1. DIMENSIONING

2. Standard
Apply correct dimensioning procedures

3. Being able to dimension well requires you to develop three different abilities:
Learn the technique of dimensioning
Understand the different line types and techniques used to show dimensions
Learn the placement of dimensions
Can you pick the most logical and practical place to put dimensions with respect to an object?
Learn the choice of dimensions
Which dimensions should you show and which ones should you not show?

4. Dimension
The numerical value that defines the size, shape, location, surface texture, or geometric characteristic of a feature.

5. Dimension Line Thin, black line (0.5mm graphite)
Ends with an arrowhead
Arrowhead indicates direction
and length of a dimension
Gap for dimension is usually near the middle
Distance from the object line is 3/8”
Distance away from other dimension lines is ¼”

6. Extension Line Thin, black line (0.5mm graphite)
Extends from the point on the drawing that the dimension refers to
Drawn at right angles to dimension lines
Distance (gap) from object line before the extension line starts is 1/16”
Distance that the line extends past the last arrow is 1/8”

7. Arrows Drawn free hand Uniform in size and style
Do not vary according to size of drawing or length of dimension
3 times as long as they are wide
1/8” long
Narrow and solid

8. Lettering Typically centered on the dimension line
If dimensions are right above one another they are staggered
1/8” tall
Fractions are a ¼” tall

9. Sample Dimensioning Dimension refers to the number.20 11 23 10
Largest dimension to the outside.
Extension lines may cross
Leave enough room between object and dimension lines.

10. Group Dimensioning
Dimensions should be placed outside the drawing whenever possible
Extension lines should not cross dimension lines

11. Stagger Dimension Text
Stagger the dimension text on parallel dimensions

12. Unidirectional and Aligned Methods
Unidirectional: All dimensions are horizontal
Aligned: Dimensions are parallel to object lines

13. Principles of Good Dimensioning
Each feature of an object is only dimensioned once
Dimensions should be placed in the most descriptive view of the feature
Dimension lines should be aligned and grouped when possible