Page 94 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

EXERCISE 6 : Sectional views

Sectional views

In the normal Orthographic views (plan, elevation and side view), the internal details, their features and relative
positions which cannot be seen are shown by dotted lines.
For example in the object shown in figure 1 the hole is invisible in the elevation and side view. Hence it is repre-
sented by dotted lines.
When there are too many dotted lines in a drawing (Fig 2) it is difficult to conceive the details of the object. In
such a cases, details can be shown clearly and reading of drawing can be made easier by resorting to what are
known as "Sectional views".

Fig 1 Fig 2

Sectional views: For obtaining sectional views an object it is assumed to be cut by an imaginary plane called
cutting plane. The part between the cutting plane and the observer is assumed as removed to reveal the internal
details. Then the projection of part left out is projected/drawn as usual and the view thus made is the sectional
view. (see Fig 3)
To distinguish a sectional view the surface formed when it is cut by the cutting plane is "hatched". (Fig 4)

Fig 3 Fig 4

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