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OF

PRACTICAL ENGINEERING

AND

ALLIED TRADES

A PRACTICAL AND INDISPENSABLE WORK OF REFERENCE
FOR THE MECHANICAL ENGINEER, DESIGNER, DRAFTSMAN,
SHOP SUPERINTENDENT, FOREMAN AND MACHINIST.

Encyclopædic in scope, thorough and practical in its treatment of technical subjects, simple
and clear in its descriptive matter, and without unnecessary technicalities or formulæ. The
Articles are as brief as may be and yet give a reasonably clear and explicit statement of
the subject, and are written by men who have had ample practical experience in the

matters of which they write.

EpiteD BY

JOSEPH G. HORNER, A.M.I.MECH.E.

AUTHOR OF

PATTERN MAKING,"

PRACTICAL METAL TURNING," MODERN MILLING MACHINES,"
TOOLS FOR MACHINISTS, AND WOODWORKERS,"

ETC., ETC.

ASSISTED BY A CORPS OF PRACTICAL MEN, EACH A SPECIALIST

IN THE SUBJECT OF WHICH HE WRITES.

PROFUSELY

ILLUSTRATED.

VOL. I.

A-BOI,

NEW YORK
THE NORMAN W. HENLEY PUBLISHING COMPANY,

132 NASSAU STREET.

1906.

125361 JAN 1 1909

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SBH H 38 1-2

PREFACE.

a

a

The publication of this comprehensive work, intended to cover the entire practice of civil and mechanical engineering, is justified by the present conditions of that practice. Men in the offices and shops, in active professional and commercial work, and students in the schools are all to a great extent hampered by the everextending character of engineers' work, and its intensified specialisation. The term "engineering" alone has now too vague a meaning to denote anything definite, without some qualifying prefix. The vast profession, or industry, or craft, is subdivided into more than a hundred well-defined and separate fields, and many of these are broken up into still more specialised departments. It is thus a fact, that competent and experienced engineers who have devoted their whole lives with absolute singleness of purpose to their chosen pursuits, cannot possibly intimately know the practice of more than a few of the related sections. Every great industry in which motors and machines are used is now catered for by manufacturers who mostly confine their business to the demands of a single industry, and in which alone their experience lies. Of all outside that, their knowledge is in a sense that of amateurs.

What is true of the individual fields of action is true also of the separate crafts which are carried on in the separate shops and sub-departments of a single big works. The divisions between these, following the passing of the old race of millwrights, grow sharper, more stringent, and more minute as time goes on. A workman is no longer a turner, or a machine hand, or a boilermaker, or a moulder, but he is a man doing one sub-section of work, or an attendant of one kind of machine. He is also either a mechanic, or a machine-minder. His speciality is

a thus as well defined as that of the group of manufactures carried on in the firm of which he forms a unit.

This intensity of specialisation produces narrow views, and narrow ideals, and tends to induce only a languid interest in the related work that lies beyond. It renders the acquisition of minute knowledge in the other fields very difficult. Especially on those of limited means do these conditions press hardly. The mass of technical literature is too great to be purchased or even assimilated, neither is it essential except to a few. The requirements of most people are met by a special knowledge in one branch, and a general acquaintance with others related thereto. Hence the popularity enjoyed by encyclopædias of a literary and scientific cast.

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It is believed that there is scope for such a work for the engineering and allied trades. Almost every one makes or uses machinery now, and to all such, whether employers, or workpeople, these volumes will appeal. It is hoped that nothing which is of interest to those engaged in any of the Engineering industries will be omitted from its pages. All the different subdivisions have been well considered in the selection of subject matter, and in the due balance of articles, according to their relative importance

None know better than those who are engaged in the work, how inadequate the space included within ten volumes is to deal with all that is involved in presentday engineering in its numerous branches. Brevity is necessary, yet this must not be secured at the sacrifice of comprehensiveness. A method of treatment is however adopted which will combine and balance both requirements. No articles will be very long, but there will be many separate articles on related subjects of importance. The idea is, that a reference to a tool, or machine, or process will be found under the heading that first occurs to the mind. This will be preferable to an arrangement involving long articles, in which one has to hunt through many pages for some bit of information. Cross-references will also assist in finding any article wanted.

A special feature of this work is its "shoppy” character. It is written for the men in the shops more than for any other class. For this reason too it is of especial value to students, who, whatever they may learn of theory in technical schools, certainly do not learn shop work as it is performed under factory conditions.

The contributors are mostly men whose names are well known as reliable writers on technical matters, and who either have been, or are engaged in active engineering pursuits.

A feature of these volumes is that all the blocks have been made specially for the work from drawings prepared uniformly under the Editor's supervision, or from photographs. It would have been easy to fill the work with borrowed catalogue blocks at a considerable saving of expense, but the publishers have wisely decided to give subscribers original drawings instead—a more satisfactory course. The illustrations of machines, &c., have been prepared from originals supplied by representative firms. In all cases they are to exact scale, being reduced proportionately, and they are therefore of as much utility as though dimensioned up. Representing as they do therefore actual practice in manufacture, their superiority over bald diagrams, or patent specification drawings, is evident. These, though used freely in many books, too often convey but a poor and incorrect idea of a mechanism as it is commercially made-scale and proportions of parts especially being bad.

It is with great pleasure that the Editor records his sense of the courtesy with which so many firms have freely placed working drawings at his disposal for this work.

THE EDITOR.

a

The Encyclopædia

OF

Practical Engineering and Allied Trades.

A1.—The highest classification of vessels in is retained “so long as they are found upon Lloyd's Register of British and Foreign Ship- careful annual and periodical survey to be in a ping. The letter A has reference to the hull, fit and ethicient condition for the safe

conveyance the figure 1 to the equipment of a vessel. of dry and perishable cargoes." But vessels that

The classification of vessels is sanctioned by do not come up to the requirements of the firstthe Committee of “Lloyd's Register” on the named, but which exceed those of the second, basis of Reports sent in by their Surveyors, who

may

be classed as 95 A at the discretion of the are located at all the principal ports of the world. Committee. Surveys may take place during or subsequent The letter A occurs in several different to the construction of the vessels, full particu- classes, as A for river purposes only, A for lars for the carrying out of which are given in channel purposes, &c. &c., to which the name of the “Rules and Regulations” issued by the the channel must be added, as English Channel, Society. These surveys are strict, without being Bristol Channel, &c. of a hard-and-fast character. That is, though The figure 1 placed after the A, as 100A1, the officers of the Society have no power to

denotes that the equipment is of the highest sanction deviations from their printed condi- class. If this is not found to be the

case, tions and the Rules laid down for their guidance, though the hull is of the best, a dash takes the deviations from the Rules are often sanctioned place of the figure, thus 100A by the Committee, provided these are equi- The "good order of the equipment” includes valent to the requirements of the Rules. In the proper maintenance of the masts, spars, any case, drawings have to be supplied, giving rigging, sails, and a sufficiency of anchors and particulars of the scantlings of the vessel, the cables, the number of which increases with deck tests of steel used in the case of steel vessels); erections. Certificates of tests of anchors and coal bunkers have to be cleared ; all the vital cables must be produced. Anchor cranes and portions, as frames, stringers, floor plates, keel- boats' davits are included. The sons, engine and boiler bearers, ends of beams, engines and boilers is the subject of another water-tight bulkheads, rivets, and inner sur- certificate, namely, (L.M.C.) Lloyd's Machinery faces of the plating, all exposed to view; with Certificate, with a mark in the form of a cross other provisions made in order to facilitate in prefixed. spection. The Committee then, from the data Periodical special surveys take place in vessels furnished to them, assign the vessel to her class. classed from 100A to 90A inclusive, at periods

The retention of a vessel in a certain class of four, eight, and twelve years respectively depends on periodical surveys, which from the date of building, and subsequently at compulsory

the expiration of like periods from the date The letter A, relating to the hulls of steel recorded in the Register Book of the previous vessels, is prefixed by the numbers 100, or 90, special survey No. 3. But if a vessel is subthus :-100A or 90A :-and the classification mitted to special survey No. 3 before being

survey of

are

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