1. Engineering Graphics IV
Prof. Paul Kurowski
October 30, 2012

2. Engineering Graphics IV
Section Views
Auxiliary Views
Dimensioning
Tolerancing

3. Section Views

4. Section Views Clearly show interior features
Avoid confusing hidden lines

5. Cutting Planes Cutting planes define section views
Lines of sight are perpendicular to the cutting plane
Section views are parallel to cutting plane and perpendicular to lines of sight
Objects shown in true size
Cut surface is cross-hatched

8. Cutting Plane Lines Show where cutting plane passes through object
Represent edge view of cutting plane
Appear in views adjacent to section view

9. Full Section

10. Half Section

11. Offset Section

12. Broken Out Section

13. Sketch Section View

14. Solution
E-drawing

15. Sketch Section View

16. Solution

17. Cross Hatching (Section Lines)
General symbol (cast iron) used for most purposes and for sketching
Section lines are normally drawn at 45° from the horizontal but can be changed for adjacent parts in the same section
Normally section lines are not shown on thin parts
Components like bolts are usually not sectioned

18. Cast Iron/ B) Sound C) Thermal
General Insulation Insulation
D) Water E) Steel F) Titanium/
Refractory
Material
G) Concrete H) Wood (across/along grain)

19. Auxiliary Views

20. What is an Auxiliary view?
It is an extra view of an object
It is used when the 6 principal views don’t describe an object (or some of its features) clearly or completely - in particular inclined features
It is used to show the true lengths of lines
It is used to show the true size of planes

21. Why use an Auxiliary View?
None of these views shows the angled face in true size and shape.

22. An extra view is needed.

23. Constructing an auxiliary view
It is an orthographic projection
Lines of sight are perpendicular to the plane of the feature (or object)
The projection plane is perpendicular to the lines of sight and parallel to the plane of the feature

24. Auxiliary Views

25. - Dimension on true size and shape views only - Use Auxiliary views if necessary
YES

26. Question Which of the following is NOT true of an auxiliary view?
They are used to show the true size and shape of features
They are orthographic projections
They are used to replace the traditional multiviews
They are used when the traditional multiviews do not fully describe the object

27. Question Which of the following is NOT true of an auxiliary view?
They are used to show the true size and shape of features
They are orthographic projections
They are used to replace the traditional multiviews
They are used when the traditional multiviews do not fully describe the object

28. Dimensioning

29. Multi-view Drawing Specify: Size of features Location of features
Details and notes

30. Dimensioning Dimensioning is necessary to specify: Size of features
Location of features
Details and notes for construction or manufacture
Dimensioning is important in the communication of the design, from the designer to the manufacturer/contractor to the quality control inspection

31. Dimensioned Multi-View Drawing
Units must be stated
Typically inches or millimeters
Mixed dimensions sometimes used

32. Terminology and Standards
Leave gap
Note arrow direction
Limits indicate tolerance

33. Terminology and Standards
Use diameter for circles, radius for arcs
Show extra dimensions as reference only (or better, omit)
Plus/minus indicates tolerance

34. Question Why are dimensions used? To specify the size of features
To specify the location of features
To specify details and notes for construction or manufacture
To fully communicate the design
All of the above

35. Question Why are dimensions used? To specify the size of features
To specify the location of features
To specify details and notes for construction or manufacture
To fully communicate the design
All of the above

36. Good Drafting Practices Dimensioning

39. Show all necessary views
Make sure center lines are shown in all views!
Bottom view shows important features

40. Make sure views are alignedNO
YES

41. Don’t dimension hidden linesNO
Dimension visible lines if possible
YES

42. Dimension to centre lines of cylindrical features and holes
Remember to show centre lines! NO
YES

43. Dimension the most descriptive view

44. Don’t over or under-dimension
Show necessary dimensions exactly once
All dimensions can be derived from given dimensions
Don’t show the same dimensions different ways

45. Don’t over-dimension
YES NO

46. Don’t crowd dimensions
YES NO

47. Extension lines should not cross dimension lines
YES

48. - Dimension on true size and shape views only - Use Auxiliary views if necessary
YES

49. Add Dimensions

50. More than one solution is possible

51. Add Dimensions

52. Solution

53. Add Dimensions

54. Solution