1. Section Views
Chapter 12

2. Section Views
Used to describe interior details of a part that cannot be seen in an orthographic view
Eliminates the need to dimension hidden lines
Better describes the shape than hidden lines
Easier to understand

3. Cutting plane lines
Shows the location of the section view (where the part has been cut)
Can be multiple line types

5. Simplified cutting plane

6. Arrowheads Indicate the direction of sight
Points toward the area to be described in the section view
Most common mistake is to point arrows the wrong direction

8. Crosshatching (Section lines)
Used to show the material that has been cut by the cutting plane line

9. Guidelines for crosshatching
Typically drawn at 45˚
30˚ and 60˚ also common
Any angle between 15˚ and 75˚ is acceptable
Cannot be parallel or perpendicular to any object lines
Must be evenly spaced
Spacing must ensure that it’s understood to be crosshatching

10. Common hatching mistakes

12. Crosshatching styles (coded section lines)
Can be used to represent specific materials
Not commonly used on engineering drawings

13. Section views of thin parts
If part is too thin to see hatching thin parts are commonly filled

14. Types of section views Full Sections
Cutting plane line extends completely through the part
Usually through the center of the part or a feature on the part

16. Half Sections
The section view is half sectioned and half orthographic view
Used on symmetrical parts

18. Offset Sections
Cutting plane line is staggered to pass through multiple features that are not on the same plane
View is drawn as if all features are on the same plane

20. Aligned Sections
Cutting plane line is staggered to pass through offset features
Section views drawn as if the cutting plane is rotated to the plane perpendicular to the line of sight

22. Unsectioned Features
Some features that appear on the cutting plane are left without crosshatching
Bolts
Nuts
Rivets
Screws
Springs
Shafts
Bearings
Gear teeth
Pins
Keys
Ribs
Webs
Spokes
Can be difficult on 3D CAD

25. Conventional Revolutions
For symmetrical objects
Practice of revolving features to the cutting plane of the section view of a symmetrical part
All symmetrical features revolved to the cutting plane
Showing these features in true projection would result in confusion
Difficult to do with CAD
Drawing data is tied to 3D models, so it can be hard to follow this practice

28. Broken-out Sections
Small area of a standard orthographic view is removed to show details behind it
No cutting plane line
Hard to tell the location of the section

30. Auxiliary Sections
Section view that appears as an auxiliary view

31. Using Section Views in place of orthographic views
Acceptable to replace orthographic views with section views
Must make sure that no details of the part are omitted by removing an orthographic view

34. Conventional Breaks
Used to show a part that is a constant shape for a long length
Makes the view shorter/take up less space
2 methods of showing breaks

36. Revolved Sections
Section view is revolved 90˚ about a centerline on an orthographic view
Superimposed on view
Can be broken away or not

38. Removed Sections
Similar to revolved except they are removed from the orthographic view

39. Labeling section views
Necessary when there is more than one section view on a drawing or the scale of the section view differs from that of the drawing
Views are labeled alphabetically
Letters are placed at the ends of the cutting plane line or arrows
Large text: tall

40. View labels Labels placed under section views
SECTION A-A (large text)
Letters not used: I, O, Q, S, Z (look like numbers)

41. Arrangement of drawing views
Section views should be arranged in order that they are labeled (alphabetically)
Makes them easier to find