Page 119 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

Exercise 7.7
Draw the development of a cone of base 60 mm and height 40 mm. (Fig 7)

Fig 7

• Draw the plan and elevation of the cone.

• Divide the plan circle into number of equal parts (say 12 parts) and mark.

Development is more accurate if the number of equal parts are more.

• Project these parts to the base of the cone.
• Join these points to the vertex of the cone.
• Locate O vertex for the development of cone.

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• Draw an arc from the vertex as centre and length of slope as radius.
• Set divider on the straight distance between two consecutive points on the plan.

• Transfer the distance along the arc as many times according to the divisions on the plan.
• Join points 1 O 1and complete the development.
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This method is only an approximate method. The straight line distance taken is slightly smaller
than the arc length. More accurate method is by calculating actual circumference and dividing it
into number of segments.

Exercise 7.8
Draw the lateral surface of a truncated cylinder. (Fig 8)

Fig 8

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CITS : Engineering Drawing (Mechanical) - Exercise 7