PREFACE. THERE are in this country some thousands of civil and mechanical engineers, architects, and surveyors who find they have, in increasingly numerous cases, to design and superintend erections involving in some form or other the employment of mild steelwork. A few years ago this material was seldom used except by railway companies, Government departments and a few consulting engineers; but with its adaptation to building and to the ordinary requirements of the smaller engineering enterprises, it has become imperative that every designer should know something about it. So far as its mere mathematics go, any educated man may easily, in a short time, extract sufficient from any of the many excellent text-books now published to assure himself that his ideas are theoretically beyond reproach, and that he has got a sufficient quantity of metal in the right places to ensure stability. He is, however, badly handicapped by his lack of practical knowledge. He does not know, of himself, the best practical dispositions to make for economy, and all unconsciously he wastes valuable time and money every time he shapes his ideas on paper. This is not his fault, but is due to the lack of opportunity hitherto to correct any notions he may have formed, by reference to some plain account of the essentials and modes of manufacture. Text-books cannot within their limits do more than merely skirt this question, although in reality it is quite as serious and worthy of earnest study as is pure theory. The present work is an effort to afford to designers generally an indication of what they should seek to embody in their creations; it is hoped that it may be also a handbook for those practically engaged in the trade. As the outcome of a series of articles appearing in The Engineer between 1900 and the present time, on various phases of modern steelwork design and practice, some of Part I. of the book will not be altogether new, although it has been entirely rewritten. Part II. has never previously appeared. The author desires to express his indebtedness to the editor of The Engineer for kind counsel and help. His thanks are also due to the following firms for their courtesy in lending blocks for illustration, or for photographs of special machines:-Messrs Sir Wm. Arrol & Co., Ltd.; Henry Berry & Co., Ltd.; Buck & Hickman, Ltd.; J. Butler & Co.; John Cameron & Co., Ltd.; Campbell & Hunter, Ltd.; Consolidated Pneumatic Tool Co., Ltd.; De Bergue & Co., Ltd.; The Proprietors of The Engineer; Messrs Fielding & Platt, Ltd.; Wm. Muir & Co., Ltd.; Peter Pilkington, Ltd.; Rice & Co., Ltd.; Scriven & Co.; Hugh Smith & Co., Ltd. A. W. FARNSWORTH. THE STRAND, Derby, December 1904. Nineteenth-century developments-Contributory causes-Abnormal development— CHAPTER II. THE GOVERNING FACTOR-ECONOMY. Higher aims-Beauty-Personal standpoint-Geometrical patterns-Steel and PAG 1-5 Critics-Human nature-Engineering-Energy conserved-Disposition of forces-Nature spots-Our best-Monetary standards-First efforts-The first law-Hampering facts-New country railways-Public memorials- Estimation of duty-The consultant's obligations-Types of honour-Obvious duties-Minimum cost-Strenuous competition-International trade rivalry -The irreducible minimum-Dividends-Luxurious works-Hotels and warehouses-Application of monetary knowledge-The steelwork specialist -Judicious combination-Choice of design-Faulty application-Personal Actual manufacture--Custom in specifying-Process-Separate methods of pro- duction-The business of the metallurgist-Question of tests-Commercial possibilities—Mechanical attainments-Wrought-iron-Desirable properties -Proportions and ingredients-Percentages-Foreign elements-Carbon- Manganese-Phosphorus-Silicon-Sulphur-Excesses of ingredients— Narrowing production-Accepted standards of tests-Ultimate strength— Elongation-Contraction of areas-Bending and heat tests-Methods of testing-At the mills-Certificates of tests-Representation at the mills- Mode of procedure-Inspectors' duties-Test-strips-Measurements of strips -Analyses-Proportions — Additional tests - Rolling programme-Cast- iron-Its forte-Tests of-Mixtures-Moulders --Foundries-The best tests Codification-Government specifications-Their handicap-Independent engineers' -Its function-Its origin-An institution-Its scope-Desirable points- Standardisation-Manufacturers' standard specifications-American com- petition-Our traditions-Pet clauses-The "time "limit-Penalties- Increase in costs-The same data-Inspectors' clauses and powers-Con- CHAPTER VI.-THE DRAWINGS-(a) RIVETS. Common state of drawings-Impractical arrangements-What they should be— Essentials-Desiring details-Riveting arrangements - Designing rivet- ing The correct way - Reactions and bending moments — B.M. diagram-Shear-Pitches-Moving stiffeners-Method of setting out holes -Tee stiffeners-Economy in pitches-Choice of diameters-Modification for stiffeners-Sizes of rivets-Relation of diameters to thicknesses of plates-Calculations-Extra rivets-Doubtful economies-Wöhler's theory -Girder flanges-Stanchion sections and arrangements-Proportions of rivets-Osborn's system-Field rivets-Distance from plate edges, |