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In
the 3rd century BC, Greek mathematician Archimedes invented
a device consisting of a screw inside a hollow tube used to
move water between two levels. There's also some evidence that
a version of this apparatus, used in olive presses and as a
rudimentary clamping mechanism, existed 200 to 300 years earlier.
In the late 15th century, Leonardo da Vinci created drawings
of a threadlike rod passing through an opposite-mated half to
create a force for moving objects either through tension (pulling)
or compression (pushing). The basic definition of a screw thread
has not changed in over 2,000 years: it is a helical ridge running
around the outside of a cylinder or cone.
The transition from wooden to metal screws began in the 1500s,
as evidenced by hand-cut examples of the screw and worm produced
in Nuremberg, Germany. Metalworkers found a way to accurately
cut repetitive forms, thus allowing greater force to be applied
to the flank (the side of the thread). Around 1800, Henry Maudsley
developed the screw-cutting lathe, which allowed for standardization
of screw thread sizes. Prior to that, individuals created threads
that varied in pitch, diameter and thread angle, according to
each maker.
Commonly
called a screw box with tap, neither part of this tool can function
without the other. (In fact, trying to identify the coarsely
made thumbscrew without its mate proved most difficult.) The
artisan-built tool was used to create wooden screws and functioned
much the same as later-made commercial sets. |
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