engineering symbols model documentation. what is a symbol? symbol: an arbitrary or conventional sign...

Engineering Symbols

Model Documentation

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.

Everyday Symbols

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Technical Symbols

In this lesson:

Symbols used in Engineering Drawings Linetypes

Holes

Screw thread notation

LinetypesGroup 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.

Object Line

Hidden Line

Center Line

Group 1:

Object lines showing the front view of this part

View Dire

ction

Object Line

Hidden lines showing hidden details such as a hole or surface

Hidden Line

Center lines showing center locations of circular geometry

Center Line

Dimension Line

Extension Line

Leader Line

Group 2:

2.5’

Dimension lines show the sizeof the shape ofa part.

{

Dimension Line

2.5’

Extension Line

Extension lines used in combination with dimension lines

Notes or dimensionscan be added here, at the end of aleader line.

Leader Line

Group 3:

Break Line

Cutting Plane Line

Section Line

Phantom Line

Break lines

Break Line

Cutting Plane Line

Section lines indicatingsurfaces cut by cuttingplane line

Section Line

Phantom lines:

Phantom linesshowing the path of abouncing ball

Holes

Drilled

Countersink

Counter bore

Diameter

Depth

Drill Hole

Diameter

Depth

Countersink

Countersink Hole

Diameter

Depth

Counterbore

Counterbore Hole

Screw Threads:

Diameter

Type of Thread

Class of fit

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Everyday Symbols

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

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