ROLLING mill, in mechanics, a ma chine fbr working metals into plates, or bars, which are required of an even thick ness. In the Plate Rolling-Mill, are three elevations of a machine for this purpose, A B, I) E, in all these figures is a massive frame of cast iron, consisting of two dis tinct cheeks, A B and D E, which are connected together by being both affixed to an iron plate, F F, bolted down upon two ground sills, G G, supported on ma sonry, and forming the foundation for the whole machine ; each cheek has an oblong mortice, a b, through it ; a strong iron screw, d, is screwed through the upper end of each cheek, and has a wheel on the top of it, with teeth, to receive a handspike to turn it by. I K are the two rollers made of cast iron, and very truly turned in a lathe ; they have pivots, i 1, k in, at each end, turned at the same time, and with the greatest accuracy ; these pivots are supported on bearings of brass in the cheeks ; those of the lower roller, K, fit in the bottom of the mor tices, a b, (fig. 1 and 3) through the cheeks ; the upper ones, e e, are movea ble, sliding up and down in the mortices by the action of the screw, d. The weight of the upper roller, when nothing is be tween the rollers, is sustained by an iron strap, n, at each end, embracing the pi vots, and going through the brass bear ing, ee. Its ends are tapped, and have nuts screwed upon them to prevent their return through the ends of the collar, p, which fits in a groove cut round the screw, d, so that it cannot come off; the collar is made in two halves, which are held together by the ends of the strap, n, going through both at the place where they overlap each other ; by this means the upper bearings are firmly connected with the screws, to rise and fall with them ; and at the same time, the pivots of the tipper roller are held rp to their bearings by the straps, a, going under them. The end of the pivots of the rol lers are formed into squares beyond the bearings, and the pivots of one end of each roller have two cog wheels, L M, fitted on them ; they are shown faceways, (in fig. 1) and are both alike ; they cause the two rollers to move with an equal ve locity ; the other square, k, on the lower roller, is fitted into a box, M, by which it is joined to a strong shaft, 0, which com municates a rotatory motion to the rol lers. This shaft receives its power from
a water-wheel, steam engine, horses, or other first moving power : a is a small trough made of iron plate, punched full of holes, it is supplied with water by a pipe, n, and constantly drops a small quantity of water upon the rollers, and thus keeps them cool when they are roll ing hot work : VJ is a bar of iron fixed be tween the two cheeks by wedges, the upper side is on a level with the top of the lower roller ; a small distance above this is another iron bar, x, parallel to the former ; between these the article in tended to be rolled is introduced to the rollers.
Rolling mills are chiefly used for draw ing out iron bars after they have been manufactured into bar iron by the forge hammer ; the rollers leave a smoother surface, and make a bar of more even thickness, than the hammer can be made to do ; the iron hoops for barrels are also made in this machine ; its operation is exceeding simple ; a furnace is placed close to the machine where the iron bars are to be rolled ; are heated to a white heat ; a workman stands between the furnace and the mill, and takes a bar from the furnace with a pair of pincers, and puts its end between the bars, av and s, advancing it forwards until the rollers take it between them and draw it tor wards, spreading it as it goes both in length and breadth ; another workman, behind the machine, receives the bar as it conies through, andbonveys it away, to make room tor the next. The small stream of water brought by the pipe, r, cools and hardens the iron as it is rolled without plunging in water. The rollers can be set nearer or further apart by turning the screws, d d, to make thicker or thinner work. The iron will pass through the rollers at the rate of three and a half or four inches per second, and thus will do a great quantity of work ; but the power required to turn them, when they have large and heavy work in them, is immense ; for the same reason the frame of the machine must be ex ceedingly strong and well put together.