1028 



tube was elongated from a thick cylinder, or billet of lead, by means of the 

 drawbench, the l)illet in its interior being supported by a mandril of steel ; and in 

 that condition it was drawn through a succession of wortles or tools which diminished 

 the external diameter of the billet until the desired external diameter of the tube 

 was arrived at. As, however, the drawbench. is an important machine in the 

 production of tube formed of every kind of metal, a cut is here introduced to show its 

 construction. 



In Jig. 2025, an elevation of drawbench, A A A A represents the frame of the draw- 

 bench ; c the pinion connected with the driving shaft of the engine ; B the toothed 

 wheel ; D D D D, the endless chain ; E the clip to which the plyers are attached ; F the 

 two snags or standards against which the die M is held in the process of drawing. 

 Fig. 2026, represents an end section of the drawbench at F ; 

 Jig. 2028, representation of a section of endless chain ; fig. 

 2029, section of wheel and pinion. H represents the driving 

 shaft, and G the pulley or sheaf in which the chain moves. 

 Fig. 2030, K shows hook which is inserted into interstices 

 of endless chain at N, into which the plyers or nippers are 



2034 



2035 



2036 



attached in which the spit, mandril, or metal is placed and held in the process of 

 drawing the tube. Fig. 2027 represents the ' snags ' or standards against which the 

 tool M is held. Fig. 2031 represents section of tool M; fig. 2032 section through G 

 showing projections which catch the interstices or apertures in chain, Jig. 2028, 

 and drag it along ; a corresponding pulley or sheaf is placed at i, fig. 2025. 



Reverting to the manufacture of lead-tube, the billet was cast in metal moulds or chills, 

 thus,y?gr. 2033, AAArepresents metal mould and B the steel mandril; into the space cc, the 

 lead was poured; the result was a casting or 'billet,' when the mould was opened, and the 

 mandril B withdrawn. The result was a hollow cylinder, fig. 2034, in section. Into 

 the space M B a mandril was introduced, fig. 2035, in form corresponding to its internal 

 diameter, the parallel part of mandril D D being of the length of the intended tube. 

 The ' billet' alluded to was passed on to the mandril D D ; and held by the shoulder of 

 the diminishing part thereof in front of the nose of the billet, and on the reduced 

 portion of the mandril a series of ' wortles ' or ' dies ' 

 were placed, diminishing in diameter to the required 

 external size of the tube ; in this condition the mandril 

 and billet was taken to the drawbench, the largest die 

 placed against the snags or rest for the die, and the 

 billet drawn through and thereby reduced in diameter 

 and elongated: then followed drawing through the 

 other and smaller or diminishing dies in succession as 

 described ; the last operation consisted in withdrawing 

 the spit or mandril : an easy operation, and simply 

 effected by reversing the billet and using a die, the full 

 size of the mandril to be withdrawn, the drawbench 

 assisting in the operation. By a similar process, 

 BLOCK TIN tube, now so largely used in gas-fitting, for 

 liquor-fountains, and Bother purposes, is still made ; its 

 brightness being produced in the process of drawing 

 by a cutting-die, which shaves off a thin- portion of the 

 metal and exposes its brilliancy : the polish is given by 

 the dies which follow in succession. It will, however, 

 bo evident that the process alluded to is a slow one, and 

 but imperfectly adapted to supply the great demand for 

 lead-pipes now existing. An exceeding rapid process 

 for its production is now adopted, in which an hydraulic 

 press, operating on a molten mass of lead, forces it in 

 its melted state through a suitably-formed annular 

 space, and produces lengths of tube limited only in 

 their length by the quantity of liquid lead operated 

 upon. The process will be best understood by reference 

 to tlio cut, fig. 2036, which consists of a double-ended piston, operated upon by a 

 hydraulic apparatus, a lead furnace, and a ijosel or exit from which issues the pipe 



