WIRE. 



of hard or foft parts. The fofteft iron 18 not always found 

 the beft, as it will dimiiiifh by the ftrain of drawing it 

 through the holes alone : and to obviate this, the workman 

 muft draw fuch iron through a greater number of holes to 

 Dbtain the required extenfion. 



The iron is wrought at the tilt-mills from fquare bars 

 nto round rods of a proper fize to commence drawing. 

 The operation of tilting is nearly the fame as tilting ofjleel. 

 'See that article.) The tilt-hammer for a wire-work 

 generally makes twenty ftrokes per minute, and weighs 

 ibout fifty pounds. There is alfo a larger hammer worked 

 )y the fame mill, which ftrikes about 130 times ^cr minute, 

 md weighs 100 pounds. This hammer is only ufed for the 

 irft preparation of the iron, or for welding a faggot of 

 mall bars together, in order to give the iron a better 

 juality by a preparation fimilar to the German fteel. To 

 [raw out the iron bars into rods of a proper fize to begin 

 Irawing, the workman heats fix or eight inches of the end 

 )f a large bar, which comes from the great forge where the 

 ron is made, and when properly heated he works it regu- 

 arly under the fmall tilt, until it is drawn out to a fmall 

 ind regular round rod of five or fix feet in length. A 

 [ood workman can thus draw out two hundred weight of 

 ron in a day, or an ordinary workman one and a half 

 lundred weight. The lofs of metal in the operation is near 

 \6 ptr cent, by weight. 



The fmall rod, before it is cold, is taken by another 

 workman, who itraightens the rod with a hammer upon an 

 nvil, then cuts it off, and places the end of the great bar 

 gain in the forge. This fame workman alfo fuperintends 

 he heating of the iron, and muft be very careful not to 

 iverheat it, but to heat the whole regularly. 



It is a good praftice to pafs the iron-rod through a pair 

 (f grooved rollers, the grooves of the two rollers being 

 )ppofite, fo as to form a round between them. By thefe 

 neans, the iron may be reduced fmall, and rendered very 

 rue, previoufly to beginning the drawing. For common 

 vire, the whole reduAion may be done by the rolHng-mill 

 vithout a tilt ; but the hammer will give a more tenacious 

 [ualily to the iron than can be obtained by rolling. 



A fmall round bar, thus prepared, muft be drawn through 

 I hole in a draw-plate, by a ftrong machine with a chain, 

 ir elfe by the lever-machine,^^. 7. The end of the iron 

 s firft reduced, fo that it will enter the hole in the draw- 

 jlate, and pafs through fufBciently for the pincers to take 

 lold. This is done at the forge by a hammer and anvil. 

 By pafling through the plate the wire becomes lengthened, 

 n proportion as it is diminifhed in fize. It muft then be 

 innealed to foften it, the end pointed anew, and again put 

 hrough a fmaller hole. 



The workman who attends the procefs muft ftudy the 

 lature of the iron, and regulate the manner of drawing ac- 

 :ordingly. This he does by altering the figure of the hole 

 hrough which the wire is drawn. The hole muft be conical ; 

 :he fmalleft part, being that which afts principally on the 

 •netal, muft be at that fide of the plate where the wire 

 comes through. If the taper of the hole is not properly 

 proportioned, the iron will be ftrained in drawing ; for 

 jhough the machine will force it through, grains of harder 

 inetal than the reft of the wire will form themfelves, which 

 jvill occafion the wire to break when it comes to be much 

 deduced. This is particularly the cafe in foft iron. To 

 iivoid this, the hole muft be chofen very httle fmaller than 

 Ihe iron, and muft be made with a regular taper. It muft 

 1)6 well fupplied with greafe, to diminiih as much as pof- 

 |ible the friftion ; and the motion of the draught muft be 

 regulated according as the metal will bear it. 

 I Vol. XXXVIII. 



Much depends upon the quality of the draw-plate ; al- 

 though the metal of the plate is fufliciently hard to draw 

 the wire, it will not refift the blow of a hard fteel hammer 

 and punch. The punch is driven into the hole from he- 

 hind, until it enlarges it to the required fize and figure. In 

 the operation of drawing, the hole becomes gradually en- 

 larged, and that in a greater degree at the fmalleft end of 

 the hole, fo that it becomes nearer to a cylinder. To rectify 

 this, the punch muft be applied, or the wire would not pafs 

 eafily ; that is, if the fame degree of rcduftion in the fize of 

 the wire was attempted, it would break or ftrain the wire, 

 if the hole was cylindrical, although it would pafs through 

 a regular taper hole. The hole fometimes wears irregularly, 

 and lofes its circular figure. In this cafe, the plate is ham- 

 mered around the fmall end of the hole, and the hole is 

 thereby reduced. The punch is then driven in, to enlarge 

 It again to the required fize : fometimes the punch is intro- 

 duced at the fmall end, and then at the large end, as it may 

 be required to form the hole. In all cafes, the punch 

 muft be driven very gently ; and after every ftroke of the 

 hammer it muft be loofened in the hole, and turned round 

 before another blow is ftruck, and without this precaution 

 it would fix faft in the hole. 



The French draw-plates are the moft efteemed ; and, 

 in time of war, a good French draw- plate has been fold for 

 its weight in filver. M. Du Hamel, in Les Arts et Metiers, 

 vol. XV. gives the following account of the procefs of making 

 the draw-plates for the large iron-wire. 



A band of iron is forged of two inches broad and one 

 inch thick. This is prepared at' the great forge. About 

 a foot in length is cut off, and heated to rednefs in a fire of 

 charcoal. It is then beaten on one fide with a hammer, fo 

 as to work all the furface into furrows or grooves, in order 

 that it may retain the fubftance called the potin, which is 

 to be welded upon one fide of the iron, to form the hard 

 matter on which the holes are to be pierced. This potin 

 is nothing but fragments of old caft-iron pots ; but thofe 

 pots which have been worn out by the continued aftion of 

 fire are not good : the fragments of a new pot which has 

 not been on the fire are better. 



The workman breaks thefe pieces of pots on his anvil, 

 and mixes the pieces v/ith charcoal of white wood. He 

 puts this in the forge, and heats it till it is melted into a fort 

 of pafte ; and to purify it he repeats the fufion ten or twelve 

 times, and each time he takes it with the tongs to dip it in 

 water. M. Du Hamel fays, this is to render the matter 

 more eafy to break into pieces. 



By thefe repeated fuilons with charcoal, the caft iron is 

 changed, and its qualities approach thofe of fteel, but far 

 from becoming brittle ; it will yield to the blows of the 

 hammer and to the punch, which is ufed to enlarge the holes. 

 The bar of iron which is to make the draw-plate is covered 

 with a layer of pieces of the potin, or caft iron, thus pre- 

 pared. It is applied on the fide which is furrowed, and 

 (hould occupy about half an inch in thicknefs. The whole 

 is then wrapped up in a coarfe cloth, which has been dipped 

 in clay and water mixed up as thick as cream, and is put 

 into the forge. The potin is more fufible than the forged 

 iron, fo that it will melt. The plate is withdrawn from 

 the fire occafionally, and hammered very gently upon the 

 potin, to weld and in fome meafure asnalgamate it with the 

 iron, which cannot be done at once ; but it muft be re- 

 peatedly heated, and worked until the potin fixes to the 

 iron. The workman then throws dry powdered clay upon 

 it, in order, they fay, to foften the potin. 



The union being complete, the plate is again heated, and 



forged by two workmen, who draw out the plate of one 



3 Z foot 



