Take one type of the thousands manufactured by the Roebling Company and see what must be done to make the finished product for the Signal Corps. This process, which includes both the manufacture of steel wire for the outer protection and copper wire for transmission, may be divided into the following parts:
All steel materials are analyzed and inspected. Acid open hearth steel is made in ingot form in special furnaces. The steel is classified, and the ingots are reheated and rolled into billets, which are cropped to eliminate all segregation. The steel billets are reheated and rolled into rods of about 3/16 inch diameter. The rods are then tempered for wire drawing. Then comes an inspection and testing for physical characteristics of the metal, and the rods are cleaned in acid, washed, lime coated and left to dry.
These rods are then drawn cold through dies to intermediate sizes requiring a repetition of the tempering, inspecting and cleaning operations. There is another series of drawing and then the final one through the hardest and toughest dies obtainable to a diameter of 12/100 inch. At this diameter one foot of the original rod has been extended to about 350 feet.
Then comes another inspection and test of the mechanical properties. The wire is next cleaned in alkaline and acid solutions to remove all trace of the lubricants used in the wire drawing, and the wire is subjected to a bath in pure hot tin. Finally there is a Government inspection and test.
So much for the manufacture of steel wire. The copper first appears in bars, which are inspected and tested for their metallic purity. The bars are heated and rolled into rods of about 3/8 inch diameter. These rods are cleaned in acid baths to remove all scale, and the wire drawn with the necessary annealing and cleaning until wire that is only .0285 of an inch in diameter is the result.
The final drawing of this wire requires the use of diamond dies with the necessary equipment and great skill of the wire drawers in piercing these minute openings. The copper wire then is annealed free from all scale and discoloration, and the tin coat applied by means of a liquid tin bath. Then the Government inspectors test the copper wire.
Ten strands of the steel wire are twisted about the one copper wire, and the Government inspectors again make tests to see if the inner copper wire is intact and properly protected by steel wire. All grease is removed from the strand, and tussah silk wrapped over the whole. To this is applied a compound with 30 per cent rubber, which is later vulcanized. Then come inspections for mechanical injuries and electrical characteristics. The single conductors are braided, the braid waterproofed, polished, twined, inspected, reeled for shipment, inspected by the Government agents, packed, inspected again by the Government agents and finally shipped.
All this is done with a great deal of rapidity but with no less care, the skill obtained by the workmen only by years of experience and by the technical men only by years of study. It required a thorough knowledge of steel and of the materials entering into the manufacture of steel, such as ore, pig iron and fuel, as well as of the properties and tests and manufacture of copper, tin, rubber, cotton, and various lubricants. And in the more general use of wire and wire rope, a thoroughly comprehensive knowledge of many other materials, all mechanical and electrical phenomena in fact, are essential.
CHAPTER VII
A CITY BUILT OUT OF HAND
All up and down the Delaware, between Trenton and Philadelphia, the “quality folks” in olden times used to build stately homes, with broad acres at their backs and looking lordly, with their Grecian porticos, out from the high banks that command the stream. You may see some of them yet, faded and old and full of family history, most of which was not so important as it seemed to the builders. In the little towns that you pass on the trolley and the Camden and Amboy road, there is a certain Eighteenth Century somnolence, and a dingy pride of priority. They sleep on, as if it were creditable not to be busy. Bordentown, a few minutes’ ride from Trenton, sits complacent amid its memories of the Bonapartes. It is there you change for Roebling.