chain thick Sand-paper block 15 Chain thick double-dots Duster Lettering Drafting machine 1 Download pdf engineering drawing drawiny Roll-N-Draw 2 Gothic letters General suggestions for drawing a sheet Dimensioning 1 Dowbload the instruments Sheet layout 2 Unidirectional system prf Sheet sizes Enyineering of dimensioning 2 Margin General rules for dimensioning 3 Border lines Introduction 8 List of parts or the bill of materials Types of machine drawings Scales on drawings 1 Production drawing Types of scales 2 Exploded assembly нажмите чтобы увидеть больше 1 Plain scales 3 Schematic assembly drawing 2 Diagonal scales 4 Drawing for instruction manual dfawing Comparative scales 5 Drawing for installation 4 Vernier scales 6 Drawing for catalogue 5 Scale of chords 7 Tabular drawing Exercises IV 8 Patent drawing Introduction 2 Sketching materials Http://replace.me/20147.txt a line 3 To sketch straight lines To draw perpendiculars 4 To sketch circles and arcs To draw parallel lines 5 Sketching procedure To divide a line 6 Steps in sketching To divide a circle Exercises II To bisect an angle Charotar Publishing House Pvt.

To find the centre of an arc To construct an ogee or reverse enginewring A point is situated in the first quadrant To construct equilateral triangles A point is situated in the second quadrant To construct squares A point is situated in the third quadrant A point is situated in the fourth quadrant To construct regular polygons General conclusions Special methods of drawing regular polygons Exercises IX Regular polygons inscribed in circles To draw tangents Lengths of arcs Line parallel to one or both the planes Line contained by one or both the planes Circles and lines in contact Line perpendicular to one of the planes Inscribed circles down,oad Line inclined to both the planes Projections of lines inclined to both the planes Conic sections Line contained by a download pdf engineering drawing perpendicular to both the reference Ellipse planes True length of a straight line and its inclinations with the Parabola reference planes Hyperbola download pdf engineering drawing Traces of a line Tangents and normals to conics Methods of determining traces of a line Cycloidal curves Traces of a eengineering, the projections of which are perpendicular Cycloid to xy Trochoid Positions of traces of a line Epicycloid and hypocycloid Additional illustrative problems Epitrochoid Exercises X нажмите чтобы увидеть больше Draqing Evolutes Types of auxiliary planes and views Spirals Projection of a point on an auxiliary plane Archemedian spiral Projections of lines and planes by the вот download winamp songs сообщение of auxiliary Download pdf engineering drawing or equiangular spiral planes Helix To determine true length of a line To obtain point-view of a line and читать далее of a plane A нажмите чтобы узнать больше of drawing a helical curve To determine true shape of a download pdf engineering drawing figure Helical springs Exercises XI Screw threads

Отключение – сложный процесс. Это была правда. Банк данных АНБ был сконструирован таким образом, чтобы никогда не оставался без электропитания – в результате случайности или злого умысла. Многоуровневая защита силовых и телефонных кабелей была спрятана глубоко под землей в стальных контейнерах, а питание от главного комплекса АНБ было дополнено многочисленными линиями электропитания, независимыми от городской системы снабжения.

Поэтому отключение представляло собой сложную серию подтверждений и протоколов, гораздо более сложную, чем запуск ядерной ракеты с подводной лодки.

 

Engineering Drawing for Beginners.Download pdf engineering drawing

 

Now set off distances AB around the circumference of the circle, and draw the sides through these points. Given: Number of sides and diameter of inscribing circle. At each point of intersection draw a tangent to the circle. The tangents will meet each other at 1, 2, 3, 4…… etc. Then ….. Label the end points of the chord thus formed as A and B.

Locate points C and D where these two lines pass through the circle. Where these lines cross is the exact center of the given circle. Place a compass point on the center point; adjust the lead to the edge of the circle and swing an arc to check that the center is accurate.

This arc will touch the line AB and the given arc. Center locations given Radius given Fig. It forms a gentle curve that reverses itself in a neat symmetrical geometric form. In this example, from point B to point C. Draw a perpendicular from line C-D at point C to intersect the perpendicular bisector of C-X which locates the second required swing center.

Place the compass point on the second swing point and swing an arc from X to C. This completes the ogee curve. Note: point X is the tangent point between arcs. Check and. If r1 , r2 and AB are given draw them accordingly. If value of r1 , r2 are given simply draw the arc EF taking radius as r2- r1 and center as B.

Then PQ will be the required tangent. Thus the ellipse will be completed. Divide a line of length 40mm into 7 equal parts. Draw a regular pentagon inscribing a circle of diameter 80mm.

Avoid use of protractor. Draw a regular pentagon out scribing a circle of diameter mm. Draw a regular pentagon having length of side as 45mm.

Draw a regular hexagon inscribing a circle of diameter 80mm. Draw a regular hexagon out scribing a circle of diameter mm. Draw a regular hexagon having length of side as 45mm.

Draw a regular octagon inscribing a circle of diameter 80mm. Draw a regular octagon out scribing a circle of diameter mm. Draw a regular octagon having length of side as 45mm. Draw a 9 sided regular polygon inscribing a circle of radius 50mm. A 80mm long horizontal straight line is located outside a circle of radius 30mm, such that a 50mm line drawn from center of the circle meets the mid-point of the straight line at right angle.

Draw two arc tangents, each having a radius of 40mm touching the circle and one of the ends of the straight line. Draw a common arc tangent of radius 70mm to the two circles having their centers 80mm apart and having diameters of 50mm and 30mm respectively. Draw an ogee curve to connect two parallel lines each of length 20mm and their mid-points spaced 30mm vertically and 70mm horizontally. Two wheels with diameters 3. Draw the line diagram of the arrangement. Use a reduced scale.

Draw an ellipse having major and minor axis length as 90mm and 60mm. Why have you studied geometric drawings? Name the geometric nomenclatures and draw a qualitative shape of them. Name and draw the different types of lines. What do you mean by isosceles, equilateral and scalene triangle? What are different types of quadrilaterals? Draw them. What is the difference between parallelogram, trapezoid, rectangle, square and rhombus?

What do you mean by regular polygon? How can you calculate summation of all internal angles of a polygon? A circle has a diameter of cm. Draw a circle showing chord, diameter, radius, arc, segment and sector. Name some solid geometric form. Draw a parallel or perpendicular line to a given line at any point using set-square. Transfer a given polygon to other specified point. Locate the center of a given circle. Draw a tangent to the two given circle. A complete set of dimensions will permit only one interpretation needed to construct the part.

In some cases, engineering drawing becomes meaningless without dimensioning. Maintaining scale only does not make a drawing sufficient for manufacturer. By direct measurement from drawing according to the scale is very laborious, time-consuming and such a part cannot be manufactured accurately. But for overcrowded drawing they can be drawn at an oblique angle as well.

Correct Wrong Fig. They are usually drawn freehand. It must not be either away from the line or cross the line. They are also used to present note, symbols, item number or part number etc. R3 Fig. Unidirectional system: All the dimensions are oriented to be read from the bottom of drawing. It is also known as horizontal system. This system is preferred to aligned system. Aligned system: All the dimensions are oriented to be read from the bottom or right side of the drawing.

These are dimensions which indicate the overall size of the object and the various features which make up the object. Locational dimensions are dimensions which locate various features of an object from some specified datum or surface.

Figure gives examples of size and location dimensions. Sometimes the space may be even too small to insert arrows, in such case dimensions as well as arrows can be provided on outside of the extension lines as shown in Fig. Sometimes smaller circular dots are used in place of arrowhead for space limitation. Portion to be enlarged Enlarged view of A Use of small dot Fig. The symbols used to depict degrees, minutes, and seconds are also shown in this figure.

Angular measurements may also be stated in decimal form. This is particularly advantageous when they must be entered into an electronic digital calculator. The key to converting angular measurements to decimal form is in knowing that each degree contains 60 minutes, and each minute contains 60 seconds. If space is limited then leaders can be used comfortably.

An arc symbol is placed above the dimension. Why have you studied dimensioning? Which information are provided in dimensioning system? What are the conditions for a good dimension system? Name the elements of dimensioning system. What are the rules that must be followed while dimensioning? What is the purpose of extension line and what are the rules to be followed for extension line? What is the purpose of dimension line and what are the rules to be followed for dimension line?

What is the purpose of leaders and what are the rules to be followed for leaders? What are the uses of arrowheads in dimensioning and what are the rules to be followed for arrowheads? What is the proportion of width and length of an arrowhead? Draw a square out scribing a circle and complete dimensioning. What is the difference between aligned and unidirectional dimensioning? Give examples. What will you do when the space between extension lines is too small to accommodate the dimension line with text at its middle?

What will you do when the space between extension lines is too small to accommodate the dimension line with arrows? What will you do when the feature is too small to make the dimension visible? What is the difference of dimensioning of chord, arc and angle? Give example. Draw a circular hole of 2cm deep and give dimensions to it.

It is not possible always to make drawings of an object to its actual size as the extent of drawing paper is limited and also sometimes the objects are too small to make it clearly understandable by drawing its actual size in drawing paper.

Scale is the technique by which one can represent an object comfortably as well as precisely within the extent of drawing paper.

In other words, a scale is a measuring stick, graduated with different divisions to represent the corresponding actual distance according to some proportion. Numerically scales indicate the relation between the dimensions on drawing and actual dimensions of the objects. It is represented as scale. If possible, drawing should be done in full scale. Reducing Scale The scale in which the actual measurements of the object are reduced to some proportion is known as reducing scale.

The standard formats of reducing proportions are: – drawing made to one-half of the actual size – drawing made to one-fifth of the actual size – drawing made to one-tenth of the actual size – drawing made to one-fiftieth of the actual size – drawing made to one-hundredth of the actual size Enlarging Scale The scale in which the actual measurements of the object are increased to some proportion is known as reducing scale. The standard formats of enlarging proportions are: – drawing made to twice the actual size – drawing made to five times the actual size – drawing made to ten times the actual size Md.

It is simply a line divided into a number of equal parts and the 1st part is further sub-divided into small parts. It is so named because the 2nd sub-unit or 2nd decimal of main unit is obtained by the principle of diagonal division. Table 6. Scale is constructed by simply dividing the line Scale is constructed by dividing the line longitudinally.

For example let us consider a plan drawn in inch units and scale provided with drawing can measure in feet and inch. If we draw another scale taking same R. Also if we draw another scale that can measure in cm and mm with same R.

It consists of a fixed main scale and a movable vernier scale. This scale is usually marked on a rectangular protractor. Therefore, to get the actual measurements, it is a must to know the proportion using which the drawing is prepared.

Sometimes the drawing may need to be prepared to an odd proportion like In such case individual scale construction is required for that specific drawing. It is often found helpful and convenient to construct and draw the corresponding scale on the drawing than mentioning the proportion in language.

On the other hand if a drawing is to be used after decades, the paper may shrink or Md. Taking measurements from such a drawing using the proportion mentioned will give some inaccurate result. But if a scale is constructed an drawn during the preparation of 1st time, the drawn scale will also shrink or expand in the same proportion to the drawing.

Thus if one take measurements with the help of the drawn scale, accurate measurements will be obtained. The ratio of the distance on drawing paper of an object to the corresponding actual distance of the object is known as the representative fraction R. It is to be remembered that for finding RF the distances used for calculation must be in same unit. And being a ratio of same units, R. Calculation Example 6. Calculate R. Solution: Representative Fraction of the scale for this map,. Find out RF of the scale for this drawing.

Solution: Representative Fraction of the scale,. What will be the R. Solution: Here 1 sq. However, sometimes British system is also used.

It is important to have clear understanding about unit conversion in both system. Avoid fractions, consider the next integer value. For instance, if maximum length to be measured is 6. For instance if the scale need to measure in feet and inches, number of minor divisions will be If space is limited they can be marked after every 2 division like 0, 2,4,…..

Find R. Solution: 2. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4 and 5. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6, 8 and 10 toward left.

Thus the scale is constructed and the required distances are indicated. Draw a plain scale to show units of 10 miles and single miles. Thus we have to construct the scale for 70 miles of maximum distance.

From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 10, 20, 30, 40, 50 and On a scale one centimeter represents one third of a kilometer. Construct the scale and show the distance travelled by the car in 3 minutes and 30 seconds.

What is the R. Solution: 1 1. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3 and 4. The 1st division is further divided into 6 divisions so that each minor division shows 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked as 10, 20, 30, 40, 50 and 60 toward left. Thus the scale is constructed and the required time is indicated.

Let the given short line AB which is required to be divided into 12 equal parts. Thus dividing is complete indirectly. For instance if the scale need to measure in yards, feet and inches, number of horizontal sub-divisions will be 3. For instance if the scale need to measure in yards, feet and inches, number of vertical sub-divisions will be At every horizontal sub-division point draw a parallel line to this diagonal line.

At left end a perpendicular of length equal to one major division is drawn and a rectangle is completed considering the mutually perpendicular lines as two sides. The vertical line at left end is divided into 10 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 9hm is connected with a diagonal line. At the remaining 9 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8 and At all the horizontal major division points vertical lines are drawn. Also show 2 yds. The 1st division is further divided into 3 divisions and starting at 0 mark placed earlier the sub-divisions are marked as 1, 2 and 3 toward left.

The vertical line at left end is divided into 12 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 2ft is connected with a diagonal line. At the remaining two horizontal sub-division points parallel lines are drawn to the 1st diagonal line.

Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8, 10 and Construct a scale for this drawing showing meters, decimeters and centimeters and measure 2 meters, 5 decimeters and 8 centimeters on it. Solution: 20 1. Assume the drawing scale length is 15 cm standard value.

Both are acceptable as we have to show a distance only 2m 5dm 8cm on this scale. Let us take 7. Now a horizontal line 15cm long is drawn and is divided into 7 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4, 5 and 6.

Top left corner and the point corresponding to 9dm is connected with a diagonal line. Maximum measuring length is given here i. Considering a drawing scale length as 15 cm. So our major unit should be th of meters, 1st sub-unit should be 10th of meter and 2nd sub-unit or diagonal sub-unit should be single meters. Now a horizontal line 15cm long is drawn and is divided into 3 equal parts.

From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, and 2. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40, 60, 80 and toward left. Top left corner and the point corresponding to 90m is connected with a diagonal line.

Construct a scale to read miles, furlongs and minimum 20 yards distance and mark 4 miles 6 furlongs and yards on it.

Let us assume the drawing scale length is 6 inch. The 1st division is further divided into 8 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6 and 80 toward left. The vertical line at left end is divided into 11 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 7 furlongs is connected with a diagonal line.

At the remaining 7 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 20, 60, , , and The scale should be such that 4mm length is represented by 10cm and it should be able to measure upto 5mm.

Construct the scale and measure 3. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 0. Top left corner and the point corresponding to 0. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 0. Draw a scale to represent 6 km by 1 cm and to show distance upto 60 km. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3…… and 9.

The 1st division is further divided into 6 divisions so that each sub-division represents 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40 and 60 toward left. Top left corner and the point corresponding to 50 seconds is connected with a diagonal line.

At the remaining 5 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Construct a plain scale to show meters and decimeters, when 3 centimeters are equal to 2 meters and long enough to measure upto 5 meters. Show a distance of 2 meters 7 decimeter and 4.

Construct a plain scale that can measure 1m to 50m. Show a distance 38m on the scale. Construct a scale to show miles and furlongs, when 2. In a certain map 1 acre represents square kilometers of land area. Construct a scale for a portion of that map which can measure in kilometers and its 1st decimal point. The scale should be long enough to measure upto 9. Construct a plain scale to measure a maximum distance of 55 km and show the measurement of 42 km on it. The volume of a room is cubic metre.

It is represented by a volume of 80 cubic cm. By measuring R. Also show the measurement of 12 metre on it. The distance between Dinajpur and Joypurhat railway station is km and it is covered by the Drutajan Express in 4 hours. Draw a plain scale to measure the time upto single minute. Take R. Calculate and show the distance covered by the train in 45 minutes on the scale. Construct a diagonal scale to read meters, decimeters and centimeters and long enough to measure upto 5 meters when 1 meter is represented by 3 centimeters.

Indicate on the scale a distance of a. Construct a diagonal scale of R. A plan of a house 12 cm represents m. Construct a diagonal scale to read metres to one metre and show the measurement metres on it. The distance between two station is km. On a map it is represented by a 12 cm length line. Construct a diagonal scale to show kilometers and to measure a distance of km. Find the R. Also mark a distance 46 metres and 5 decimetres on it. Ina drawing of machine parts, the original shapes are magnified 50 times.

Construct a scale to measure upto 2nd decimal point of a single millimeter and long enough to measure upto 4mm. Show a length of 2. A person is running at a speed of 6 kmph.

Why have you studied scale? Define scale. When scale becomes necessary? Why have you learned to draw scale? In which situation scale is to be drawn along with the drawing? Classify scales according to scale size. Define each type and give practical examples. Classify scale according to measurement capacity. Define each type. Which scales are usually used by engineers? Differentiate between plain and diagonal scale.

Which information you think necessary to construct a scale? Define R. What is the unit of R. Give logic to your answer. What do you understand when an R. It is mentioned in a drawing that R. What is its meaning? On a map of Bangladesh you measured the distance from Dinajpur to Dhaka as 6 inch.

Actually the distance is miles. What should be the possible R. A 15 cm scale measures a maximum length of 10 km. What is its R. If 9 hectares of area is represented by 1mm2 in a map, what is the value of R. During the construction of scale why the zero notation placed at 2nd division? How can you divide a 1mm line in 7 equal parts? To provide necessary information about an object to the manufacturer or to any other concerned party, it is usual practice to provide projection s of that object.

If straight lines rays are drawn from various points on the contour of the object to meet a transparent plane, thus the object is said to be projected on that plane. The figure or view formed by joining, in correct sequence, the points at which these lines meet the plane is called the projection of the object. Pictorial Projection 3.

Perspective Projection 7. When the projectors are perpendicular to the plane on which the projection is obtained, it is known as orthographic projection. Following six views are possible in orthographic projection of a solid object. Top View b. Front view c. Left View d. Right View e. Rear view f. Bottom view Fig. They have the advantage of conveying an immediate impression of the general shape and details of the object, but not its true dimensions or sizes. Pictorial projections may be of two types as a.

Axonometric b. Oblique 7. Axonometric projections are classified according to how the principle axes are oriented relative to the projected surface.

There may be three types as: i. Isometric ii. Dimetric iii. Trimetric Fig. The angle is usually kept This may be of two types: i.

Cavalier Projection: In this case, the dimensions along all the axes are plotted in full scale. Cabinet Projection: In this case, the dimensions along the diagonal axis are plotted by reducing it to half of the actual value. Dimensions along other axes are plotted in full scale. In case of perspective projection observer is considered to be at finite distance where in case of any other type of projection observer is considered to be at infinity.

In short, orthographic projection is the method of representing the exact shape of an object by dropping perpendiculars from two or more sides of the object to planes, generally at right angles to each other; collectively, the views on these planes describe the object completely. Descriptive geometry is basically the use of orthographic projection in order to solve for advanced technical data involving the spatial relationship of points, lines, planes, and solid shapes.

The most common means of understanding these types of orthographic projection is – The Glass Box method. It can be suitably used for understanding the generation of orthographic views. The box is unfolded to obtain the arrangement of views. In figure 7. The line of sight is always perpendicular to the plane of projection, represented by the surfaces of the glass box top, front, and right side.

Projection lines C connect the same point on the plane of projection from view to view, always at right angle. A point is projected up on the plane of projection where its projector cuts that image plane. In the figure 7. When it intersects the horizontal plane top plane of projection , it is identified as 1H, when it intersects the frontal plane front plane of projection , it is identified as 1F, and where it intersects the profile plane right side plane of projection , it is labeled 1P.

On these planes, views of the object can be obtained as is seen from the top, front, right side, left side, bottom and rear. Consider the object and its projection in fig.

In actual work, there is rarely an occasion when all six principal views are needed on one drawing. All these views are principal views. Each of the six views shows two of the three dimensions of height, width and depth. In general, when the glass box is opened, its six sides are revolved outward so that they lie in the plane of the paper.

And each image plane is perpendicular to its adjacent image plane and parallel to the image plane across from it. Before it is revolved around its hinged fold line reference line. A fold line is the line of intersection between any hinged adjacent image planes. The left side, front, right side, and back are all elevation views.

Each is vertical. The top and bottom planes are in the horizontal plane. But in most cases the top, front, and right sides are required. Sometimes the left- side view helps to describe an object more clearly than the light side view. Orthographic views are arranged in two techniques as a. First Quadrant Fig. When an inclined or oblique line is to be projected it is helpful to identify and draw the end points and then joining them to obtain the projection.

Parallel Inclined Fig. Oblique Fig. The edges, intersections, and surface limits of these hidden parts are indicated by a discontinuous line called a dashed line or hidden line. Particular attention should be paid to the execution of these dashed lines. If carelessly drawn, they ruin the appearance of a drawing.

All the center lines are the axes of symmetry. Hidden portions of the object may project to coincide with visible portions. Center lines may occur where there is a visible or hidden out line of some part of the object. Since the physical features of the object must be represented full and dashed lines take precedence over all other lines since visible out line is more prominent by space position, full lines take precedence over dashed lines. A full line could cover a dashed line, but a dashed line could not cover a full line.

When any two lines coincide, the one that is more important to the readability of the drawing takes precedent over the other. The following line gives the order of precedence of lines. Full line 2. Dashed line 3. Careful line or cutting — plane line 4. Break lines 5.

Dimension and extension lines. Crosshatch lines. The points which are connected by lines in original object should be connected in the vertical plane.

All other 5 views can be obtained in similar way. The plane of projection vertical, in case of front view should be parallel to the face for which views are being drawn. For example, in case of top view the plane will be horizontal.

In the projection there is a relationship of different views. It is usual practice to draw the front view first, then top and side views are drawn with the help of the vertical and horizontal projection lines.

This can be done using T-square, set-squares and compasses. Here only the figure C requires the use of compass in addition to T-squares and set- squares. The spacing between views has to be determined or decided beforehand and if equal spacing is needed then fig. A can be followed and if a different spacing is needed then fig. B can be followed. Sufficient space should be provided in order to give dimensions avoiding any crowding and also excessive space should be avoided.

If not mentioned or required otherwise 30mmmm spacing can be provided between two successive views. Position of this line depends on the spacing requirement between side view and front view. If equal spacing is required then the line should originate at the corner of the front view.

These lines will cut the diagonal line. It is to be noted that for 1st angle projection the lines should be projected according to position of views. For example to draw top view, vertically downward lines need to be projected from front view so that the top view is generated below the front views; for getting right side view horizontal lines from front view are to be projected toward left and so on.

The length along the third axis cannot be shown in same view. This makes it difficult to understand them and only technically trained persons can understand the meaning of these orthographic views. A layman cannot imagine the shape of the object from orthographic projections. To make the shape of an object easy to understand for both technical persons and non-technical laymen pictorial projections are used. Most commonly used pictorial drawing is Isometric drawing.

When a drawing is prepared with an isometric scale or otherwise if the object is actually projected on a plane of projection, it is an isometric projection. For this purpose the object is so placed that its principle axes are equally inclined to the plane of projection. In other words, the front view of a cube, resting on one of its corners is the isometric projection of the cube as shown in fig.

But as the object is tilted all the lengths projected on the plane appears to be shortened and thus they are drawn shortened in isometric projection. In the isometric projection of a cube shown in Fig.

The extent of reduction of an isometric line can be easily found by construction of a diagram called isometric scale. For this, reproduce the triangle DPA as shown in Fig. Mark the divisions of true length on DP.

Through these divisions draw vertical lines to get the corresponding points on DA. The divisions of the line DA give dimensions to isometric scale. The lines that are parallel on the object are parallel in the isometric projection.

Vertical lines on the object appear vertical in the isometric projection. A line which is not parallel to any isometric axis is called non-isometric line and the extent of fore- shortening of non-isometric lines is different if their inclinations with the vertical planes are different. Drawing of objects is seldom drawn in true isometric projections, as the use of an isometric scale is inconvenient. Instead, a convenient method in which the foreshortening of lengths is ignored and actual or true lengths are used to obtain the projections, is applied which is called isometric drawing or isometric view.

This is advantageous because the measurement may be made directly from a drawing. The isometric drawing is An isometric drawing is so much easier to execute and, for all practical purposes, is just as satisfactory as the isometric projection.

Box method. Off-set method. In this method, the object is imagined to be enclosed in a rectangular box and both isometric and non-isometric lines are located by their respective points of contact with the surfaces and edges of the box. It is always helpful to draw or imagine the orthographic views first and then proceed for isometric drawing.

In the off-set method, the curved feature may be obtained by plotting the points on the curve, located by the measurements along isometric lines. If there are some inclined lines in the plane it will be helpful to enclose the plane with a rectangle and then obtain the projection with reference to the sides of that rectangle. ABCD is the required isometric projection. This can also be drawn as shown in Fig.

Arrows show the direction of viewing. Arrow at the top shows the direction of viewing. Similarly the fig. The line 3-A will intersect the line at point M. Similarly obtain the intersecting point N. With center 3 and radius 3-D draw an arc AD.

Similarly the isometric views can be obtained on vertical planes as shown in fig. Then the isometric box is constructed and the orthographic views are reproduced on the respective faces of the box. Finally by joining the points relating to the object and erasing unnecessary lines the isometric view is obtained.

In a specific isometric drawing three maximum faces can be shown. Usually front view, top view and either left or right side view are selected. Introduction Exercises VI Traces of planes Loci of points Simple mechanisms 1 Traces The slider crank mechanism 2 Projections 1 Simple slider crank mechanism Projections of planes parallel to one of the reference planes 2 Offset slider crank mechanism 1 When the plane is parallel to the H. A four-bar mechanism 2 When the plane is parallel to the V.

Exercises VII Introduction 1 Plane, inclined to the H. Principle of projection Projections of oblique planes Methods of projection Exercises XII Orthographic projection Four quadrants Types of solids First-angle projection 1 Polyhedra Third-angle projection 2 Solids of revolution Reference line Projections of solids in simple positions Typical Problems Axis inclined to the V. Axis inclined to the H.

Projections of solids with axes inclined to both the H. Line of intersection and the V. Methods of determining the line of intersection between Projections of spheres surfaces of two interpenetrating solids 1 Spheres in contact with each other 1 Line method 2 Unequal spheres 2 Cutting-plane method Exercises XIII ii Intersection of cylinder and cylinder Intersection of cone and cone Sections of prisms 1 Section plane parallel to the V.

Intersection of sphere and cylinder or prism 2 Section plane parallel to the H. Introduction 4 Section plane perpendicular to the V. Isometric scale Sections of pyramids Isometric drawing or isometric view 1 Section plane parallel to the base of the pyramid 2 Section plane parallel to the V.

Isometric graph 3 Section plane perpendicular to the V. Illustrative problems to the H. Isometric drawing of planes or plane figures 4 Section plane perpendicular to the H. Isometric drawing of prisms and pyramids to the V. Isometric drawing of cylinders Sections of cylinders Isometric drawing of cones 1 Section plane parallel to the base Isometric drawing of sphere 2 Section plane parallel to the axis Introduction angle smaller than the angle of inclination of the Principle of the oblique projection generators with the base The oblique projection and the isometric projection 4 Section plane parallel to a generator of the cone Types of the oblique projection an angle greater than the angle of inclination of the generators with the base Rules for the choice of position of an object Sections of spheres Steps for drawing the oblique projection 1 Section plane parallel to the H.

Oblique drawing of pyramid 2 Section plane parallel to the V. Oblique drawing of circle 3 Section plane perpendicular to the V. Oblique drawing of cylinder to the V. Oblique drawing of prism Typical Problems of Sections of Solids Methods of development Introduction 1 Parallel-line development Principle of perspective projection 2 Radial-line development Definitions of perspective elements 3 Triangulation development 1 Ground plane 4 Approximate method 2 Station point Developments of lateral surfaces of right solids 3 Picture plane Cube 4 Horizontal plane Prisms 5 Auxiliiary ground plane Cylinders 6 Ground line Pyramids Cone 7 Horizon line Development of transition pieces 8 Perpendicular axis Station point Forms of screw threads Angle of vision Triangular or V threads Picture plane 1 Unified thread Methods of drawing perspective view 2 Metric thread Vanishing-point method threads Types of perspective 5 Sellers thread 1 Parallel perspective or one point perspective 6 British Association thread 2 Angular perspective or two point perpective Square thread 3 Oblique perspective or three point perspective 1 Acme thread Distance points 2 Knuckle thread Measuring line or line of heights 3 Buttress thread Conventional representation of threads SP: Typical problems of perspective projection Multiple-start threads 1 Visual-ray method — by means of the top view and Introduction 3 Vanishing-point method Types of nuts Exercises XIX Hexagonal nut Introduction 2 Cap nut Reading of orthographic views Blue-print reading 3 Dome nut Missing lines and missing views 4 Cylindrical or capstan nut Identification of planes 5 Ring nut Conversion of pictorial views into orthographic views 6 Wing nut Washers Procedure for preparing a scale-drawing Bolts Illustrative problems Introduction 5 T-headed bolt Centre of gravity 6 Countersunk-headed bolt Centres of gravity of symmetrical areas 7 Hook bolt Centres of gravity of unsymmetrical areas 8 Headless tapered bolt Illustrative problems on centre of gravity 9 Eye-bolt Moments of inertia of areas 10 Lifting eye-bolt 1 Definition, 2 Unit 11 Tap-bolt or cap-screw 3 Graphical method 12 Stud-bolt or stud Illustrative problems on moments of inertia Set-screws Exercises XXI Introduction 3 Slotted nut Types of nomographs 4 Castle nut Definitions of various terms 5 Sawn nut or Wiles nut Method of constructing parallel scale nomographs 7 Penn, ring or grooved nut Layout of nomographs 8 Stop-plate or locking-plate Introduction 3 Lewis bolt Spanner 8 Core or minor diameter Longitudinal or bar stay 9 Effective diameter Processor CPU Display Riveting Caulking and fullering Graphic Output Devices Forms and proportions of rivet-heads CAD Software Failure of riveted joints AutoCAD Dimensions of a riveted joint Types of riveted joints Lap joint

Еще. На пальцах ничего. Резким движением Халохот развернул безжизненное тело и вскрикнул от ужаса. Перед ним был не Дэвид Беккер.

WebENGINEERING DRAWING [ PLANE AND SOLID GE O M ETRY ] By N. D. Bhatt Edition: 53rd Edition: (Reprint) ISBN: Authors: HAMZA ALI. AdUpload, Edit & Sign PDF Documents Online. Easily-navigable interface. Start Free Trial! Easily Automate, Manage & Optimize Document Workflow. Try Now for Free!replace.me has been visited by 1M+ users in the past monthService catalog: Document Management, Electronic Signatures, Cloud Storage. AdConfidently Tackle Any Design, Construction, Operations Project Regardless of Complexity. Easy Online Ordering for Affordably Priced BIM Software & Customizable Training Bundles.
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WebENGINEERING DRAWING [ PLANE AND SOLID GE O M ETRY ] By N. D. Bhatt Edition: 53rd Edition: (Reprint) ISBN: Authors: HAMZA ALI. AdUpload, Edit & Sign PDF Documents Online. Easily-navigable interface. Start Free Trial! Easily Automate, Manage & Optimize Document Workflow. Try Now for Free!replace.me has been visited by 1M+ users in the past monthService catalog: Document Management, Electronic Signatures, Cloud Storage. AdConfidently Tackle Any Design, Construction, Operations Project Regardless of Complexity. Easy Online Ordering for Affordably Priced BIM Software & Customizable Training Bundles.

Given: Number of sides and diameter of out scribing circle. Then AB is the length of one side. Now set off distances AB around the circumference of the circle, and draw the sides through these points. Given: Number of sides and diameter of inscribing circle. At each point of intersection draw a tangent to the circle. The tangents will meet each other at 1, 2, 3, 4…… etc. Then ….. Label the end points of the chord thus formed as A and B. Locate points C and D where these two lines pass through the circle.

Where these lines cross is the exact center of the given circle. Place a compass point on the center point; adjust the lead to the edge of the circle and swing an arc to check that the center is accurate. This arc will touch the line AB and the given arc. Center locations given Radius given Fig. It forms a gentle curve that reverses itself in a neat symmetrical geometric form.

In this example, from point B to point C. Draw a perpendicular from line C-D at point C to intersect the perpendicular bisector of C-X which locates the second required swing center.

Place the compass point on the second swing point and swing an arc from X to C. This completes the ogee curve. Note: point X is the tangent point between arcs. Check and. If r1 , r2 and AB are given draw them accordingly. If value of r1 , r2 are given simply draw the arc EF taking radius as r2- r1 and center as B. Then PQ will be the required tangent. Thus the ellipse will be completed. Divide a line of length 40mm into 7 equal parts.

Draw a regular pentagon inscribing a circle of diameter 80mm. Avoid use of protractor. Draw a regular pentagon out scribing a circle of diameter mm. Draw a regular pentagon having length of side as 45mm. Draw a regular hexagon inscribing a circle of diameter 80mm. Draw a regular hexagon out scribing a circle of diameter mm. Draw a regular hexagon having length of side as 45mm. Draw a regular octagon inscribing a circle of diameter 80mm. Draw a regular octagon out scribing a circle of diameter mm.

Draw a regular octagon having length of side as 45mm. Draw a 9 sided regular polygon inscribing a circle of radius 50mm. A 80mm long horizontal straight line is located outside a circle of radius 30mm, such that a 50mm line drawn from center of the circle meets the mid-point of the straight line at right angle.

Draw two arc tangents, each having a radius of 40mm touching the circle and one of the ends of the straight line. Draw a common arc tangent of radius 70mm to the two circles having their centers 80mm apart and having diameters of 50mm and 30mm respectively. Draw an ogee curve to connect two parallel lines each of length 20mm and their mid-points spaced 30mm vertically and 70mm horizontally.

Two wheels with diameters 3. Draw the line diagram of the arrangement. Use a reduced scale. Draw an ellipse having major and minor axis length as 90mm and 60mm. Why have you studied geometric drawings?

Name the geometric nomenclatures and draw a qualitative shape of them. Name and draw the different types of lines. What do you mean by isosceles, equilateral and scalene triangle? What are different types of quadrilaterals? Draw them. What is the difference between parallelogram, trapezoid, rectangle, square and rhombus? What do you mean by regular polygon? How can you calculate summation of all internal angles of a polygon? A circle has a diameter of cm.

Draw a circle showing chord, diameter, radius, arc, segment and sector. Name some solid geometric form. Draw a parallel or perpendicular line to a given line at any point using set-square. Transfer a given polygon to other specified point. Locate the center of a given circle.

Draw a tangent to the two given circle. A complete set of dimensions will permit only one interpretation needed to construct the part. In some cases, engineering drawing becomes meaningless without dimensioning. Maintaining scale only does not make a drawing sufficient for manufacturer. By direct measurement from drawing according to the scale is very laborious, time-consuming and such a part cannot be manufactured accurately.

But for overcrowded drawing they can be drawn at an oblique angle as well. Correct Wrong Fig. They are usually drawn freehand. It must not be either away from the line or cross the line. They are also used to present note, symbols, item number or part number etc. R3 Fig. Unidirectional system: All the dimensions are oriented to be read from the bottom of drawing.

It is also known as horizontal system. This system is preferred to aligned system. Aligned system: All the dimensions are oriented to be read from the bottom or right side of the drawing. These are dimensions which indicate the overall size of the object and the various features which make up the object. Locational dimensions are dimensions which locate various features of an object from some specified datum or surface.

Figure gives examples of size and location dimensions. Sometimes the space may be even too small to insert arrows, in such case dimensions as well as arrows can be provided on outside of the extension lines as shown in Fig.

Sometimes smaller circular dots are used in place of arrowhead for space limitation. Portion to be enlarged Enlarged view of A Use of small dot Fig.

The symbols used to depict degrees, minutes, and seconds are also shown in this figure. Angular measurements may also be stated in decimal form. This is particularly advantageous when they must be entered into an electronic digital calculator. The key to converting angular measurements to decimal form is in knowing that each degree contains 60 minutes, and each minute contains 60 seconds. If space is limited then leaders can be used comfortably. An arc symbol is placed above the dimension.

Why have you studied dimensioning? Which information are provided in dimensioning system? What are the conditions for a good dimension system? Name the elements of dimensioning system. What are the rules that must be followed while dimensioning? What is the purpose of extension line and what are the rules to be followed for extension line? What is the purpose of dimension line and what are the rules to be followed for dimension line?

What is the purpose of leaders and what are the rules to be followed for leaders? What are the uses of arrowheads in dimensioning and what are the rules to be followed for arrowheads? What is the proportion of width and length of an arrowhead? Draw a square out scribing a circle and complete dimensioning. What is the difference between aligned and unidirectional dimensioning?

Give examples. What will you do when the space between extension lines is too small to accommodate the dimension line with text at its middle? What will you do when the space between extension lines is too small to accommodate the dimension line with arrows?

What will you do when the feature is too small to make the dimension visible? What is the difference of dimensioning of chord, arc and angle? Give example. Draw a circular hole of 2cm deep and give dimensions to it. It is not possible always to make drawings of an object to its actual size as the extent of drawing paper is limited and also sometimes the objects are too small to make it clearly understandable by drawing its actual size in drawing paper.

Scale is the technique by which one can represent an object comfortably as well as precisely within the extent of drawing paper. In other words, a scale is a measuring stick, graduated with different divisions to represent the corresponding actual distance according to some proportion. Numerically scales indicate the relation between the dimensions on drawing and actual dimensions of the objects. It is represented as scale. If possible, drawing should be done in full scale.

Reducing Scale The scale in which the actual measurements of the object are reduced to some proportion is known as reducing scale. The standard formats of reducing proportions are: – drawing made to one-half of the actual size – drawing made to one-fifth of the actual size – drawing made to one-tenth of the actual size – drawing made to one-fiftieth of the actual size – drawing made to one-hundredth of the actual size Enlarging Scale The scale in which the actual measurements of the object are increased to some proportion is known as reducing scale.

The standard formats of enlarging proportions are: – drawing made to twice the actual size – drawing made to five times the actual size – drawing made to ten times the actual size Md. It is simply a line divided into a number of equal parts and the 1st part is further sub-divided into small parts. It is so named because the 2nd sub-unit or 2nd decimal of main unit is obtained by the principle of diagonal division.

Table 6. Scale is constructed by simply dividing the line Scale is constructed by dividing the line longitudinally. For example let us consider a plan drawn in inch units and scale provided with drawing can measure in feet and inch. If we draw another scale taking same R. Also if we draw another scale that can measure in cm and mm with same R.

It consists of a fixed main scale and a movable vernier scale. This scale is usually marked on a rectangular protractor. Therefore, to get the actual measurements, it is a must to know the proportion using which the drawing is prepared. Sometimes the drawing may need to be prepared to an odd proportion like In such case individual scale construction is required for that specific drawing.

It is often found helpful and convenient to construct and draw the corresponding scale on the drawing than mentioning the proportion in language. On the other hand if a drawing is to be used after decades, the paper may shrink or Md. Taking measurements from such a drawing using the proportion mentioned will give some inaccurate result.

But if a scale is constructed an drawn during the preparation of 1st time, the drawn scale will also shrink or expand in the same proportion to the drawing. Thus if one take measurements with the help of the drawn scale, accurate measurements will be obtained.

The ratio of the distance on drawing paper of an object to the corresponding actual distance of the object is known as the representative fraction R. It is to be remembered that for finding RF the distances used for calculation must be in same unit.

And being a ratio of same units, R. Calculation Example 6. Calculate R. Solution: Representative Fraction of the scale for this map,. Find out RF of the scale for this drawing. Solution: Representative Fraction of the scale,. What will be the R. Solution: Here 1 sq. However, sometimes British system is also used. It is important to have clear understanding about unit conversion in both system.

Avoid fractions, consider the next integer value. For instance, if maximum length to be measured is 6. For instance if the scale need to measure in feet and inches, number of minor divisions will be If space is limited they can be marked after every 2 division like 0, 2,4,….. Find R. Solution: 2. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4 and 5.

The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6, 8 and 10 toward left. Thus the scale is constructed and the required distances are indicated. Draw a plain scale to show units of 10 miles and single miles. Thus we have to construct the scale for 70 miles of maximum distance.

From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 10, 20, 30, 40, 50 and On a scale one centimeter represents one third of a kilometer.

Construct the scale and show the distance travelled by the car in 3 minutes and 30 seconds. What is the R. Solution: 1 1. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3 and 4. The 1st division is further divided into 6 divisions so that each minor division shows 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked as 10, 20, 30, 40, 50 and 60 toward left.

Thus the scale is constructed and the required time is indicated. Let the given short line AB which is required to be divided into 12 equal parts. Thus dividing is complete indirectly. For instance if the scale need to measure in yards, feet and inches, number of horizontal sub-divisions will be 3. For instance if the scale need to measure in yards, feet and inches, number of vertical sub-divisions will be At every horizontal sub-division point draw a parallel line to this diagonal line.

At left end a perpendicular of length equal to one major division is drawn and a rectangle is completed considering the mutually perpendicular lines as two sides.

The vertical line at left end is divided into 10 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 9hm is connected with a diagonal line. At the remaining 9 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8 and At all the horizontal major division points vertical lines are drawn.

Also show 2 yds. The 1st division is further divided into 3 divisions and starting at 0 mark placed earlier the sub-divisions are marked as 1, 2 and 3 toward left. The vertical line at left end is divided into 12 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 2ft is connected with a diagonal line. At the remaining two horizontal sub-division points parallel lines are drawn to the 1st diagonal line.

Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8, 10 and Construct a scale for this drawing showing meters, decimeters and centimeters and measure 2 meters, 5 decimeters and 8 centimeters on it. Solution: 20 1. Assume the drawing scale length is 15 cm standard value. Both are acceptable as we have to show a distance only 2m 5dm 8cm on this scale.

Let us take 7. Now a horizontal line 15cm long is drawn and is divided into 7 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4, 5 and 6. Top left corner and the point corresponding to 9dm is connected with a diagonal line. Maximum measuring length is given here i. Considering a drawing scale length as 15 cm.

So our major unit should be th of meters, 1st sub-unit should be 10th of meter and 2nd sub-unit or diagonal sub-unit should be single meters. Now a horizontal line 15cm long is drawn and is divided into 3 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, and 2. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40, 60, 80 and toward left.

Top left corner and the point corresponding to 90m is connected with a diagonal line. Construct a scale to read miles, furlongs and minimum 20 yards distance and mark 4 miles 6 furlongs and yards on it. Let us assume the drawing scale length is 6 inch.

The 1st division is further divided into 8 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6 and 80 toward left. The vertical line at left end is divided into 11 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 7 furlongs is connected with a diagonal line. At the remaining 7 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 20, 60, , , and The scale should be such that 4mm length is represented by 10cm and it should be able to measure upto 5mm.

Construct the scale and measure 3. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 0. Top left corner and the point corresponding to 0. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 0. Draw a scale to represent 6 km by 1 cm and to show distance upto 60 km.

From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3…… and 9. The 1st division is further divided into 6 divisions so that each sub-division represents 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40 and 60 toward left.

Top left corner and the point corresponding to 50 seconds is connected with a diagonal line. At the remaining 5 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Construct a plain scale to show meters and decimeters, when 3 centimeters are equal to 2 meters and long enough to measure upto 5 meters.

Show a distance of 2 meters 7 decimeter and 4. Construct a plain scale that can measure 1m to 50m. Show a distance 38m on the scale. Construct a scale to show miles and furlongs, when 2. In a certain map 1 acre represents square kilometers of land area. Construct a scale for a portion of that map which can measure in kilometers and its 1st decimal point.

The scale should be long enough to measure upto 9. Construct a plain scale to measure a maximum distance of 55 km and show the measurement of 42 km on it. The volume of a room is cubic metre. It is represented by a volume of 80 cubic cm. By measuring R. Also show the measurement of 12 metre on it. The distance between Dinajpur and Joypurhat railway station is km and it is covered by the Drutajan Express in 4 hours. Draw a plain scale to measure the time upto single minute.

Take R. Calculate and show the distance covered by the train in 45 minutes on the scale. Construct a diagonal scale to read meters, decimeters and centimeters and long enough to measure upto 5 meters when 1 meter is represented by 3 centimeters.

Indicate on the scale a distance of a. Construct a diagonal scale of R. A plan of a house 12 cm represents m. Construct a diagonal scale to read metres to one metre and show the measurement metres on it. The distance between two station is km. On a map it is represented by a 12 cm length line. Construct a diagonal scale to show kilometers and to measure a distance of km.

Find the R. Also mark a distance 46 metres and 5 decimetres on it. Ina drawing of machine parts, the original shapes are magnified 50 times. Construct a scale to measure upto 2nd decimal point of a single millimeter and long enough to measure upto 4mm.

Show a length of 2. A person is running at a speed of 6 kmph. Why have you studied scale? Define scale. When scale becomes necessary? Why have you learned to draw scale? In which situation scale is to be drawn along with the drawing? Classify scales according to scale size. Define each type and give practical examples. Classify scale according to measurement capacity. Define each type. Which scales are usually used by engineers? Differentiate between plain and diagonal scale.

Which information you think necessary to construct a scale? Define R. What is the unit of R. Give logic to your answer. What do you understand when an R. It is mentioned in a drawing that R. What is its meaning? On a map of Bangladesh you measured the distance from Dinajpur to Dhaka as 6 inch. Actually the distance is miles.

What should be the possible R. A 15 cm scale measures a maximum length of 10 km. What is its R. If 9 hectares of area is represented by 1mm2 in a map, what is the value of R. During the construction of scale why the zero notation placed at 2nd division? How can you divide a 1mm line in 7 equal parts? To provide necessary information about an object to the manufacturer or to any other concerned party, it is usual practice to provide projection s of that object.

If straight lines rays are drawn from various points on the contour of the object to meet a transparent plane, thus the object is said to be projected on that plane. The figure or view formed by joining, in correct sequence, the points at which these lines meet the plane is called the projection of the object. Pictorial Projection 3. Perspective Projection 7. When the projectors are perpendicular to the plane on which the projection is obtained, it is known as orthographic projection.

Following six views are possible in orthographic projection of a solid object. Top View b. Front view c. Left View d. Right View e. Rear view f. Bottom view Fig. They have the advantage of conveying an immediate impression of the general shape and details of the object, but not its true dimensions or sizes.

Pictorial projections may be of two types as a. Axonometric b. Oblique 7. Axonometric projections are classified according to how the principle axes are oriented relative to the projected surface.

There may be three types as: i. Isometric ii. Dimetric iii. Trimetric Fig. The angle is usually kept This may be of two types: i. Cavalier Projection: In this case, the dimensions along all the axes are plotted in full scale. Cabinet Projection: In this case, the dimensions along the diagonal axis are plotted by reducing it to half of the actual value.

Dimensions along other axes are plotted in full scale. In case of perspective projection observer is considered to be at finite distance where in case of any other type of projection observer is considered to be at infinity. In short, orthographic projection is the method of representing the exact shape of an object by dropping perpendiculars from two or more sides of the object to planes, generally at right angles to each other; collectively, the views on these planes describe the object completely.

Descriptive geometry is basically the use of orthographic projection in order to solve for advanced technical data involving the spatial relationship of points, lines, planes, and solid shapes. The most common means of understanding these types of orthographic projection is – The Glass Box method.

It can be suitably used for understanding the generation of orthographic views. The box is unfolded to obtain the arrangement of views. In figure 7. The line of sight is always perpendicular to the plane of projection, represented by the surfaces of the glass box top, front, and right side. Projection lines C connect the same point on the plane of projection from view to view, always at right angle.

A point is projected up on the plane of projection where its projector cuts that image plane. In the figure 7. When it intersects the horizontal plane top plane of projection , it is identified as 1H, when it intersects the frontal plane front plane of projection , it is identified as 1F, and where it intersects the profile plane right side plane of projection , it is labeled 1P.

On these planes, views of the object can be obtained as is seen from the top, front, right side, left side, bottom and rear. Consider the object and its projection in fig. In actual work, there is rarely an occasion when all six principal views are needed on one drawing. All these views are principal views. Each of the six views shows two of the three dimensions of height, width and depth. In general, when the glass box is opened, its six sides are revolved outward so that they lie in the plane of the paper.

And each image plane is perpendicular to its adjacent image plane and parallel to the image plane across from it. Before it is revolved around its hinged fold line reference line. A fold line is the line of intersection between any hinged adjacent image planes. The left side, front, right side, and back are all elevation views.

Each is vertical. The top and bottom planes are in the horizontal plane. But in most cases the top, front, and right sides are required. Sometimes the left- side view helps to describe an object more clearly than the light side view.

Orthographic views are arranged in two techniques as a. First Quadrant Fig. When an inclined or oblique line is to be projected it is helpful to identify and draw the end points and then joining them to obtain the projection. Parallel Inclined Fig. Oblique Fig. The edges, intersections, and surface limits of these hidden parts are indicated by a discontinuous line called a dashed line or hidden line.

Particular attention should be paid to the execution of these dashed lines. If carelessly drawn, they ruin the appearance of a drawing. All the center lines are the axes of symmetry. Hidden portions of the object may project to coincide with visible portions. Center lines may occur where there is a visible or hidden out line of some part of the object. Since the physical features of the object must be represented full and dashed lines take precedence over all other lines since visible out line is more prominent by space position, full lines take precedence over dashed lines.

A full line could cover a dashed line, but a dashed line could not cover a full line. When any two lines coincide, the one that is more important to the readability of the drawing takes precedent over the other. The following line gives the order of precedence of lines. Full line 2. Dashed line 3. Careful line or cutting — plane line 4. Break lines 5. Dimension and extension lines. Crosshatch lines. The points which are connected by lines in original object should be connected in the vertical plane.

All other 5 views can be obtained in similar way. The plane of projection vertical, in case of front view should be parallel to the face for which views are being drawn. For example, in case of top view the plane will be horizontal. In the projection there is a relationship of different views. It is usual practice to draw the front view first, then top and side views are drawn with the help of the vertical and horizontal projection lines.

This can be done using T-square, set-squares and compasses. Here only the figure C requires the use of compass in addition to T-squares and set- squares. The spacing between views has to be determined or decided beforehand and if equal spacing is needed then fig.

A can be followed and if a different spacing is needed then fig. B can be followed. Sufficient space should be provided in order to give dimensions avoiding any crowding and also excessive space should be avoided. If not mentioned or required otherwise 30mmmm spacing can be provided between two successive views. Position of this line depends on the spacing requirement between side view and front view.

If equal spacing is required then the line should originate at the corner of the front view. These lines will cut the diagonal line. It is to be noted that for 1st angle projection the lines should be projected according to position of views. For example to draw top view, vertically downward lines need to be projected from front view so that the top view is generated below the front views; for getting right side view horizontal lines from front view are to be projected toward left and so on.

The length along the third axis cannot be shown in same view. This makes it difficult to understand them and only technically trained persons can understand the meaning of these orthographic views.

A layman cannot imagine the shape of the object from orthographic projections. To make the shape of an object easy to understand for both technical persons and non-technical laymen pictorial projections are used. Most commonly used pictorial drawing is Isometric drawing. When a drawing is prepared with an isometric scale or otherwise if the object is actually projected on a plane of projection, it is an isometric projection. For this purpose the object is so placed that its principle axes are equally inclined to the plane of projection.

In other words, the front view of a cube, resting on one of its corners is the isometric projection of the cube as shown in fig. But as the object is tilted all the lengths projected on the plane appears to be shortened and thus they are drawn shortened in isometric projection. In the isometric projection of a cube shown in Fig. The extent of reduction of an isometric line can be easily found by construction of a diagram called isometric scale. For this, reproduce the triangle DPA as shown in Fig.

Mark the divisions of true length on DP. Through these divisions draw vertical lines to get the corresponding points on DA. The divisions of the line DA give dimensions to isometric scale. The lines that are parallel on the object are parallel in the isometric projection.

Vertical lines on the object appear vertical in the isometric projection. A line which is not parallel to any isometric axis is called non-isometric line and the extent of fore- shortening of non-isometric lines is different if their inclinations with the vertical planes are different.

Drawing of objects is seldom drawn in true isometric projections, as the use of an isometric scale is inconvenient. Instead, a convenient method in which the foreshortening of lengths is ignored and actual or true lengths are used to obtain the projections, is applied which is called isometric drawing or isometric view. This is advantageous because the measurement may be made directly from a drawing. The isometric drawing is An isometric drawing is so much easier to execute and, for all practical purposes, is just as satisfactory as the isometric projection.

Box method. Off-set method. In this method, the object is imagined to be enclosed in a rectangular box and both isometric and non-isometric lines are located by their respective points of contact with the surfaces and edges of the box.

It is always helpful to draw or imagine the orthographic views first and then proceed for isometric drawing. In the off-set method, the curved feature may be obtained by plotting the points on the curve, located by the measurements along isometric lines. If there are some inclined lines in the plane it will be helpful to enclose the plane with a rectangle and then obtain the projection with reference to the sides of that rectangle. ABCD is the required isometric projection.

This can also be drawn as shown in Fig. Arrows show the direction of viewing. Arrow at the top shows the direction of viewing. Similarly the fig. The line 3-A will intersect the line at point M. Similarly obtain the intersecting point N. With center 3 and radius 3-D draw an arc AD. Similarly the isometric views can be obtained on vertical planes as shown in fig. Then the isometric box is constructed and the orthographic views are reproduced on the respective faces of the box.

Finally by joining the points relating to the object and erasing unnecessary lines the isometric view is obtained. Archemedian spiral Projections of lines and planes by the use of auxiliary Logarithmic or equiangular spiral planes Helix To determine true length of a line To obtain point-view of a line and edge-view of a plane A method of drawing a helical curve To determine true shape of a plane figure Helical springs Exercises XI Screw threads Cam Introduction Exercises VI Traces of planes Loci of points Simple mechanisms 1 Traces The slider crank mechanism 2 Projections 1 Simple slider crank mechanism Projections of planes parallel to one of the reference planes 2 Offset slider crank mechanism 1 When the plane is parallel to the H.

A four-bar mechanism 2 When the plane is parallel to the V. Exercises VII Introduction 1 Plane, inclined to the H. Principle of projection Projections of oblique planes Methods of projection Exercises XII Orthographic projection Four quadrants Types of solids First-angle projection 1 Polyhedra Third-angle projection 2 Solids of revolution Reference line Projections of solids in simple positions Typical Problems Axis inclined to the V.

Axis inclined to the H. Projections of solids with axes inclined to both the H. Line of intersection and the V. Methods of determining the line of intersection between Projections of spheres surfaces of two interpenetrating solids 1 Spheres in contact with each other 1 Line method 2 Unequal spheres 2 Cutting-plane method Exercises XIII ii Intersection of cylinder and cylinder Intersection of cone and cone Sections of prisms 1 Section plane parallel to the V.

Intersection of sphere and cylinder or prism 2 Section plane parallel to the H. Introduction 4 Section plane perpendicular to the V. Isometric scale Sections of pyramids Isometric drawing or isometric view 1 Section plane parallel to the base of the pyramid 2 Section plane parallel to the V. Isometric graph 3 Section plane perpendicular to the V. Illustrative problems to the H. Isometric drawing of planes or plane figures 4 Section plane perpendicular to the H. Isometric drawing of prisms and pyramids to the V.

Isometric drawing of cylinders Sections of cylinders Isometric drawing of cones 1 Section plane parallel to the base Isometric drawing of sphere 2 Section plane parallel to the axis Introduction angle smaller than the angle of inclination of the Principle of the oblique projection generators with the base The oblique projection and the isometric projection 4 Section plane parallel to a generator of the cone Types of the oblique projection an angle greater than the angle of inclination of the generators with the base Rules for the choice of position of an object Sections of spheres Steps for drawing the oblique projection 1 Section plane parallel to the H.

Oblique drawing of pyramid 2 Section plane parallel to the V. Oblique drawing of circle 3 Section plane perpendicular to the V. Oblique drawing of cylinder to the V. Oblique drawing of prism Typical Problems of Sections of Solids Methods of development Introduction 1 Parallel-line development Principle of perspective projection 2 Radial-line development Definitions of perspective elements 3 Triangulation development 1 Ground plane 4 Approximate method 2 Station point Developments of lateral surfaces of right solids 3 Picture plane Cube 4 Horizontal plane Prisms 5 Auxiliiary ground plane Cylinders 6 Ground line Pyramids Cone 7 Horizon line Development of transition pieces 8 Perpendicular axis Station point Forms of screw threads Angle of vision Triangular or V threads Picture plane 1 Unified thread Methods of drawing perspective view 2 Metric thread Vanishing-point method threads Types of perspective 5 Sellers thread 1 Parallel perspective or one point perspective 6 British Association thread 2 Angular perspective or two point perpective Square thread 3 Oblique perspective or three point perspective 1 Acme thread Distance points 2 Knuckle thread Measuring line or line of heights 3 Buttress thread Conventional representation of threads SP: Typical problems of perspective projection Multiple-start threads 1 Visual-ray method — by means of the top view and Introduction 3 Vanishing-point method Types of nuts Exercises XIX Hexagonal nut Introduction 2 Cap nut Reading of orthographic views Blue-print reading 3 Dome nut Missing lines and missing views 4 Cylindrical or capstan nut Identification of planes 5 Ring nut Conversion of pictorial views into orthographic views 6 Wing nut Washers Procedure for preparing a scale-drawing Bolts Illustrative problems Introduction 5 T-headed bolt Centre of gravity 6 Countersunk-headed bolt Centres of gravity of symmetrical areas 7 Hook bolt Centres of gravity of unsymmetrical areas 8 Headless tapered bolt Illustrative problems on centre of gravity 9 Eye-bolt Moments of inertia of areas 10 Lifting eye-bolt 1 Definition, 2 Unit 11 Tap-bolt or cap-screw 3 Graphical method 12 Stud-bolt or stud Illustrative problems on moments of inertia Set-screws Exercises XXI Introduction 3 Slotted nut Types of nomographs 4 Castle nut Definitions of various terms 5 Sawn nut or Wiles nut Method of constructing parallel scale nomographs 7 Penn, ring or grooved nut Layout of nomographs 8 Stop-plate or locking-plate Introduction 3 Lewis bolt Spanner 8 Core or minor diameter Longitudinal or bar stay 9 Effective diameter Processor CPU

– Ты найдешь терминал Хейла, а я тебя прикрою. Сьюзан была отвратительна даже мысль об. – Разве нельзя дождаться звонка Дэвида о той копии, что была у Танкадо. Стратмор покачал головой. – Чем быстрее мы внесем изменение в программу, тем легче будет все остальное.

 
 

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