Engineering drawing sheets

Drawingpaper: These are of two types:

• Hand-made paper
• Mill-made paper

Hand-made papers have rough surfaces, pale in colour and not used for regular work, but meant for charts. Mill-made papers are most commonly used for regular work, and are available in different sizes and rolls. They are specified by their weight in kg per ream or density in grams per square meter.

Size of drawing sheets (in mm): While working or handling, the papers are liable to tear on the edges. So slightly large size (untrimmed) sheets are preferred. They are trimmed afterwards. IS:10811:1983 lays down such as designation of preferred trimmed and untrimmed sizes.

The basic principle involved in arriving at the sizes of the drawing paper is as under. The area of the biggest size (A0) is 1m² and its length and breadth are in the ratio 1:√2  . Let x and y are the sides of the paper. The surface area of A0 is 1m² , then the sides are x = 0.841 m and y = 1.189 m

Two series of successive sizes are obtained by either halving or doubling along the length. The area of the successive sizes are in the ratio of 1:2.

Designation of sheets: The drawing sheets are designated by symbols such as A0,A1,A2,,A3,A4 and A5. A0 being the largest. Table 1 below gives the length and breadth of the above sizes of sheets. (Trimmed and untrimmed)

The relationship between two sides is same as that of a side of a square and its diagonal.

For drawings which cannot be accommodated in above sheets, elongated series are used. Elangated series are designated by symbols A1 x 3; A2 x 4 etc.