1. Chapter 10
Conventional Practice
in Section View

2. TOPICS
Section view representation
of rib, web, spoke and lug.
Aligned section
Conventional break

3. Section view representation of
rib, web, spoke and lug

4. CONVENTIONAL PRACTICE
There are some exceptions to the general rules of sectioning:
Webs, ribs, lugs, spokes,
Shafts, rods, spindles,
Bolts, nuts and thin washers.
Rivets, dowels, pins and cotters.

5. The cross-section is technically correct.
CONVENTIONAL PRACTICE
The cross-section is technically correct.
The convention in a drawing is to show the preferred method for sectioning this type of object.
NOT RECOMMENDED
CORRECT
Convention Rotation

6. TERMINOLOGY
Rib and Web are thin, flat feature of an object that acts as a structural support.
Rib
Rib

7. TERMINOLOGY
A web or rib is a strengthining or supporting part of a component.
Web

8. TERMINOLOGY
Spoke is the rod radiating from the hub to the rim of a wheel.
Hub
Hub
Spoke
Rim
Spoke
Rim

9. TERMINOLOGY
Lug is an ear which is built as portion of an object for attachment.

10. TERMINOLOGY
Lug is an ear which is built as portion of an object for attachment.

11. CONVENTIONAL PRACTICE
Omit the section lines on the section view of
Rib, Web and Lug, if the cutting plane is passed flatwise through.
Spoke, if the cutting plane
is passed longwise through.

12. CONVENTIONAL PRACTICE
When the cutting plane passes through a rib longtudinally it is not sectioned

13. CONVENTIONAL PRACTICE
When the cutting plane passes through the rib transversely it should be sectioned

14. EXAMPLE : RIB Normal multiview drawing Normal section view
Section view drawing with convention

15. EXAMPLE : WEB : flatwise cut
Normal multiview drawing
Normal section view
Section view drawing with convention

16. EXAMPLE : WEB : crosswise cut

17. EXAMPLE : WEB : multiple section view

18. Misleading impression
EXAMPLE : SPOKE
Misleading impression

19. EXAMPLE : LUG

20. Aligned Section

21. DEFINITION
Aligned section is used when features are located on radial lines
Aligned section is a section view that is drawn
by imaginary rotating the object’s features
appeared in a principal view about symmetry
axis

22. Gives the impression that this holes are at unsymmetrical position.
Example : Hole
Gives the impression that this holes are at unsymmetrical position.

23. Example : Hole

24. Example : Rib

25. Example : Ribs & Holes

26. Example : Spoke & Keyway
Example : Aligned section of keyway

27. Example : Lug

28. Conventional Break

29. CONVENTIONAL PRACTICE
For long objects that have to draw in a small scale to fit them on the paper, it is recommended to remove its long portion (which contains no important information) and draw the break lines at the broken ends.

30. Example
SCALE 1:1

31. Example
SCALE 2:1

32. STANDARD BREAK LINES Rectangular cross section Cylindrical
Wood
Rectangular
cross section
Metal
Cylindrical
cross section
Tubular
cross section

33. TO DRAW CYLINDRICAL BREAK

34. not to scale dimensions
TO DIMENSION A BROKEN PART
f16
Typical
dimensioning
method
800
f16
800
not to scale dimensions