Milling cutters were made in America by one of the early machinists, a Frenchman named Vaucanson, who died in 1872. A sample of these had a hexagonal instead of a round hole, and the pitch of the teeth was very fine, so that the cutter was more like a circular saw than the cutters in use at present. It is said that a man by the name of Bodmer, in Manchester, England, had made a milling machine in 1824.
It is altogether probable that Eli Whitney, the inventor of the cotton gin, had built and used milling machines previous to this date, as the following item of mechanical history would seem to indicate. In January, 1798, Eli Whitney received from the United States Government an order to furnish ten thousand muskets, of which four thousand were to be delivered in one year, and the balance in two years. Mr. Whitney went at the undertaking in a very thorough and systematic manner. He first developed a water power; then erected suitable buildings; considered and developed ways and means for a larger and better product than had previously been realized; designed and built machinery to effect it; and trained workmen to a degree of skill necessary to success in their new employment.
The difficulties which Mr. Whitney encountered and the obstacles which he had to overcome, were so much greater than he anticipated that it was really eight years instead of two before he had succeeded in completing the government order for the ten thousand muskets. However, the progress which he had made in this new enterprise, and the character of the product which he turned out and delivered, were so satisfactory to the government officials that Congress treated him with the greatest courtesy and consideration.
His shops were situated in the city of New Haven, Conn., and soon became the Mecca of government officials, manufacturers, traveling notables, and foreigners, who had heard of this wonderful American mechanic and came to see his work for themselves - to find that the system, the machines, and the tools which he had perfected were well worth the journey. His innovations in the manufacture of arms formed as great an epoch in mechanical history as had his invention of the cotton gin.
Jigs and fixtures were among his equipment; and it is altogether probable that milling machines were also in use, since he must have had practical knowledge of the utility of the milling cutter at this time, as it is generally assumed that the first practical use of the milling machine was in the making of parts of muskets.
The buildings which Mr. Whitney erected for his use were substantial stone structures, and stand in a part of the city called in his honor "Whitneyville." They form a part of the extensive plant of the Winchester Repeating Arms Company.
At this point and at this early day, therefore, was inaugurated the modern system of interchangeable manufacturing - or the manufacturing, in large numbers, of duplicate parts, within such a limited degree of variation as to admit of their ready interchangeability with one another. The system was not one that would be confined to the manufacture of arms, but was adaptable to the production of all kinds of small and moderate-sized machinery, and was the initial effort which in due time revolutionized the then existing shop methods, and which has since built up the American system of manufacturing to the proud distinction of being superior to anything of the kind in other manufacturing countries.
In the operations of modern manufacturing, the principal object sought is to turn out the product economically and accurately. To produce these results economically, the parts must be produced very rapidly. To produce them rapidly, not only must there be a very complete and efficient equipment of machines, attachments, tools, jigs, fixtures, and gauges or measuring devices, but there must also be a very complete system of shop methods by which the operation of this equipment is carried on.
It has been well said that "the man in whose brain the manufacturing system was born was he who first took a piece of scrap iron and drilled two holes in it, to guide a drill in making another piece with two holes in it the same distance apart as in the first piece." The men who now fill our drafting rooms and tool rooms, and who devise and construct tools for the production of interchangeable metal parts, are his descendants. They have made possible the manufacture of the breech-loading gun, the typewriter, the cheap sewing machine, the cash register, the machine-made watch, the automobile, as well as a thousand and one other mechanical articles, machines, and devices which form an integral part of our twentieth-century civilization.
To render these systems efficient and economical for these purposes, the work must be repetition or duplicate work. That is, there must be very large numbers of each of the different parts; and to carry out the scheme of operation for the division and subdivision of work, a single operation on a large number of parts is performed; then the work is handled again, perhaps in another machine, and another operation is performed; and so on until the part is complete. Thus a piece of comparatively simple form may require a large number of separate and distinct operations to complete it. But, as each single operation is performed by one operator, he may give his undivided attention to the accuracy of that operation; hence very accurate work can be produced.
In the development of these systems, the work has continually grown more and more complex, as have also the requirements as to the buildings in which manufacturing work is performed, and as to the equipment necessary to perform it. Conditions have been continually changing; greater speed as well as greater accuracy in all machine operations has been demanded; and a largely increased output per employee has been required. So great and urgent has been this demand that the employee of today will turn out from three to ten times the volume of product of a given kind that he did only a few years ago. Undoubtedly this result has been brought about in large measure by the great improvement in machines, tools, and fixtures; also by the use of tools composed of high-speed steel; and still more to improved systems for handling work.
But all of these do not fully explain the enormous increase in product per employee. This has been brought about by various methods of shop management. One of these is the specialization of operations and the division and subdivision of departments, whereby each operator has a certain well-defined and very limited number of operations to perform. These operations he performs over and over, hundreds and sometimes thousands of times daily, until he becomes so accustomed to each movement that the operations are performed not only with great rapidity but also with great accuracy. Still another factor in the question of individual output, is the efforts that have been made through systems of premiums, bonus, and similar methods of reward for individual effort when the output reaches or exceeds a certain fixed limit. These rewards are not confined to the operatives, but are often extended to the foremen, assistant foremen, gang bosses, and others of the "non-productive" force who have indirectly contributed to the efficiency of individuals and hence to departmental efficiency.
In the succeeding articles, these matters will be taken up and treated in detail, giving the actual practice as now prevailing in some of the best organized manufacturing plants.