1. Dimensioning Hand Drawings
ENGR 1182
Graphics 04

2. Today’s Objectives Formal Drawing Components:
Dimensioning Hand Drawings
GP04 Activity
GP04 Application

3. Basic Dimensioning
Dimensioning is used to define an object so that it could be manufactured and must:
Define the overall size of the part in all 3 dimensions.
Define the size and location of the features of the part in all 3 dimensions.

4. Dimensioning Definitions
Ø 1.0
Note GAP
Extension Lines
Dimension Lines
The Dimension
If space available, place Dimension between Extension lines
If no space available, place Dimension outside of Extension lines
Radial Diameter Dimension
Radial Radius Dimension
R 1.0
2.0
0.10

5. Features Size and Location
Basic Dimensioning
.75
.75 2 2
Overall Size
Features Size and Location
.25 1 2 2

6. Basic Dimensioning: Arcs and Circles.5 .5
Overall Size
Features Size and Location
OBJECT IS SYMMETRICAL
TOP TO BOTTOM
OBJECT IS SYMMETRICAL
TOP TO BOTTOM 1 R1 1 R1 1
WITHOUT THE SYMMETRY NOTE PRESENT, THIS DIMENSION WOULD BE REQUIRED Ø1

7. When dimensioning objects with Center Marks it is usually advantageous to establish the Center Marks location early in the dimensioning process
Note that by dimensioning the Center Mark offset early, it becomes readily apparent that by using it, in combination with the radius (R1), the width of the object is fully specified.

8. Baseline Vs. Chain Dimensioning
There are many ways to use dimensions to locate features.
Chain
Baseline
(Both techniques are acceptable, however baseline dimensions are preferred.)
Chain Dimensioning
Baseline Dimensioning

9. Dimensioning Guidelines
Lecturer should discuss each of these Guidelines since not all of them will apply in the following example.

10. Dimension this Object Using the Guidelines

11. Dimension this Object Using the Guidelines
First define the overall size of the part in all 3 dimensions.
Then define the size and location of the features of the part in all 3 dimensions.
Carefully follow the Dimensioning Guidelines

12. Establish Height, Width and Depth
Define the overall size of the part in all 3 dimensions
The SYMMETRY note greatly simplifies dimensioning in this example since it locates the all the cylindrical features front to back and left to right.

13. Define the size and location of the features of the part in all 3 dimensions

14. Define the size and location of the features of the part in all 3 dimensions.5
If this dimension was added, object would be over-dimensioned

15. Any Dimensions Missing ??
Final Result
Using a NOTE here greatly reduces dimensioning effort!!

16. Dimensioning Wrap Up Basic Rules of Dimensioning
Overall size in all 3 dimensions
Size and location of all features in all 3 dimensions
Follow Dimensioning Guidelines

17. Activity (GP04-DIM): Adding Dimensions
GP_04 DIM-IN CLASS
GP04 - DIM-Activity
GP_04 DIM IN CLASS

18. Application (GP04-DIM): Adding Dimensions (On Paper- All dimensions are even numbers)
GP_04 DIM-OUT OF CLASS
GP04-DIM Application

19. What’s Next? Due Next Class: GP04 - Dimensioning Application
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