TUBES 1035 



substituted in the drawbench for the tool shown in tho preceding fnj. the thick end 

 of mandril A, passed through this, is taken hold of by the plycrs of the drawbench ; 



2055 



the end of the metal of tho tube presents a resistance, while the force of tho draw- 

 bench drags out or releases the mandril from the drawn tube. Mandril, or drawn 

 ' inside ' and ' out' tubes, as they are familiarly called by the ' users,' may be made of 

 any form or size. When of extra thick metal, very powerful, slowly moving draw- 

 benches are required. 



The Manufacture of Patent Brass-cased Tube, or iron tube, cased with brass. This 

 variety of tube largely used in tho construction of articles in which the external 

 appearance of brass is desired with the strength of iron, as in balustrades for stairs, 

 railingr; of various kinds, picture-rods, window and other rods, and bedsteads, chairs, 

 and other articles of furniture made in metal of a portable character, and otherwise 

 was introduced to tho brass-foundry trade of Birmingham in tho year 1803, and is 

 stated to have originated in the observation of the difficulty of removing a man- 

 dril-drawn brass tube from the steel mandril on which it was drawn. The inventor, 

 Sir Edward Thomason, was largely engaged in the silver and plated ware manufac- 

 tures in Birmingham. As a manufacturer of sliding hearth-brushes, toasting-forks, 

 und other articles telescopically formed, ho used large quantities of mandril-drawn 

 tubes, and in the production of such tubes, and the difficulty of getting these off the 

 internal support, the manufacture of patent tube originated. Thomason first also 

 originated the idea of covering solid iron rods with copper and brass, with tho 

 intention of their being used instead of solid copper bolts for ship-building purposes. 

 Though unsuccessful as regards the application of iron-cased bolts for the purpose, 

 solid iron rods cased with brass became, and have become, an article of large con- 

 sumption in the form of tho rods which retain the carpetings on stairs. Eventually 

 an iron tube took the place of the solid iron rod, and the manufacture of cased tube 

 took its place as an article of extensive demand for the purposes already named. The 

 manufacture of patent cased brass or iron tube is thus practised : Sheet iron of good 

 quality, if for articles which do not require to be bent in manufacture, as in rods for 

 pictures, straight railings, &c. ; but if the tube is to be bent, charcoal-iron is selected ; 

 the sheets of iron are cut up with circular cutters, as shown at Jiff. 2043 ; and the 

 ribbon arising from the cutting or slitting of sheet iron is concaved in its entire 

 length by passing it through rolls, as shown in fig. 2044. It is drawn into tube at 

 tho drawbench, in this state: if the tube is intended for articles which are to remain 

 straight, tho iron tube is in a condition to allow of its receiving its case of brass ; 

 if it is intended that the tube should be bent, the iron tube is soldered together at 

 the seam, as already described in the manufacture of soldered brass tube, the brass 

 sheath intended to cover the iron tube or to case it with, is made of such an internal 

 diameter as will slide over the iron tube it is intended to ' case ' or cover, the brass 

 case being turned up, made, and soldered, as already described in the manufacture 

 of soldered brass tube. The brass sheath is then slid over the iron tube, and in this 

 position the end of the two united tubes of iron and brass is passed through the 

 drawing tool : tho pressure resulting from the action of the drawbench causes tho 

 external brass sheath or tube to embrace firmly the iron tube in its interior, and 

 an externally brass and internally iron tube is produced thereby. During the 

 many years this branch of tube manufacture has been practised, no change or 

 improvement has been made in its manipulation if we except that, within the last 

 few years, hoop-iron has been substituted in the manufacture of second-rate cased 

 tube, instead of cutting up the broad sheet-iron as formerly. 



Taper Tubes of Brass or Iron. This form of tube, formerly made entirely by hand, 

 is now drawn with ease and facility. The old method of production consisted of 

 cutting out the metal from the sheet requisite to produce the desired taper tube. It 

 was then malleted into a taper tubular form, and the metal soldered together at the 

 junction ; then, after the extra solder was removed, it was hammered on a taper 

 mandril or stake, as in Tise among tinmen. Many ingenious drawing tools were mado 

 for tho purpose of producing taper tubes. These consisted of dies made in sections, or 

 various pieces ; they were united in frames, and when used in the drawbench tho 

 parts of tho die were operated upon by springs, which permitted of their expansion as 

 the taper increased in the tube and mandril intended to be drawn. Such tools, 



