NEEDLE MANUFACTURE

When we consider the simplicity, smallne , and moderate price of a needle, we would be naturally led to suppose that this little instrument requires neither much labour nor complicated manipulations in its construction; but when we learn that every sewing needle, however inconsiderable its size, pa es through the hands of 120 different operatives, before it is ready for sale, we cannot fail to be surprised. The best steel, reduced by a wire-drawing machine to the suitable diameter, is the material of which needles are formed. It is brought in bundles to the needle factory, and carefully examined. For this purpose, the ends of a few wires in each bundle are cut off, ignited, and hardened by plunging them into cold water. They are now snapped between the fingers, in order to judge of their quality; the bundles belonging to the most brittle wires are set aside, to be employed in making a peculiar kind of needles. After the quality of the steel wire has been properly ascertained, it is calibred by means of a gauge, to see if it be equally thick and round throughout, for which purpose merely some of the coils of the bundle of wires are tried. Those that are too thick are returned to the wire-drawer, or set apart for another size of needles. IMG:4147767755307473660_illo0880a.png:Wire unwinding apparatus The first operation, properly speaking, of the needle factory, is unwinding the bundles of wires. With this view the operative places the coil upon a somewhat conical reel, fig. 750. , whereon he may fix it at a height proportioned to its diameter. The wire is wound off upon a wheel B , formed of eight equal arms, placed at equal distances round a nave, which is supported by a polished round axle of iron, made fast to a strong upright C , fixed to the floor of the workshop. Each of the arms is 54 inches long; and one of them D , consists of two parts; of an upper part, which bears the cro bar E , to which the wire is applied; and of an under part, connected with the nave. The part E slides in a slot in the fixed part F , and is made fast to it by a peg at a proper height for placing the ends of all the spokes in the circumference of a circle. This arrangement is nece ary, to permit the wire to be readily taken off the reel, after being wound tight round its eight branches. The peg is then removed, the branch pushed down, and the coil of wire released. Fig. 751. shows the wheel in profile. It is driven by the winch-handle G . IMG:4147767755307473660_illo0880b.png:Shears The new made coil is cut in two points diametrically opposite, either by hand shears, of which one of the branches is fixed in a block by a bolt and a nut, as shown in fig. 752. , or by means of the mechanical shears, represented in fig. 753. The crank A is moved by a hydraulic wheel, or steam power, and rises and falls alternately. The extremity of this crank enters into a mortise cut in the arm B of a bent lever B G C , and is made fast to it by a bolt. An iron rod D F , hinged at one of its extremities to the end of the arm C , and at the other to the tail of the shears or chisel E , forces it to open and shut alternately. The operative placed upon the floor under F presents the coil to the action of the shears, which cut it into two bundles, composed each of 90 or 100 wires, upwards of 8 feet long. The chisel strikes 21 blows in the minute. These bundles are afterwards cut with the same shears into the desired needle lengths, these being regulated by the diameter. For this purpose the wires are put into a semi-cylinder of the proper length, with their ends at the bottom of it, and are all cut acro by this gauge. The wires, thus cut, are deposited into a box placed alongside of the workman. IMG:4147767755307473660_illo0881a.png:Straightening tools Two succe ive incisions are required to cut 100 wires, the third is lost; hence the shears, striking 21 blows in a minute, cut in 10 hours fully 400,000 ends of steel wire, which produce more than 800,000 needles. The wires thus cut are more or le bent, and require to be straightened. This operation is executed with great promptitude, by means of an appropriate instrument. In two strong iron rings A B , fig. 754. , of which one is shown in front view at C , 5000 or 6000 wires, closely packed together, are put; and the bundle is placed upon a flat smooth bench L M , fig. 757. , covered with a cast-iron plate D E , in which there are two grooves of sufficient depth for receiving the two ring bundles of wire, or two openings like the rule F , fig. 757. , upon which is placed the open iron rule F , shown in front in fig. 756. upon a greater scale. The two rings must be carefully set in the intervals of the rule. By making this rule come and go five or six times with such pre ure upon the bundles of wires as causes it to turn upon its axis, all the wires are straightened almost instantaneously. The construction of the machine, represented in fig. 757. , may require explanation. It consists of a frame in the form of a table, of which L M is the top; the cast-iron plate D E is inserted solidly into it. Above the table, seen in fig. 755. in plan, there are two uprights C H , to support the cro bar A A , which is held in forks cut out in the top of each of the two uprights. This cro bar A A , enters tightly into a mortise cut in the swing piece N , at the point N , where it is fixed by a strong pin, so that the horizontal traverse communicated to the cro bar A A affects at the same time the swing piece N . At the bottom of this piece is fixed, as shown in the figure, the open rule F , seen upon a greater scale in fig. 756. When the workman wishes to introduce the bundle B , he raises, by means of two chains I K , fig. 757. , and the lever G O , the swing piece and the cro bar. For this purpose he draws down the chain I ; and when he has placed the bundle properly, so that the two rings enter into the groove E D , fig. 755. , he allows the swing piece to fall back, so that the same rings enter the open clefts of the rule F ; he then seizes one of the projecting arms of the cro bar A , alternately pulling and pushing it in the horizontal direction, whereby he effects, as already stated, the straightening of the wires. IMG:4147767755307473660_illo0881b.png:Thumb-piece The wires are now taken to the pointing-tools, which usually consist of about 30 grindstones arranged in two rows, driven by a water-wheel. Each stone is about 18 inches in diameter, and 4 inches thick. As they revolve with great velocity, and are liable to fly in pieces, they are partially encased by iron plates, having a proper slit in them to admit of the application of the wires. The workman seated in front of the grindstone, seizes 50 or 60 wires between the thumb and forefinger of his right hand, and directs one end of the bundle to the stone. By means of a bit of stout leather called a thumb-piece, of which A , fig. 758. , represents the profile, and B the plan, the workman pre es the wires, and turns them about with his forefinger, giving them such a rotatory motion as to make their points conical. This operation, which is called roughing down , is dry grinding; because, if water were made use of, the points of the needles would be rapidly rusted. It has been observed long ago, that the siliceous and steel dust thrown off by the stones, was injurious to the eyes and lungs of the grinders; and many methods have been proposed for preventing its bad effects. The machine invented for this purpose by Mr. Prior, for which the Society of Arts voted a premium, deserves to be generally known. IMG:4147767755307473660_illo0882.png:Prior A A , fig. 759. , is the fly-wheel of an ordinary lathe, round which the endle cord B B pa es, and embraces the pulley C , mounted upon the axle of the grindstone D . The flywheel is supported by a strong frame E E , and may be turned by a winch-handle, as usual, or by mechanical power. In the needle factories, the pointing-shops are in general very large, and contain several grindstones running on the same long horizontal shaft, placed near the floor of the apartment, and driven by water or steam power. One of the extremities of the shaft of the wheel A has a kneed or bent winch F , which by means of an intermediate crank G G , sets in action a double bellows H I , with a continuous blast, consisting of the air feeder H below, and the air regulator I above. The first is composed of two flaps, one of them a a , being fast and attached to the floor, and the other e e , moving with a hinge-joint; both being joined by strong leather nailed to their edges. This flap has a tail g , of which the end is forked to receive the end of the crank G . Both flaps are perforated with openings furnished with valves for the admi ion of the air, which is thence driven into a horizontal pipe K , placed beneath the floor of the workshop, and may be afterwards directed in an uninterrupted blast upon the grindstone, by means of the tin tubes N O O , which embrace it, and have longitudinal slits in them. A bra socket is supposed to be fixed upon the ground; it communicates with the pipe K , by means of a small copper tube, into which one of the extremities of the pipe N is fitted; the other is supported by the point of a screw Q , and moves round it as a pivot, so as to allow the two upright branches O O , to be placed at the same distance from the grindstone. These branches are soldered to the horizontal pipe N , and connected at their top by the tube P . The wind which escapes through the slits of these pipes, blows upon the grindstone, and carries off its dust into a conduit R , fig. 759. , which may be extended to S , beyond the wall of the building, or bent at right angles, as at T , to receive the conduits of the other grindstones of the factory. A safety valve J , placed in an orifice formed in the regulator flap I , is kept shut by a spiral spring of strong iron wire. It opens to allow the superfluous air to escape, when, by the rising of the bellows, the tail L pre es upon a small piece of wood, and thereby prevents their being injured. IMG:4147767755307473660_illo0881c.png:Wire holder The wires thus pointed at both ends are transferred to the first workshop, and cut in two, to form two needles, so that all of one quality may be of equal length. For each sort a small instrument, fig. 760. , is employed, being a copper plate nearly square, having a turned up edge only upon two of its sides; the one of which is intended to receive all the points, and the other to resist the pre ure of the shears. In this small tool a certain number of wires are put with their points in contact with the border, and they are cut together flush with the plate by means of the shears, fig. 752. , which are moved by the knee of the workman. The remainder of the wires are then laid upon the same copper or bra tool, and are cut also even; there being a trifling waste in this operation. The pieces of wire out of which two needles are formed, are always left a little too long, as the pointer can never hit exact uniformity in his work. These pointed wires are laid parallel to each other in little wooden boxes, and transferred to the head-flattener. This workman, seated at a table with a block of steel before him, about 3 inches cube, seizes in his left hand 20 or 25 needles, between his finger and thumb, spreading them out like a fan, with the points under the thumb, and the heads projecting; he lays these heads upon the steel block, and with a small flat-faced hammer strikes succe ive blows upon all the heads, so as to flatten each in an instant. He then arranges them in a box with the points turned the same way. The flatted heads have become hardened by the blow of the hammer; when annealed by heating and slow cooling, they are handed to the piercer . This is commonly a child, who laying the head upon a block of steel, and applying the point of a small punch to it, pierces the eye with a smart tap of a hammer, applied first upon the one side, and then exactly opposite upon the other. Another child trims the eyes, which he does by laying the needle upon a lump of lead, and driving a proper punch through its eye; then laying it sidewise upon a flat piece of steel, with the punch sticking in it, he gives it a tap on each side with his hammer, and causes the eye to take the shape of the punch. The operation of piercing and trimming the eyes, is performed by clever children with astonishing rapidity; who become so dexterous as to pierce with their punch a human hair, and thread it with another, for the amusement of visitors. IMG:4147767755307473660_illo0881d.png:Pincers The next operative makes the groove at the eye, and rounds the head. He fixes the needle in pincers, fig. 761. , so that the eye corresponds to their flat side; he then rests the head of the needle in an angular groove, cut in a piece of hard wood fixed in a vice, with the eye in an upright position. He now forms the groove with a single stroke of a small file, dexterously applied, first to the one side of the needle, and then to the other. He next rounds and smooths the head with a small flat file. Having finished, he opens the pincers, throws the needle upon the bench, and puts another in its place. A still more expeditious method of making the grooves and finishing the heads has been long used in most English factories. A small ram is so mounted as to be made to rise and fall by a pedal lever, so that the child works the tool with his foot; in the same way as the heads of pins are fixed. A small die of tempered steel bears the form of the one channel or groove, another similar die, that of the other, both being in relief; these being worked by the lever pedal, finish the grooving of the eye at a single blow, by striking against each other, with the head of the needle between them. The whole of the needles thus prepared are thrown pell-mell into a sort of drawer or box, in which they are by a few dexterous jerks of the workman’s hand made to arrange themselves parallel to each other. The needles are now ready for the tempering; for which purpose they are weighed out in quantities of about 30 pounds, which contain from 250,000 to 500,000 needles, and are carried in boxes to the temperer . He arranges these upon sheet-iron plates, about 10 inches long, and 5 inches broad, having borders only upon the two longer sides. These plates are heated in a proper furnace to bright redne for the larger needles, and to a le intense degree for the smaller; they are taken out, and inverted smartly over a cistern of water, so that all the needles may be immersed at the same moment, yet distinct from one another. The water being run off from the cistern, the needles are removed, and arranged by agitation in a box, as above described. Instead of heating the needles in a furnace, some manufacturers heat them by means of a bath of melted lead in a state of ignition. After being suddenly plunged in the cold water, they are very hard and exce ively brittle. The following mode of tempering them is practised at Neustadt. The needles are thrown into a sort of frying-pan along with a quantity of grease. The pan being placed on the fire, the fatty matter soon inflames, and is allowed to burn out; the needles are now found to be sufficiently well tempered. They must, however, be re-adjusted upon the steel anvil, because many of them get twisted in the hardening and tempering. IMG:4147767755307473660_illo0883a.png:Polishing bag and table