Screws Paradigm

Around the first century, screw shaped tools became common however historians do not know who invented the first. Early screws were made from wood and were used in wine presses, olive oil presses, and for pressing clothes. Metal screws and nuts used to fasten two objects together first appeared in the fifteenth century. However Archimedes (ref. lecture 11) is considered responsible for applying the screw mechanism (helicoids) for extracting ground water to higher grounds.

About Screws

Plate 43A Helix Screw Thread	43B Types of Gear	43C Conical Screw		43D Bolt Screw

(Source: 43A&B http://en.wikipedia.org/wiki/Helix_angle ; Sept. 8, 2012
43C&Dhttp://www.google.co.in/search?q=Screw&hl=en&sa=N&prmd=imvns&tbm=isch&tbo=u&
source=univ&ei=WNKUMzoOYaIrAfX5YCIDA&ved=0CDIQsAQ&biw=1332&bih=581 ; Sept. 8, 2012)
(Read more: http://en.wikipedia.org/wiki/Helix_angle ; Sept. 8, 2012 & http://en.wikipedia.org/wiki/
Screw ; Sept. 8, 2012)

Screw is directly related to the topic of bigger and smaller or contraction or expansion. Commonly as we experience, screw inserts inside the body of a material (wood, metal, etc.). In technical terms, a screw is a helix or inclined plane wrapped around a cylindrical or conical body. In industrial applications, a screw typically refers to a threaded fastener with a conical form and a specialized head; threaded cylindrical forms (plate 43C) are instead referred to as bolts (plate 43D). Whatever the definition, screws are used for joining and connecting two bodies together.