ENGINEERING GRAPHICS FOR

F. E. : FIRST YEAR DEGREE COURSE IN ENGINEERING ACCORDING TO NEW REVISED CHOICE BASED CREDIT SYSTEM SYLLABUS OF SAVITRIBAI PHULE PUNE UNIVERSITY, PUNE (EFFECTIVE FROM ACADEMIC YEAR 2019-2020)

COMMON FOR ALL DEGREE ENGINEERING COURSES

Dr. AVINASH M. PAWAR M.E. Ph.D. (Mechanical Engineering) Associate Professor & Head Engineering Science Department Bharati Vidyapeeth’s College of Engineering for Women Dhankawadi, PUNE.

PIYUSH ASHOKRAO DALKE M.Tech. (Mechanical Engineering) Assistant Professor, Mechanical Engineering Department JSPM’s / TSSM’s Padmabhooshan Vasantrao Patil Institute of Technology Bavdhan, PUNE

N5162

Engineering Graphics First Edition ©

: :

ISBN 978-93-89825-75-6

January 2020 Authors

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Dedicated to, Family, Friends, Friends, Dear Students and Late Shri Shankarrao Pawar

PREFACE It gives us great pleasure in publishing this text book on “Engineering Graphics” for the Students of First Year Degree Courses in Engineering. This book is strictly written According to New Revised Choice Based Credit System Syllabus of Savitribai Phule Pune University (2019 Pattern). As per the policy of the University, Engineering Syllabi is revised every five years. Last revision was in the year 2015. New revision is coming little earlier, as Savitribai Phule Pune University has introduced new Choice Based Credit System from Academic Year 2019-2020. For Engineering Graphics only. End-Semester Examination of 50 marks theory based on third, fourth, fifth and sixth units. The book not only covers the entire scope of the subject but explains the philosophy of the subject. This makes the understanding of this subject more clear and makes it more interesting. The book will be very useful not only to the students but also to the subject teachers. We would like to express our deepest gratitude to Hon. Dr. Patangraoji Kadam, Founder Chancellor, Bharati Vidyapeeth, for providing the excellent research environment and facilities for carrying out this work successfully. We wish to register our thanks to Hon. Dr. Shivajirao Kadam, Chancellor, Bharati Vidyapeeth (Deemed to be University), and Hon. Dr. Vishwajeet Kadam, Secretary, Bharati Vidyapeeth, who have always supported and encouraged us with their best wishes. Also our sincere gratitude to Hon. Dr. M. M. Salunkhe, Vice-Chancellor, Bharati Vidyapeeth (Deemed to be University) for his valuable support for this book. We take this opportunity to express our sincere thanks to Shri. Dineshbhai Furia of Nirali Prakashan, pioneer in all fields of education. Also thanks to Shri. Jignesh Fuira, whose dynamic leadership is helpful to all the authors of Nirali Prakashan. We specially appreciate the efforts of Mrs. Anagha, Mr. Ilyas Shaikh, Chaitali Takale and entire staff of Nirali Prakashan for making the publication of this book possible well in time. We thank, Prof. Dr. Sujit Pardeshi, Prof. Dr. L. B. Abhang, Prof. Dr. S. R. Patil, Prof. Dr. P. J. Awasare, Prof. Dr. S. A. Kale, Prof. Dr. R. N. Patil, Prof. Y. D. Kute, Prof. A. M. Deshmukh, Prof. S. M. Satpute, Prof. M. S. Mali, Prof. Dr. S. G. Ghalme, Prof. R. D. Shelke, Prof. K. H. Munde, Prof. V. Y. Patil, Prof. S. G. Thorat, Prof. S. R. Patil, Prof. Dr. K. V. Chandratre, Prof. A. G. Waghmare, Prof. Dr. D. S. Bilgi, Prof. Amol Chavan, Dr. Sachin S. Chavan, Prof. S. R. Mitkari, Sheetal Pawar, Arya Pawar, Vardhan Pawar, Prof. A. R. Dalke, Dr. U. A. Dalke, Miss Sunanda Dalke for their support, guidance, suggestions and inspiration in nurturing this research work. Last but not the least; we acknowledge the composure of our entire family which helped us to devote our energies towards this work. We have no doubt that like our earlier texts, student’s community will also respond favourable to this new venture. The advice and suggestions from our esteemed readers to improve the text are most welcomed, and will be highly appreciated.

Authors

102012 : ENGINEERING GRAPHICS Teaching Scheme: Credit Examination Scheme: TH : 01 Hr/week 02 End-Semester : 50 Marks PR : 02 Hrs/Week TW : 25 Marks TUT : 01 Hr/Week Course Objectives: 1. To acquire basic knowledge about engineering drawing language, line types, dimension methods, and simple geometrical construction. 2. To draw conic sections by various methods, involutes, cycloid and spiral. 3. To acquire basic knowledge about physical realization of engineering objects and shall be able to draw its different views. 4. To visualize three dimensional engineering objects and shall be able to draw their isometric views. 5. To imagine visualization of lateral development of solids. 6. To acquire basic knowledge about the various CAD drafting software’s and its basic commands required to construct the simple engineering objects. Course Outcomes: On completion of the course, learner will be able to: CO1 : Draw the fundamental engineering objects using basic rules and able to construct the simple geometries. CO2 : Construct the various engineering curves using the drawing instruments. CO3 : Apply the concept of orthographic projection of an object to draw several 2D views and its sectional views for visualizing the physical state of the object. CO4 : Apply the visualization skill to draw a simple isometric projection from given orthographic views precisely using drawing equipment. CO5 : Draw the development of lateral surfaces for cut section of geometrical solids. CO6 : Draw fully-dimensioned 2D, 3D drawings using computer aided drafting tools.

SYLLABUS Unit I : Fundamentals of Engineering Drawing

(01 Hrs.)

Need of Engineering Drawing and design, Sheet layout, Line types and dimensioning and simple geometrical constructions Unit II : Introduction to 2D and 3D Computer Aided Drafting Packages

(02 Hrs.)

Evolution of CAD, Importance of CAD, Basic Commands - Edit, View, Insert, Modify, Dimensioning Commands, setting and tools etc. and its applications to construct the 2D and 3D drawings. Unit III : Engineering Curves

(01 Hrs.)

Introduction to conic sections and its significance, various methods to construct the conic sections. Helix for cone and cylinder, rolling curves (Involutes, Cycloid) and Spiral. Unit IV : Orthographic Projection

(02 Hrs.)

Principle of projections, Introduction to First and Third angle Projection methods, Orthographic projection of point, line, plane, solid and machine elements/parts. Unit V : Isometric Projection

(03 Hrs.)

Introduction to isometric projection, oblique projection and perspective projection. Draw the isometric projection from the given orthographic views Unit VI : Development of Lateral Surfaces

(03 Hrs.)

Introduction to development of lateral surfaces and its industrial applications. Draw the development of lateral surfaces for cut section of cone, pyramid, prism etc.

✍✍✍

CONTENTS

1.

Fundamental’s of Engineering Drawing

1.1 − 1.28

2.

Introduction 2D and 3D Computer Aided Drafting Packages

2.1 − 2.52

3.

Engineering Curves

3.1 − 3.26

4.

Orthographic Projection

4.1 − 4.86

5.

Isometric Projection

5.1 − 5.60

6.

Development of Lateral Surfaces

6.1 − 6.38

Model Question Paper

P.1 − P.10

✍✍✍

Chapter 1 FUNDAMENTAL’S OF ENGINEERING DRAWING 1.1 INTRODUCTION Drawing is a human being’s way of expressing thoughts and ideas with the help of pictures. All objects begin as an idea conceived and visualized by the engineer. Engineering drawing is a graphic language of engineer which he/she communicates to others by describing its shapes and size with the help of different lines, curves, signs and standards. As other languages have a grammar as the base, Engineering Graphics (Engineering Drawing) has a set of universal rules as a base, which are to be followed and thoroughly understood. Engineers in the world have agreed to use the same lines and symbols and the same method of drawing. That’s why Engineering Graphics (Engineering Drawing) is called the universal language or language of engineers. All engineered products or objects manufactured, begin as ideas and ideas must be communicated to manufacturer, learner and reader effectively. Engineering drawing is the pictorial representation of real-world objects. Engineering drawing is a technical drawing language, which is systematically and scientifically developed as well as effectively used to fully and clearly define ideas of engineered products. To signify an object using engineering drawing, special drawing instruments necessity to be used to create drawings of high quality that provide the greatest accurate and correct image of the object. For effectively making of engineering drawings, knowledge and understanding of the working of these instruments is a necessity. Need of Engineering Drawing and Design: Technical drawing is a means of communication between a designer and a producer. Based on this simple definition, technical drawing is important in engineering because it is a language without broader among all stakeholders (designers, engineers, technicians, machines, electricians, builders and technical/engineering teachers) in the production/ manufacturing line in engineering and technical fields. Additionally, it is important because it simplifies their jobs using 3D and 2D drawing and sketches. Engineering drawing is the language with which Engineers interact, share ideas anytime, anywhere, anyhow - using any medium/material they can sketch on. Engineering drawing is an Engineers way of respecting Engineering design/idea instantaneously before testing using softwares. The essence of softwares is to reduce cost - as going from just drawing diagram to construction may cost more if the design fails.

1.2 ESSENTIAL DRAWING INSTRUMENTS FOR STUDENTS Drawing instruments are used to prepare drawings easily and accurately. Good quality of instruments gives better accuracy in drawing. 1.

Drawing Board [B2/B3 Size]

2.

Mini Drafter

3.

Set Square with Protractor [45°]

4.

Eraser

5.

Drawing Board Clips

6.

Compass

7.

Roll-N-Draw

8.

French Curve

9.

Drawing Pencils [‘2H Grade’ for construction lines and ‘HB Grade’ to Darken Lines]

10. A3 Size Drawing Book or A2 size Drawing sheets 1. Drawing Board [B2/B3 Size] Drawing board is rectangular in shape. It is made of strips of well-seasoned soft wood about 25 mm thick. In order to prevent warping, the drawing board is made of narrow strips glued edge to edge. One of the edges of the board is used as working edge which is ebony working edge. Surface of board should be free from cracks and it should be absolutely flat. On other side of board two battens fixed by screws are fitted in the slots to allow for seasonal expansion and contraction. (1.1)

ENGINEERING GRAPHICS

(1.2)

FUNDAMENTAL’S OF ENGINEERING DRAWING

The standard sizes of board as per I.S. 1444 are as follows: Table 1.1 Sr. No.

Designation

Dimensions (mm)

Name

1.

B0

1500 × 1000

Antiquarian

2.

B1

1000 × 700

Double-elephant

3.

B2

700 × 500

Imperial

4.

B3

500 × 350

Half-imperial

5.

B4

350 × 250

Quarter imperial

Top Bottom

Battens

Working edge

Working Edge

Ebony

Fig. 1.2 : Drawing Board

Fig. 1.1 2. Mini Drafter:

“All the function of the T-square, set-squares, scales protractor and the roll-n-draw are combined in the drafting machine called mini drafter.” It is used to do drawing work faster. It serves the combined purpose of T-square, set-squares, protractor and scales. During the operation, two blades of the drafter always remain parallel to their set position, no matter where they are moved on the sheet. Two blades of the drafter are accurately set at right angles to each other. The blades are detachable and hence blades with different scales can be used. To set and clamp two blades at any desired angle, there is provision of adjusting head with vernier protractor. Setting of mini drafter: Steps: (I) (II)

Clamp the min-drafter by tightening the screw on left top corner of drawing board. Align 0° on protractor head with reference mark and tighten the locking knob.

(III) Set the horizontal edge of mini-drafter and drawing sheet in a line and fix to drawing board with the help of drawing clips or pins/adhesive tapes.

Fig. 1.3

ENGINEERING GRAPHICS

(1.3)

FUNDAMENTAL’S OF ENGINEERING DRAWING

3. Protractor: Its circumferential edge is graduated to 1° divisions, and numbered at every 10° interval. Uses : •

To draw any angle.

•

To measure any angle.

Protractors are used for measurement of angles. They are available in circular and semi-circular shapes. They are made of paper, wood, plastic, brass or celluloid materials. Transparent protractors with bevelled edges are very much in use. They are graduated to 1/2° or 1° and numbered at an interval of 10°.

Fig. 1.4: Protractor 4. Eraser : Soft grade India-rubber is most suitable for erasing pencil work. It should not stain the paper surface and spoil it. Frequent use of eraser should be avoided. You must also keep a piece of clean cloth to lightly dust the paper and clean the paper surface of left over eraser residues 5. Drawing Board Clips/Pins/Adhesive tapes: These are used to fix the drawing paper on the drawing board. The needle part is made of steel, while head is made of plated mild steel or brass. Pins of about 15 to 20 mm diameter and 1 mm thick flat heads made of brass are very convenient. They do not rust. Pins should be so inserted that heads sit on the surface of the paper. Clips or adhesive tapes are also used instead of pins. 6. Compass or Divider: It is like a compass or divider except it has metal points at legs. Dividers are used to transfer distances or dimensions. It is also used for dividing spaces into equal divisions. Divider is similar to the compass except that it has a metal point on each leg. It is used to lay-off distance and to transfer measurements.

Fig. 1.5: Compass

ENGINEERING GRAPHICS

(1.4)

FUNDAMENTAL’S OF ENGINEERING DRAWING

7. Roll-N-Draw: This instrument is useful to draw parallel lines. The lines may be horizontal, vertical or inclined. While drawing lines parallel to a given line, the straight edge of the ruler is kept on it. Further, it is rolled to new locations and then parallel lines are drawn. Uses : This is used for drawing parallel lines horizontal as well as vertical.

Fig. 1.6: Roll-n-Draw 8. French Curve: They are made of wood, plastic or celluloid. They are made of various shapes, one of which is shown in Fig. 1.7. Some set squares are provided with French curves cut in their middle Curves which are difficult to draw with the help of compass, are drawn with French curves. Faint freehand curve is first drawn through the known points. Longest possible curve coinciding with freehand curve is then drawn out from French curve. Finally neat continuous curve is drawn. •

First mark the irregular curves to be drawn by a series of dot.

•

Start from one end of required curve. Place and move the French curve such that a portion of the curve aligns along as many dotted points as possible

Hold down the French curve firmly and draw the curve join the points with pencils.

Fig. 1.7: French Curve 9. Drawing Pencils: H or 2H grade pencils should be used for drawing so that the lines are faint, and unneeded or incorrect lines can be easily erased. The final fair work may be done by a softer pencil to have dark lines. For freehand sketching, HB pencil may be used. Proportions of graphite and clay decide the softness and hardness of the pencil. Soft pencils produce dark black lines, while hard pencils produce thin gray lines. Now-a-days refill pencils or push pencils are used. Lead size in these pencils is generally 0.5 mm. Good quality pencils must be used for drawing lines of uniform shade and thickness

Fig. 1.8: Drawing Pencil

ENGINEERING GRAPHICS

(1.5)

FUNDAMENTAL’S OF ENGINEERING DRAWING

10. A3 Size Drawing Book or A2 size drawing sheets: Smooth handmade paper is used for the purpose of drawing. It needs to be uniformly white in color and the texture should be adequately grained in order to produce sharp and clear drawing using a pencil. When ink is used, it should not spread on the paper. When rubber eraser is used, fibers of the paper should not separate out. The smoothness, whiteness and weight of a paper decide its cost. Weight of drawing paper per rim is about 25 to 30 kg. The various sizes in which a drawing sheet is available are given in table. Sheet designation Trimmed size (mm)

Untrimmed size (mm)

A0

841 × 1189

880 × 1230

A1

594 × 841

625 × 880

A2

420 × 594

450 × 625

A3

297 × 420

330 × 450

A4

210 × 297

240 × 330

A5

148 × 210

165 × 240

The drawings are designated as A0, A1, A2, A3, A4 and A5. A0 is the largest while A5 is the smallest.

841

A0

594 A1 420 297 148 0

A2 A4

A3

A5 210

420

594

841

1189

Fig. 1.9

1.3 DRAWING SHEET LAYOUT A proper sheet layout is necessary for the easy reading of the drawing. The following are the important features considered while layout a drawing sheet. 1. Sheet size : Students are advised to use A3 or A4 size of sheet. 2. Boarder lines : Boarder lines are used to obtain clear working space on the drawing sheet. Boarder lines should be drawn 10 mm inside the edges of the drawing sheet. 3. Title block : Space for the block must be provided in the bottom right corner of the drawing sheet as shown in Fig. 1.10. The size of the title block varies depending upon the contents to be filled in it. The size of the title block for drawings in colleges is recommended by the B.L.S. as 185 mm × 65 mm.

(1.6)

FUNDAMENTAL’S OF ENGINEERING DRAWING

10

ENGINEERING GRAPHICS

20

10 Drawing Space

Left margin

63

10

160

Title block

Trimmed sheet

Drawing frame

Fig. 1.10 : Drawing Sheet Layout In Engineering Graphics, it is mandatory to draw a title block in each and every sheet of drawing. Title block is a rectangular block which is an important feature of drawing. It should be placed at the bottom right corner of the drawing sheet. The recommended specifications as per IS:11665-1985 provides the following information as shown in the picture below. 1.

Name of the student preparing the drawing.

2.

Roll number.

3.

Section.

4.

Title of the drawing.

5.

Drawing sheet number.

6.

Scale.

7.

Name of the institution.

8.

Date.

9.

Symbol denoting the method of projection. 150

10

50

5

5

75

Name :

Roll No :

Class :

College :

Plate No. :

Date :

Title : Scale 1:1 1

All Dim. are in mm

37.5

37.5

Fig. 1.11

ENGINEERING GRAPHICS

(1.7)

FUNDAMENTAL’S OF ENGINEERING DRAWING

The drawings are prepared and drawn either in the first angle projection or third angle projection method and the symbols to represent it are as follows,

(a) Symbol for First Angle Projection

(b) Symbol for Third Angle Projection Fig. 1.12

As per IS:SP 46-1988, first angle projection method is to be followed in engineering drawings. The above mentioned procedure to draw a title block is a standard procedure whereas in order to follow the examination rules, certain changes should be made in the title block such as, •

The columns 'Name and Roll No' are merged and replaced with 'Register Number (Reg. No.)'.

•

'Class' is replaced with 'Semester (Sem)'.

•

'College' is replaced with 'Session'.

•

Since the Indian Standard states to follow first angle projection method, showing the symbol of projection method is optional.

•

All the other options stay same without any change.

1.4 LETTERS AND NUMBERS Lettering is used for writing titles, dimensions, notes and other important particulars on a drawing paper. Drawing may be accurate and descent but if lettering is not proper its total appearance is spoiled by poor lettering. It is therefore necessary that all lettering should be upright and in block capitals. All written information on the drawing is always in the form of clear and simple style lettering so that it can be done free-hand and speedily. Careful and continuous practice improves lettering efficiency. Single Stroke Letters : These letters are used in most of the drawings. They are the simplest type of letters. The thickness of the letters is such that they can be drawn by single stroke of the pencil and hence the name, single stroke letters. Single stroke letters are of two types : (i) Vertical and (ii) Inclined. Inclined letters are inclined to the right with the slope angle 67.5° to 75° with the horizontal. The size of a letter is decided by its height. The ratio of height to width varies but mostly it is kept as 6 : 5. Lettering is generally done in capital letters. Different size of letters are used for different purposes For most of the capital letters the ratio of height to width is 6 : 5. Thus, if the height of letters like B,C, D etc. is 12 mm then the width would be 10 mm. Most of the lower case letters like a, c, e, n, o etc. have the ratio of height to width to be 1:1. shows various characteristics of lettering.