The Iron and Steel Manufactures page 2

The largest works for the manufacture of Bessemer steel are situated at Barrow-in-Furness. This town, situated in the north of Lancashire, is, indeed, itself the most striking practical illustration of the rapidity with which British industry and commerce have progressed in the second half of the nineteenth century. In 1861 Barrow-in-Furness was still so insignificant, that it was not noticed as a separate place in the report of the census of that year. It is only from local chronicles that we learn that in 1850 Barrow was a small hamlet consisting " of three or four farmhouses, eight or ten low-roofed cottages, and two public-houses." Its population in 1861 numbered but a few hundreds; but in 1871 the census showed that the hamlet had grown into a borough of more than 18,000 inhabitants, enjoying the dignity of self-government under a mayor and corporation. Railways radiate from it in all directions on the land side, while wharves and quays and docks are constantly extending along the shores. The principal cause of this sudden growth of Barrow is to be found in the development of the iron manufacture. " To the north and east it is surrounded by rich deposits of hematite ores, which in ancient times had been worked by charcoal, the wood having been obtained from adjoining forests. Even as late as 1840 charcoal iron was made from hematite ores, and some of the oldest ironmasters of that part of the country still continue to manufacture it." In the year 1859, however, new works were erected, where more modern processes were adopted. The blast-furnaces, commenced in 1859 at Hindpool, and the steel-works established in the neighbourhood by Mr. Ramsden in 1864, were in 1866 amalgamated under the Barrow Hematite Iron and Steel Company, and from this time forth the progress of the town was most rapid. The company in question produce nearly a quarter of a million tons of pig-iron annually. The mines of iron ore in the neighbourhood are of great richness. About one hundred and twenty thousand tons of ore are annually shipped for South Wales and Staffordshire, while of four hundred and eighty thousand tons more, part is sent to other districts by rail, and the remainder is smelted on the spot. In 1868 it was estimated that the eleven blast-furnaces at Hindpool would yield 55,000 tons of railway iron weekly, or 286,000 tons annually, which, at only £4 a ton, would be worth £1,444,806. " The steel-works, when in full operation, could convert weekly about a thousand tons of pig-iron into Bessemer steel and the 52,000 tons of Bessemer steel thus annually produced, selling at £12 to £14 per ton, would be worth more than three-quarters of a million sterling. The quantity of pig-iron manufactured by the Barrow company was only 22,592 tons in 1860. It was 167,584 tons in 1867, and was, as above stated, estimated at 286,000 tons in 1868. It was considered that at that time the firm, if not already, would soon become the largest iron-manufacturing company in the world.

Such was the description given, as it were but yesterday, of this youngest of the more notable manufacturing towns of England. But so rapid is its progress, that every day makes~ the description more and more inadequate. On a recent occasion, Sir John Ramsden, to whose intelligence, energy, and enterprise the town is greatly indebted for its marvellous growth and prosperity, stated that the works in process of erection would, in the course of a few years, bring the population of the town and district up to between fifty and sixty thousand souls.

Another town which has been recently called into existence by the development of the iron manufactures is Middlesborough, in the North Riding of Yorkshire. The enormous iron trade of the Cleveland district dates only from the year.1851 - that is, about ten years earlier than that of Barrow. In 1829 there was but a single farmhouse where Middlesborough now stands. A shipping trade sprang up after that date, and by 1851 the town had a population of between seven and eight thousand (7,431). Then commenced the new industry; and in the course of the next twenty years the population had multiplied itself fivefold, the inhabitants in 1871 numbering no fewer than 39,563. The discovery of iron ore in the Cleveland district, of which Middlesborough is the centre, took place a little before 1851, in which year the first blastfurnace was erected in the district. In 1871 there were seventy blast-furnaces within four miles of the centre of Middlesborough, some of them producing each from four to five hundred tons of pig-iron weekly. The Cleveland district, in fact, in 1871 produced nearly as much pig- iron as all Scotland or the whole of South Wales; the produce in each case being more than a million tons per annum. The iron, however, is not of such quality as that of South Wales or Scotland. Some of the works in this new district are on an immense scale - at one of them there being as many as seven thousand men employed.

The quantity of ore raised from the mines of the United Kingdom in 1871 was 16,334,889 tons, from which there were more than six and a half million tons of pig-iron produced. In 1855 Mr. Touran estimated the total producing power of the country at less than four and a half million tons annually, and the actual produce of that year was only 3,218,154 tons. The value of the latter was £8,045,385, while the value of the pig-iron produced in 1871 was £16,667,947 sterling. The quantity produced had, therefore, increased in the sixteen years by 3,409,025 tons, and the value by £8,622,562 sterling. Our total exports of all classes of iron and iron manufactures was not more than 919,479 tons in 1851; the value of which was less than eight millions sterling, in 1871 our iron exports were not less than 3,169,219 tons in weight, and their value was £27,647,772. In fact, Great Britain produces now about half the iron annually obtained throughout the world. The rapid progress the manufacture has made in the United Kingdom is apparent when it is stated that it rose from 124,879 tons in 1796 to 1,512,000 tons in 1839, or to rather more than twelve times the quantity in this interval of forty- three years. In 1871 the quantity produced was 6,627,179 tons, or more than four times as much as in 1839.

The great establishments of English mechanical engineers and workers in iron are among the modern wonders of the world. Here, to use the words of Mr. Sime, the spectator may see " iron blocks squeezed between rollers or compressed in the jaws of an iron alligator, - two or three welded into one, or formed into a sheet, and squeezed out to greater thinness; huge shears working with marvellous rapidity, clipping three-quarter- inch (iron) plates at the rate of ten feet each stroke; circular saws, moving with greater speed than the fastest railway trains, cutting railway bars in two with a precision otherwise unattainable; heavy hammers uniting ponderous bars of iron; slight ones, striking a thousand times a minute, assisting in manufacturing the smallest articles required with the utmost rapidity and accuracy; holes punched through masses of iron almost a foot thick as easily as if they were pieces of wood or cheese; and sheets nailed together with a firmness that gives to hundreds of united plates the stiffness of one."

Without some invention similar to the steam hammer of Mr. Nasmyth, many modern forgings in iron could not have been executed. That gentleman patented this remarkable and powerful machine originally in the year 1842, since which time it has been variously improved. The merit of the original invention, however, belongs to Mr. Nasmyth, who, like his contemporaries, Sir Joseph Whitworth and Sir W. Fairbairn, was a mechanical engineer, of Manchester. A steam hammer may be described as consisting of a ponderous hammer carrying with it the engine which works it. The steam cylinder is fixed in a vertical position high above the anvil. The steam acts directly on the hammer-rod, without the intervention of flywheels, cranks, or levers. The hammer moves up and down in the grooves of the frame. The power of steam until recently was applied only in raising the hammer. In this arrangement it is the weight of the hammer alone which brings it down, and which is applied in the process of hammering. The force, however, with which the hammer falls, is nevertheless placed under the control of the self-acting apparatus, which is, indeed, one of the most admirable parts of the machine. This portion of the machine is so fitted as to modify the degree in which the steam is allowed to act on the piston, whereby it is possible to cause the hammer at one moment to fall with sufficient force to crush a huge mass of iron, and yet the next moment to give a tap so light as to crack a nutshell without crushing the kernel. In the words of Mr. Sime, " The heaviest work is forged under the blows of this ponderous hammer, which acts with an energy that the strength of iron cannot withstand, and yet is kept in such control that a nutshell may be cracked or an egg chipped as easily as iron beams are welded or shaped." Within the last few years steam hammers of enormous size have been coming into use. Their weight, but ten years ago, was generally stated in hundredweights, but they have so grown apace that they are now commonly estimated in tons. Steam hammers whose heads weigh twenty tons are not uncommon in the larger iron and steel works. In the arsenal at Woolwich is a steam hammer of thirty tons; and a still more ponderous example, in which steam is used in depressing as well as elevating the hammer, is being fitted up at the time this is written.

Another invention, which has greatly contributed to accuracy in iron work, is an instrument invented by Mr. Henry Maudslay, and which is known as the slide-rest.

In the manufacture of the cylinders of steam-engines, for instance, the workman formerly had only his eye to depend on in making them of uniform diameter, as it is requisite they should be, from top to bottom. The same was the case also in the planing of the valve faces, or turning the piston-rods, and in all the most critical operations of machine making. In using the cutting tool, the workman held one end of it against his chest, and a certain want of uniformity in the workmanship was inevitable. Now, by the use of the slide-rest, the planing- machine takes off the shavings to a uniform depth, and secures a uniform thickness. The machine slides the cutting tool along of itself, and the workman has nothing to do, except at the commencement and conclusion of the operation. " This principle, so simple in its nature, has been applied to the turning of rods, the planing of surfaces, the boring of cylinders, the formation of cones, the cutting of screws, and other purposes; and nine- tenths of all the fine mechanism is through the agency of the slide-rest and the planing-machine."

This latter machine owes its perfection to Sir Joseph Whitworth; and, indeed, the accuracy of workmanship which has of late years become general in the productions of mechanical engineering is largely to be attributed to the improvements introduced at various times by this celebrated engineer. As early as 1840 he described before the British Association a method he had devised for giving to plates of metal a greater perfection of surface than it had before been possible to attain. His mode of preparing plane metallic surfaces has since then been generally adopted, and by enabling greater accuracy to be attained in fittings, and by diminishing friction, this improvement has greatly added to the excellence and utility of all the most important and delicate kinds of mechanism.

Another valuable result of Sir J. Whitworth's labours was the introduction of a uniform and accurate system of cutting the threads of screws. The importance of the screw as an element in accurate mechanical construction can hardly be exaggerated, as any one may convince himself, by observing the number of screws employed in holding together the parts of a steam- engine. Some improvements had been introduced by Mr. Henry Maudslay; but it was not until Whitworth turned his attention to the subject, and had drawn up a methodical scale, that a uniform system was generally adopted. Previously to this period, every manufacturer followed his own ideas. The bolts and nuts coming from different quarters never fitted each other, and the want of uniformity caused constant trouble, confusion, and expense.

Sir Joseph Whitworth remedied the evil by collecting screw bolts from all the principal manufacturers in England. He then took the average of the pitch and depth of the threads of each dimension, and thereon founded a systematic scale. The uniformity of thread he introduced has since then been adopted by all the leading railway and private engineering establishments, as well as at the arsenals, dockyards, and other works belonging to the Government; and it has even extended to the best engineering works abroad.

It was with the same purpose of improving the quality of workmanship that Sir Joseph Whitworth invented his measuring machine. In describing this exquisite piece of apparatus before the Institution of Mechanical Engineers, the inventor said: "I have brought with mo for your inspection a small machine by which a difference in length of one-millionth part of an inch is at once detected. The principle is that of employing the sense of touch instead of sight. If any object be placed between two parallel true planes, adjusted so that the hand can just feel them in contact, you will find, on moving the planes only one fifty- thousandth of an inch nearer together, that the object is distinctly tighter, requiring greater force to move it between them. In the machine the object to be measured is the standard inch, in the form of a small square bar, both ends being true planes; and in this case, in order to measure with the utmost accuracy, a thin, flat piece or bar is also introduced, having its two sides also made perfect planes.

" This is placed between the inch bar to be measured and one of the end surfaces of the machine. If this thin bar is brought into closer contact by even the one-millionth of an inch, it will be suspended, friction overcoming its gravity. This machine and a larger one are used for making standards of length. When the standard yard, which is a square bar of steel, is placed in the larger machine, and the thin, flat piece is adjusted so as just to fall by its weight, the heat imparted by the slightest touch of the finger instantly prevents its fall, thus showing the lengthening of the bar by so small an amount of heat as that I have indicated. We have, therefore, in this mode of measurement, all the accuracy we can desire; and we find, in practice in the workshop, that it is easier to work to the ten-thousandth of an inch from standard of end measure - that is, by help of the new machine - than to the one-hundredth of an inch from the lines on a two-foot rule." With the help of the new machine, it is therefore possible, with less trouble, to attain workmanship a hundred times as accurate as could be accomplished without it.