1. Line Conventions Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Project Lead The Way, Inc.
Copyright 2007

2. Make a table of three columns
Line Conventions
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
A drawing should convey as much information as the physical object (if not more).
Following standards (e.g. line conventions) minimizes confusion and miscommunication.
Fabricators should be able to make your design based solely on your drawing.
Make a table of three columns
Name
Description
Use
Project Lead The Way, Inc.
Copyright 2007

3. Fill in the first row of your table
Line Conventions
Object Lines
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Object lines are thick, solid lines.
Used to show visible edges or outlines of objects.
Fill in the first row of your table
Project Lead The Way, Inc.
Copyright 2007

4. Hidden Lines Thick, dashed lines.
Line Conventions
Hidden Lines
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Thick, dashed lines.
Used to show edges not visible in that view.
Dashes are short and evenly-spaced.
Dashes start and end in contact with the object line.
Project Lead The Way, Inc.
Copyright 2007

5. “Never” erase construction lines
Very Thin, Solid line.
Used as an aide in drawing and to line up views.
Should be barely visible; disappear if squint or photocopy.
“Never” erase construction lines

6. Center lines Thin, with long and short dashes.
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Thin, with long and short dashes.
Used to indicate center of a circle, arc, or any symmetrical object.
Dashes alternately and evenly spaced, with a long dash at each end.
Short dashes cross at intersecting points.
STOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.
Project Lead The Way, Inc.
Copyright 2007

7. Dimension lines
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Thin lines terminating in arrowheads, broken in center for the dimension figure.
Used to show size or location.
Dimension lines are not on object.
Dimension lines can’t touch object.
Understanding Line types and when to use them will help your sketches look cleaner and more professional.
Project Lead The Way, Inc.
Copyright 2007

8. Presentation Name
Extension lines
Course Name
Unit # – Lesson #.# – Lesson Name
Thin solid with a 1/16" gap (to avoid confusion with object lines).
Used to define the extent of dimensions.
May cross other extension lines.
Can’t cross dimension lines.

9. Leader lines Thin, solid lines that end in an arrowhead or dot.
Line Conventions
Leader lines
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Thin, solid lines that end in an arrowhead or dot.
Used for notes or dimensions (e.g. diameter of circle).
Arrowheads to outline.
Dot to surface of object.
Project Lead The Way, Inc.
Copyright 2007

10. Long Break Lines Very thick, Zigzag lines
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Very thick, Zigzag lines
Used to save space when you have a long object of continuous shape and size.
Called break lines because you figuratively break away an unimportant segment of an object.
Shorten very long objects with uniform detail. Typically represented as a jagged cut or break
Understanding Line types and when to use them will help your sketches look cleaner and more professional.
Project Lead The Way, Inc.
Copyright 2007

11. Short Break Lines thick, solid (and/or wavy) freehand lines.
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
thick, solid (and/or wavy) freehand lines.
Used to indicate a short break in an object,
Rods, tubes, and bars have additional conventions that not only break their length but also imply the material or texture of the object.
Project Lead The Way, Inc.
Copyright 2007

12. Viewing or Cutting Plane Lines
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Viewing or Cutting Plane Lines
Thickest of all lines, dashed with bent arrows.
Viewing lines used to give a clearer view of obscure or oblique planes.
Cutting plane lines used to show interior or hidden features that cannot be clearly observed from outside.
STOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.
Project Lead The Way, Inc.
Copyright 2007

13. Viewing or Cutting Plane Lines
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Viewing or Cutting Plane Lines
Cutting plane lines, together with arrowheads and letters, make up the cutting plane indications.
Arrowheads indicate the direction from which you view the section.
Cutting plane may be a simple, continuous plane, or it may be offset to show the interior detail to better advantage.
STOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.
Project Lead The Way, Inc.
Copyright 2007

14. Phantom or Datum Lines
Medium weight series of one long dash and two short
Used to indicate alternate positions of parts, repeated detail, or to indicate a datum plane.
Dashes are evenly spaced and terminate in a long dash.

15. The Bottom Line 15 Name Description Use Object Thick, Solid
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
The Bottom Line
Name
Description
Use
Object
Thick, Solid
Edge or outline of object
Hidden
thick dashed
Edges hidden from view
Construction
Very thin, solid
aide in drawing, line up views
Center
Thin, long short dash.
center of circles or arcs
Dimension
Thin, Arrow, Number
size or location
Extension
Thin, solid, 1/16" gap
extent of dimension
STOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.
Project Lead The Way, Inc.
Copyright 2007 15