Mechanical engineering

“ Such are among the triumphs of modern mechanical engineering, due in a great measure to the perfection of the tools by means of which all works in metal are now fashioned. These tools are themselves among the most striking results of the mechanical invention of the day. They are automata of the most perfect kind, rendering the engine and machine-maker in a great measure independent of inferior workmen. For the machine tools have no unsteady hand, are not careless nor clumsy, do not work by rule of thumb, and cannot make mistakes. ”

“ Circumstances had changed, mechanical engineering had made much progress; the tools required and trained workmen were to be found in the workshops of the leading mechanists, the founder's art was so advanced that casting had been substituted for cutting, in making the change wheels, even of screw-cutting engines, and therefore it was very probable that persons would be found willing to undertake to complete the Difference Engine for a specific sum. ”

“ All machinery, whether it be printing-presses or automobiles or steam-engines, is the work of mechanical engineers, though in the matter of automobiles this has become a profession by itself, one of the minor branches known as automotive engineering. The mechanical engineer as a rule works26 within doors, just as the civil engineer works out of doors, and his work, consequently, is more confining. ”

“ No other branch so overlaps the other branches as does mechanical engineering. The work of the mechanical engineer is seen in almost every piece of construction reared by the civil man, just as it is seen in every bit of construction work of the mining and the electrical engineers. ”

“ In the pursuit of his profession he spends much of his time supervising the design of mechanical units, and is the one man responsible for correct construction and security against fracture of the machine itself when in operation. Actually the mechanical engineer has more opportunities in his daily routine for the exercise of his creative faculties than has any one of the other kinds of engineers, for the simple reason that no two machines even for the same purpose—speaking of types, always—are exactly similar in construction. ”

“ Dynamical engineering can be divided into mechanical engineering, which covers the construction of all prime motors, the transmission of power, and the use of machines422 and machine tools. Closely allied is electrical engineering, the art of the transformation and transmission of energy for traction, lighting, telegraphy, telephoning, operating machinery, and many other uses, such as its electrolytic application to ores and metals. ”

“ As is seen above, the course of instruction in mechanical engineering includes some trade education. The engineer is dependent upon the machinist, the founder, the patternmaker, and other workers at the trades, for the proper construction of the machinery and structures designed by him. He is himself, in so far as he is an engineer, a designer of constructions, not a constructor. ”

“ The profession of mining engineering, last of the major branches, embraces all work having to do with the locating and construction of mines—coal-mines, iron-mines, copper-mines, diamond-mines, gold-mines, and the like. Also it establishes the nature of the apparatus used, though more often than otherwise the mechanical engineer in this regard is consulted, since much of the machinery utilized in mining operations is the direct work of mechanical engineers. Screens and hoppers are mechanical devices the result of mechanical engineering genius ”

“ CAMPIN.—A Practical Treatise on Mechanical Engineering: Comprising Metallurgy, Moulding, Casting, Forging, Tools, Workshop Machinery, Mechanical Manipulation, Manufacture of Steam-Engines, etc. With an Appendix on the Analysis of Iron and Iron Ores. By Francis Campin, C.E. To which are added, Observations on the Construction of Steam Boilers, and Remarks upon Furnaces used for Smoke Prevention; with a Chapter on Explosions. By R. Armstrong, C.E., and John Bourne. Rules for Calculating the Change Wheels for Screws on a Turning Lathe, and for a Wheel-cutting Machine. ”

“ The above are instances where science has come to the aid of engineering. Here is one in which the obligation is reversed. The rapid stopping of railroad trains, when necessary, by means of brakes, is a problem which has long occupied the attention of many engineers; and the mechanical solutions offered have been correspondingly numerous. Some of these depend on the action of steam, some of a vacuum, some of compressed air, some of pressure-water; others again ingeniously utilize the momentum of the wheels themselves. ”

“ The diversity of the mechanical work around a refinery is remarkable, and the engineer in charge must be a man of exceptional mechanical ability, as his duties include not only steam, electrical and civil engineering, but construction engineering of an advanced character. ”

“ Yet this remarkable contrivance, with all its massive steel beams and chains and cog wheels, employs no other principles than the simple ones of lever and pulley and inclined plane that we have just examined. The power that must be applied to produce a given effect may be calculated to a nicety. The capacities of the machine are fully predetermined in advance of its actual construction. But of course this is equally true of every other form of power-transmitter with which the modern mechanical engineer has to deal. ”

“ It must be admitted, too, that the sense of the reality of this separation has been felt not only by Engineers or others actually engaged in machine design, but also by those theoretical writers who have had any practical knowledge of machinery, in spite of the increasing tendency in the treatment of mechanical science to thin away machine-problems into those of pure mechanics. ”

“ The machine tools did all the working (for the thinking had been embodied in them beforehand) , and they turned out all manner of geometrical forms with the utmost correctness. This sort of training educated the faculties of the lads, and trained their ideas to the perception of exactness of form, at the same time that it gave them an intimate acquaintance with the nature of the materials employed in mechanical structures. The rapidity with which they thus acquired the efficiency of thoroughly practical mechanics was surprising. ”

“ Patents have been granted for many ingenious mechanical combinations to impart to the propelling surfaces such angles as appeared to the respective contrivers most advantageous. In most of these, however, the mechanical complexity has formed a fatal objection. ”

“ The perfection of modern machine-tools is such that the utmost possible precision is secured, and the mechanical engineer can calculate on a degree of exactitude that does not admit of a deviation beyond the thousandth part of an inch. ”

“ How to Experiment with Machines.—Any one who possesses the slightest bent for mechanics can work out improvements on devices like egg-beaters and monkey-wrenches and feel their way as they go along.
But when it comes to designing and building real machines where numerous levers, gears, and springs are combined to make a working unit you should by all means read up on the subjects of work, energy and power, learn about the six mechanical powers—and the action of machines in general. ”

“ The study of kinematics has been considered for nearly 80 years as a necessary part of the mechanical engineer's training, as the dozens of textbooks that have been published over the years make amply clear. ”

“ This shows within what distinct limits machine-problems lie, and that they allow themselves to be readily separated from the general problems of Mechanics, as we have already maintained.
While the science of Mechanics examines motion caused in the most general cases by the action of mechanical forces, Machine-mechanics occupies itself with certain special cases only, with motions produced by a limited circle of means. It draws its first laws from the same fountain as Mechanics, to which, as the more comprehensive science, it is subordinate. ”

“ If a mechanical engineer invents an improvement on any of the appendages of a steam-engine, such as the valve-gear, the condenser, the steam-chest, the walking-beam, the parallel motion, or what not, he is not obliged, in order to make himself understood, to describe the engine, nor the particular appendage to which the improvement refers, nor its mode of connection with the principal machine. These are already familiar to others skilled in that kind of machinery. He may begin at the point where his invention begins, and describe what he has made that is new, and what it replaces of the old. ”

“ As, however, the actual machinery itself, deriving its existence from various sources, and having its own characteristic features and methods of classification and treatment, forms a quite distinct and special subject, a separation of its scientific mechanical problems from those of Mechanics in general is possible, and indeed has already been made. ”

“ We are far from having described all the implements of the mechanical engineer, or even all the more interesting ones; for example, we have given no account of the powerful lathes in which great masses of iron are turned, or of the analogous machines, which, with so much accuracy, shape the internal surfaces of the cylinders of steam engines, of cannons, &c. ”

“ The velocity ratio of the former machine is nearly double that of the latter, and its mechanical efficiency is nearly four times as great. Less than half the applied power is wasted in the wheel and axle, while more than half is wasted in the differential pulley. This makes the wheel and axle both a more powerful machine, and a more economical machine than the differential pulley. ”

“ All over the country, and even on the Continent of Europe, and in America, thousands of mechanics, and many men of mechanical tastes in other professions, were familiar with the principles of the new machine, and were speculating upon its value for all the purposes to which it has since been applied; and a multitude of enthusiastic mechanics, and a larger multitude of visionary and ignorant schemers, were experimenting with every imaginable device, in the vain hope of attaining perpetual motion, and other hardly less absurd results, by its modification and improvement. ”

“ The improvement so much to be desired, will speedily follow upon the discontinuance of grinding. Recourse must then be had to the natural process. The surface plate and the scraping instrument will come into constant use, affording the certain and speedy means of attaining any degree of truth which may be required. A higher standard of excellence will be gradually established, the influence of which will be felt throughout all mechanical operations, while, to the mechanic himself, a new field will be open, in which he will find ample scope for the exercise of skill, both manual and mental. ”

“ To this day the mechanical means by which his famous gold paint is produced remains a secret. The machinery is driven by a steam-engine in an adjoining room; and into the room where the automatic machinery is at work none but the inventor and his assistants have ever entered. When a sufficient quantity of work is done, a bell is rung to give notice to the engine-man to stop the engine ”

“ But another conclusion follows more irresistibly, namely—that the mechanical engineer who devotes his attention to the construction and management of massive machinery, such as pumps, hydraulic and lever presses, looms, and steam-engines, whether locomotive, marine, or other, must, in order to be master of his profession, be thoroughly familiar with every step of their construction; and such familiarity can only be acquired by a course of practical study in the machine-tool shop. ”

“ Let us enter the engine-room of a big liner, and see for ourselves. It is a triumph of engineering. Still, at first, you cannot understand anything of the complicated mass of machinery. Then you notice three large cylinders—for these are triple-expansion engines—with pistons shooting in and out downwards, and attached by connecting rods to the cranks of the propeller shaft below. The cranks are bent at different angles so that they can never all be in the same position at once. There is a maze of machinery and shining rods, bewildering to the uninitiated eye. ”

“ We cannot say how long the period was from the age of iron tools to the building of the pyramids, but we know that before those stupendous structures arose, the six elementary mechanical powers, the lever, the wheel, the pulley, the inclined plane, the wedge and the screw, were invented. And without those powers, what mechanical tool or machine has since been developed? The age of inventions in the times of the ancients rested mainly upon simple applications of these mechanical powers. ”

“ How shall a machine be constructed that shall most efficiently embody, and accord with, not only those scientific principles, but also all of those principles of engineering practice that so vitally affect the economical value of every machine? ”

“ As regards the construction of the engine as a piece of mechanism, the principles and practice of good engineering are precisely the same, whether applied in the designing of the compound or of the ordinary type of steam-engine. ”

“ The supremacy of Machinery in the mechanical field is due to the care with which all matter offered for publication in its pages is scrutinized. Only the best of the material offered by mechanical writers is published, and, as a result, its pages contain the most authoritative, practical and up-to-date mechanical information. ”

“ This invention consisted in the contrivance of a scheme of mechanical notation which is generally applicable to all machinery whatsoever; and which is exhibited on a table or plan consisting of two distinct sections. In the first is traced, by a peculiar system of signs, the origin of every motion which takes place throughout the machinery; so that the mechanist or inventor is able, by moving his finger along a certain line, to follow out the motion of every piece from effect to cause, until he arrives at the prime mover. ”