B4    Use Appropriate Line-types

Information Sheet

Textbook - pages 40 to 48

1. 

Describe the need for line-types
See pages 40-48

 

In Drafting, there are several different line types. Each linetype has a specific function and is drawn to a specified thickness. 

In Manual Drafting, different hardnesses of lead (graphite) were used to achieve desired line weights and thickness. Lead hardnesses were designated by letters and numbers. (i.e. bold Object lines used an H lead, and thin centerlines used a 4H lead. The higher the number before the letter, the harder the lead, and the thinner the line would be.) 

In CAD (Computer Aided Drafting) we can assign pen thicknesses to colors.
We can tie a color to a linetype by using LAYERs.

The Table below specifies Linetype (Layer name) and thickness examples.

 Go to B4- Layer/Linetype Exercise
 
2.  Identify line-types (style, weight, scale)

Correct Lead Hardness and Thickness (Colour, Thickness and Linetype in CAD) 

Line-type
(Layer Name)

 

 Colour in AutoCAD

Thickness

Lead

Construction

 Grey (9)

 

.2

blue

Object

 White (7)

 

.7

H

Center

 Red (1)

 

.3

4H

Hidden

 Yellow (2)

 

.5

2H

Phantom

 Blue (5)

 

.3

4H

Dimension

 Green (3)

 

.3

4H

Section Line

 

 Magenta (6)

.9

H

Cross Hatching

 Blue (5)

 

.2

4H

   

 
3.  Identify precedence of each line-type
Sometimes one line will coincide with another line. In this case Object lines take precedence over Hidden lines, and Hidden lines take precedence over Center lines.

The most important drawing lines are:

  • Object
  • Hidden
  • Center
  • Cross-hatching
  • Phantom

Then comes reference lines:

  • Dimension line
  • Extension line
  • Section Line

Construction lines are the least important to view, but the MOST important with respect to accuracy.