720 



COINING MACHINERY. 





I 

 tin f , 



b....ilc>. 

 PL*T CCI, 



cular piece* from the plate*, of the proper tize to form 

 the coin ; 3d, The machine fur milling on the edge* ; 

 and +th, The coining preii for stamping the impression 

 on both *ii! 



The !ir t operation is the mixing of the metal, became 

 there . . of pure gold or ilver, quantity of 



copper or alloy bfing always mixed with them, to ren- 

 der the com harder, aud lets liable to be diminished by 

 fraud. When the metal ia mixed in crucible), and melt- 

 ed in an air furnace, it is cast into long flat bars or in- 

 gots, by the same methods as are used by founder* in 

 land, both with regard to the frames, the manner of 

 working the earth, and the use of the models or pat- 

 tern*. These patterns are flat plates of copper about fif- 

 teen inches long, and nearly the thickness of the coin to 

 be (truck. The bars or ingots, when taken out of the 

 mould*, have the sand (craped and brushed off ; and are 

 passed several times through the rollers of the mill, to 

 flatten and bring them to the just thickness of the specie 

 to be coined. Before the ingots of gold are passed through 

 the mill, they are annealed, that is, they are heated red in 

 a furnace, and plunged in water, to soften and render the 

 metal more ductile. The silver ingots pass through the 

 mill, just as they are, without any annealing, but are after- 

 wards put into the furnace and left to cool gradually. 

 The plates, whether silver, gpld, or copper, being thus 

 reduced as near as possible to their thickness, are cut 

 Tutting out jot,, round pieces called blanks or planchets, very near 

 ...il> jj^ $ j ze Q f t | ie i, lten( i e (i specie. This is done with a ma- 

 chine similar to that called by mechanics, a fly press ; 

 see fig. 6. Plate CCI. It consists of a proper iron frame 

 AA, supporting a perpendicular screw B, which ha* 

 a handle C at the top to work it by, and at the lower 

 end is a cylindrical steel punch a, of exactly the same 

 size as the pieces intended to cut out. When it is depres- 

 sed by the screw, this punch or cutter enters a hole made 

 in a steel dye or bed b, which hole is exactly the size of 

 the punch. The slip of plate D being placed over this 

 hole, and the screw turned by its handle, force, the 

 punch through the plate, carrying a round piece with it. 

 The workman guides the plate D with one hand and 

 works the screw C with the other, so as to cut out the 

 pieces with great rapidity. 



These pieces are now given to proper officers to be 

 adjusted, and brought by filing the edges to the weight 

 of the standard, whereby they are to be regulated : the 

 remainder of the plate between the circles is melted 

 again under the denomination of size!. The pieces are 

 adjusted in a fine balance ; and those which prove too 

 light are separated from those which are too heavy, ttic first 

 to be melted again, and the second to be tiled down ; 

 for the rollers of tlir flatting mill, by which the plates 

 are reduced, are never so exact, but there will be some 

 inequality in the thickness, causing a difference in the 

 blanks, which inequality may indeed be owing to the 

 quality of the matter, as well as of the machine, some 

 parts being more porous than other*. 



When the blanks are adjusted, they are carried to the 

 blanching or whitcnm.; house, where they have their 

 colour given them ; and the silver ones are whitened, 

 which u done by heating them in a furnace, to anneal 

 and soften the metal, and when taken out and cooled, 

 they are boiled successively in two copper vessels with 

 water, containing common salt and tartar, and after that 

 they are scoured well with sand, and washed with com- 

 mon water, then dried over a wood fre in a copper 

 sieve, into which they are put when taken out of the 

 Milting ilic boiler*. The planchets arc now marked with letters, 

 graining on UK edge, to prevent the clipping and 



Adjusting. 



JUinchJnj. 



paring of the specie, which is one of the ways wherein Coining 

 the ancient money used to be damaged. The method of NI 

 performing this operation, in the English mint, is by its """"Y"*"' 

 very constitution kept a profound secret ; but is shewn 

 publicly in the mints of foreign countries. The machine, 

 used by them, for marking, or milling the edges, is very 

 simple, yet ingenious) see PlateCCi. rig. 7. It consists of Pi.triCCI 

 two plates of steel, an and bit m the form of rulers, and V'S- "> 

 about the same thickness as the coin. On the adj 

 edges of the^e the legend or edging is engraved, half on 

 the one, and half on the other. One of these rulers ad is 

 immoveable, being strongly bound with clamps t > a cop- 

 per plate dd, and that again is fixed to a strong board 

 or table AA. The other plate bb is moveable in the di- 

 rection of its length, and shdts on the copper plat" dd, 

 by means of a handle B, and a pinion D ; the teeth of 

 which catch into the teeth of a rack ee, attached t>> the 

 moving ruler bb. The distance between the edges of 

 the two rulers is made to correspond with the diameter 

 of the money, by advancing the immoveable ruler to- 

 wards the other by two screws/^ No-v the blank being 

 placed horizontally between these two ruler-,, is carried 

 along by the motion of the m veable one, so that by the 

 time the handle B has made half a turn, it is found 

 marked all round. The Figure shews that the machine 

 will do two blanks at once. 



This machine is so easily wrought, that a single man ii 

 able to mill twenty thousand blanks in a day. Savang says 

 it was invented by the Sieur Casta^in, engineer to the 

 French king, and first used in 1685. But it is cert iin 

 we had the art of lettering the edges in En^l.md long 

 before that time. Witness the crowns and halt crowns 

 of Oliver Cromwell, struck in 1658, which, for beauty 

 and perfection, tar exceed any French coins we have 

 ever seen. 



The planchets being thus prepared, are to be stamped Cumin? b 

 in the coining press, bhewn in Fig. 8. of Plate CCl. thc P reM - 

 This machine has a massive iron frame, consisting of two JViTiCC 

 upright sides or cheeks, AA, united by cross pieces or Vig. 8. 

 sills, B and C, at top and at bottom. Thr ugh the top 

 piece B, a strong perpendicular screw D works in the 

 center of the frame, and actuates the upper die or steel 

 matrix a, on which the impression of the coin is en- 

 graved or sunk ; this die is fixed in a square slider E, 

 moving in collars b,b, attached to the frame A, so that it 

 merely rises and falls by the movement of the screw, with- 

 out turning round. The lower die c, is fixed in the 

 center of the bottom sill C of the press, being held in a 

 box furnished with screws to adjust it immediately be- 

 neath the upper one. The presr. i wrought by four men. 

 The screw D has a lever, or pair of arms F, F, fixi d on 

 the top of it, called by the French halancitr or fly, from 

 being loaded at the ends with hi avy weights d,il ; a ,d the 

 men pull by ropes or straps G,G and H,H, fastened at 

 the ei.ds of these arms; another person sits in a hole in 

 the floor before the press, and places the blanks, one by 

 one, upon the lower die c, then the two men, by the ropes 

 GG, give a sudden motion to the arms of tin 1 fly dd, 

 which turning the screw D, presses the upper die up,m 

 the money with sufficient force to give it nit impression, 

 the momentum acquired by the motion of the wei^iits of 

 the fly giving it a very great p >\ver. The recoil of the 

 press, aided by the two workmen who hold the two 

 shafts HH, returns the arms of the fly ; then the person 

 beneath puts in another blank, which 11 struck as before, 

 and in this manner the operation proceeds very rapidly. 

 The blanks having now all their marks and impressions, 

 both on the edges and faces, become money ; b-.it tSey 

 have not currency till they have been weighed and < 



