Technology Education Department
Technical Drawing Survey

• Sectional views are used to clarify interior or hidden details on a multi-view drawing of an object. A sectional view usually replaces one of the principle views (top, front or side) but may also be an additional view or a series of supplemental views depending on the type.
  
• There are many types of sectional views: Full, Half, Removed, Revolved (Rotated), Aligned, Offset, Broken-out, Partial, Assembly and Pictorial.
  
• A Full Section view is used to show the object as if one half of the object was removed.
  A Half Section view is used to show the object as if one quarter of the object was removed.
  A Removed Section view is used to show the variable shape of the object from end to end.
  A Revolved (Rotated) Section view is used to show the uniform shape of the object from end to end.
  An Aligned Section view is used to show the shape of features that do not align with the vertical and horizontal center lines of the object.
  A Broken-out Section view is used to show the material thickness of a hollow object.
  A Partial Section view is similar to a Broken-out but usually covers a larger area but less than a Half Section.
  An Assembly Section is used to show the arrangement and relationship of parts that makeup an object.
  A Pictorial Section is used to show the arrangement and relationship of parts that makeup an object in a three dimensional view with a quarter to a half of the object removed.

• Sectional views are located by creating a Cutting Plane Line in one view. The Cutting Plane Line is a thick, dark line composed of a long dash, two short dashes and a long dash. An optional Cutting Plane Line consisting of thick, dark, long dashes may also be used. Short perpendicular lines with arrowheads pointing away from the line are added to each end to indicate the viewing direction or line of sight. The arrows should also point away from the view that is sectioned. Identification "Letters" (A-A, B-B, C-C, etc.) should be placed above the arrows when more than one section view is needed on a drawing.

• "Section Lining" or "Cross Hatching" or "Hatching" is added to the Section view to distinguish the solid portions from the hollow areas of an object and can also be used to indicate the type of material that was used to make the object. General Purpose "Section Lining", which is also used to represent "Cast Iron", uses medium, thick, lines drawn at a 45° angle and spaced 1/8" apart. Different materials have different patterns of lines and spacings. Section lining should be reversed or mirrored on adjoining parts when doing an Assembly Section.

• To avoid confusion, "Hidden Lines" are omited from Section views.
  
• Spokes (that are used to hold the rim and hub of a wheel together) and ribs (that are used to reinforce or support a hub and a plate) are not sectioned.
  
• Keys, key ways, nuts, bolts and other fasteners on Assembly Sections are not sectioned.

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