Information on types of section views used in mechanical drafting.

1. Sectioned Views

2. Learning Objectives
 List and recognize by name; symbol; and ANSI number
these materials:
- Cast Iron - Aluminum - Brass, Bronze,
- Steel - Zinc or Copper
 Identify a drawing as being a:
- Full Section - Offset Section - Revolved Section
- Half Section - Broken-Out Section - Removed Section
 Given an orthographic view; draw section views:
- In Pencil or - In AutoCAD
 Use revolutions and partial views (as conventional
practices) to construct sectional views of an object.
 List the parts of a drawing which do not get
crosshatched, even if the cutting plane passes through
them.
 Sketch a cutting plane for any of the sections listed
above

3. Readiness Assessment Test 9.2.1
Individually answer the following
questions. You will be given 2
minutes:

4. Readiness Assessment Test 9.2.1
Individually answer the following
questions. You will be given 2
minutes:
List 4 types of sectional views.

5. Team Discussion Item
As a team, discussing the following
question:
What is the purpose of sectional
views?

6. Purpose of Sections
Show internal detail
Replace complex
orthographic views
Describe materials
in an assembly
Depict assembly of
parts

7. Sectioning Practices
Different parts at different angles
Hatch spacing of about 1/16”-1/8”
Cutting plane line .020” wide (bold)
Section or hatch lines -- thin .007”
Visible lines -- wide .015”
Not parallel or perpendicular to
boundary

8. When sectioning
an assembly of
several parts,
draw section lines
at varying angles
to distinguish
separate parts.
Sectioning Practices

9. Most common
ANSI Material Patterns
ANSI 31 -- Cast Iron, General
ANSI 32 -- Steel
ANSI 33 -- Brass, Bronze,
Copper
ANSI 38 -- Magnesium,
Aluminum
Earth
ANSI No. Name Pattern

10. What is ANSI?
.

11. Available Hatch Patterns in
AutoCAD

12. Cutting Plane
The sight arrows at
the end of the cutting
plane are always
perpendicular to the
cutting plane.
Line thickness of the
cutting plane is the
same as the visible
object line.
The direction of the
arrow indicates the
line of sight.
CUTTING PLANE LINE

13. Types of Sections……..Fig #:
Broken-out section……………6.3
Conventional breaks………….6.4
Full section……………………..6.5
Half section……………………..6.8
Revolved section……………..6.10
Removed section……………..6.11
Offset section………………....6.12
(See Essentials of Engineering Design Graphics by Vinson for figure references)

14. Full Section
Cutting plane
passes through
entire object
Hidden lines are
omitted
Visible lines
“behind” the
cutting plane must
be shown

15. Individual Exercise (7 min)
● Sketch a full section of the object shown below

16. Individual Exercise (7 min)
● Were you correct ?
● What material (hatch pattern) did you use?

17. A quarter of assembly removed
Half of view is cross-hatched
Half section:
ALL hidden lines may be omitted
Center line divides halves
Center line remains only if associated feature is
sectioned
CUTTING PLANE LINE

18. Bend the cutting plane to show more
features
Offset section: CUTTING PLANE LINE

19. Sectional view does not denote location
of offset
Offset section: CUTTING PLANE LINE

20. Show cross- sections by rotating sections 90o
The section view stays on the object.
Revolved section:

21. Removed section:
Removed sections are offset from the object.

22. Broken out section:
Used to section a small portion of the object
Does not modify the rest of the view

23. Conventional Practices
Conventional practices are
accepted drawing techniques that
violate the rules of orthographic
projection
They are designed to simplify
orthographic drawing of complex
features.

24. Aligned Parts:
Arms Lugs

25. Aligned Parts:
Single Arm Ribs & Holes

26. Parts Not Sectioned.
Don’t crosshatch (even though the
cutting plane may pass thru them):
– Ribs, webs, spokes
– Thin parts like gaskets
– Ball bearings, roller bearings
– Most vendor items:
 Bolts  Washers  Shafts
 Nuts  Screws  Pins

27. Partial Views
Use partial views to conserve space
Which half depends on whether you
section the view or not.

28. Conventional breaks:
…….For extremely large parts

29. Crosshatching in AutoCAD
AutoCAD can
apply a given
pattern to fill
an area
The area must
be a closed
area
To fill the area
use the
BHATCH
command.

30. Pair Homework Assignment
Drawings (in AutoCAD):
– 28 all
– 29 all
– 32 a, b, c
– 34 all
Due: Beginning of class 10.2

31. Stop