35EG07–SectionalViews-Userpages.PDFVIP

35 EG07 – Sectional Views Sectional views, commonly called sections, are used to show interior detail that is too complicated to be shown clearly and dimensioned by the traditional orthographic views and hidden lines. A sectional view is obtained making an imaginary cut through the part, and by drawing the features on the cut surface, as shown in Figure 18. In a drawing, the exposed or cut surfaces are identified by section lining, or crosshatching. Section views show internal part detail as solid lines instead of hidden lines, which improve communication. Hidden lines and details behind the cutting-plane line are usually omitted unless they are required for clarity. A sectional view can sometimes replace one of the regular views, for example, a regular front view as shown in Figure 19. Figure 18. Cutting a part and showing a section view. Figure 19. A section drawing. 36 The Cutting-Plane Line A cutting-plane line indicates where the imaginary cutting takes place. The position of the cutting plane is indicated, when necessary, on a view of the object or assembly by a cutting- plane line, as shown in Figure 20. The ends of the cutting-plane line are bent at 90 degrees and terminated by arrowheads to indicate the direction of sight for viewing the section. Cutting planes are not shown on sectional views. The cutting-plane line may be omitted when it corresponds to the centerline of the part or when only one sectional view appears on a drawing. Figure 20. A section drawing. If two or more sections appear on the same drawing, the cutting-plane lines are identified by two identical large, single-stroke, Go