1. Blueprints: Basics of Blueprint Lines
Developed by: IML
Vocational Agriculture Grades 9-12

2. Basics of Blueprint Lines
Understanding what the drafter is trying to convey requires a standard use of symbols and lines.
The standard thick line weight:
.030 to .038 of an inch.
The standard thin line weight
.015 to .022 of an inch.

3. 8 Main Line Types Visible Hidden Center Dimension Extension Section
Phantom
Break

4. Visible Lines Dark, heavy lines. Show the outline and shape
Defines features in a visible view.

5. Hidden Lines Light, dashed lines.
Shows the outline of feature that can not be seen in a particular view.

6. Section Lines Thin line at 45 degree angle.
Shows cross-sectional view.
Section Line

7. Center Lines Thin line consisting of long and short dashes.
Shows center of holes for measurement purposes.

8. Dimension Lines Show the length, width, and height of object.
Terminated with arrowheads.

9. Extension Lines Shows starting and stopping points of dimension lines.

10. Break Lines Used for shortening parts too large for blueprint.
Wavy Lines most common.
Used for
Long Breaks.
Cylindrical Breaks.

11. Phantom Lines
Thin lines made of long dashes alternating with pairs of short dashes.
Two purposes in drawings.
1. Show the alternate position of
moving parts.
2. Show relationship of parts
that fit together.

12. Alternate Position Phantom lines show where part is moving to or from.
Eliminates the confusion of thinking there may be 2 parts instead of 1.
Phantom Lines

13. Relationship of Mating Parts
Phantom lines can also show how two or more parts go together without having to draw and dimension both parts.

14. Summary Discussed 8 common line types. Student Objectives:
1. Identify lines and understand simple blueprints.
2. Identify where specific line types are used.
3. Produce lines on project blueprints for vocational agriculture courses.