ROL 



R O L 



different directions, till the furface fward is pretty muuh fockets or boxes, as L, are fitted, and thefe, at the other 



broken, then fowing the grafs-feed o\ r the land, and after ends, are fitted upon fimilar fquarea on the ends of the 



;, be well drefled with the fward-dreffer, and all the water-wheel axis. A little play or Ioofenefs is admitted 



rubbifh collected cleared away, rolling it well down with the in all thefe fquares, becaufe the upper roller is fet at dif- 



plain roller, and admitting no fort of live-ftock afterwards ferent heights, according to the thicknefs of the work 



upon it. In this method cf nfing the roller, vail improve ■ 

 mentsmay, in many cafes of degenerated or worn-out grafs- 

 lands, be effected, without incurring any very heavy ex- 

 pences, or much trouble. See SwAUD-ZJrjfr. 



RoLUN'd- Bridge fignifiesi among Canal-Makers, an IN- 

 CLINED Plane} whichfee. 



RoLLlX(j-6VrAr. See CARTS. 



RoLLIHG-Mi/1, in Metallurgy, and particularly in the Iron 

 Manufaclure, is a mill for reducing maffes of iron or other 

 metals into even parallel bars, or flat thin plates : this is ef- 

 fected by palling the metal, whild red-hot, between two cy- 

 lindrical rollers of iron or ileel, which are put in motion by 

 the power of the mill ; and being fo mounted in a Itrong 

 metal frame, that they cannot recede from each other, they 

 comprefs the metal which is paffed between them, and re- 

 duce it to a thicknefs equal to the fpace between their 

 furfaces. 



which n to be rolled between them : this play is required to 

 allow the rollers to move freely, when they are not exactly 

 in the line of the water-wheel axis: it is to accommodate this 

 circumftancethat the principal care i< required in condruct- 

 mg a rolling-mill. Our readers will gain a good idea of the 

 bed proportions of a mill, with two independent water- 

 wheels, from the following dire&ions for building one in 

 Northumberland, which were given by Mr. Smeaton near 

 40 years ago. The two water-wheels are to be under-lhot, 

 and of different lizes, viz. 15 ft. 4 in. and 14ft. Sin., the 

 mean diameter being 15 ft. The breadths in their float- 

 boards are to be three feet each, the final] wheel being laid 

 lowerthan the other by feven inches : this, with the difference; 

 of their diameters, will make the centre of the large wheel 

 1 1 inches higher than the other. The different heights of the 

 crowns of the falls or breads, down which the water defcendj 

 to aft upon the wheels, and the pofitions of the water-fhut- 



It requires a mod enormous power to put in motion the ties, are to be fo adjuited, that the gates or fliuttles beinr 

 rollers which are employed for laminating iron in the large equally drawn up by their Harts, the wheels will, as near as 

 xvay ; and for this reafon, the greateft number of rolling- poffible, revolve in equal times, and with equal power. The 



mills are fituated upon the banks of rivers which have the 

 advantage of a fufficient fall to turn the machinery. Of late 

 years, the improvements of (team-engines have been car- 

 ried to fuch a high perfection, as to put them on a par with 

 water, for mod purpofes, and particularly for rolling-mills, as 

 the wafte heat of the furnaces ufed for heating the metal 

 may be employed, in part, to raife deam for the engines which 

 turn the rollers. 



Rolling-mills were not very generally ufed in the iron ma- 

 nufacture till within thefe fixty years. The old mills which 

 were fird ufed are extremely fimplc ; two feparate water- 

 wheels are placed on the 

 their axles in the fame d: 



rings of the water-wheels are to be made of caft iron, that their 

 weight may ad as flies : the ring of the leffer wheel is to be 

 made fix inches in thicknefs by fix inches deep, while that 

 of the larger is to be only five by fix. The greater quantity of 

 matter in the lefler wheel, therefore, will give it nearly the 

 fame momentum as the larger wheel. 



The rings of the water-wheels are each to be formed by 

 eight pieces or fellies, the exterior circle of the greater 

 wheel being thirteen feet diameter, and that of the lefs twelve 

 feet four inches : the length of the fellies is to be 



- about 

 halt an inch fhorter than their true length, in order to admit 

 he oppofite fides of the mill, with an oak wedge of one inch thick to be introduced into every 

 irection, but at different heights, fo joint after the rings are fcrewed together by the joint-plates 

 that one wheel can be conneded with the upper, and the of wrought iron, which unite the fellies. Thefe plates are 

 other with the lower roller : it therefore requires the two to lay upon the plain furface of the felly, and not to be let 

 wheels to have the water delivered at oppofite fides, to make in as the common wooden rings of water-wheels, in order 



them revolve in different directions, in order that the up 

 per furface of the lower roller, and the under furface of the 

 upper roller, may move in the fame direction, and pafs the 

 iron between them. The conftruction of the rollers generally 

 ufed in fuch mills is fhewn at Jigs. 3, 5, and 6, of Plate V. Iron 



that the oak wedges may completely fill the joints at the 

 ends of the fellies. The wheels are to have wooden arms, 

 and it mud be obferved, that the mortifes through each of the 

 iron fellies, for receiving the ends of the arms of the wheels, 

 are to be about two inches and a half in width, and that 



Manufacture, except that the two rollers, F and G, are there they are to be a little dove-tailed, in their length only, fo 

 fhewn with equal pinions, d and e, fixed upon the ends of that the mortifes being longer on theoutlide of the ring, and 

 their pivots, to compel the two to revolve equally together ; the wood of the arm being fpread into them with wedges, 

 whereas, in the mills with two feparate wheels, no provifion will produce firm ties to the centre; but as a farther fecurity,' 

 is made to enfure the equal motion of the two. The gud- pins are to be put in after the wedging is completed. The 

 geons, or necks, of the lower roller, G, are fupported in mortifes in the rings for the darts, which fupport the 

 braffes, fitted into firong carriages of iron E, E, which float-boards, are to be four inches by two, without dove- 

 have holes through their ends, to receive four drong iron tailing, or rather they fhould be larger outride than infide. 

 bolts, A A, BIS; thefe dand perpendicular, and form The bread or float-boards will fix by nails into the joint* 

 the frame, to retain the rollers at the proper didance, being and arms, where they fall.; but that the bread-boards for 

 fitted through the carriages E with heads below, fo that 

 they cannot draw out. The upper ends of the bolts are cut 

 with fcrews, upon which nuts, a, a, are fitted ; and thefe 

 being turned round by iron handles or wrenches, fcrewdown 

 the pieces D, D, and advance the rollers nearer together ; or, 

 by a contrary motion, increafe the didance between them 



the intermediate floats may alfo have a fattening, holes of 

 about one inch diameter, and about four inches deep, mud 

 be cad in the ring, at the places for every other float; 

 thefe holes, being tilled up with pieces of oak, will afford 

 places to drive the nails for fecuring the boards. The 

 axles of the water-wheel are to be of cad-iron, with Haunches 

 ' (f'Z- 6 ) ' 6 a aron g ' r on bar, extended from one bolt, A, to to fcrew the arms of the wheel againd. The total length ot 



the other, B, and hxed fad ; it fupports an iron plate, form 

 ing a kind of table before the rollers, to guide the iron 

 through them. The rollers have fquare heads upon the ends 

 of their gudgeons ; and upon thefe fquares, large cad-iron 



each axis is to be feven feet one inch, and the diameter 

 throughout the axis is to be a circle of nine inches, The 

 manner of fixing the arms upon (launches is to be found in 

 Plate XXXIV. Mechanics, in our article Mill. 



3K z The 



