This book makes possible the accurate geometrical solution of all problems of pattern development normally encountered by giving examples arranged according to a systematic plan which progressively illustrates the underlying principles. In the five courses" into which the book is divided the three basic methods of Radial Line Parallel Line & Triangulation are applied in more & more complex examples culminating in the solution of difficult problems of pipe intersection twisted surfaces & spiral chutes. Each stage in the solution of the problem is clearly explained & shown in detailed drawings & the superiority of the accurate geometrical method in terms of time & material saved is effectively demonstrated. All sheet metal workers will find this book invaluable."