1. ENGINEERING DRAWING & GRAPHICS
Lecture 1: Introduction
By Engr. Sajjad Ahmad

2. Assessment Marks Examination: 30 % mid term 50% final term
Assignments & Quizzes
20 %

3. Syllabus Introduction Orthographic Projections
Loci of points and Generated Curves
Development of solids
Intersection of surfaces
Projection of solids
Free hand sketches

4. Recommended Books Engineering drawing by ND Bhatt
Engg Drawing by AC Parkinson
Technical Graphics Communication By Bertoline Wiebe, Miller. Mohler, Irwin McGraw-Hill 1997
Practical Geometry & Engineering Graphics By Abbot.
Engineering Graphics By Craft, Meyers & Boyer
Technical Graphics Communication, 3rd Edition By Gary R. Bertoline and Eric N. Wiebe; McGraw-Hill
Mathematical Elements for Computer Graphics By D.F. Rogers and J.A. Adams; McGraw-Hill 1976

5. Importance of Engg Drawing
“a picture is worth a thousand words”
In engineering, a good drawing is worth even more than a thousand words

6. Importance of Engg Drawing
Engineering drawings are important in conveying useful information to other engineers and machinists
Allow the readers to visualize what the proposed product would look like
Provide information on dimensions and material used to make the proposed product
Provide views from the top, the side, and the front

7. Aim of the Course Knowledge of engineering drawing instruments
Understanding and interpretation of technical drawings
Ability to develop projections of a 3D object

8. Technical drawing is the language of engineers and designers
Waterfall
M. C. Escher

9. Topics of Interest
Drawing Instruments
Lines
Lettering & Dimensioning

10. Drawing Board DRAWING INSTRUMENTS 1
Layout of a typical drawing shet should be same as the background of this presentation. Nameplate at the bottom right corner.

11. Drawing Sheets A Series Formats (mm) A0 841 × 1189 A1 594 × 841 A2
DRAWING INSTRUMENTS
Drawing Sheets
A Series Formats (mm) A0
841 × 1189 A1
594 × 841 A2
420 × 594 A3
297 × 420 A4
210 × 297 A5
148 × 210 A6
105 × 148 A7
74 × 105

12. Layout of a Drawing Sheet
DRAWING INSTRUMENTS
Layout of a Drawing Sheet
Layout of a typical drawing sheet

13. Tee square/ Drafting Machine
DRAWING INSTRUMENTS
Tee square/ Drafting Machine

14. DRAWING INSTRUMENTS
Use of T Square

15. DRAWING INSTRUMENTS
Set squares (a pair)

16. DRAWING INSTRUMENTS
Use of set squares

17. DRAWING INSTRUMENTS
Use of set squares

18. Irregular/ French curves
DRAWING INSTRUMENTS
Irregular/ French curves

19. Use of French Curves The french curve is
DRAWING INSTRUMENTS
Use of French Curves
The french curve is
used to draw a smooth line through predetermined points.

20. Compasses Divider Protractor Ruler/Scale Pencil Different Grades
DRAWING INSTRUMENTS
Compasses
Divider
Protractor
Ruler/Scale
Pencil
Different Grades
6B,5B,4B,3B,2B,B,H,2H,....9H

21. TYPES OF LINES 3 Main Types DRAWING LINES 1
HIDDEN LINES WHERE EXTENSION OF VISIBLE LINES SHOULD HAVE A GAP BETWEEN THE TWO Lines
Single centre line for longitudinal view and crossed centre lines for cross sectional view

22. Lines to aid understanding
DRAWING LINES
Lines to aid understanding

23. LETTERING
Most common font used in drafting is

24. Approved Gothic lettering for Engineering Drawings

25. Reasons for using single-stroke Gothic lettering
Saves time in production
Easy to read and provides drawing consistency
Easier to learn and use

26. Lettering is drawing, not writing

27. Recommended Strokes for Vertical Uppercase Letters

28. Lettering Rules
The type of lettering recommended by ANSI for mechanical drafting is single stroke gothic (vertical freehand lettering).
The minimum recommended lettering size on engineering drawings is .125 inches (1/8”).
All dimension numerals, notes and other lettered information should be the same height except for titles, drawing numbers and other captions. Titles and subtitles, for example, may be 0.5 inch (1/2”) and.25 inches (1/4”) high respectively.

29. Lettering Rules Continued
The composition or spacing of letters in words and between words in a sentence should be such that the individual letters are uniformly spaced with approximately equal background areas. This requires the letters such as I, N or S be spaced slightly father apart from their adjacent letters than L, A, or W.
A minimum recommended space between letters in words is approximately inches (1/16”).
The space between words in a note or sentence should be about the same at the height of the letters. The horizontal space between sentences in a note or paragraph should be equal to twice the height of lettering.

30. Spacing of Lettering

31. Lettering Rules Continued
All notes should be lettered horizontally on the sheet.
Use H, HB pencils for lettering. Try them all, but use the one that gives you the best results.
Many drafters prefer using a .5 mm automatic pencil for lettering.

32. Lettering Rules Continued
Place a clean paper under your hand when lettering to prevent smudging.
As a rule of thumb, curved letters can be placed close together and straight letters should be placed further apart.

33. Use a Piece of Clean Paper to Prevent Smudging

34. Spacing of Fractions and Decimals

35. DIMENSIONING
Dimension Lines (DL)
Position of DL

36. Alignment of DL DL of Small Features Dimensioning Angles
Dimensioning Circles

37. DIMENSIONING

38. Correct Practice of Dimensioning
Drawing should only carry dimensions needed to manufacture

39. Rules for Dimensioning
Dimensions should be placed outside the views
Dimension line should not cross each other
As far as possible dimension should not be shown between dotted lines
Dimension line should be placed at least 8 mm from the outlines and from one another
Dimension figures are placed perpendicular to dimension line
Dimension figure should be easily readable from bottom and right edge of paper

40. Assignment
Get your instruments sorted- buy them or borrow them