Page 116 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

Procedure

Development of surfaces of solids
Exercise 7.1
Draw the development of the surfaces of a cube of side 30 mm. (Fig 1)

• Draw the elevation and plan of the cube.

Fig 1

• From the front view stretch out (Project) the line AA & A'A' from points b' b' horizontally.
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• Set off AB, BC, CD & DA equal to 30 mm each. (side of square)
• From C & D draw perpendiculars and mark off/CB' & DA' equals to 30 mm.
• Similarly erect perpendiculars from points C' & D' such that C'B' & D'A' equals to 30 mm.
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• Darken the lines as shown in Fig 1 to get the required development of the cube.
Exercise7.2
Draw the development of the surface/a rectangular prism of size 40 mm x 20 mm and height 60 mm by parallel
line method. (Fig 2)

• Draw a rectangle of length equals to the perimeter of the prism. Length = 2 (l + b) = 120 mm and height equals
to the height of prism (60 mm).
• Mark AB; BC; CD and DA equals to 40, 20, 40 & 20 mm respectively.

• Draw perpendiculars from the points A,B,C,D and mark as A', B', C', D'.
• Draw a rectangle A'B'C'D' on A'B' of size 40 x 20 mm.
• Draw another rectangle CD A B on CD of size to 40 x 20 mm, the end faces of the prism. Figure obtained is
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the development of the total prism.

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CITS : Engineering Drawing (Mechanical) - Exercise 7