1. The
ALPHABET of
L I N E S

2. Visible Object Lines
are thick dark solid (unbroken) lines that are used on drawings to indicate the edges and details of an object.

3. ALPHABET OF LINES
The different lines and line symbols used on drawings form a kind of graphic alphabet commonly known as the alphabet of lines. Two line widths-thick and thin-are generally used. Drawings are easier to read when there is good contrast among different kinds of lines. All lines must be uniformly sharp and black.

4. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

5. Hidden Lines are thin dashed lines used to indicate a surface, edge, or contour of an object that cannot be seen, or is hidden from view.

6. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

7. Center lines are thin lines made up of alternating long and short dashes. They are used to indicate the center of symmetrical features, such as circles or arcs. They are used as an aid in dimensioning.

8. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

9. Section Lines are thin “cross hatching” lines used in sectional views to symbolize different parts of an object or different materials from which an object is manufactured.

10. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

11. Dimension, Extension and Leader Lines
are thin lines used for dimensioning purposes. Dimension and leader lines generally end with arrow heads and are accompanied by a number indicating a size or location dimension.

12. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

13. Cutting Plane or Viewing Plane Lines are very thick lines that indicate where an imaginary cutting plane passes through an object, for viewing or sectioning purposes. Arrowheads on both ends of the line point toward the surface to be viewed.

14. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

15. Break Lines are used to shorten a view, or to eliminate repetitive details when an entire view is not necessary. Short break lines are thick wavy freehand lines. Long break lines are thin straight zig zags.

16. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

17. Phantom Lines are thin lines used to indicate alternate positions of moving parts, lines of motion, adjacent parts and repetitive details.

18. 1. Phantom 2. Section 3. Hidden 4. Cutting/viewing
5. Leader 6. Hidden 7. Center 8. Visible/object
9. Extension 10. Break 11. Visible/object
12. Section 13. Extension 14. Break 15. Dimension

19. THE END