2. 9
Dimensioning

3. Identify terms and measurements associated with dimensioning mechanics.
Identify symbols that have been standardized for dimensioning notations.
Explain the choice and placement rules drafters use.
Identify and discuss various systems and methods for dimensioning.
Describe the additional types of dimensions used in special ways.

4. Dimensioning Mechanics
Dimensioning mechanics involves the size and spacing for all components of the dimension

5. Standard Dimensioning Symbols

6. Placement of Dimensional Values

7. Small Dimension Mechanics

8. Angular Dimension Mechanics

9. Dimensioning Rules of Choice and Placement
Contour rule

10. Dimensioning Rules of Choice and Placement
Cylinder rule

11. Dimensioning Rules of Choice and Placement
Bolt circles

12. Dimensioning Rules of Choice and Placement
Angles

13. Dimensioning Rules of Choice and Placement
Datums

14. Dimensioning Rules of Choice and Placement
Rounded ends

15. Reference Dimensions Not for manufacturing purposes
Informational reference only

16. Tabular Dimensions
Dimensions are sometimes placed in tables for clarity
Tabular dimensions also allow for multiple parts on one drawing

17. Tabular Dimensions

18. Hole Charts
Often used for a part with a large number of repetitive features

19. Arrowless Dimensioning
Sometimes called coordinate or ordinate dimensioning

20. Dual Dimensioning
Values in U.S. customary and metric units are both given, with one value in brackets

22. What are dimensioning mechanics?
Instructions or guidelines for what size and spacing to use for all of the components and dimensions.

23. In the past, the abbreviation DIA followed a dimension value to indicate a diameter. What method is used now?
The diameter symbol () precedes the dimensional value.

24. What is contour dimensioning?
A rule regarding dimensioning choice and placement that states a feature should be dimensioned in the view where its shape is most descriptive.

25. What is the difference between location, size, and reference dimensions?
Location dimensions indicate the location of a feature. Size dimensions indicate the size of the feature. Reference dimensions are for informative purposes only—not layout, machining, or inspection—and may be related to location or size.

26. What are three other terms for arrowless dimensioning?
Ordinate, coordinate, and datum dimensioning