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From the 1924 book, A Popular History of American Invention. Original chapter title, “AUTOMATIC MACHINE-TOOLS.”
IT has been pointed out in the chapter “Putting Steam to Work” that when Watt gave the world his great invention he also created the machine-tool industry. By this we do not mean that he actually designed and made the wonderful lathes, planers, and shapers which do their work far more precisely and rapidly than saws, files, and chisels in human hands; but it is obvious that without some machine that would bore cylinders with reasonable accuracy he could not build engines.
Indeed, when it came to “the practice of mechanics in great,” as he called it, no one could bore a cylinder for him by machine or by hand, for which reason his first large engine had a cylinder which was actually hammered.
For ten years he sought a man who could provide him with cylinders in which a piston would slide snugly. Unless such cylinders could be obtained, the steam would flow between the piston and cylinder-wall, power would be wasted, and his engine could not be a great mechanical success.
The leading engineers of his day tried to help him. Smeaton, one of the most noted, declared that “neither the tools nor the workmen existed who could manufacture so complex a machine.”
Before Watt’s day there were engines of a kind, the cylinders of which had been bored out. The boring tool had simply followed the incorrect form given to the cylinder when it was cast; it made no pretense of shaving off all portions that were not wanted. In Watt’s engine better work was demanded.
Luck was with Watt when he met gruff John Wilkinson, known all over England as an ironmaster of more than ordinary imagination and mechanical daring. He had devised ways of smelting iron cheaper than those of his competitors, and he made cannon for the British Government.
Cannon must be bored. The cannon of Wilkinson’s time—the time of the American Revolution—fired shot more or less round. Wilkinson devised a machine which bored them more accurately than had been possible before, and it was this machine that overcame Watt’s disheartening difficulty.
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|DRAWING OF THE FIRST STEAM-CYLINDER BORING MACHINE. This drawing copied from the original in the Boulton and Watt collection of Birmingham, represents the cylinder boring-mill which was invented by John Wilkinson in 1775, and on which all James Watt’s steam-engine cylinders were bored between 1775 and 1795. It was the first boring machine that could bore a true cylinder.
The earliest cast-iron Newcomen engine cylinders were bored on a cannon-mill by a rotatating cutter-head fixed on the end of an overhanging bar, driven by a water-whell or horse. Wilkinson’s invention consisted in fixing the cylinder in a cradle and passing through it a long, stiff, hollow boring-bar, mounted in bearing at each end. A sliding cutter-head was mouned on the bar, and was traversed along it, by means of a long rod passing down inside the bar. Courtesy of the South Kensington Museum, London.
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|(left) JOHN WILKINSON. (right) THOMAS BLANCHARD. John Wilkinson, the great eighteenth-century ironmaster, made it possible for Watt to build his steam-engines. It was Wilkinson who introduced the modern boring-mill. He ordered one of the first Watt engines for his foundry, first applied steam-power to forging, supplied the castings for an iron bridge, launched the first iron barge, and devised the modern method of drawing lead pipe. Thomas Blanchard manifested a strong mechanical bent even as a boy. He invented a machine for making tacks, the profile lathe for manufacturing gun-stocks, and many other special machines used in making of guns and other articles.|
JOHN WILKINSON’S BORING MACHINE
The old machines could not bore true because there was no way of preventing them from following the irregularities of the casting. John Wilkinson did what we all do when we want to draw a straight line. He gave the boring tool a kind of straightedge or ruler, and this it had to follow as it dug its way on.
The boring tool itself was a long shaft, which was driven by water-power and which carried a wheel with cutting blades. In this there was nothing new.
The new idea was the ruler—a straight, heavy bar placed in the central axis of the cylinder and rigidly supported so that it could not move. The borer simply slid along this bar, just as we would slide a lead-pencil along a ruler’s edge to draw a straight line. When the cutters encountered metal in their path they cut it away.
This was the first modern metal-cutting tool. It did its work for Watt in 1775. Wilkinson played as great a part in the history of the steam-engine as Boulton, Watt’s partner. He had courage as well as gruffness. He bought the first engine that Watt turned out at Soho, while other ironmasters stood by, waiting and watching.
Wilkinson was no mere waiter and watcher. He helped to erect the first iron bridge in 1779 and built the first iron vessel in 1787. Men feared and respected him. Boulton wrote of him to Watt:
“I can’t say but that I admire John Wilkinson for his decisive, clear, and distinct character, which is, I think, a first-rate one of its kind.”
“A first-rate one of its kind”—what a character he must have had! No wonder that he was constantly quarrelling with his family.
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|JOHN WILKINSON’S BORING MILL, 1800. In this machine was first utilized the guide principle for machine-tools in boring steam-engine cylinders and cannons.|
THE WORK OF JOSEPH BRAMAH AND HENRY MAUDSLAY
It was an opponent of Watt’s, a man who testified against him in patent-infringement suits with no little bitterness and prejudice, who ranks with John Wilkinson as the father of the machine-tool. He was Joseph Bramah, who was born on a Yorkshire farm and who might have lived and died a farmer had he not been lame. His infirmity made it necessary for him to learn the trade of a cabinet maker. A Yorkshire farm was no place to ply a trade.
He went to London, there to become famous in the history of mechanics. Like Wilkinson, Bramah had ideas and a will of his own. His head teemed with inventions, nearly all of them practical. He devised the hydraulic press, the beer-pump, the four-way cock, an automatic machine for numbering the notes of the Bank of England, a quill-sharpener, and important wood-working machinery.
It was a lock that paved the way for Bramah’s entrance into the field of machine-tools, a lock of his own contriving, a burglar-defying lock. Bramah thought so much of this invention that he exhibited it in his shop in Piccadilly and offered two hundred guineas to the man who could pick it. The challenge was taken up time and time again. Sixty years after Bramah had posted his offer, Alfred Hobbs, an American, won the prize in 1851 after fifty hours’ application.
This, being no ordinary lock, could hardly be made by ordinary means. To make it entirely by hand, as a watch was made, was out of the question. Locks had to be made by the hundred to sell at a reasonable price. Bramah saw that he needed machine-tools. But who could design and build them?
“Send for Henry Maudslay of the Woolwich Arsenal” said some one in Bramah’s shop.
Bramah sent for him. A youth of eighteen presented himself. Bramah was amazed. A boy do his work! It seemed impossible. But the boy talked so convincingly, so intelligently, that Bramah engaged him.
One year later Maudslay was the superintendent of the shop. He continued with Bramah for eight years and finally had to give up his place because Bramah would not pay him more than thirty shillings a week, which he did not consider enough to support himself and his family. Maudslay then set up in business for himself and eventually became a rich man.
Henry Maudslay was one of the ablest mechanics that ever lived. Even after he had become rich and hired men by the hundred he loved to go into the shop and do a particularly fine piece of work himself. Nasmyth, himself a fine craftsman, said of him:
“No one I ever met could go beyond Maudslay in the dexterous use of the file. By a few masterly strokes he could plane surfaces so true that when their accuracy was tested by a standard plane surface of absolute truth they were never found defective; neither convex nor concave nor cross-winding—that is, twisted.”
These two men, Bramah and Maudslay, were probably the finest mechanics of their time. Both were able inventors. The device with which their name is forever linked is the slide-rest, the value of which will be seen if we consider the lathe of the eighteenth century.
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|THE EUROPEAN POLE LATHE OF THE SEVENTEENTH AND EIGHTEENTH CENTURIES. The earliest known form of lathe, the pole lathe, consisted of two fixed centres between which the work was supported, and motion was given to the work by a bow, the string of which was wrapped around it, or by a cord the ends of which were pulled by an assistant. The turner was seated upon the ground holding a tool against a rest with one hand, and working the bow with the other, the cutting being performed during one-half of the motton when the work was revolving toward him.
Such lathes are still used in the East. In Europe, probably owing to the erect position generally adopted by the turner, the fixed centres were placed higher, and an improved method of locating the work was employed. For the bow a spring-beam or pole above the lathe was substituted, and a cord was fastened to the free end of it, then wrapped around the work, and its lower end attached to a treadle to be worked by the foot. This method largely increased the power and left both hands free for the management of the tool. Machines of this type were used as early as the sixteenth century. Courtesy of the South Kensington Museum, London.
The lathe was set up between two centres so that it could turn freely, and a cord was passed around it. The cord was attached at one end to a light, springy pole fastened to the ceiling of the shop, while at the other end it was secured to a foot-board resting with one edge on the floor.
When the workman stepped on the board the cord was pulled down and, in doing so, turned the work on its centres; as soon as he lifted his foot the pole, springing back, pulled the cord up and the work turned in the opposite direction.
How the “pole lathe” worked will be evident after a glance at the next picture. By holding a chisel against the work, the mechanic, if he was skilful, could turn out a very creditable piece of work in wood; but it was a far more difficult matter to turn brass and iron with such a crude lathe.
Even when the lathe was improved by using pedals and a fly-wheel to turn the work always in the same direction, it took a skilled mechanic to hold the cutting tool steady while he was jigging up and down on the pedal.
With such a pole-lathe, the cutting tool could not be held firmly. The lathe needed an iron fist. Of course, the fist would have to move along the work, and to do this steadily Bramah and Maudslay made it in the form of a carriage that was fed the length of the lathe-bed by means of a screw. There were no quivering nerves in the iron fist, no throbbing pulse. It did not tremble or shake, but held the tool with a firm and rigid grip and made it travel along the work at a uniform speed.
The output of the new lathe was far superior to anything turned out with the old pole-lathe and hand-rest. By means of gears, the feed-screw could be made to turn so fast that the tool would cut a spiral groove in the work. In this way screws were cut on the lathe.
It is not certain whether Bramah or Maudslay invented the slide. Probably it was a joint invention, certainly an invention that came out of Bramah’s shop. Independently of Bramah and Maudslay, the slide-rest was invented in America by David Wilkinson, a man who built a steamboat long before Fulton, devised cannon-boring machinery, designed sperm-oil presses, improved the mechanical process of making nails, and did more than any other man, except his son-in-law Samuel Slater, to establish an American textile industry.
His slide lathe patented in 1798 was not generally introduced for many years. In 1849 Congress granted him $10,000, “for benefits accruing to the public service for the use of the principle of the gauge and sliding lathe, of which he was the inventor.”
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|DRAWING OF THE BRAMAH-MAUDSLAY SLIDE-LATHE OF 1795, PREPARED BY PROFESSOR JOSEPH W. ROE. (Split into 3 drawings for this web presentation.) Who invented the slide-lathe it is impossible to determine with absolute certainty. It has been attributed to both Bramah and Maudslay. Probably it was a joint invention of the two, for it came out of Bramah’s shop, where Maudslay was employed. By courtesy of the American Machinist.|
|ORIGINAL MAUDSLAY SCREW-CUTFING MACHINE. This is a small example of the original screw-cutting apparatus invented by Henry Maudslay, about the year 1800, and preserved in the South Kensington Museum, London. A mechanical tool-holder or a slide-rest is combined with a power-driven screw-feed, the result being a screw-cutting lathe. Courtesy of the South Kensington Museum, London.|
|MAUDSLAY’S THREAD-CUTTING LATHE. This lathe was constructed at the end of the nineteenth century, and is believed to be the first workshop machine in which Henry Maudslay combined a leading screw and change-wheel for producing screw-threads. Courtesy of the South Kensington Museum, London.|
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|MAUDSLAY’S MACHINE FOR PRODUCING SCREW-THREADS OF ANY DESIRED PITCH. This appliance was made by Henry Maudslay, about 1800, for the purpose of producing screw-threads of any desired pitch. He had tried to obtain an accurate thread by winding steel-tape around a cylindrical bar, and by other means, but the method introduced in this machine consists in the use of a chisel-edge secured at the calculated angle with the axis of the bar to be screwed and free to travel without turning along the revolving bar under the action of the inclined edge. Cylinders of hard wood and soft steel were employed, and from the best of the screws thus obtained copies were produced in steel for use as standard screws, which were subsequently still further improved by various methods. Courtesy of the South Kensington Museum, London.|
PARLIAMENT’S EMBARGO ON BRITISH MACHINERY
A new industrial era was opened by the invention of textile machinery and the steam-engine. The age of power, the age of the factory, had dawned. There was a growing demand for machinery that could be driven by the steam-engine, a demand that could not be met by the old boring tools and lathes.
Englishmen, like John Wilkinson, Joseph Bramah, and Henry Maudslay, were in a sense the creatures of industrial circumstances. They were great inventors, great mechanics, but the character of the times dictated the character of their inventions.
And so it was in America. David Wilkinson and many who followed him were also creatures of circumstances, but of circumstances that were not the natural outgrowth of remarkable inventions.
The British Parliament provided the stimulus that men like David Wilkinson needed. They would have been willing enough to buy their tools from England, but England would not have it so.
When the American colonists began to turn their attention to the development of their iron mines, England, fearing that she might lose her commanding position, prohibited the building of furnaces, rolling-mills, slitting-mills, and forges in America and opposed manufacturing of all kinds.
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|We did have our factories, legal or not.|
This attitude of the mother country toward her colonies was one of the causes of the Revolution. After the war, when England could no longer dictate what might and might not be done in America, Parliament foolishly passed a law prohibiting any mechanics or skilled workmen from leaving the shores of England, hoping to prevent other nations and particularly America from learning her trade secrets and acquiring her skill in manufacture.
It was because of this law that Samuel Slater (whose work in the textile industry is described in another chapter) had to disguise himself when leaving his native land for America. Slater was not only an all-around mechanic but a man who had a thorough knowledge of textile machinery.
Slater had not dared to bring any drawings with him, but he carried in his head the details of Arkwright’s spinning machinery, and, trusting to his memory alone, he designed and built, with his own hands, America’s first carding and spinning machinery.
He came to be known as “the father of the American cotton industry,” and it was this industry that gave the machine-tool development its early start in America.
To build the machinery demanded by the budding American textile industry called for skilled mechanics, and as these could not be imported from abroad they had to be developed at home. Besides that, the scarcity of mechanics skilled in the use of hand-tools acted as a spur to the invention of machine-tools, and the Parliamentary embargo upon mechanics, instead of assuring England’s monopoly of manufacturing, had the very opposite effect.
America was forced to build its own machinery and develop its own tool builders. As a result, before long, “Yankee genius” came to be a by-word the world over, and, in time, American machinery began to find its way into English markets.
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ELI WHITNEY AND THE INTERCHANGEABLE-PARTS SYSTEM
We are accustomed to think of Eli Whitney only in connection with the cotton-gin, forgetting that he was one of the pioneers in the building of machine-tools and that he established what became known in England as the “American system of manufacture.” Whitney’s father, who was a farmer, had a workshop where farm implements were repaired. The shop was fairly well equipped with tools, and young Eli learned how to use them with remarkable skill.
The story of how Eli Whitney went down South after graduating from Yale University, to serve as a tutor in a rich Southern planter’s family; how he chanced to learn of the difficulty the planters experienced there of separating cotton-fibre from the tenacious seed, how he invented a machine in which the cotton-seeds were held back by a grating while a set of circular saws reached in between the bars and pulled the fibre off the seeds—all this and more about cotton is told under “Cotton: from Plantation to Loom,” in this book.
What concerns us most at the moment is that the cotton-gin came just after Slater had established the first cotton-spinning mill in America, and thus an industry was started which was largely responsible for the development of machine-tools in America.
We can pass over the trouble that Whitney had in maintaining his patent rights in the cotton-gin, and pick up his history again at the point where, discouraged over his fight with persistent infringers and despairing of the outcome of his legal battles, he tried his hand at an entirely new venture. Possibly it was these very battles that turned his thoughts from the peaceful cotton-fields to the field of war.
At any rate, in 1798 he obtained a contract from the United States Government to manufacture 15,000 muskets. Whitney had no experience in making guns, but he was sure that he could make them successfully and was bold enough to try, even though failure meant a heavy money penalty. But the interesting thing about this contract was that Whitney undertook to manufacture these muskets in an entirely new way.
There is a big difference between building a thing and manfacturing it. We build yachts and houses, but we manufacture automobiles and sewing-machines. No two yachts are exactly alike. They are built to order, and, even where the same plans are used, there are slight differences. The parts must be trimmed, sawed, planed, filed, or drilled as they are put together.
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Sewing-machines, on the other hand, are turned out by the thousands, all exactly alike. The parts are made in large quantities. Wheels, shafts, levers, pins, plates are all gauged with such precision that they do not vary in important measurements by one or two ten-thousandth parts of an inch, so that when it comes to assembling the machine, no filing or scraping is required.
Any wheel out of ten thousand will fit perfectly on any one of ten thousand shafts. The work of manufacturing the machine is divided into hundreds of different tasks. One mechanic will do nothing but turn out foot-plates, another will do nothing but turn out studs.
This is what we mean by manufacturing in these days. “Quantity production” is the designation used in many industries.
In Whitney’s time no such system was known, because hand-work was not sufficiently accurate and such few machine-tools as were in use did not operate with the necessary precision. Besides that, there were not many standard articles that had to be turned out in large enough quantities to make such a system pay.
Even muskets which should have been of standard size and were needed by the tens of thousands were “built” rather than “manufactured.” Trained gunsmiths who had acquired their skill by years of labor in the shop, built the entire musket from barrel to flint-lock, filing, grinding, and drilling the parts to fit as they went along.
Consequently, there were no two muskets exactly alike. Hence, if any part of a musket was injured or broken in service it had to go back to the machine-shop, where a skilled gunsmith forged a new piece and shaped it to take the place of the damaged part.
Such a thing as having on hand a quantity of stock parts which could be slipped into place without filing or fitting was something unheard of, and in time of war gunsmiths could not begin to keep pace with the damage done on the field of battle. Thousands of broken muskets could not be fired for lack of ready repair parts.
At the time of the War of 1812, the British Government had over 200,000 muskets either partly finished or awaiting repairs.
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When Whitney obtained his contract from the government there was an unfortunate shortage of skilled mechanics in this country, owing to the objectionable policy of the British Parliament; and since it took years to train an all-around mechanic, Whitney had to depend upon machines.
By perfecting his machines he believed that he could avoid the slight differences that invariably show themselves in hand-work, and make the parts with watch-like precision. He planned to have his men specialize on different parts of the gun and make these parts so accurately that they would be interchangeable and would not require an experienced gunsmith to fit them together into a finished musket.
Whitney built a mill at a spot near New Haven, now known as Whitneyville. The mill was located by a stream from which he obtained the power to drive his machinery.
For nearly two years not a musket was turned out. Those who visited the shop found him busy building machinery instead of guns. He was organizing his system and building “machines for rolling, floating, boring, grinding, and polishing.” Whitney outlined his plan to some English and French ordnance officers, explaining the advantages of having interchangeable parts in stock in time of war. They laughed at him. A Frenchman had tried to do the same thing fifteen years previously, but his plan had not met with success.
As time went by and the government officials watched Whitney build his equipment without turning out a single musket, they began to grow uneasy. Unruffled by criticism and with his accustomed determination, the inventor kept steadily at work. According to his contract he must begin to make deliveries inside of two years, but the time was nearly up and still not a single musket had come out of his shop.
Then one day Whitney turned up at the office of the Secretary of War with an assortment of miscellaneous pieces which he arranged in piles. Each pile consisted of ten pieces, all the pieces in a pile exactly alike.
Then to the astonishment of every one present he picked out a piece at random from each pile, fitted the pieces together and produced a complete and perfectly working musket. Again he repeated the performance and handed out a second perfect musket. Whitney kept on until all the pieces had been used up and he had handed out ten complete muskets for inspection.
The fame of this exploit spread over the civilized world. But gunmakers of Europe were slow to adopt what they called the “American system.” It was difficult for them to get out of the rut in which they and their forefathers had been travelling. In this country, however, Whitney’s system was tried in other lines of manufacture with great success.
HOW CHAUNCEY JEROME FOOLED THE BRITISH CUSTOMS
Forty years after Whitney showed the way, a Connecticut Yankee, Chauncey Jerome, hit upon the idea of making brass clocks with interchangeable parts. Before that, clocks were largely made of wood, and the cheapest movements cost five dollars, even when made by machinery; hand-made clock movements brought as much as fifty dollars.
But Jerome, by using the interchangeable system of manufacture, turned out one-day brass clocks that cost less than fifty cents each. To produce them at any such price he had to make them in large quantities, and soon the markets were flooded with Jerome’s cheap timepieces.
They were peddled all over New England and the neighboring States, and Jerome began to wonder where he was going to dispose of the ticking stream that poured out of his factory. Then it occurred to him that England ought to offer a good market for his wares. He made arrangements with a British dealer and sent over a shipment of clocks in 1842.
The British Government placed a duty on time-pieces in those days, and when Jerome’s cheap clocks arrived, the custom’s authorities thought he had put a low price on them merely to reduce the amount of duty he would have to pay.
They had an ingenious way of punishing any one who undervalued his goods, which consisted in buying the goods at the invoice price.
Much to Jerome’s surprise a letter came to him from the British Customhouse informing him that his clocks had been confiscated and enclosing a draft for the full invoice valuation of the goods. But the punishment sat very lightly on Jerome’s shoulders. He was just as willing to sell to the British Government as to any one else, particularly as he did not have to wait for his money, and did not have to pay any agent’s fee.
He sent over a larger shipment of clocks and awaited results. Sure enough, in due course a second draft came back from the British Government. Jerome roared with laughter. The next time he sent over a whole ship-load of clocks. This was too much for the British Customs authorities. It dawned on them that the Yankee clockmaker could really make cheap clocks, and they let the shipment in at his invoice price without any further trouble.
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|Chauncey’s brother, Noble Jerome submitted this clock patent in 1839.|
WHITNEY INVENTS THE JIG
Whitney was so hard put to it for skilled workmen that he had to invent machines that would serve as human arms and fingers. One of his most important devices, found in every machine-shop, rejoices in the frivolous name of the “jig.”
Suppose a plate is to be drilled with ten holes which must register exactly with ten holes in another part. It would be a tedious matter to measure them off and lay out their positions with any great degree of precision. Only an experienced mechanic could be trusted to do the work, and Whitney had all too few such mechanics.
If ten thousand such pieces were to be drilled the work would take an eternity, and even if the same man laid out the positions of the holes in each case, there would be certain slight variations in the different pieces, because it is impossible for a man to avoid slight errors.
A jig makes errors impossible. A box is made into which the plates are fitted. Over the box is a lid or frame in which holes are drilled by a skilled workman at exactly the required spacing. After that no further skill is required. One after the other the plates are fitted into the box and drilled through the holes in the lid without stopping for measurement, and in all, the pieces the holes must be spaced exactly alike.
It was in this way that Whitney obtained machine-like precision, even though he had to do largely without machines and had scarcely any trained mechanics. Whether he invented the jig or not is a disputed question, but he was certainly one of the earliest users of it. To-day we cannot get along without the jig. It is a holder for the piece of work and at the same time a guide for the tools that are to be used on it. It helps us properly to set up a piece of work in a machine.
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WHITNEY AND THE MILLING-MACHINE
One would suppose that the inventor who gave us the cotton-gin and who founded the “American system” of manufacture had done about enough for one man; but there was one other invention of Whitney’s which is of the utmost importance in machine-work.
Most of the standard machine-tools had been invented either before or at about the time that Whitney turned his thoughts to gun-manufacture. In all machine-tools either the work is fed to the tool or the tool to the work. In a lathe the work is revolved against the tool. In the planer the work is fastened to a table and slides against the tool.
The boring-mill is a cross between a lathe and a planer, the tool being held as in a planer and the work fastened to a table, but in such a way that it revolves against the tool as in a lathe.
Moreover, the work revolves on a vertical axis instead of a horizontal axis. In a shaper we have the reverse of a planer—the work stands still, while the tool moves back and forth over it. In none of these machines does the tool rotate. But when we come to the drill we find the tool turning and feeding itself into the work while the latter remains stationary.
Now it remained for Whitney to invent a milling-machine in which the tool rotates while the work is fed against it. To-day no machine-shop is complete without milling-machines. Of course they have been vastly improved. If Eli Whitney could visit a modern busy machine-shop and see a battery of “universal millers” at work, he would probably not recognize in these marvellous machines the grandchildren of the simple little milling-machine which he built about 1818. Whitney’s original milling-machine may be seen in the Mason Laboratory at Yale University.
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|ELI WHITNEY MILLING MACHINE.|
BLANCHARD’S GUN-STOCK LATHE
The making of muskets, pistols, rifles, and revolvers played a very important part in the history of American machine-tools. This is perfectly natural when we consider that firearms were really the first machines that had to be built with great precision and in large quantities.
One of the men who helped materially in the manufacture of muskets was Thomas Blanchard. People who knew him as a boy never thought he would amount to much because he stammered badly and was very timid, but he had a mechanical turn of mind and was always tinkering at something.
When he was but eighteen years old he began working on a machine that would make tacks. It took him six years to perfect his invention, but then he had a machine that would turn out two hundred tacks per minute. He sold his patent for $5,000, which was considered a very handsome price, and continued to devote his inventive genius to various problems and produced many labor-saving devices.
One day he overheard a couple of workmen in the Springfield Armory talking about his inventions and complaining that they were robbing mechanics of their jobs. One of them said: “Well, I don’t care, he can’t take away my job. He can’t invent a machine that will turn out gun-stocks.”
Blanchard took that as a challenge. Shortly after he build a “gun-stocking” lathe. Instead of a fixed tool he used a rotary cutter. The roughed-out wooden block was mounted to turn in a swinging frame which also carried a finished stock as a pattern.
As the pattern turned against a fixed wheel it moved the wooden block in and out against the cutter, varying the depth of cut so as to turn out an exact duplicate of the gun-stock.
That was the first “profile lathe,” as we call it, and it was the forerunner of many ingenious wood-working machine-tools. The original machine, built in 1818, is still on exhibition in the Springfield Armory.
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|BLANCHARD’S PROFILE LATHE. Original form of the Blanchard profile lathe for turning gun-stocks or shoe-lasts. It is preserved in the United States National Museum, instead of the customary fixed tool Blanchard used a rotary cutter. The rough-hewn wood block was mounted to turn in a swinging frame, which also carried a finished gun-stock or shoe-last as pattern to be followed. As the pattern turned against a fixed wheel it moved the wooden block in and out against the Cutter, varying the depth of cut so as to turn out exact duplicates of the gun-stock, shoe-last, or other eccentric form. Courtesy of the U. S. National Museum.|
Another leading figure in the history of American machine-tools was Richard S. Lawrence. When he was only nine years old, his father’s death forced him to give up schooling and work on a farm. At the age of fifteen he found a job in a woodworking-shop. There was a gun-shop in the basement of the building, and here young Lawrence spent all his spare hours until he became an expert gunmaker.
He was twenty-one years of age when an incident occurred that gave him a real start in life. He was visiting a Doctor Story in Windsor. The doctor had a rifle that he highly prized but which at the time was sadly in need of repairs. Lawrence offered to repair the gun and fit it with a peep-sight. The doctor was very reluctant to give his permission, but he was so greatly interested in the peep-sight, which was something he had heard of but had never seen, that he finally consented.
The next day Lawrence took the gun all apart, cleaned it thoroughly, leaded out the barrel, forged a peep-sight, and fitted it to the gun. The doctor on his return that night was enthusiastic in his praise of the job. Most of the next day Lawrence spent in trying out the gun and adjusting the sights.
When the doctor returned from his daily visits he went out to witness the shooting qualities of the gun. He paced off twelve rods from a maple-tree in which a three-quarter-inch auger-hole had been bored for drawing off sap. This was to be the target. Lawrence lay down on the ground, took careful aim, and fired.
The doctor, who was tending target, told him he had missed. Again Lawrence fired with the same result. The doctor became irritated and declared that his rifle was spoiled. When Lawrence offered to make the gun all right he would not consent to any further tampering with his rifle. As the gun was loaded Lawrence said he would take one more shot.
After he pulled the trigger he went up to the tree to examine it for himself, and to the great astonishment of the doctor he dug out the three bullets from the auger-hole. Doctor Story had never heard of such accurate marksmanship, and he was delighted with the peep-sight.
He insisted that Lawrence go down with him to show off his peep-sight to N. Kendall & Co. at Windsor Prison, where they were making guns. They employed a number of freemen as well as prisoners, and here Lawrence obtained a two-years’ job at $100 per year and board. In six months he had risen to the position of foreman of one of the shops, and as such, acted as a turnkey and had a section of the prisoners to lock up.
Six years later (1844) Lawrence formed a partnership with his former employer, Kendall, and another man, S. E. Robbins, and started in to make rifles for the government. They had a contract to finish 10,000 rifles in three years’ time. It was a notorious fact that gun contracts were never finished on time, but Lawrence determined that this was to be a grand exception.
They had nothing to start with, no machinery, and not even a building in which to do the work. However, Lawrence started in with a vim, and much to the astonishment of the War Department the contract was completed within a year and a half.
It was this concern which, in 1857, exhibited a set of rifles built on the interchangeable system at the Exposition in London. British ordnance officers were greatly interested in the exhibit and sent a commission to investigate the “American system” of manufacture.
Although they had learned of Whitney’s work half a century before, they had not really awakened to the importance of this method of manufacture. In a few years’ time the “American system” was installed not only in England but in the leading gun-factories of Europe.
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THE INVENTION OF THE TURRET-LATHE
It was from th works of Robbins and Lawrence that there came, in 1854, the most important improvement in lathes since the day when Maudslay and David Wilkinson invented the slide-rest.
Up to that time lathes were fitted with a single tool, but Robbins and Lawrence put out a lathe which was fitted with a revolving tool-holder or “turret” in which a number of tools were fitted. These were set so that after one tool completed its work the turret could be turned to bring the next tool into operation. And so, without taking time to change tools and set them, a whole series of operations could be performed.
There were two men in the plant to whom credit for the turret-lathe belongs—Henry D. Stone and Frederick W. Howe, though it is quite probable that Lawrence himself had much to do with developing this machine. Of course, when any really important invention is brought out, men who claim to be prior inventors turn up. As a matter of fact, a lathe with a turret was built by Stephen Fitch in 1845, but the Robbins and Lawrence machine was the first to be manufactured and put on the market.
This was the forerunner of those marvellous automatic screw-machines that deem to work with human intelligence, bringing one tool after another into play until the piece of work is completed, and then feeding forth another piece of rough stock to be operated upon. There is no machine in our shops that turns out so much and so great a variety of work as the automatic screw-machine.
In the first turret-lathes the turret had to be turned by hand; then came the machine which took care of itself, automatically bringing the tools into play as needed. The man who did most to make the turret-lathe automatic was Christopher
M. Spencer, and it is interesting to note that he also was a crack shot with the rifle and made his start as a gurmaker.
Just before the Civil War broke out he obtained a patent on a repeating rifle, and he supplied the Federal armies with 200,000 of the type. At the close of the war he invented a machine for turning out spools for sewing-machines, and then was fired with the ambitious scheme of building a machine that would make machine screws automatically.
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Of course he had to use a turret-lathe for this work, but he fitted the lathe with cams, to feed each tool into the work, withdraw it after it had finished its cut, and turn the turret to present the next tool to the work. A cam ought to be familiar to any one who has ever driven an automobile. The cams of an automobile are on a shaft, and they automatically lift the engine valves at the right time.
The most important improvement in Spencer’s machine was the use of these cams, which he built in an ingenious way. Of course, for each job a special form of cam would be required; so Spencer made his cams in the form of a plain cylinder on which he fastened strips of metal that were adjustable for different settings.
Spencer applied for a patent on his machine, but unfortunately his patent attorney did not understand or appreciate the importance of these adjustable cams and did not cover them in his claims, so that Spencer failed to get patent protection on the most important part of his invention.
SINGLE-SPINDLE AND MULTIPLE-SPINDLE LATHES
We cannot go on detailing all the improvements in “automatics” down to the present day, nor mention all the inventors who played a part in their development. The most important steps were the provision of a hollow spindle through which the stock is automatically fed to the tools, and the multiple-spindle lathe which will be explained presently.
In the single-spindle machine, the bar of steel, out of which the pieces are to be made, is placed in the hollow spindle and is seized by what is called a “chuck,” with a portion of the stock projecting from the faceplate. The tools that are to work on the end of the piece are mounted in the turret, while those that work on the side of the piece are mounted in cross slides working from opposite sides of the piece.
One after another the tools come into play until the piece is completed; then one of the side tools cuts it off the stock and it drops into a hopper. At the same instant the jaws of the chuck open and the stock bar or rod is moved forward to present a fresh length for the tools to operate upon.
Except for setting the tools in the first place and seeing that there is plenty of lubricant flowing over them, the machine requires practically no attention and will keep on turning out finished pieces all day long, if it is kept supplied with stock to work upon. One man can therefore take care of a number of machines.
This would seem to be perfection, but mechanical engineers were not content. The machine was not doing as much work as it should because, while one of the tools carried by the turret was busy, all the others had to stand idle until their turn came.
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|OPERATING A MODERN SIMPLE LATHE.|
This led to the invention of the multiple-spindle lathe. In such a lathe, four hollow spindles are geared together so that they all turn at the same time. Four bars of stock are fed through these spindles, and the turret, with its four tools, is mounted on a horizontal shaft, so that each tool is opposite a spindle.
All the tools are working simultaneously, but each is doing its own task. One may be facing, another drilling, the third reaming, and the fourth counter-sinking. At the same time the side tools are forming, knurling, or thread-rolling, finishing, and finally severing the pieces one after the other.
The output of such a machine is four times that of the single-spindle lathe.
There have been countless improvements in the automatic lathe until it stands to-day the most nearly automatic tool in the machine-shop, and its perfection, with that of the milling-machine, has placed American machine-work well in advance of the whole world. A pen-picture of these modern “automatics” has been drawn by the editor of this volume in an article from which the following has been abstracted:
“Extraordinarily human are these automatics. . . . Would you like to see one in action? If you were to work on a piece of steel, you would first mark off the length of material that you want. A bolt machine does that. Then it presents the marked bar to a cutting tool. The first thing that the tool does is to feel the bar. ‘Oh,’ it says, ‘you’re too thick,’ and so it proceeds to peel off the outside by just the right amount.
“Then that peeler backs off all by itself, and the bar is revolved and brought in line with a second tool. Now that tool’s business is to cut a groove in the bolt and nothing else. So it gouges out the groove. ‘That will do for you,’ says the groover, and backs away; whereupon the bar is turned by a bloodless steel arm into line with a third tool.
“What does that do? It comes out and bores a hole in the end of the bolt. While it does so the first three tools attack fresh bars of steel. When the borer mechanically decides that the hole is deep enough it withdraws itself. And so the bar is presented to tool after tool.
“Finally the last cutter is reached. It notices, as it were, that the bolt is about finished, and so it proceeds to cut the bar off. Just as the bolt is ready to fall, metal fingers reach out and clutch it. ‘You’re not done yet,’ says the machine. ‘You need a hole for a pin.’ And the fingers carry the bolt to a little drill, which bores a transverse hole for the pin.
“The job is done. The machine knows it and drops the finished bolt into the basket.”
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|THIRTY-SIX-INCH LATHE-TURNING PROPELLOR-SHAFTS AT THE TACONY ORDNANCE WORKS.|
The grinding-machine is another tool that was strictly an American invention. In order to finish the needles and foot-bars of a certain type of sewing-machine, Joseph R. Brown hit upon the scheme of using an emery-wheel on a lathe in place of the ordinary tool. With this he was able to finish the pieces to an exact measurement after they had been hardened.
This machine was put on the market in 1865. Out of it grew the universal grinder, which plays an important part in the machine-shops of to-day. Brown himself perfected a universal grinder, which was exhibited at the Centennial Exposition in Philadelphia, but he died just before the machine was put on the market in the summer of 1876.
JOSEPH BROWN’S UNIVERSAL MILLER
Brown was also a pioneer in other types of machine-tools. The machines that he was manufacturing called for very careful and accurate work, and it was in his shop that the modern micrometer was developed, with which it is possible to measure down to the thousandth part of an inch.
In Eli Whitney’s day certain parts of a gun were made with such accuracy that they varied by less than the thickness of two sheets of paper, or say six one-thousandths of an inch. Brown in his sewing-machine worked to one one-thousandth of an inch. To-day, on certain classes of work, the parts are gauged to one ten-thousandth of an inch, and it is common practice to work to half a thousandth of an inch.
It was Brown who invented the universal milling-machine; that is, one in which the work could be revolved and fed crosswise and longitudinally. Frederick W. Howe suggested the machine. Howe saw some men making twist drills by the slow method of filing spiral grooves in a fine steel rod.
It occurred to him that the work could be done more accurately and speedily by machine; so he discussed the matter with Brown, who was beginning to use twist drills in the manufacture of sewing-machines. Acting on Howe’s hint he brought out the first universal milling-machine in 1862.
Brown also invented the first machine for cutting gears. We cannot attempt to describe all the developments in gear-cutting machinery that followed. The automatic machines for cutting bevel-gears are too complicated to be explained in this brief chapter, particularly those which cut bevel-gears with spiral teeth.
As was stated in the early part of this chapter, it was the textile industry and England’s effort to keep the secrets of machine-work to herself that first spurred Americans to develop their own line of machine-tools; then it was the large government orders for firearms and the lack of skilled mechanics that brought about the interchangeable system of manufacture; after that the manufacture of clocks and watches and of sewing-machines did much to stimulate the invention of new machines and put us ahead of all other nations in machine-work.
But the greatest stimulus of all came with the beginning of the present century, when America took hold of the automobile in earnest. It was not long before we outdistanced European engineers. We paid our workmen much higher wages than they did on the other side of the Atlantic, but because of our wonderful automatic machinery we could turn out automobiles of such high quality and so cheaply that they could be sold in Europe at a lower price than European manufacturers could afford to make them.
The “American system” of manufacture is now carried out to the smallest details. Special machines are built to cut down expense and turn out the various parts in large quantities.
Machines are fitted with gangs of tools that work simultaneously. There are drills with many spindles all working at the same time, so that all the holes in a piece of work may be properly spaced and drilled in a single operation.
Machines are set in rows so that as soon as one machine has completed its task the work passes on to the next machine in line; there is a steady procession to the assembly-room, where the parts are put together and the finished machine turned out.
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|BECKER CONTINUOUS MILLING-MACHINE, MILLING ALL FOUR FALLS OF AUTOMOBILE CONNECTING—RODS AT ONE OPERATION. Courtesy of the Packard Motor Co.|
TAYLOR’S REVOLUTIONARY METHODS
But the story of American machine-tools is not complete without an account of the work of Frederick W. Taylor. In fact, Taylor caused a veritable revolution in the industry. It was at the Paris Exposition in 1900 that European engineers first came in touch with his work.
There they saw American machine-tools working so fast and taking such deep cuts that the chips and shavings which were turned off were at blue heat and the tools that did the cutting were red hot. Despite this heat the tools kept their temper and did not lose their cutting edge. This astonishing exhibit was the culmination of twenty years of experiment in the hands of a man of persistent and unflagging zeal.
Taylor was the father of what is called “efficiency engineering” or “scientific management.” When he entered the Bethlehem Steel Works in 1880 he was distressed at the inefficiency of the workmen at that plant. It seemed to him that they did not begin to turn out as much work as they should; so he undertook to speed them up.
But the men did not take kindly to his suggestions. Who was he to tell them how much work they could turn out? What did this young man know about the output of a machine?
Taylor realized that before he could make any progress he must study machine-tools and find out just what they were capable of doing. Strangely enough this matter had not been thoroughly studied before. No one could tell him what was the best cutting speed for different tools and how deep a cut they should make.
To be sure, there were certain standards that had been handed down from one mechanic to another, but Taylor was not satisfied that these were the very best. He was a man of the type that had to try things out for himself. He was not content with the mere “say so” of another.
Unless a statement was proved by searching tests he would not accept it. So he began to experiment with different machine-tools, trying various speeds and depths of cut, and various shapes of tools. It has been estimated that in the course of his experiments he converted 800,000 pounds of steel into chips and shavings. The experiment lasted twenty-six years and cost over $200,000.
The results of this searching investigation were revolutionary. He found that the established practice was all wrong. Mechanics had shown a preference for a fine cut at high speed, but Taylor proved that a heavy, coarse cut at low speed was more efficient.
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|SHARP BIT—HIGH-SPEED. Taylor’s experiments refuted such myths.|
It had been supposed that a tool with a diamond-shaped point was to be preferred to a round-nosed tool, but Taylor’s research proved the contrary. All the old traditions were questioned and in many cases proved fallacious. He even questioned the advantage of pouring oil on the tools and tried water instead.
The best tool steel of the day was known as “self-hardening steel,” and he was warned by the manufacturers that he must not use water on it. But Taylor would not accept their word for it. In place of oil he played a solution of kitchen soda on the cutting tools, and to his great delight found that he could increase the speed of cutting by over thirty per cent.
Then he began investigating various alloys of steel. Associated with him in this work was Maunsel White, and together they hit upon an alloy of chromium and tungsten, which showed a 300 per cent. improvement over the self-hardened steel. Later vanadium was added and still better results were obtained.
Needless to say, Taylor’s researches had a revolutionary effect on the industry. Machines had to be redesigned to run at higher speeds and the output of the machine-shops was doubled and even trebled. His discoveries, coming just at the time when the automobile industry was beginning to get its stride, gave American machine-tools another impetus, which sent them far ahead of European rivals.
Like textile machinery, shoe-making machinery, type-casting machinery, electric lamps, and many other contrivances that play an ever-increasing part in our daily lives, machine-tools are no longer invented by Wilkinsons, Bramahs, Maudslays, and Whitneys.
Great companies maintain staffs of hired inventors—men who design the most remarkable machines for specific purposes and do nothing else year in and year out. To them we owe the wonderful multiple-drill presses which bore eighty-seven holes at once in an automobile part, the machines that pare off the tops of a score of cylinders at once as if the steel were so much butter, the devices for reaming out several cylinders at a time—devices that would make Watt stare if he could but see them—and machines that do everything that lies within the power of the human hand.
They are really automatons, these machines, for they simply mimic human motions. Each of them does the work of a score, even of a hundred men. They are characteristically American in the sense that they were invented to solve a distinctly American problem—the problem of producing vast quantities of metal articles cheaply in the face of high labor costs.
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|A MODERN MULTIPLE DRILL. Machines of this type drill as many as eighty-one holes at one operation in a modern automobile factory; without them the modern cheap automobile would be an impossibility. Courtesy of the Packard Motor Co.|
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|A GERMAN LATHE MADE ABOUT 1750 FOR ORNAMENTAL TURNING. This is the bench portion of the lathe which was driven from a pulley on an overhead shaft carrying a fly-wheel which received its motion from a cord connected with a treadle in the base. The shaft was supported in an adjustable bearing-box, carried by a frame-box secured to a massive wooden cabinet with which the lathe was combined, but the whole machine was covered with a mass of rococo decoration by which the frame was concealed.
The art of rose-turning, or producing waved lines in the lathe, appears to have originated about 1650, and reached the height of its popularity about the middle of the eighteenth century, when all kinds of articles were ornamented in this way. After a revival about 1800 the art declined, and is now applied only to such articles as the backs of watch-cases. Courtesy of the South Kensington Museum, London.