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