Module 3| First and Third Angle Orthographic Projection
    First-Angle Orthographic Projection

 

 

 

 

 

  

 

Worked example 1

Figure 3.9 on the next page shows a pictorial view of a support bracket.

1. Draw the following to a 1:1 scale and in first-angle orthographic projection:

  • A front view as indicated by the direction of the arrow
  • A top view as indicated by the direction of the arrow
  • A left view as indicated by the direction of the arrow.

2. Show all the hidden detail.

3. Insert the projection system symbol in the space below the left view.

4. Print the following title freehand and scale centrally below the layout: support bracket; scale 1:1.

 

 

Figure 3.9

Pictorial view of a support bracket

 

Table 3.1 Shows the steps you would use to draw the support bracket in first-angle orthographic projection

 

Step 1

Use a separate sheet of paper to calculate the required drawing space as shown. This will ensure a neat balanced layout.

Step 2

  • Draw a feint vertical and horizontal line.
  • Place the front view in the position as shown in Figure 3.9
  • Draw a feint construction line at 45°.

Step 3

  • Measure off the space between the front view and left view.
  • Mark off the width of the left view
  • Project, with feint projection lines, all the edges from the front view.
  • Complete the left view.

Step 4

  • Measure off the space between the front view and top view.
  • Project down from the front view with feint construction lines to the top view as shown.
  • Project down from the left view with feint construction lines to the 45° line and horizontally across to the top view as shown in the figure

Step 5

  • Complete the three views with bold visible lines. These are type A lines.
  • Insert the projection system symbol below the left view.
  • Print freehand the title and scale centrally beneath the layout. (See Figure 3.14)

 

Table 3.1

Drawing a support bracket in first-angle orthographic projection

 

 

 
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