Problem 7.7 Section of Solids – A square prism of side of base 55 mm and axis height 90 mm is resting on H.P. on its base such that all the edges of the base are equally inclined with the V.P. One triangular hole of side of base 30 mm is cut through the square prism such that the axis of the square prism and the triangular hole are the same and one of the sides of the triangular hole is parallel with the one of the sides of the square prism. One cutting plane which is perpendicular to V.P. and inclined at an angle 60° with H.P. and bisecting the axis of the prism is cutting the object. Draw front view, sectional top view and true shape of the prism.
Step-1 Draw a horizontal x-y line of some suitable length.
Step-2 Draw a square of side of base 55 mm below the x-y line at some suitable distance from it, such that all sides of the square should be equally inclined with x-y line. Give notations on it.
Step-3 From the center of the square, draw a vertical center line of length 90 mm from the x-y line as shown into the figure. And from all notations of the square draw vertical projectors of the length equal to its height i.e., 90 mm. It is a rectangular shape & front view. And Give the notations on it.
Step-4 Draw a cutting plane line passing at the distance 45 mm from the base & on the center line of the front view, such that its inclination with the x-y line should be equal to 60°, as shown into the figure.
Step-5 Give the cutting points name at the intersection of the previously drawn cutting plane line with the vertical projectors of the square prism in front view, i.e., p’, q’, r’ etc. as shown into the figure.
Step-6 Now from these cutting points on the cutting plane line, draw vertical downward projectors in the top view, such that these projectors will intersect at respective lines in the top view, as shown in the figure. Then draw hatching lines in the region bounded by these projectors in the top view. But the triangular shape in the top view will be blank since it is hollow triangular hole. It is the Sectional Top View.
Step-7 Now draw a line x’’-y’’, parallel with the cutting plane line in the front view, which should be outside of the boundary of the front view as shown into the figure. From the cutting points, i.e., p’, q’, r’ etc., in the front view draw projectors which should be perpendicular to the cutting plane line and should be of some suitable length as shown into the figure.
Step-8 Now measure the distance of the cutting points from the x-y line, into the Sectional Top View and transfer the same at the respective projectors drawn from the cutting points in the front view, on the previously drawn x’’-y’’ line, which is parallel to the cutting plane line in the front view.
Step-9 Connects all the points in sequence with medium dark straight lines as shown in the figure, and draw hatching lines in it. And triangular shape in this view is blank because of triangular hole. It is the True Shape of the section.
Step-10 Give the dimensions by any one method of dimensions and give the notations as shown into the figure.