Question

A cone with base 30mm diameter and axis 45mm long lies on a point of its base on V.P such
that the axis makes an angle 45° with V.P. Draw projections of the cone? ​

Answer 1

Answer:

The Projection of the cone is draw.

Explanation:

Given Data

Diameter of cone = 30 mm

Axis length = 45 mm

Resting on circular rim on HP

Axis inclination with HP = 45°

Top view of an axis is inclined 45° with VP

Step 1

• Draw XY line.
• Cone is resting on HP, so TV will be a circle and FV will be a triangle.
• Draw TV as a circle of diameter 30 mm.
• Draw vertical and horizontal axis of circle.
• Divide the circle into 12 equal parts (You can divide it into 8 parts also). Name all the points 1, 2, 3,….12.
• Take the projections of all point into FV.
• Complete the FV taking axis length 60 mm. Draw all the generators of cone.
• Name the FV of cone on base as 1’ 2’ 3’….12’ and O’ as apex.

Step2:

• As axis is inclined at 30° to XY line the base line 1’7’ will be inclined at 60° to XY line.
• So first mark point 7’ at some convenient distance on XY line. Then draw line 1’ 7’ at angle of 60°, so that the axis will be inclined at 30°.
• Using compass mark all the points from stage 1 to stage 2 on line 1’ 7’.
• Complete the FV in inclined position using compass.
• Take the vertical projections of all 12 points 1’, 2’, 3’, …12’ and apex points O’ in TV.
• Take horizontal projection all points along with apex towards right side from the TV of 1st stage.
• Mark the intersection points 1,2,3..12 and apex O.
• Draw a smooth curve passing through all the 12 points.
• Join end generators with apex.

Step3:

• Now in third stage the top view of an axis is inclined to VP.
• Draw a line inclined at angle of 45° to XY line.
• Mark point O at some convenient distance below XY line.
• Using compass complete the TV in inclined position
• Take the projection all points along with apex into FV.
• Take the projection all points along with apex towards right side from the FV of 2nd stage.
• Mark intersection points 1’ 2’ 3’, ...12’ and apex O’
• Draw a smooth curve passing through all the 12 points.
• Join end generators with apex O.