A Text-Book of Engineering Drawing and Design Volume 1; Practical Geometry

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1905 Excerpt: ... Fig. 64, and of a model of the H P and V P, together with pieces of cardboard or set squares, to represent planes, the student should verify the following:--(a) A plane parallel to the HP or VP has no H T or VT respectively; therefore, when a plane is parallel to another plane, it has no trace npon that plane. Also, a plane parallel to one oi the planes of projection is perpendicular to the other plane. (b) When a plane is perpsndicular to the H P its V T is a line perpendicular to the ground line; and when it is perpendicular to the V P, its H T is a fine perpendicular to the ground line. (c) When a plane is inclined to the H P, and perpendicular to the V P, its inclination is shown by the angle which its V T makes with the ground line; and similarly when a plane is inclined to the V P, and perpendicular to the H P, its inclination is shown by the angle which its H T makes with the ground line. (d) When a plane is perpendicular to both the H P and V P, its traces form one straight line, perpendicular to the ground line. («) When a plane is inclined to both the H P and V P, its traces make angles with the ground line, which are not equal to the angles of inclination of the plane to the H P and V P. (/) The H T and V T of a plane intersect in the ground line, whenever the plane has two traces, except in the case where the plane is inclined to both the H P and V P, so that the sum of its inclination equals 90, when its traces are parallel to the ground line. (a) Parallel planes have parallel traces. It should be noticed that a number of planes may be arranged relatively to the H P and V P in such a way as to intersect each other. In such cases the lines of intersection are represented by their plans and elevations. EXAMPLES. EX. 13.--Show the following ...