TUBES 



1031 



2040 



2041 



2042 



of with the plyers of the drawbouch and drawn through its entire length, the tool 

 either being a pair of rolls, as in fig. 2040, or a two-part conical pair of dies united 

 together as a pair of plyers ; see Jig. 2038. In fig. 2039 the operation of the die, &c., 

 is shown in welding, after a second heating: A A is section of bell-mouthed tool; uthe 

 unwelded tube ; c, the portion drawn through the tool or die, and welded in passing 

 through ; this completes the manufacture of a ' butt or jump-joint welded tube for gas 

 or the transmission of a fluid in which the pressure is not great." 



In the manufacture of a ' lap ' welded tube, the manipulation is more complicated, 

 as the edges of the iron to be welded require to be thinned preparatory to welding, and 

 this is effected by drawing the edge of the sheet against a suitably-formed cutter, 

 which cuts away the desired metal from the opposite sides of the metal, which come 

 together, and form the 'lap' to be welded; see fig. 

 2041. The flat strip is then worked into an oval form 

 in its entire length, the lap being in the centre of the 

 longest diameter of the oval in a transverse section ; 

 see fig. 2042. Down the centre of this oval-formed 

 tube or unwelded cylinder, a mandril is introduced, A, 

 which forms an internal support : the tube being 



heated, and the mandril inserted, the tube is passed 



through rolls to effect and complete the weld. The 

 tube is brought into a cylindrical form bypassing through rolls, the reverse or largest 

 diameter being compressed or converted thereby into a cylindrical tube ; the rolls are 

 operated upon by screws which permit of their being pressed down into closer con- 

 tact, and to convert an oval opening in the rolls when asunder or not screwed dosvn 

 into a circular opening, when the rolls arc brought into closer contact. 



The Manufacture of Steel Tubes for Ordnance, Gun-barrels, and other purposes, has 

 recently been carried into practical usefulness, and more particularly so since the 

 extensive application of the Bessemer process. Ingots of iron produced by the process 

 named are reheated, and hammered in every direction, so as to ensure perfect homo- 

 geneity of substance and material, and the ingot reduced in thickness and increased 

 in breadth. To form a cylinder for a heavy gun or rifle, the centre of the blank of 

 steel is operated upon by a punch moved by machinery, which not only condenses the 

 metal operated upon, but in moving radially forms or raises the disk-like mass into a 

 partially-formed solid-ended crude cup, eventually into a steel billet : into the centre 

 of the billet a mandril is inserted, and it is elongated and compressed until the 

 desired length and dimensions of the tube required are arrived at. The lightness and 

 strength of steel in a tubular form suggests its applicability to large-sized shafting 

 hitherto made of solid iron, and to other purposes where great masses of steel wero 

 forged solid and bored out. When this process of manufacture is perfected, and 

 consequently cheapened by being more generally applied, steel tubes, cylinders, and 

 hollow shafts will supersede the use of tubes, large solid shaftings, and many tubular 

 articles now made of iron. 



The Manufacture of Brass Tube of the ordinary kind, known as Soldered. This 

 variety of brass tube, so largely used in the manufacture of gas-fittings, cornice-poles, 

 and other articles in which brass tube is employed in the construction, is made from 

 brass cast in thick strips, and rolled out into sheets of the thickness required. These 

 sheets are cut into ribbons in breadth corresponding to that necessary to produce, when 

 turned up, tubes of the various diameters required. This is done by means of revolv- 



2043 



ing disks of steel, or cutters fitted into a frame, and operated 

 upon by a winch-handle when worked by hand, or attached to 

 a shaft in connection with an engine when moved by power, 

 see Jig. 2043: B E, represents a cast-iron frame; cc, the re- 

 volving disks of steel, or cutters; A, a moveablo gauge, in 

 order to determine the breadth and guide the edge of the 

 sheet brass to be cut ; B B are pinions which are attached to the 

 spindles which carry the cutters, and D the winch-handle to 

 move the cutters when worked by hand. 



When the metal of which the tube is made is thin, and the tube is small in dia^ 

 meter, it is readily formed into a cylinder by simply converting the end of the ribbon 

 into a tange by hammering together the metal which forms the end of the ribbon, in 

 order to allow it to enter the drawing tool, using also an additional funnel-shaped tool 

 to gather up or concave the ribbon in its width. This is assisted by a tapering iron 

 plug held in the funnel-shaped gathering-up tool already alluded to. This arrange- 

 ment is represented in fig. 2044 : A representing the snag of drawbench against which 

 the tool rests ; i?, the tool or die ; c, the trumpet-shaped or 'gathering-up ' die ; E, an 

 iron tapering plug; D, a wedge, in order to prevent nfrom being drawn in and stopping 

 the metal being turned up in its passage through the ' gathering-tip ' tool and die, thus 



