Outspinning the Spider: The Story of Wire and Wire RopeMumford, John Kimberly
History
Outspinning the Spider: The Story of Wire and Wire Rope
Mumford, John Kimberly
John A. Roebling's Sons Company; Wire; Wire rope
No thinkable effort is omitted that will help to make the wire material
perfect in quality and service condition, but the proof of the pudding
in the making of wire is in the Olsen machines--miraculous things that
will smash a big wire rope or snap a hair of wire and register to a
decimal the breaking strength of each. There are tests for tensile
strength, for torsion to show how many twists a piece of wire will
stand, and for bending. There are microscopic tests for molecular
condition and men who will almost tell you from a microscopic section
the maximum service of which the rope made from a given wire is
capable. Any bundle of wire that doesn't pass the test for the job on
hand is discarded and used for something else, and a record of it all
is kept with scrupulous care. Any foot of wire that passes through the
shipping room on the way to market has a clean bill of health, ample
for the use to which it is destined, and the amount of material that is
scrapped for faults, where work is on stringent specifications, would
be sudden death to a business that hadn't a wide range of uses for
product of whatever quality. Fortunately for the users of high-grade
wire the market for the lower grades is always hungry and crying for
more.
[Sidenote: THE WONDER OF DUCTILITY]
There are complexities without end in the making and finishing of wire,
but the real wonder of it lies after all in the initial principle which
the German inventor in Bavaria gave to the world six hundred years
ago--the simple but even now almost incredible fact that a rod of cold
steel of the hardest quality--plow steel is the convincing name for
it--can be seized by its sharpened end with a clamp they call a dog and
drawn through a smaller hole, in a still harder piece of steel, three
or four feet until it can be fastened to a drum, and then be wound off
in miles almost without interruption. It is a wonder that grows as you
watch it and yet it seems so simple. To see that steel, of tremendous
strength and hardness, drawn through a tiny hole as if it were molasses
candy--and yet it may have a tensile strength of two or three hundred
thousand pounds to the square inch.
There is nothing spectacular about the wire mill where this is done. On
long benches the die-holding appliances are set up and the dies set
into them. The wire--or at first the rod--is run from a portable bobbin
they call a swift, that stands on the floor, and the wire, after it has
been given the hole, passes to a bobbin they call a block. Then it is
taken on to a still smaller die and the same process repeated, with
occasional reheatings, until it has the diameter of a thread.
[Sidenote: CUTTING THE DIES]
Public-domain text, read in full here on John Shaqi.
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