ROLLING-MILL. 



The braffes upon which the necks of the water-wheel 

 axles are fupported, are intended to be let into call-iron 

 ftocks, which are again iupported upon wooden bed-planks, 

 and thofe upon the cap-ftones of the walls, which (under 

 thefe at leall) are fuppofed to reach all acrofs the thicknefs 

 of the walls, thofe necks being firft truly and fmoothly 

 turned ; at each end, beyond the neck, is formed an aftragal 

 or moulding, to keep the wheel in its place from moving 

 endways. The ends of the axis are terminated by an in- 

 dented head, fhaped fomewhat like a fquare citadel in for- 

 tification, and an iron box is fitted upon this to commu- 

 nicate the motion to the rollers, the furface lines of the 

 indented head being formed a little rounding, that the box 

 may not only be certain of taking its bearing in the middle, 

 but likewife be capable of complying with the motion of 



the rollers : and in order to give ftill more liberty, the end laltly, raife the under roll another quarter, fo as to be an 



inch above the line, and the upper roll will be reduced 

 to half an inch below it, fo that when it is come down 

 to an inch below it, the rolls will be reduced to nine inches. 

 In this way the departure of the rolls from a right line 

 will never become more than half an inch, while they arc 

 reducing from twelve to ten inches ; nor more than three 



neither will need to comply or vacillate more than half an 

 inch. The roll being now of a juft diameter to anfwer the dif- 

 ferent heights of the axis, let the lower roll be raifed to its 

 juft height, and then both the rolls will work true till they 

 are further reduced ; but when the j I com reduced to ten 

 inches and a half diameter, the upper roll will become half 

 an inch too low ; then raife the under roll half an inch 

 above the line, and the upper roll will then be truly in the 

 line ; fo that when the upper roll is come down to be half 

 an inch below the line, the rolls will be reduced to ten 

 inches ; then railing the under roll a quarter of an inch 

 more, it will be three quarters above the line, and the 

 upper roll will be a quarter of an inch under the line ; and 

 when it comes down to three quarters below the line, the 

 rolls will be reduced to nine inches and a half ; therefore, 



of the box which is fartheft from the water-wheel, is 

 formed into a fquare of eight inches, which is again fur- 

 rounded by another box, whofe external furface is round. 

 This box is formed at the end of a round fpindle or axis 

 three feet long, and terminated at the other end with a 

 fquare of eight inches, which enters one end of a fquare 



box, and at its other end receives the fquare of the roller, quarter.-, while they are reducing from ten to nine and a 

 fuppofed to be of fix inches, but may be of any other half inches; at the word they will be no more than an inch, 

 fize which is thought neceflary. It is to be noted, that while they are reducing from nine and a half to nine inches. 

 all the fquares are to be made larger than thofe of the The greatelt inequality is purpofely made at this place, both 

 rollers, in order that they may wear longer; and all the in- becaufe the purchafe of the wheels is then greatelt and moll 



fertions are to be lefs than thofe at the end of the water- 

 wheel axles, that the axis may not be rendered ufelefs by 

 the wear or failure of the citadel heads which are intro- 

 duced, as they are expefted to laft many years ; and if any 

 thing ihould happen to them, the axes are made alike on 

 both fides of the water-wheels, that they may change 

 ends ; therefore, there is nothing of confequence likely to fail 

 by wear or breakage, except the fmaller intermediate work 

 between the axis and the roll , which is ealily replaced. 

 Holes are to be made through the boxes and joint parts 

 for iron bolts to pafs through rather loofely, fo as to pre- 

 vent the boxes and fquares leparating, but not to confine 

 the joints from yielding to the motion of the rolls. The 

 water-wheels are fuppofed to be clofely adapted to their 

 conduits, and their axes to remain immoveable as to height, 

 at the difference of eleven inches in level, while the rolls 

 are fuppofed to vary in their diameter from twelve inches 

 to nine. This will be allowed for, by the diftance that the 

 fquares upon the rolls are from the end of the axis ; for 

 though the houfe is fuppofed no more than ten feet wide 

 between the walls, the diftance between the middle of the 

 citadel heads at the end of the water-wheel axis, and the 

 middle of the fquares of the rolls refpec/hvely, is upwards of 

 four feet ; and in that length no lefs than four joints are in- 

 troduced, every one of which complying a little, a fmall 

 in 



able to overcome an addition of friction, and becaufe the 

 time that they will continue in this ftate is the leaft. If 

 the axles are placed at ten and a half inches dittance in- 

 llead of eleven, the vacillation each way will never ex- 

 ceed three quarters of an inch ; nor more than one inch to 

 reduce the rolls to eight and a half diameter. 



The railing of the under roll is not to be done by raifing 

 the whole of the bed of the roller-frame ; this is to be fet 

 originally half an inch lower than the true line ; and when 

 the lower roll requires raifing, it is to be effected by putting 

 iron plates under the carriages of the lower roll gudgeons, 

 fo that they will ftand as much higher than before, and not 

 to make the feveral riles by additional plates, but to have 

 plates of the different gages, fo that each will lay in one 

 folid piece. 



Mills, on this con(tru£lion, are ftill ufed in many iron- 

 works for rolling coarfe iron bars, but are unfit for any 

 better purpofe, from the difficulty of adjtifting the two 

 water-wheels to an equal velocity ; and if one roller moves 

 quicker than the other, the metal becomes more extended 

 on that fide than upon the other, and is thus rendered 

 convex. Another defect is, the want of proper fly-wheels 

 to regulate the mill ; for the caft-iron rims to the water- 

 wheels by no means anfwers the purpofe of fly-wheels, 

 unlefs they are made to revolve fo quickly that the water 



difference in the height of the roll will produce no fenfible lofes much of its effect upon the floats. Fly-wheels are, 

 difference in the communication of the motion from that perhaps, more ufeftil for rolling than in any other kind of 

 of a right line; all the joints being kept oiled or greafed, which mills, becaufe the refiftance to be overcome is fo variable ; 

 will be not lets proper on that account than to keep the parts being at one moment very great for a large piece of iron, 

 from wearing. In order to preferve the directions as near as then fmaller whilft it is paffed through a fecond time, be- 

 poffible to a right line, Mr. Smeaton propofes that the lower caufe the iron is to be lefs reduced : and in the interval of re- 

 roll fhall be placed originally half an inch below the centre of turning the iron, to put it through again, there is no other 

 the axis which turns it : fuppefe the rolls were firll made of refiftance than that of the friction of the machinery. Again, 

 twelve inches diameter, while the difference of the height of when the iron has been paffed through feveral times, the 

 the axis is only eleven, the upper roll will be juft half an refiftance is greatelt of all, becaufe the metal has become 

 inch too high, fo that the compliance in each will be equal, harder, both by the compreflion it has undergone, and from 



thinner, 

 larger 



and no more than half an inch in four feet length 

 it appears, that when the rolls are reduced by wearing 

 twelve inches to eleven each, then the upper roll as well as 

 the lower will be half an inch too low for its axis ; itill 



Thus being gradually cooled ; alfo, the metal, being 

 from will not yield fo readily to the preffure, as when in 



mats. By the proper addition of a heavy fly-wheel, great 

 advantages, in point of power, are gained, as it tends to 



i equalize 



