linguistic:translation, structural:expansion
Cables

The first temporary wire was stretched between the towers on August 15, 1876, using chrome steel provided by the Chrome Steel Company of Brooklyn. The wire was then stretched back across the river, and the two ends were spliced to form a traveler, a lengthy loop of wire connecting the towers, which was driven by a 30 horsepower (22 kW) steam hoisting engine at ground level. The wire was one of two that were used to create a temporary footbridge for workers while cable spinning was ongoing. The next step was to send an engineer across the completed traveler wire in a boatswain's chair slung from the wire, to ensure it was safe enough. The bridge's master mechanic, E.F. Farrington, was selected for this task, and an estimated crowd of 10,000 people on both shores watched him cross. A second traveler wire was then stretched across the span, a task that was completed by August 30. The temporary footbridge, located some 60 feet (18 m) above the elevation of the future deck, was completed in February 1877.

By December 1876, a steel contract for the permanent cables still had not been awarded. There was disagreement over whether the bridge's cables should use the as-yet-untested Bessemer steel or the well-proven crucible steel. Until a permanent contract was awarded, the builders ordered 30 short tons (27 long tons) of wire in the interim, 10 tons each from three companies, including Washington Roebling's own steel mill in Brooklyn. In the end, it was decided to use number 8 Birmingham gauge (approximately 4 mm or 0.165 inches in diameter) crucible steel, and a request for bids was distributed, to which eight companies responded. In January 1877, a contract for crucible steel was awarded to J. Lloyd Haigh, who was associated with bridge trustee Abram Hewitt, whom Roebling distrusted.

The spinning of the wires required the manufacture of large coils of it which were galvanized but not oiled when they left the factory. The coils were delivered to a yard near the Brooklyn anchorage. There they were dipped in linseed oil, hoisted to the top of the anchorage, dried out and spliced into a single wire, and finally coated with red zinc for further galvanizing. There were thirty-two drums at the anchorage yard, eight for each of the four main cables. Each drum had a capacity of 60,000 feet (18,000 m) of wire. The first experimental wire for the main cables was stretched between the towers on May 29, 1877, and spinning began two weeks later. All four main cables were being strung by that July. During that time, the temporary footbridge was unofficially opened to members of the public, who could receive a visitor's pass; by August 1877 several thousand visitors from around the world had used the footbridge. The visitor passes ceased that September after a visitor had an epileptic seizure and nearly fell off.

As the wires were being spun, work also commenced on the demolition of buildings on either side of the river for the Brooklyn Bridge's approaches; this work was mostly complete by September 1877. The following month, initial contracts were awarded for the suspender wires, which would hang down from the main cables and support the deck. By May 1878, the main cables were more than two-thirds complete. However, the following month, one of the wires slipped, killing two people and injuring three others. In 1877, Hewitt wrote a letter urging against the use of Bessemer steel in the bridge's construction. Bids had been submitted for both crucible steel and Bessemer steel; John A. Roebling's Sons submitted the lowest bid for Bessemer steel, but at Hewitt's direction, the contract was awarded to Haigh.

A subsequent investigation discovered that Haigh had substituted inferior quality wire in the cables. Of eighty rings of wire that were tested, only five met standards, and it was estimated that Haigh had earned $300,000 from the deception. At this point, it was too late to replace the cables that had already been constructed. Roebling determined that the poorer wire would leave the bridge only four times as strong as necessary, rather than six to eight times as strong. The inferior-quality wire was allowed to remain and 150 extra wires were added to each cable. To avoid public controversy, Haigh was not fired, but instead was required to personally pay for higher-quality wire. The contract for the remaining wire was awarded to the John A. Roebling's Sons, and by October 5, 1878, the last of the main cables' wires went over the river.