Problem 5.1 Projection of Planes – Draw the projection of a circle of 60 mm diameter resting on the H.P. on a point A of the circumference. The Plane is inclined to the HP such that plan of it is an ellipse of minor axis 40 mm. The plan of the diameter through the point A is making an angle of 45˚ with the V.P. Measure the angle of the plane with the H.P.
Step-1 Draw a horizontal x-y line of some suitable length.
Step-2 Draw a circle of radius 30 mm below the x-y line at some suitable distance. It is the plan of the 1st stage.
Step-3 Divide the circle into 12 equal divisions, and give the notations.
Step-4 From the notations given on the circle, draw vertical projectors up to the x-y line, through these projectors, draw a horizontal medium dark line on the line x-y & give the notations. It is the front view of the 1st stage.
Step-5 From the top of the 1st stage, draw horizontal projectors from all the points in right hand side direction. From theses projectors, mark point a & g at the distance equal to 40 mm from each other. From the points a & g, draw vertical projectors on x-y line.
Step-6 Mark a point a’ on the x-y line on the projector from the point a. With a’ as center and radius equal to 60 mm cut the vertical projector from the point g & mark the point g’. And draw a medium dark line between these points a’ & g’. It is the front view of the 2nd stage.
Step-7 Transfer the distance of all the points from the front view of the 1st stage in to the front view of the 2nd stage. From the points on the front view of the 2nd stage, draw vertical downward projectors which will intersect with the horizontal projectors from the top view of the 1st stage at respective points.
Step-8 From the respective points of intersections of the above projectors with each other, draw a medium dark smooth free hand curve, which is the top view of the 2nd stage.
Step-9 Copy the top view of the 2nd stage at an angle 45° with the x-y line as show into the figure with the same dimensions. And give all the notations on it. It is the top view of the 3rd stage.
Step-10 From the front view of the 2nd stage, draw horizontal projectors, and from the top view of the 3rd stage draw vertical projectors in upward direction, which will intersect with the previously drawn projectors at respective points.
Step-11 From these respective points of intersections, draw a smooth medium dark free hand curve, and give the notations. It is the front view of the 3rd stage.
Step-12 Give the dimensions by any one method of dimensions and give the notations as shown into the figure.