722 



COINING MACHINERY. 



M, :,:..v. 



Melting 

 F**- 



I't.T.CC. 



fig. 5. 



Melting. 



Tasting. 

 fig. 1. 



Al ,r. 



Rolling 

 mill. 



PuTtfC. 



Figs. 6 & 7. 



f . . 



ii much more regular, and has not to much tendency to 

 burn away in the throat or flue, as if it were'tingle. 



The melting pots, Fig. 5, are made of cast-iron, and 

 of sufficient capacity to hold 4OOlbs. of metal. They 

 have each a lip or spout a, at which the metal is poured 

 out, and two ears b, c, by which they arc taken up with 

 the tones of the crane, as before described, and lifted in- 

 to the furnaces. The pot is supported by proper pedes- 

 tals from the grate of the furnace, and has a large ring of 

 cast iron placed on the top of it to prevent the fuel from 

 falling into it : As soon as it arrives at a red heat, the 

 metal, properly prepared and mixed, is put in, and oc- 

 casionally stirred up while it is melting, which takes 

 tome hours. The moulds, in this interval, are prepared 

 by warming them in a stove, and when they are taken 

 out to be placed in the frame upon the carriage, the in- 

 side iurfaces are severally rubbed with a cloth dipped in 

 oil, which preparation, as well as the heating, is found to 

 give the ingot a better surface. When the proper number 

 of moulds are placed in the carriage, as shewn in Fig. '2, 

 the screws /, / at the ends, arc screwed fast to fix them all 

 tight ; and in this state they are prepared for casting. 



The pot of metal, as before mentioned, is lifted out of 

 the furnace by the crane, then swung round, and lowered 

 down into the cradle tin HO of the pouring machine, until 

 the ring on the edge of it rests on the iron hoop n, which 

 being screwed up tight, holds it fast, and the tongs of 

 the crane are disengaged. Oneof the attendants now takes 

 the handle s in one hand, and y in the other ; and by turn- 

 ing the latter of these he advances the carriage forwards to 

 bring the first mould beneath the lip of the melting pot, 

 then by turning the other he inclines the pot, and pours 

 the metal into the mould ; when this is full, the second 

 is brought beneath it, and so on in succession. The whole 

 four hundred weight is very quickly cast into ingots 

 without any loss or waste, which could scarcely be avoid- 

 ed in any other way of casting. The first metal which 

 is poured from the pot is received in a small iron spoon, 

 and is reserved for the assay master, who examines its 

 quality, and it is not allowed to pass through the succeed- 

 ing processes, until, from this specimen, he has ascertained 

 it to be standard. A second sample is taken from the 

 middle of the pot, and a third from the last of it. The 

 pouring machine was, we understand, invented by Mr 

 Morrison, an officer of the Mint. 



The ingots thus cast are about 10 inches long, 7 broad, 

 and 6 tenths of an inch thick. They are next carried to 

 the rolling mill, which is represented in Figs. 6. and 

 7. in Plate CC. In the former, A represents a large 

 cog wheel, fixed on ihe extremity of a long horizontal 

 shaft BB, extending beneath the whole mill : This wheel 

 and shaft receive their motion from a smaller wheel, fixed 

 on the main or flay wheel shaft of tteam engine of 36 

 horse power. The main shaft B of the rolling mill has 

 wheels C, D, fixed upon it, to give motion to the re- 

 spective rollers, which are mounted at Fand G, in strong 

 iron frames bolted to the iron sills a a, which extend 

 through the whole length of the mill, and rest upon the 

 masonry, in which the wheels are concealed. The two 

 large wheels C and E give motion to the wheels H, I, 

 which are supported on bearings between two standards 

 b b bolted down to the ground sills ; as is also shewn at 

 b b in the perspective view, Fig. 6. On the ends of the 

 axes of these wheels are heads for the reception of coup- 

 ling boxes dd, which unite them to short connecting 

 shafts K,L; and these again, by means of coupling boxes, 

 convey motion to the upper rollers ee of each pair, at F 

 and G. The middle wheel D upon the main shaft B 

 gives motion to the lower rollers in a similar manner 



thus : It turns the wheel M, by mean? of an intermediate Coining 

 wheel, not shewn in the Figures. This at each end of its ^ ^ 

 axis, gives motion to the Tower rollers FF by the con- jT^j t c. 

 nccting thaft p p. By this ingenious arrangement, both pjg. g. 

 the rollers e,J'of each frame, receive their motion from 

 the main shaft with equal velocity, and by means of 

 wheels of large radius, which act with much more cer- 

 tainty than the small pinions usually employed in rolling 

 mill*), to connect the upper and lower rollers, and cause 

 them to move together. The wheel M, in consequence 

 of its intermediate wheel, revolves in a contrary direction 

 to the wheels H, I ; but all the pairs of wheels being of 

 equal diameters, and having the same numbers of teeth, 

 they revoive in precisely the same period ; and the two rol- 

 lers r, /"being of the same diameter, their surfaces accom- 

 pany each other, without which the metal rolled between 

 them would be buckled ; that is, one side being more ex- 

 panded than the other, would render the plate co 

 The connecting shafts K, L. and , and coupling boxes 

 dd, which give motion to the rollers, have sufficient play 

 in their joints, to allow that small deviation which takes 

 place, when the rollers are set nearer together for redu- 

 cing the plate to its intended thickness. Tiic detail re- 

 specting the frame, and parts of the rollers, is explained 

 by the perspective view, Fig. 7. in which a represents pi?. 7. 

 one of the sills before mentioned, which runs through 

 the whole length of the mill ; upon these are bolted the 

 two checks, or side frames of the rollers, marked NX : 

 Each of these has a large mortise, or opening in it, to re- 

 ceive the bearings for the Decks or gudgeons of the rol- 

 lers ef, between which the metal is passed. Their dis- 

 tance from each other, and consequently the thickness 

 of the rolled plate, is regulated by two strong screws 

 OO, passing through the upper part of the cheeks of 

 the frame, and their points pressing upon the bearings 

 PP, or the pivots of the upper roller. The weight of 

 the roller is suspended by two bolts, passing through the 

 frame, and they are united to a collar Q, which is fitted 

 on the upper end of the screws; and this collar being a 

 long plate, is common to both screws, as the Figure 

 shews. Immediately above this plate, the screws have 

 wheels RR fitted upon them, which are cut with teeth 

 on the lower part of them, to receive motion from two 

 endless screws, formed upon a spindle SS, which moves 

 in bearings projecting from the plate Q. By turning this 

 spindle, its endless screws act upon the wheels RR, to 

 turn them round ; and the great screws partaking of the 

 same motion, elevate or depress the upper roller c, with 

 co delicate a movement, that it can be adjusted to roll 

 the plate to the greatest nicety ; and the adjustment being 

 made at both ends at the same time, the two rollers al- . 

 ways preserve their parallelism. The metal, when intro- 

 duced to the rollers, is placed upon a small table V, fix- 

 ed between the frames NN. Its upper surface being ex- 

 actly level with the top of the lower rollers, it is fasten- 

 ed by means of a cross bar T, and wedges which press 

 it fast up against projecting pieces of the frames. 



The cheeks NN of the frame, are connected by strong 

 wrought iron holts, which are too plainly shewn in the 

 figure to require any particular description. 



The rolling mill contains four pair of rollers, each 

 driven by ita train of wheel work ;w shewn in Fig. 6 ; Fig. e. 

 the mill therefore consists of two such sets of wheels and 

 rollers, as are represented in Fig ri. The two shafts are 

 situated parallel to each other, and receive their motion 

 from the same steam engine j tin; wheel before mentioned, 

 which is on the main axis of it, being situated between, 

 ttiem iid giving motion t" one of the main wheels AA 

 on each tide. The whole machine forms the most com- 



