The document discusses various types of engineering drawings including isometric drawings, which show a three-dimensional view of a component or assembly from three surfaces in one view. It also covers orthographic projections, which use front, top, side, and other views to represent a three-dimensional object in two dimensions. The document explains techniques for drawing boxes, more complex shapes, threaded parts, and using section views to show hidden details. It also discusses dimensions, title blocks, line types, and other aspects of creating technical drawings.

1. Engineering Drawings
Gary Trowles

2. ISOMETRIC DRAWINGS
Three dimensional picture
of a component or
assembly
Shows three surfaces of
an assembly in one view

3. ISOMETRIC DRAWINGS
Vertical lines are shown
in a vertical position
Horizontal lines are
drawn at 30 degrees to
the horizontal.
30° 30°

4. ISOMETRIC DRAWINGS
A technique called
exploded views is
used to show more
clearly how the parts
of an assembly fit
together.

5. Isometric projection : Drawing a box
1.Draw the front vertical edge of the cube.
2.The sides of the box are drawn at 30
degrees to the horizontal to the required
length.

6. Isometric projection : Drawing a box
3.Draw in the back verticals.
4.Drawn in top view with all lines drawn 30
degrees to the horizontal.

7. Isometric projection : Drawing more
complicated shapes
5
1
3
5
5
1

8. Isometric projection : Drawing more
complicated shapes
Draw a guide box.
The box is the size
of the maximum
dimensions. In this
case, 5 long, 3 wide,
and 5 high.
Draw the box in
very lightly.
5
5
3

9. Isometric projection : Drawing more
complicated shapes
Draw a box 4
x 1 x 5, the
shape that
needs to be
removed from
the box to
create the
shape we
require. Draw
the box in
very lightly.

10. Isometric projection : Drawing more
complicated shapes
Now draw in the outline
of the object using a
heavier line.
Using this technique
you can draw complex
shapes accurately
because you can use
the guide box as a
means to measure your
engineering drawing
views.

12. Orthographic projections

13. Six views of orthographic projection

14. Orthographic projections

15. Orthographic projections

16. Orthographic projections

17. Orthographic projections

18. ORTHOGRAPHIC PROJECTION
1ST
Angle
Projection

19. 1st
Angle Projection (Europe)

20. 1st
Angle Projection (Europe)

21. 1st
Angle Projection (Europe)

22. 1st
Angle Projection (Europe)

23. ORTHOGRAPHIC PROJECTION
3rd
Angle
Projection

24. 3rd
Angle Projection

25. 3rd
Angle Projection

26. 3rd
Angle Projection
THIRD ANGLE ORTHOGRAPHIC PROJECTION

27. 3rd
Angle Projection
THIRD ANGLE ORTHOGRAPHIC PROJECTION

28. Difference between 1st
and 3rd
angle
Bottom view
Right view Rear viewLeft view
Top view
Front view
Bottom view
Top view
Front view Right viewLeft view Rear view

29. Try to visualise this part....

30. Which block represents the part?
(C)
(B)(A)
(D)
(C)

31. Concentricity

32. Concentricity

33. Line types
 Visible lines - solid lines that
show visible edges and surfaces.
 Hidden lines - short dashes that
show edges and surfaces not
visible in that view.
 Centre Lines - alternate long
and short dashes. show the centre
of a circle, a shaft, or other
symmetrical part.
 Extension lines - solid lines
that indicate where dimensions
start and end.
 Dimension lines - arrows on
either side of a dimension showing
where it starts and ends.

34. Cutting Plane line
Cutting Plane line for short distances
AA
AA
Cutting plane line – can be thick alternately long
and double short dashes or thick medium dashed
lines ending in arrow heads. Used to define
sections for sectional views. Arrow heads indicate
the direction of viewing.

35. Section lines
A A
B
B
Section
AA
Section
BB
Section lines – are thin
lines in a parallel pattern
used to indicate surfaces
in section views resulting
from “cutting.” Section
lines are commonly
referred to as “cross-
hatching.”

36. Is this drawing
1st
or 3rd
angle?

37. Sectional views
Sections and sectional views are used to
show hidden detail more clearly
Created by using a cutting plane to cut the
object
A section view shows how the object
would appear if it was cut along the line of
the cutting plane.

38. Sectional views
Sectional views are produced to:
clarify details
show internal features clearly
reduce number of hidden detail lines
aid dimensioning
show cross-section shape
clarify an assembly

39. Sectional view to show internal
features and clarify an assembly

40. Sectional views

41. Sectional views

42. Sectional views

43. Sectional views

44. Sectional views

45. Sectional views

46. Sectional views

47. Sectional views

48. Sectional views

49. Sectional views

50. Sectional views

51. Sectional views
A
A
SECTION
AA

52. Drawing a threaded part

53. Sectioning a threaded part

54. Dimensions

55. Dimensions

56. Dimensions

57. Dimensions

58. Dimensions

59. Dimensions

60. Dimensions

61. Dimensions

62. Dimensions

63. Dimensions

64. Dimensions

65. Dimensions

66. Dimensions

67. Dimensions

68. Dimensions

69. Title block

70. Title block

71. Title block

72. Title block

73. Abbreviations

74. Abbreviations

75. Question 1
Hole Shaft
Basic
Size
Upper
tol
Lower
tol
Max
size
Min
size
Basic
Size
Upper
tol
Lower
tol
Max
size
Min
size
40 +0.025 -0.000 40.025 40.000 40 -0.009 -0.025 39.991 39.975
90 +0.030 -0.000 90.030 90.000 90 -0.010 -0.029 89.990 89.971

76. Question 2
Hole Shaft
Basic
Size
Upper
tol
Lower
tol
Max
size
Min
size
Basic
Size
Upper
tol
Lower
tol
Max
size
Min
size
35 +0.021 -0.000 35.021 35.000 35 +0.015 +0.002 35.015 35.002
85 +0.030 -0.000 85.030 85.000 85 +0.021 +0.002 85.021 85.002

77. Question 3
Hole Shaft
Basic
Size
Upper
tol
Lower
tol
Max
size
Min
size
Basic
Size
Upper
tol
Lower
tol
Max
size
Min
size
45 +0.025 -0.000 45.025 45.000 45 +0.042 +0.026 45.042 45.026
95 +0.030 -0.000 95.030 95.000 95 +0.051 +0.032 95.051 95.032