1. Engineering Symbols Model Documentation

2. What is a Symbol? Symbol: An arbitrary or conventional sign used in writing or printing related to a particular field to represent operations, quantities, elements, relations or qualities.

3. Everyday Symbols 1 2 3 4 5 6 7 8 9 10 11 12 13

4. Technical Symbols

5. In this lesson: Symbols used in Engineering Drawings Linetypes Holes Screw thread notation

6. Linetypes Group 1 lines are used to define an object’s geometry and visible limits of a shape. Group 2 lines are meant to show an object’s size and place notes, where needed. Group 3 lines are used to define how an object is going to be cut or sectioned to clarify its description, a part’s movement or its relationship to another part.

7. Object Line Hidden Line Center Line Group 1:

8. Object lines showing the front view of this part View Direction Object Line

9. Hidden lines showing hidden details such as a hole or surface Hidden Line

10. Center lines showing center locations of circular geometry Center Line

11. Dimension Line Extension Line Leader Line Group 2:

12. 2.5’ Dimension lines show the size of the shape of a part. { Dimension Line

13. 2.5’ Extension Line Extension lines used in combination with dimension lines

14. Notes or dimensions can be added here, at the end of a leader line. Leader Line

15. Group 3: Break Line Cutting Plane Line Section Line Phantom Line

16. Break lines Break Line

17. Cutting Plane Line

18. Section lines indicating surfaces cut by cutting plane line Section Line

19. Phantom lines: Phantom lines showing the path of a bouncing ball

20. Holes Drilled Countersink Counter bore

21. Diameter Depth Drill Hole

22. Diameter Depth Countersink Countersink Hole

23. Diameter Depth Counterbore Counterbore Hole

24. Screw Threads: Diameter Type of Thread Class of fit

25. 1 2 3 4 5 6 7 8 9 10 11 12 13 Everyday Symbols

26. References: Hammer, W. (1989). Blue Print Reading Basics, New York, NY: Industrial Press Inc. Jensen, C.H., Hines, R.D. (2002). Interpreting Engineering Drawings, Albany, NY: Delmar Publishing Madsen, D.A. (2004). Engineering Drawing and Design, Albany, NY: Delmar Publishing

27. Credits: Writer: Will Renauld Lesson Editor: Donna E. Scribner Narration: Donna E. Scribner PLTW Editor: Ed Hughes Production: CJ Amarosa Video Production: CJ Amarosa Audio: CJ Amarosa Project Manager: Donna E. Scribner