SECTIONAL VIEWS

What is a sectional views:

Although it is imagined that the object is cut by an imaginary section plane its interior construction is viewed by removing the portion of the object between the observer and the section plane while retaining its other portion. Then view of the retained portion of the object exposing its interior construction along with its cut surface is called sectional view. Thus it is a view which not only shows the cut surface of the object but all other its interior details the section plane.

How to obtain a sectional view:

To obtain a sectional view of an object it should be imagined as though the object is cut by a section plan and the portion of the object between the section plane and the observer is removed as then looking in the direction normal to the section plane the view of the retained portion of the object showing all the other visible details along with the cut surface in drawn as since the process of sectioning is only imaginary all other views of the object expect the sectional view are drawn as if the object is uncut.

Types of sectional views:

·      Full sectional view

·      Half sectional view

Full sectional view:

When a section plane is passed through the central line of the object so as to it completely the resulting sectional view is called full sectional view or simply sectional view. The object is cut completely by the section plane SS passing rethought the horizontal central line of the object. The view of the cut object when looking from the front becomes the sectional view. Although it is appropriate to designate the sectional views as sectional front, sectional top , sectional profile view, the Indian standards institution recommends that should be designated by the word section followed by the letters written in capitals which are used in naming the section plane thus the sectional view of the object is called of sectional front view. 

Half sectional view:

While drawing the full sectional view of an object symmetrical about the center line there will be repetition of drafting work in showing section on either side of the center line involving a good deal of drafting time and labor in such cases it will be advantageous to draw the view of an object which shows only one half of the object in section and the other half as unsanctioned and thus save the time and labor without impairing the clarity of the drawing. A view of an object which shows one half sections and the other half as unsanctioned is called half sectional views. Since a half sectional view which only exposes the interior of the half the object and shows the exterior of the other half its usefulness is therefore limited only to symmetrical objects. It is not widely used in detail drawings because of this limitation of symmetry and also because of dimensioning internal details whose one half will be in sectioned zone and the other half will be in unsanctioned zone an half sectional view is advantageous in assembly drawing as it shows internal and external constructions in one view.