1. Engineering Graphics MENG104
Lecture : Hamed Pourasl

2. INTRODUCTION:
The old saying that “necessity is the mother of invention ” is still true, and a new machine, structure, system, or device is the result of that need.
Why we need to learn this course :

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

4. Engineering drawing
An engineering drawing, a type of technical drawing, is used to fully and clearly define requirements for engineered items. Engineering drawing (the activity) produces engineering drawings (the documents). More than merely the drawing of pictures, it is also a language—a graphical language that communicates ideas and information from one mind to another. Most especially, it communicates all needed information from the engineer who designed a part to the workers who will make it

5. Classification of projection:

6. Instrument drawing

7. drawing board
T-square: drafting machine or parallel ruling
Set of instruments (Compass or drafting)
45 triangle
30*60 triangle
Ames lettering guide or lettering triangle
architects’ triangular scale
engineers’ triangular scale
Metric triangular scale
Irregular curve
Protractor
Mechanical pencils and thin lad mechanical pencils and HB, F, 2H
Lead pointer and sandpaper pad
Pencil eraser
Plastic drafting eraser or Artgum cleaning eraser

8. 16. Erasing shield 17. Dusting brush 18. drawing paper(A4) 19
16. Erasing shield 17. Dusting brush 18. drawing paper(A4) 19. Drafting tape 20. Templates 21. Calculator 22. Cleansing tissue or dust cloth

9. For our class

14. Scale 1:1 full size 1:2 Half full size 1:5 one-fifth full size
1:10 one-tenth full size
2:1 Twice full size
5:1 five times full size
10:1 Ten times full size

15. 2: Construction: Very light and thin line use to construct layout work
Alphabet of lines
1: Visible lines: thick dark line use to show outline o object, visible and surfaces.
2: Construction: Very light and thin line use to construct layout work
3: Dimension line: Thin and dark lines use to show the size of an object with a numeric value.
4: Hidden line: Short dash lines use to show non visible surface. Usually shows as medium thickness
5: Centre line: long and short dash lines. Usually indicates center of holes, circle and arcs.
6: extension line: thin and dark line use to show the starting and ending of dimension.
7: short and long break lines: short and long medium line use to show cutaway view of long section.
8: phantom line: long line followed by two short dashes use to show alternate position of moving part.
9: Section line: medium lines at 45 degrees use to show interior view of slid areas of cutting plane line.

17. Drawing a Horizontal line

18. Drawing a Vertical Line

19. The Triangle Wheel

25. Technique of lines

26. Example:

27. Example

28. Vertical Capital Letters and Numerals

29. Guide lines for Dimension

30. Example :

31. Example

32. Points and lines

33. Angles

34. Triangles:

35. Quadrilaterals:

36. Regular Polygons:

37. The Circle:

38. Bisecting a line or a Circular Arc

39. Bisecting a line with Triangle and T-square

40. Bisecting an Angle

41. Transferring an Angle :

42. Dividing a Line into Equal Parts :

43. Dividing a Line into Equal Parts :

44. Practical Applications of Dividing a Line into Equal Parts :

45. Dividing a Line into Proportional Parts

46. Drawing a Triangle with Sides Given: