Popular Science Monthly/Volume 38/March 1891/The Development of American Industries Since Columbus: Iron and Steel Industry IV
IV. IRON-WORKING WITH MACHINE TOOLS.
By WILLIAM F. DURFEE, Engineer.
WHILE the builders and operators of blast-furnaces were achieving such splendid results as have been described, the owners, managers, and engineers of rolling-mills were not idle. At the very beginning of rolling-mill construction in America the disposition to make improvements in known methods and to invent entirely new mechanisms and processes was promptly manifested. Even in the first mill of which we have any authentic account the rolls and heating furnaces w T ere decided improvements on previous practice; and from that day to the present time the best American rolling-mill practice has been characterized by originality of idea and perfection of construction. Fig. 41 is a longitudinal section
Fig. 41. Longitudinal Section of a Heating Furnace.
of a heating furnace in which coal was used as a fuel. The "fire-box" with its grate is seen at the left; to the right of this is the "bridge-wall" separating the "heating chamber" from the "fire-box." The bottom, a, of the "heating chamber" is made of silicious sand. On the extreme right of the furnace is seen the "cinder-tap," b, for the discharge of any liquid "cinder" made during the operation of heating the iron; near this "cinder-tap" is the lower part of the "chimney-flue." The iron to be heated was placed upon the sand bottom a, and the flame from the fuel in the fire-box passed over it, not only heating the metal directly but the roof and side walls and bottom of the heating chamber also, which, as was said when this form of furnace was first introduced, "reverberated" more heat upon the metal; hence the name "reverberatory furnace" often applied to such structures. The walls, roof, fire-bridge, and chimney-flue are built of very refractory
Fig. 42.—Lever Shears for cutting Bar Iron.
brick, called "fire-brick." Furnaces of similar construction (sometimes called "air-furnaces") are used for melting pig iron for making heavy castings; but in these furnaces, instead of a
Fig. 43.—Front Elevation of Boiler-plate Shears.
sand bottom of the form shown at a, the furnace at this part has its bottom depressed so as to form a basin to hold the fluid metal. Thirty to fifty tons of metal are sometimes melted in such furnaces.
Among the machine tools used in rolling-mills those called by the general name of "shears" occupy an important place; these tools vary greatly in form and constructive detail, and are designed with especial reference to the work for which each is intended. Fig. 42 is an illustration of a common form of lever shear for cutting bar iron. The cutting knives are located at a b, and when the eccentric d is revolved by the rotation of the shaft on
Fig. 44.—End View and Transverse Section of Boiler-plate Shears.
which it is placed, it lifts the long arm of the lever c and causes the upper knife b to cut or "shear" past the lower knife a, thus dividing any bar of iron that may have been between the two knives.
Fig. 43 is a front elevation of a "shear" for cutting boiler plate, and Fig. 44 is an end view and transverse section of the same machine.
In Fig. 43 at g is seen a large mass of cast iron, to the lower edge of which is attached a long, inclined cutting knife, which is designed to operate in conjunction with a straight knife attached to the frame of the machine (the relative positions of the two knives are shown in Fig. 44 at h and i) to shear any sheet metal placed between them. The "gate" g, to which the upper knife is attached, has a vertical reciprocating motion communicated to it by means of the eccentrics e and the rods f, and, as the upper knife h has an inclined edge, the shearing will commence on the right and gradually extend to the left as the "gate" g descends. Shears of this description have been made to cut ten feet in length at one movement of the "gate" g. Such tools are very heavily geared, and are usually driven by a special steam-engine.
The first iron-works in the United States in which iron was puddled and rolled into bars was built by Colonel Isaac Meason, in 1816 and 1817, at Plumsock, on Redstone Creek, between Connellsville and Brownsville, in Fayette County, Pennsylvania. Swank tells us that "Thomas C. Lewis was the chief engineer in the erection of the mill, and George Lewis, his brother, was the turner and roller. They were Welshmen."
We have no exact description of the machinery of this mill, but we are told that, in addition to the rolls, "the mill contained two puddling-furnaces, one refinery, one heating furnace, and one tilt-hammer"; and that "the iron was refined by blast and then puddled." This mill produced "bars of all sizes, and hoops for cutting into nails." The mill was started on September 15, 1817,
Fig. 45.—Train of Rolls for Square and Flat Bar Iron (1817).
and continued in operation until 1824, when it was destroyed by a flood, and never rebuilt. Although we have no details of the roll train used in this mill, it is fair to assume that, as its designers were Welshmen, they followed as closely as possible the practice with which they were familiar. Fig. 45 is an elevation of a train of rolls such as was in common use in England and Wales at the beginning of this century for rolling square and flat bar iron. In this figure, a is the foundation sill of the mill. This sill rested upon some heavy frames of timber, which in turn were supported by a pair of bottom sills; the "stands" or "housings" in which the rolls turned were placed directly on the timber sills, a, and secured by long bolts that passed through the lower sills. At this period, and for some years thereafter, in fact, timber foundations for rolling-mills were considered absolutely necessary, in order to impart a certain degree of elasticity to the machinery; and when we consider the rude way in which all machinery was constructed at that time it is not improbable that some elasticity was essential to its operation.
In Fig. 45, at b, are seen the "pinions," which were a strong pair of toothed wheels of the same diameter which served to insure an equality of rotation in the top and bottom rolls of the mill. These pinions were connected with the rolls by the spindles e e. The rolls at f could be used to make square bars, or to "rough down" the iron preparatory to passing it through the rolls g, which were intended for flat bars of various widths and thicknesses. This construction of rolling-mill is what is known as a "two-high train," and is so called from the fact that each pair of "stands" or "housings" contains but two rolls placed one above the other. It is obvious that, as the rolls revolve constantly in one direction, the iron, after passing through one of the grooves, would have to be returned over the "top roll" before it could be passed through the next groove for further reduction in section and extension in length. It is also evident that such a method of working wasted half the time and a large amount of the heat of the metal; but, notwithstanding these and other quite as serious objections to this form of mill, it continued in use until a very recent period, and it is possible that even now there may be found, in localities uninfluenced by the spirit of progress, some examples of this rotary antiquity still in operation.
Up to the year 1844 the rolling-mills of the United States produced little else than bar iron, hoops, and nail plates; all the early railroads had been equipped with strap rail (flat bar iron provided with "countersunk" holes at proper intervals, through which passed the spikes by which the "rail" was secured to longitudinal stringers of wood), which could easily be rolled in this country; or with imported T or H rails. The T rail is of American origin, it having been invented by Robert L. Stevens, President and Engineer of the Camden and Amboy Railroad. Mr. Stevens had the first of these rails rolled at Dowlais Iron Works, in Wales, and they were laid in the track of the Camden and Amboy Railroad in 1831-'32.
The first heavy railroad iron of America manufactured was made at the Mount Savage Rolling Mill, in Alleghany County, Md. This mill was designed expressly for this class of work. The first rail rolled was what is known as the U rail, and for this the Franklin Institute awarded its silver medal in October, 1844. Such was the demand for railroad iron that other mills for its
Fig. 46.—"Grooves" in Rolls of "Two-high Train" for rolling Rails (1850).
production were rapidly constructed. The Montour Rolling Mill at Danville, Pa., was built in 1845, and in October of that year turned out the first T rails made in America. On the 6th of May, 1846, the Boston Rolling Mill made its first T rail, and on the 19th of June, 1844, the rolling-mill of Cooper & Hewitt, at Trenton, N. J., commenced rolling rails. About the 1st of September, 1846, the New England Iron Company, at Providence, R. I., made their first rail. Railroad iron was rolled at Phœnixville, Pa., in November, 1846, and about the same time at the Great Western Iron Works at Brady's Bend, and at the Lackawanna Iron Works at Scranton, Pa. Rails were also rolled, early in 1847, at the Bay State Iron Works in Massachusetts; in January, 1848, at the Rough-and-Ready Rolling Mill at Danville, Pa., and in the same year at Safe Harbor, Pa., and at Avalon, Md. Some few other mills rolled rails prior to 1850, but at the beginning of that year, owing to the severity of foreign competition, only two out of the fifteen rail mills in this country were in operation.
The rail trains in all the above-named mills were "two high" (that is, one roll above another in pairs), and a general idea of the forms of the several "grooves" or "passes" in the rolls used in a two-high rail train may be derived from an inspection of Fig. 46. A two-high rail train comprised two pairs of rolls, one pair being called the "roughing rolls" and the other "the finishing rolls." Their general relations to each other were quite similar to the rolls of the "bar-mill," shown in Fig. 45.
In Fig. 46, A represents the five "passes" in the "roughing rolls," and B the six in the "finishing rolls." The progress of the metal was from left to right, through each of the "passes" in each roll successively. We have no space to describe in detail the peculiar features of the three-high train; but its more prominent peculiarity consisted in the fact that there were three rolls in each pair of housings, and that the "rail," or other form of bar being rolled, was passed between the middle and "bottom roll" and returned between the middle and "top roll," and received compression and extension at each "pass."Fig. 47 gives a very life-like view of the interior of a rollingmill as constructed about the year 1855. It will be noted that the "trains of rolls" are all "two-high," and that the building is evidently constructed of wood; and the large number of men employed is also a conspicuous feature. To those at all familiar
Fig. 47.—Interior of a Rolling-Mill (1855).
with such establishments, it will require but a slight effort of the imagination to impart to the picture all the attributes of real life; and to fill the sooty air with the hissing of steam, the jigging jingle of coupling-boxes and spindles, and the groaning of rolls, among which sounds are injected the resounding blows of a steam hammer, answered by the clattering scream of a "cutting-off saw," mingled with the hum of revolving wheels, and scores of minor sounds and reverberations; over all, the lurid glare of furnaces and hot iron, amid which the busy workmen move in orderly activity at the work in hand; the whole making a scene in which the strength of man and iron, the energy of fuel and fire, and the power of steam and machinery are combined as in no other industry on the surface of the round world. The rolls for making heavy bar iron of a rectangular section, hitherto described, have been provided with a number of "grooves" or "passes" of varying dimensions suited to the sizes of the bars required; but the manifest objection to this very common arrangement is that, in order to be able to produce a large variety of bars, a great number of rolls must be kept in stock. But the mill represented in Fig. 48 is so contrived that it will roll an almost unlimited number of sizes of rectangular bars by the use of a combination of four plain cylindrical rolls, two of which revolve on horizontal axes, and the other two on vertical ones. In the figure, for the purpose of clearness, the driving mechanism of the vertical rolls is omitted. Each of the pairs of rolls is driven at an appropriate velocity, and is adjustable, so as to adapt their relative positions to the particular cross-section of bar about to be made. The horizontal rolls can be adjusted vertically and the vertical rolls horizontally, and therefore any proportion of width and thickness can be turned out, up to the limitations imposed by the width of the cylindrical portion of the horizontal rolls and the length of the body of the vertical rolls. This highly ingenious mechanical combination was invented by Herr Daelen, a German engineer, and it was first erected at the works of Piepenstock & Co., belonging to the Hörder Society, in 1848. It found its way to America about twelve years later; but it has not received the attention from American engineers Fig. 48.—Universal Mill. that the value of its constructive ideas justifies. The first iron beams for use in buildings rolled in America were made the mill of Messrs. Cooper & Hewitt, at Trenton, N. J., in the spring of 1854. They were seven inches deep, weighing about eighty-one pounds per yard. They were used in the construction of the Cooper Institute and the building of Harper & Brothers, and also by the Camden and Amboy Railroad for rails. A special "train of rolls," the invention of William Burrows, was constructed for doing this work. An elevation of the "finishing rolls" of this "train" is given in Fig. 49. It will be seen that there are three short rolls, AAA, whose axes are vertical and supported by a cast-iron frame or housing, D I). Besides these vertical rolls there are two horizontal rolls, E E. The power was transmitted to the mill from the main driving-shaft B, through the bevel gearing B1, B2, the three spur-gears B5, and the spindles B8. This was the only mill of its kind ever erected, and after a few years it gave place to a "three-high train" which is the kind of mill exclusively used in America at the present time for the manufacture of the various forms of "beams," etc., known as "structural shapes."
The space available will not permit of a detailed description of the various improvements in machinery and methods that have been brought forward within the last thirty years, and we can only briefly mention the more prominent.In 1859 John and George Fritz (par nobile fratrum) patented
Fig. 49.—Elevation of "Finishing Rolls" for Beams—Cooper & Hewitt.
important improvements in "three-high" mills, embracing what is known as the "feed-roll" and "hanging guides." In 1864 Bernard Lauth patented the well-known form of "three-high mill" (often called "Lauth's mill") for rolling boiler plate and sheet iron. In 1872 James Moore and John Fritz patented a "three-high train," having a fixed middle roll and an adjustable top and bottom roll; and in the latter part of the same year George Fritz patented "feeding tables having driven rolls" for "three-high trains."
In December, 1873, James Moore, William George, and Alexander L. Holley patented a "three-high blooming train," having an adjustable middle roll. The first mill of this kind was made by James Moore, of Philadelphia, and was put at work in the Bessemer Steel Works at Troy, N. Y., by the late A. L. Holley, who was then manager of these works.
Among the more recent improvements in the manufacture of iron and steel the use of gaseous fuel stands conspicuous. The idea of first converting the fuel into a combustible gas, and conveying this to the point where heat was required, and there igniting it, is a very old one, and, in one form or another, it has been employed for over a thousand years; but it is only within the present century that the manifold advantages of gas as a metallurgical fuel have become fully recognized by the iron and steel workers of the world. The early gas furnaces used in Silesia, Sweden, and other European countries were but enlarged modifications of Geber's Tower of Athanor, and, although they were a great improvement on the furnaces in which solid fuel was burned on a grate, yet they were not able to produce a temperature sufficiently high and controllable to satisfy the demands of the rapidly developing iron and steel industries.
The gas furnace most commonly used in the American iron and steel works was invented about thirty years ago by the brothers Frederick and Charles William Siemens, German engineers resident in London. The first "Siemens furnace" built in this country under the sanction of these inventors was erected at the works of John A. Griswold & Co., at Troy, N. Y., in 1867, and was used as a "heating furnace." This was followed in the same year by a heating furnace at the works of the Nashua Iron and Steel Company, Nashua, N. H., and early in 1868 the first "Siemens furnace" for melting steel in crucibles (often called a "pot furnace") was started in the works of Anderson & Woods at Pittsburgh.
The first works in which the "Siemens gas furnaces" were used, to the exclusion of all other methods of burning fuel, were those of the American Silver Steel Company, at Bridgeport, Conn., which were erected from the plans and under the supervision of the author of these papers in 1868-'69. In these works were two puddling furnaces, three heating furnaces, one twenty-four-pot melting furnace, a twenty-four-pot muffle, and ten "gas-producers," all on the Siemens principle. Gas from the "producers" was used under the boilers with entire success. At the time of the erection of these works they were the largest and most perfect plant of gas furnaces in America.
"Natural gas" has been known to the nations of the Old World for thousands of years. The Persian fire-worshipers used it for their sacred fire, and it has been used as a fuel in China since a time beyond the range of authentic history.
The earliest use of natural gas in this country was as an illuminant in the village of Fredonia, N. Y., in 1827, and it is still used there. The first person to use natural gas for manufacturing purposes is believed to have been Mr. William Tompkins, who, in 1842, employed it in the Kanawha Valley for heating the kettles of a "salt-block" one hundred feet in length. In 1845 Messrs. Dickerson and Shrewsbury bored a well on the Kanawha River, in West Virginia, to a depth of one thousand feet, from which a sufficient quantity of gas issued, according to a computation by Prof. B. Silliman, Jr., "to light the city of New York for twelve years." The first use of natural gas for the manufacture of iron was in the Siberian Rolling-Mill of Rogers & Burchfield, at Leechburg, Armstrong County, Pennsylvania, in 1874; twenty-nine years after it had been successfully used under a "salt-block" in West Virginia, and forty-seven years after its first use for
lighting at Fredonia, N. Y. But now gas wells increase and multiply in the land, and lines of pipe radiate from them in all directions, conveying silently as the lapse of time, to city and mill, forge and furnace, their heat-giving product that has lain dormant in the earth for untold centuries, but which now, at the summons of modern Science, comes forth from its abiding-place to do no small share of the work of the world. Many of these lines of pipe are of great length, and suggest the possibility of converting coal into gas at the mines and conveying it to consumers in distant cities by pipes; and this proposal in our day is not nearly as uncertain of realization as was the original idea of lighting cities and buildings by gas at the time of its invention, one hundred years ago.
[To be continued.]