ENGINEERING GRAPHICS By R.Nathan Assistant Professor Department of Mechanical Engineering C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER

UNIT – 1 BASICS OF ENGINEERING GRAPHICS Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER PENCIL GRADES

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER Types of Lines

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER Types of Lines

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER Example for Lines

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER Pencil Holding Technique

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER ALPHABETS FOR TITLE BLOCK

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER ALPHABETS FOR TITLE BLOCK (FOR LEFT HAND USERS)

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER LIST OF DRAWING EQUIPMENTS & MATERIALS 1.DRAWING BOARD 2.MINI DRAFTER 3.DRAWING SHEET 4.PENCILS (HB, 2H, 4H, 2B, 4B etc…) 5.NON DUST RUBBER 6.SCALES (150 mm & 300 mm) 7. INSTRUMENT BOX 8.SET SQUARES (30°, 45°, 60° etc..) 9.DRAWING BOARD CLIPS, CLAMPS, PINS, CELLO TAPE 10.PROTECTOR or PROCIRCLE or CIRCLE MASTER 11.PENCIL SHARPENER 12.SMALL PAPER KNIFE or STITCHING THREAD to cut the sheetS 13.A HANDKERCHIEF or HAND TOWEL

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER DRAWING BOARD ERASERSCALES

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER COMPASS BOW COMPASS

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER DIVIDERBOW DIVIDER SET SQUARES

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER DRAWING CLIPS, CLAMPS, PROTRACTOR

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER PAPER KNIFE or STITCHING THREAD CIRCLE MASTER or PRO-CIRCLE

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER ROLLERMINI DRAFTER INSTRUMENT BOX

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER HOW TO KEEP DRAWING SHEET CLEAN 1.ALWAYS CLEAN YOUR HANDS & INSTRUMENTS BEFORE FIXING THE DRAWING SHEET 2.HANDS SHOULD BE FREQUENTLY WIPED WITH CLEAN HANDKERCHIEF 3.THE SET SQUARES MAY BE LIGHTLY MOVE WITH THE FINGER NAILS WHILE USING 4.CLEAN PENCIL SMULGE WITH A CLEAN CLOTH 5.THE RUBBER PPOWER OF PENCIL IS REMOVED AWAY FROM THE DRAWING SHEET 6.DRAWING SHEET SHOULD BE ERASED WITH A SOFT RUBBER ONLY 7.REMOVE RUBBER DUST WITH A CLEAN PIECE OF CLOTH or HANDKERCHIEF 8.DO NOT KEEP ANYTHING or ARTICLE ON THE DRAWING SHEET 9.AVOID UNNECCESARY RUBBING OF LINES 10.DO NOT TOUCH DRAWING SHEET WITH DIRECT HANDS

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER DIMENSIONING SYMBOLS ARROWS

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER TYPES OF DIMENSIONING 1. CHAIN DIMENSIONING2. DIMENSIONING FROM A COMMON FEATURE 3. PARALLEL DIMENSIONING

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER TYPES OF DIMENSIONING 4. SUPER IMPOSED RUNNING DIMENSIONING 5. COMBINED DIMENSIONING6. PROGRESSIVE DIMENSIONING

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER SYSTEM OF PLACING DIMENSION 1. ALIGNED SYSTEM 2. UNIDIRECTIONAL SYSTEM

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER DIMENSIONING ANGLES DIMENSIONING CIRCLES DIMENSIONING ARCS DIMENSIONING IN THE HATCHING TYPES OF DIMENSIONING

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CORRECT METHOD CORRECT & INCORRECT METHODS OF DIMENSIONING INCORRECT METHOD

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER TYPES OF TRIANGLES

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF TRIANGLES 1. Construct an equilateral triangle given the length of the side = 50 mm Solution:- Method – 1 (using Compass) 1.Draw a line AB of 50 mm length 2.With centres A & B and radius equal to 50 mm draw arcs intersecting each other at C 3.Draw lines joining C with A and B. 4.Now, ABC is the required equilateral triangle

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF TRIANGLES 2. Construct an equilateral triangle given the length of the side = 50 mm Solution:- Method – 2(using Set Squares) 1.Draw a line AB of 50 mm length 2.Draw a line through A, making 60° angle with AB 3.Similarly through B, draw a line making the same angle with AB 4.Intersecting point is C 5.Now, ABC is the required equilateral triangle

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF TRIANGLES 3. Construct a triangle given the altitude = 55 mm and two base angles = 40° and 65° Solution:- Let ∟A and ∟B are the given base angles and CD be the altitude Steps Involved:- 1.Draw a base line of any convenient length 2.Draw a ┴ at a point D 3.Make CD equal to the given altitude = 55 mm 4.Through C, draw a line EF ║ to AB 5.Make ∟ECA = 40°, ∟FCB = 65° 6.Thus ABC is the required triangle

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF SQUARE 1.Construct a square ABCD with AB = 60 mm Solution:- Steps Involved:- 1.Draw a line segment AB of 60 mm 2.At A, draw a perpendicular at B. 3.With A as centre, 60 mm as radius draw an arc and to intersect the ┴ to get the point D 4.With B as centre, 60 mm as radius draw an arc and to intersect the ┴ through B, to get the point C. 5.Now ABCD, is the perfect square

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF RECTANGLE 1.Construct a rectangle PQRS when PG = 70 mm, QR = 50 mm Solution:- Steps Involved:- 1.Draw a line segment PQ of 70 mm long 2.At P and Q erect perpendiculars 3.With P as centre, 50 mm as radius draw an arc, to cut the ┴ at the point S 4.With Q as centre, 50 mm as radius draw an arc, to cut the ┴ at the point R 5.Join R with S 6.Now PQRS is the required rectangle

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF RHOMBUS 1.Construct a rhombus ABCD, having its side equal to 40 mm and base angle at B of 105° Solution:- Let us use the properties of rhombus here. “All sides of a rhombus are equal” Steps Involved:- 1.Draw a line segment AB of 40 mm length 2.At B, draw a line BX at an angle of 105° 3.B as centre 40 mm as radius draw an arc to cut the line BX. Intersection point is C 4.With A and C as centres, 40 mm as radius draw arcs, intersecting point is D 5.Join A with D and C with D 6.Thus ABCD is the required rhombus

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF RHOMBUS 1.Construct a rhombus PQRS with diagonals 46 mm and QS = 60 mm Solution:- We know that, the diagonals of a rhombus bisect each other at right angles Steps Involved:- 1.Draw a line segment QS of 60 mm length 2.Draw a bisector of QS which passes through the point O 3.With O as centre, ½ PR (23 mm) as radius draw arcs above and below to cut the ┴ bisector. Intersection points are P & R 4.Draw lines joining P with Q & S. 5.Thus PQRS is the required rhombus

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF QUADRILATERAL 1.Construct a Quadrilateral with AB = 45 mm, BC = 55 mm, CD = 40 mm, AD = 60 mm, AC = 70 mm. Solution:- From our earlier classes, we learnt that, to draw a quadrilateral, minimum five dimensions are required. Let u now draw this quadrilateral. Steps Involved:- 1.Draw AB of 45 mm length 2.With B as centre, 55 mm as radius draw an arc 3.With A as centre, 70 mm as radius draw an arc to cut the previous arc at the point C 4.With C as centre, 40 mm as radius draw an arc 5.With A as centre, 60 mm as radius cut the previous arc to get the intersection point D 6.Draw lines joining D with C and A 7.Thus ABCD is the required quadrilateral

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF TRAPEZIUM 1.Construct a trapezium ABCD, having its sides AD = 30 mm, DC = 25 mm, CB = 35 mm and the difference of parallel sides is 20 mm Solution:- Steps Involved:- 1.Draw a line segment AB of 45 mm, difference between parallel sides = 20 mm ( =45 mm) 2.With A as centre and 30 mm as radius draw an arc 3.With E as centre 35 mm as radius draw an arc to cut the previous arc (ie; ED║BC) 4.Intersecting point is D. D as centre 25 mm as radius draw an arc 5.With B as centre, 35 mm as radius cut the previous arc. Intersection point is C 6.Draw lines joining A with D, D with C and C with B 7.Thus ABCD is the required trapezium

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF POLYGONS HEPTAGONOCTAGONNONAGON

Engineering Graphics Lecture Notes C.R.ENGINEERING COLLEGE Alagarkovil, Madurai I - SEMESTER CONSTRUCTION OF PENTAGON 1.Construct a regular pentagon given the lengh of its side as 40 mm Solution:- 1.Draw a line segment AB of 40 mm length 2.At B, draw a perpendicular BL such that BK = AB, join A with K 3.With B as centre, AB as radius draw an arc (ie; arc AK) 4.Draw a perpendicular bisector of AB 5.Mark the point of intersection of perpendicular with line AK as 4 and arc AK as 6 6.Mark a point 5 which is the midpoint of 4-6 obtained by bisecting it 7.With 5 as centre and 5A as radius draw a circle 8.With B as centre and radius = AB, draw an arc to cut the circle at C 9.In a similar way, set off the measurement of side along the circle to get the points D and E 10.Draw lines joining B with C, C with D, D with E & E with A