INTRODUCTION
Engineering drawings are to be prepared on standard size drawing sheets. The correct shape
and size of the object can be visualized from the understanding of not only the views of it but
also from the various types of lines used, dimensions, notes, scale, etc. To provide the correct
information about the drawings to all the people concerned, the drawings must be prepared,
following certain standard practices, as recommended by Bureau of Indian Standards (BIS).
DRAWING SHEET
Engineering drawings are prepared on drawing sheets
of standard sizes. The use of standard size sheet, saves
paper and facilitates convenient storage of drawings.
The basic principles involved in arriving at the sizes
of drawing sheets are:
(a) X : Y = 1 : √ 2 , (b) XY = 1
where X and Y are the sides of the sheet. For a
reference size A0 (Table 2.1) having a surface area of
1 m2, X = 841 mm and Y = 1189 mm. The successive
format sizes are obtained either by halving along the
length or doubling along the width, the areas being
in the ratio 1:2
DESIGNATION OF SIZE
The original drawing should be made on the smallest
sheet, permitting the necessary clarity and resolution.
The preferred sizes according to ISO-A series (First
choice) of the drawing sheets are given in Table 2.1.
When sheets of greater length are needed, special
elongated sizes (Second choice) are used (Table 2.2).
These sizes are obtained by extending the shorter
sides of format of the ISO-A series to lengths that are
multiples of the shorter sides of the chosen basic
format.
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