While the printed page cannot take the place of personal experience, there is, nevertheless, a great fund of information regarding tools, methods and processes that can be acquired from the printed page more effectively than from any other source. Effective as the “picking up” process is as regards the things picked up, it passes by many which are equally important and it has, at best, no logical order or sequence, the information so gathered being unassorted, fragmentary and incomplete. Few machine shops make use of more than a small fraction of the methods which are herein explained and which the properly informed should know but the learning of which commonly requires half a lifetime. While many of the methods shown are the commonplaces of the experienced mechanic, they have not, heretofore, been gathered together in print, and still less have their underlying principles or their mutual relationships been explained for the use of beginners. It is to the explanation of these things that the printed page is best adapted and to which these pages are chiefly devoted.

The volume comprises the substance of the lectures which the author has presented to the students in mechanical engineering at Columbia University for the past three years. It has been prepared in the belief, which is shared by friends who have been consulted, that it would prove useful elsewhere, in trade as well as engineering schools and to apprentices.

The volume presupposes no more than a reasonable familiarity with the more common machine tools, their general construction, uses and fields of application; in other words such a degree of mechanical intelligence as should be acquired by an apprentice in serving one or, at most, two years in any modern machine shop.

The chapters relating to actual machine tools might have been expanded indefinitely. In the embarrassment due to the voluminous material available, the author, in addition to showing basic principles, has chosen to present the less obvious features, passing by many which, while equally important, are reasonably certain to be gathered in the course of everyday experience. To those manufacturers who may feel aggrieved because their own products have not been included, although in many cases as meritorious as those shown, the author would explain that his object is to show methods, not machines, the appearance of the machines being incidental to the showing of the methods. When choice has been necessary, preference has usually been given to those machines which first introduced a given method.

The machine shop is the center from which all modern industries radiate. From the brickyard to the flying machine, from the sawmill to wireless telegraphy, from the stone quarry to the moving-picture camera, there is no modern industry more than twice removed from the machine shop. Of the works of man it is to the author the most interesting place on earth and in this spirit this volume is offered, not only as a source of instruction to the succeeding generation, but as a tribute to those great mechanics, living and dead, of this and other lands, whose active brains and deft fingers have created the marvels of which the attempt ^ here made to portray some of the inner spirit.

The object of this volume is to show how the problems of the shop are attacked and solved - not to show how machine tools are operated. This plan necessitates giving considerable attention to precision work which, in turn, emphasizes the intellectual character of the work - a feature which cannot fail to impress the reader and give him increased respect for those who are responsible for the methods and solutions herein set forth. These methods relate largely to the work of the tool maker, which has now reached a stage of development which almost entitles it to be called a profession. In this, tool making is unique among occupations commonly called manual. Its development to the point where manual skill alone is helpless is a matter of the past fifty or sixty years and the development is one the like of which was never seen before.

An attempt has been made to give credit for the leading inventions which mark the development of the machine shop. The author is well aware that in doing this he is treading on dangerous ground, as few things are more difficult than the apportionment of credit for these things. For this there are several reasons. Frequently the first appearance of an invention is in such shadowy form as to make the identification of its origin difficult and even impossible. Frequently great inventions are of a composite character - different elements being supplied by different men - and in many cases of this kind the various elements are useless until combined by someone who does nothing else. Frequently the original suggestion came at a time when the collateral arts were not sufficiently developed to make the use of the invention possible and it had to be reinvented at a later date. In such cases it is a subject of dispute which inventor is entitled to the greater credit.

Some consider the chief credit due to him who made the effective invention, as it is certainly to him that the world is indebted for its use. In many cases this is just and proper because of the fight, at first with inertia and later with infringers, with often, in the end, defeat and despair and the passing on of the benefits to others, which too often accompany the introduction of an invention and which should not be forgotten when apportioning the credit. On the other hand, in many cases it is unjust because a later inventor is frequently merely more fortunate in time and circumstance. Even more unjustly, inventions which are perfectly applicable at their first appearance, frequently lie dormant for many years through nothing but indifference and inertia. Add to these considerations the scanty records of industrial developments that exist, and the difficulties of apportioning credit for these things become apparent, as do the reasons for the disputes between friends of rival inventors.


THE TWO SYSTEMS OF MACHINE PRODUCTION

THE MAKING AND MANUFACTURING SYSTEMS

There exist two sharply contrasted systems of machine production called respectively the making and the manufacturing system. Under the first term are included the methods employed when machines are produced one at a time or, at most, in such limited numbers that the methods used are not essentially affected by the number. The second term refers to the methods followed in wholesale production of interchangeable parts.

Of these terms manufacturing is suitable and appropriate but as much cannot be said of making. Properly considered, the latter term is applicable to all methods, but it has come to be used, and will here be regularly used, in this restricted sense. For this there is excellent warrant, as these terms were used in these senses by Charles Babbage in his Economy of Machinery and Manufactures published in 1832, in which these words were defined in a manner which might be used to-day.

While the system used is commonly determined by the number of things made, nevertheless the distinction between the systems lies in the methods employed and not in the quantities produced. Because A makes a few things of a kind and B makes many, it does not follow of necessity that A works under the making and B under the manufacturing system. If we are unwise we may make things in large numbers and so also we may manufacture things in comparatively limited numbers. The two systems are frequently used conjointly in the production of a single product. For instance, in the production of Corliss engines, the larger parts, of which each machine contains but one and which differ with each size of engine produced, are naturally made, whereas the smaller parts of the valve gear, of which each machine contains several, one size of which may be used on several sizes of engines and which, by reason of their smaller dimensions, are better adapted to manufacturing processes, may be manufactured.


MACHINE TOOLS CHARACTERISTIC OF THE SYSTEMS

For the making system and the machine tools by which it is carried on, we are indebted to England, while, for the manufacturing system and the machine tools which are characteristic of it, the United States has the chief credit. Other countries have supplied plenty of things to make - Germany gave us the gas engine, France the automobile and Sweden the steam turbine - but the methods of machine production are almost exclusively the work of the English-speaking peoples.

The machine tools employed in the making process are commonly called the standard tools and they comprise the lathe, the planer, the shaping machine, the slotting machine, the boring mill, drilling and gear-cutting machines, all of which originated in England and were brought to a high state of perfection there by the close of the first half of the last century. With the exception of drilling and gear-cutting machines, the characteristic feature of these machines is that the workman determines the dimensions of the work by direct measurement and by the adjustment of the cutting tools for each piece as made.


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