Engineering Drawing By N.D Bhatt PDF

I I [IN FIRST-ANGLE PROJECTION METHOD] Revised ,1nd enlJrged by M. t"KJUVIIILH.I R. M.E. (Mactiine.), B.E. (Mech. Engg.), LMH.S.T~E.. LMJ,S....

I I [IN FIRST-ANGLE PROJECTION METHOD] Revised ,1nd enlJrged by M. t"KJUVIIILH.I R. M.E. (Mactiine.), B.E. (Mech. Engg.), LMH.S.T~E.. LMJ,S.T.E., ELI: ti l lecturer in Mech. Engg. · Formerly, Professor in Mech. ,s B.and B Institute of Technology Faculty of Technlogy and Engin ]\, Vallabh Vidyanagar M. S. University of.Baroda, VADODA!v\ · ANAND REVISED AND ENLARGED EDITION: 2011 J Opposite Amul Dairy, Old Civil Court Road ANAND 388 001 Gujarat, India  ELEMENTARY ENGINEERING DRAWING Edition 1.984 Second Edition 1985 Third Edition 1985 fourth Edition 1986 Fifth nth Edition 1987 Sixth h Edition 1988 Seventh 1989 Eighth 1990 Ninth 1991 Tenth 1.992 1993 1994 1995 1995 1996 1997 1998 1999 2000 2000 2001 2002 Revamped) ISBN 978-93-80358-17-8 I 9 789380 358178 All rights reserved by the Author. This book or parts thereof may not be reproduced in any form or translated without the written permission of the Author. Pu!Jlisfteii Bhavinkumar R. Patel and Pradipkumar R. Patel PuMishm 1/txt-.Bor/fcs Opposite Amul Dairy, Old Civil Court Road, Post Box 65 ANAND 388 001 Gujarat, India Phone: (02692) 2562371 Fax: (02692) 240089 E7mail: charotar@cphbooks;com Website: www.cphbooks.com Laserset Charotar Associates, Anand Printed Repro India Ltd., Mumbai  Affectionately dedicated to all my and It gives me plea.~ure·to introduc~ this tex~~book.Qn. Engineering Drawing by Prof. N. D;. Bhattofthe BirlaVishvakarmaMahavidyalaya to stu.dents of Engineering; Prof. Bhatt ha~ been teaching this subject for over twenty years and has deservedly earned. the}$!ptttation of being. one 4)f the best teachers in the subject. This book coyers the prescribed for the Pre-engineering and FirstY~ar of the Degree course:5 ln Engineering and deals with the Jundafoental subj~ct which have been')re·ate!l by ProCBhatt lucidity. · ·.June 6, '1958.  From the very early days, man realized that if he had to construct any structure or machine correctly and methodically, he must first record his ideas before starting construction work. These recorded ideas become more vivid and forceful if they are shown on paper in form of a drawing of the structure or machine. Such a drawing will be of very great help to the man who looks after the construction of this structure or machine. Indeed, "technical drawing is the language of engineering Without the good kmJwledge 0 of drawing, an engineer is nowhere and he could not have constructed the various magnificent structures.or intricate machines. Evidently, any one connected in any way, with engineering construction must understand this language of engineers. Technical drawing is, therefore, indispensable today and shall continue to be so as long as engineering and technology continue to be of use in the activities of man. By means of drawing, the shape, size,. finish, colour and construction of any object (no matter how complex) can be de$~f.iP:la~f'iicCurately and clearly. The engineer should develop his skill, in two phases of. \~~lj~it,1 ~r~~i11g; first, he must be. able to draw dearly and rapidly, the freehand technis~:~~,tcnes; $~. 9:~.. must be proficient in drawing to scale the instrumental dra"".illgts'1~~]pu~~e>$e of,.. ·. ,pre1,ent volume is to give the basic principles of the instrum.~r;i'~~L~K~~tng ?lllY· · ;;: / \; The book covers ~e syllabi in fngipe~ring JJ)ra.wir,ig otc ri;i~ny University Colleges and Polytechnics in lndi.,l'and has been, writte~.k · fo · in view the difficulties of a beginner in the subject of ;Engineering Drawing; I rgoing througti thejriitial man~script.and for offering constructive su~estions. Fi11ally, J.,i~el grate£ul· Jo the f~Uowing: !~ (i) The authot;ities of the.Universities of Bombay, Poprta and Gujarijt, and the Department of Technical Edu~ation, Boml:!ay, fol' t~eir kind percn:iission to inclu(Je a few questions set at their examinatiQ!ls. (ii) Mr. N M. Paqc~al and Mi'. ~- D. Bhatt fQi' their help in preparing pencil sketches. (iii) Mr. L O~ Bhatt for pr · ing the excellent typed manuscript; (iv) Mr. Ramanbhai ·.C. Patel ()f Charcitar. Book... foc.carefu\,proof-reading and for his efforts to see the boq~ out in Pf()P~f tjftle: M..Jlie ~~~.~· Presf,:authorities for the care and interest shown Jf! the' printing arid set·t1r:vof ,b061t '(vi) Tfi~ Prabhat Process Studio for the promptn~ss and good worlc 9f bJ~k".ma... ;. 8 Any suggestion to improve the value. of ·this bo~k will be gratefullyt received and will D~.:~: be incorpo~~ted subsequent> e.clitions aft~r due s.crµtiny~ · June u:: ::p:liffton,, ihe inspiration of the Indian furidamenil::.n:. stries in a large measure have switched on to the third-angle projection system. So have a vast majority of Technical Institutions. "Elementary Engineering Drawing", too, must keep step with the changes. There was a phased change-over beginning with the.seventh edition. This edition.has completed the change. Nevertheless, the first-angle projection system has not been altogether discarded. The fundamentals of both the systems· are juxtaposed and elucidated. The chapters on (i) · Development of surfaces, (ii) Isometric projection and (iii) Conversion of pictorial views into orthographic views have been treated in some greater depth. This and the increase of the illustrative problems and practice exercises have evidently enlarged the size of the book and inevitably led to a little rise in price. I should not miss this opportunity to record my gratitude to the numerous teachers for their very useful suggestions and the students for their excellent response to the book, without which this edition should not have come into being. January 26, 1970 N. D. BHATT  vii The first edition was originally published in 1958 and now has entered in its 42nd Edition during 42 years, proves its popularity and utility among the teachers as well as the students of Engineering Institutions of our country. This edition has been entirely revised and enlarged by adding the following four chapters: (1) Screw Threads (2) Screwed Fastenings (3) Riveted Joints and Welded Joints (4) Computer Aided Drafting. It was thought desirable to include this fourth chapter on 'Computer Aided Drafting' which has now acquired an important place in this subject. We are thankful to Or. S. S. Khandare of Y. C. College of Engineering, Nagpur for contributing this chapter. We are also highly obliged to Shri R. C. Patel of Charotar Publishing House, Anand for correcting the Proofs. This book provides a wealth of inforrriati~n a,nd describes an exciting new paradigm and is also a valuable tool for all the Engine2 ,... (1) Cleaning the instruments. 16 (6) Small bow ink,:pen.... (2) Pinning the pap!:!r to.the (7) Inking pen....... ··if''";':""'0"""',,'·} drawing b~ard..... '... Scales............. Border lines.............. Protractor...... ,/;·. "\1,.t4)\'.'.Su.acing of drawings.. , ,. , French curves. lntroijictt611 ,.... :. 36 Lines 'it,:... · ·... 36 (1 > Urieithi.t::kne?s.. 36 (:2) lnkec(drawings... 37 {3) Pencil drawings.......... letters..... stn1Plf.:;1·ro1,1> 37 3-1-1. Types of Lines............... 35 (2) letters............ 40 (1) Outlines................ 35 3-3. Dimensioning....... ,........ 40 (2} Margin lines............. 35 3-4. Dimensioning terms and notations 41 (3) Dimension lines......... 35 ( 1 ) Dimension lrne........ 41 (4) Extension or projection lines 35 (2) Extension line....... ,.....41 (5) Construction lines....... 35 (3) Arrowhead, (4) Leader.... 41 (6) Hatching or section lines. 35 3-5. Placing of dimensions......... 42 (7) Leader or pointer lines... 35 (1} Aligned. system..... 42 (8) Border lines............. 35 (2) Unidirectional system. 42 (9) ·Short-break lines......... 35 3-6. Unit of dimensioning... ,..... (10) Long-break lines........ 35 3-7. General rules for dimensioning. 43 (11) Hidden or dotted lines..... 35 3-8. Practical hints on dimensioning 43 (12) Ce.ntre lines............. 35 Exercises Ill....... ,.......... 48 4· L Introduction...,..... ,...... 51 (1) Plain scales.............. 52 Scales............ 51 (2) Diagonal scales......... 55 (1) Engineer's, (2) Graphical scale 52 (3} Comparative scales... ,... 59 {3) Representative fraction... 52 ( 4) Vernier scales........... 61 4-3: Scales on drawings........ 52 (5) Seate of chords......... 65 4~4. Types of scales....... :... 52 Exercises IV............... 66 5-0. lntroduction.............. To construct squares........ 5~1. Bisecting a line...... To construct regular polygons 82 5-2. To draw perpendiculars... Special methods of drawing 5-3. To draw parallel lines... regular polygons... 84 5-4. To divide a line Regular polygons inscribed 5.~s. To divide a in circles............... 86 5-6. To bisect an To draw regular figures using 5-7. T-square' and set-squares... 88 5-8. To draw tangemts............ 89 5-9, ; lengths of arcs........... 91 Circles and in contact.. 92 Inscribed circles....... 94 98..................... 130 Spirals........... ,.... , ·.'· ,.. 1 3 3. Archernedian spiral. 1 34 6~5-2. Logarithmic or equiangular spiral.. ,........ 1 36 Helix............. *'.. 138 )\,method of drawiryg a helical curve ,..... ·........ 138 Helical springs.... ~......... 139 Screw threads.......... 1 41 Helix upon a.......... 142......... 143............. 144 7-0. Introduction............ 151 ( 1) Simple slider crank mechanism 154 7~1. Loci of points.. ,........... 151 (2) Offset slider crank mechanism 154 7-2. Simple mechanisms...... 153 7-2-2. A four-bar mechanism....... 156 7-2-l; The slider crank mechanism... 153 Exercises VII........... ;.... 166 8-0. lntrodµc:tion... '. ~....... 169 8-6. First-angle projection...... 171.8-1, Prindple of projection....... 169 Third-angle projection....... 172 Methods of projection... 169 8-8. Reference line.......... 1 73 Orthographic projection... 169 8-9. BJ.S. code of practice...... 1 77 Planes of projection..... ·1 71 8-10. Typical Problems.......... 1 77 Four quadrants.......... 1 71 Exercises VIII............. 183 9-0. Introduction................ 189 9-3. A point is situated in the third quadrant............. 190 9-1. A point is situated in the 9-4. A point is situated first quadrant............... 189 in the fourth quadrant....... 191 9-2. A point is situated in the 9-5. General conclusions......... 191 second quadrant............ 190 Exercises IX................ 193 10-0. Introduction............... 195 10-7. Line contained by a plane 10-1. Line parallel to one or perpendicular to both the both the planes............. 1 reference planes ,........... 205 True length of a straight line 10-2. line contained by one or and its inclinations with the both the planes......... reference planes............ 2 06 10-3. Line perpendicular to v111::,.,1:,:1·,,,. of a line.............. 209 the planes....... l\,/1;,,th,,rlc of determining 10-4. a line............. 21 l line, the nr,lii>araUekpersij~ctive or one point pei'sp~ttive....... 486 Angular P?fjpective or two point p~pective........ 487 (2) Oblique perspective or (3 }.Picture three.point perspective.. 488 Horizontal plane........ 478 19-9. Distance points........... 489 (5)Auxiliiary ground plane.. 478 i 9-10. Measuring line.or line of heights 4 91 (6) Ground line {7) Horizon line 4 78 19-11. Perspectivces of drdes & solids 492 (8)Perpendicular axis...... 478 19-12. Typical problems of (9).Centre of vision........ 478 perspective projection... t : 494 {10)Central plane ,......... 478 (1) Visual-ray method -- 19.-4. Station point.. > 4 79 by means of the top view Angle of vision......... 4 79 and the front view... ,.. 494 19-6. Pict.ure plane...... ,....... 480 Visual-ray method - 19-7. Methods of drawing by means of the· top view perspective view.... ,...... 480 and the side view. ,.... 494 19-7-1. Visual-ray method.......... 48'1 (3) Vanishing-point method. 494 1 Vanishing-point method.... 485 Exercises XIX......... , ,.. 509  Table of Contents xiii 20-1. Introduction............ 511 20-5. Conversion of pictorial views 20-2. Reading of orthographic views into orthographic views..... 51 7 (Blue.:print reading}......... 511 20-6. Orthographic projeI I~ Due to lack of space, the I t 25 , I 15 dimension figure may be written above the extended portion of the FIG. 3-17 dimension line, but preferably on 012, DEEP20 the right-hand side (fig. 3-17). (7) Dimensions of cylindrical parts should as far as possible be placed in the views in which they are ~f -~=A-----j' Qt ___ jt SI"Q seen as rectangles (fig. 3-18). The 1._.___ _-1 dimension indicating a diameter 30 >.. _ I_ __,I should always be preceded by 50 )I the symbol 0. Dimension of a FIG. 3-18 cylinder should not be given as a radius. Fig. 3-19 shows various methods of dimensioning different sizes of circles. Dimensions should be shown in one view only, the same dimension must not be repeated in other view. *-@ I FIG. 3-19 Holes should be dimensioned 016 2 HOLES, 010 in the view in which they appear as circles (fig. 3-20). They should be located by their centre lines. As far as possible, all dimensions for one particular operation, such as diameter and depth of a drilled hole (fig. 3-18), or size and depth of a threaded hole (fig. 3-29) should be given in one view only. Art. 3-8] lines, lettering and Dimensioning 45 In case of a large-size bore or a pitch circle, the dimension may be shown by a diagonal diameter (fig. 3-21 ). But (in aligned system) a dimension should not be placed within 30° zone of the vertical centre line as shown by the shaded space in fig. 3-21. Holes on pitch circles when equally PITCH CIRCLE spaced should be dimensioned as shown in fig. 3-21. When holes are not equally or uniformly spaced on the pitch circle, they ·"~ should be located by angles with one of the two main centre lines (fig. 3-22). Arcs of circles should be dimensioned by their respective radii. Dimension line for the radius should pass through the / centre of the arc. The dimension figure must be preceded by the letter R. Fig. 3-23 shows different methods of showing the radii of arcs. FIG. 3-21 I R6 SQ24 r , 1 R3 R6 FIG. 3-22 FIG. 3-23 FIG. 3-24 (8) Letters SQ should precede the dimension for a rod of square cross-section (fig. 3-24). The word SPHERE should be placed before the dimension (radius R or diameter 0) of a spherical part (fig. 3-25). (9) Angular dimensions may be given by any one of the methods shown in fig. 3-26. (10) Fig. 3-27 shows a method of dimensioning a countersunk hole. The maximum diameter is also sometimes given. SPHERE R20 ~ (i) (ii) (iii) ~ Fie. 3-25 FIC. 3-26 FIG. 3-27  46 Engineering Drawing [Ch. 3 (11) Methods of dimensioning a chamfer is shown in fig. 3-28. 2 X 45° 2 2 X 45° 2 ffi-1>1 'l. 5 - or ·---'')3 (i) (ii) (iii) FIG. 3-28 (12) Designation and size, along with the useful length must be given while dimensioning an external screw thread (fig. 3-29). In case of internal screw thread, in addition to the size and type, the depth of the drilled hole before tapping must also be given (fig. 3-30). (13) Left-hand thread and multiple-start thread should be dimensioned as shown in fig. 3-31 and fig. 3-32 respectively. (14) A slope or taper is defined as unit alteration in a specified length. The specified length is measured along the base line in case of flat pieces and along the axis in case of shafts. M1' fi SQ. 20 x 4 J DOUBLE START 0 N L I I n lO LG 1:n---·-J FIG. 3-31 FIG. 3-32 I f= SLOPE 1:20 :::, __I_ ! ~r1.____ ____.l~:c I , 1... so I 1 L FIG. 3-29 FIG. 3-30 FIG. 3-33 r.--""""""===--i ~ (15) Fig. 3-33 shows the method of indicating slope on a flat piece. It is written parallel to the sloping line. -a ~1- __ a±_ _IA_PER 1:1,Q_. __ ~ a 0 H - h Flat taper = - L - = 1 :--===:.__!___I. 20 I~ L 60 ~ (16) The taper on a shaft is indicated FIG. 3-34 along the centre line and is accompanied by one or both the diameters (fig. 3-34). D-d 1 Taper on diameter = -L- 10 (17) Fig. 3-35 shows method of FIG. 3-35 dimensioning for frustum. It is drawn 42° fas 100 obliquely but parallel to each other.. 3-36 s h ows met ho d s o f c===3' ~ ~ ~ } } ::i (18) F1g. ANGLE ARC CHORD dimensioning chords, arcs and angles. FIG. 3-36 Art. 3-8] lines, Lettering and Dimensioning 47 (19) Study carefully fig. 3-3 7 for correct dimensioning. Incorrect dimensioning is shown by cross (X) in the figure. CORRECT INCORRECT ASONSFORINCORRECT 1. Arrow head not proportionate. 2. Hole dimension shown in figure. Leader line not ends (i) horizontally. 3. Dimension '40' is too close. 4. Placing dimensions methods mix. Dimension '40' is Dimensions should be placed outside view according to aligned method. 30 30 X 1. A key-way is shown with l~-~~ dotted line where the "'T dimensions are placed. (ii) 2. Leader line for the shaft diameter is drawn horizontal touching the boundary line. Dim. should be marked from visible outlines 1. Dimensions are given form the mid-line of the object. 2. Dimensions of holes are shown inside the figure. (iii) 3. Dimensions are shown in vertical line. 4. Smaller dimensions (25 mm) precedes the larger dimensions (30 mm). Dimensions should be given from the outlines (finished surface) or 5. Fillet radius is not shown. a centre line of a hole ~ ,f 1. Dimension lines are used as extension. h 2. Dimensions are placed inside