8 Little Known Facts about the Screw and screw press
Author: haloong Time: 2016-12-30 11:44
1) Many of the workman’s tools we use today were invented during the Roman Age or even before.
Rybczynski explores the histories of several other tools such as the saw, the plane, the chisel, and the level. He discovers that all of these tools were invented during the Roman age if not before. The chisel, for example, dates from the Bronze Age.
2) The threading on a screw forms the shape of a helix, not a spiral.
This is a common mistake. Rybczynski writes, “A spiral is a curve that winds around a fixed point with a continuously increasing radius…A helix…is a three-dimensional curve that twists around a cylinder at a constant inclined angle” (111). Spiral staircases form helixes, not spirals.
3) The screw firsts appears in machinery during the time of the Ancient Greeks, when screws were used in presses of various kinds.
Screws were first used in olive presses and grape presses. In the Middle Ages, this mechanism was adapted for use in the printing press and the paper press. The screw mechanism allows for tremendous force to be exerted on the object being pressed with minimal effort. For example, imagine a press whose large screw has a pitch of one inch and which is turned by means of a handspike three feet long. A pressure of only 40 pounds on the handspike will exert a pressure of more than nine thousand pounds on the olives or grapes.
4) Some of the earliest screws to be used as fasteners were used in military weapons.
For example, screws were widely used in putting firearms together in the early 16th century. The threads provided a snugger fit that could survive the vibrations from the firing gun. Screws were also widely used in assembly armor. When screws are inserted into metal their threads must be fairly accurate in order to fit properly into the receiving threads. These screws were created by first hammering out a head and shank and then cutting the thread using a die called a screw plate.
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