# Screw (simple machine)

Screw (simple machine)

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of the machine. More threading increases the mechanical advantage. A rough comparison of mechanical advantage can be done by taking the circumference of the shaft of the screw and divide by the distance between the threads.

A screw is a shaft with a helical groove or thread formed on its surface and provision at one end to turn the screw. Its main uses are as a threaded fastener used to hold objects together, and as a simple machine used to translate torque into linear force. It can also be defined as an inclined plane wrapped around a shaft. Screws come in a variety of shapes and sizes for different purposes.

The mechanical advantage of a screw without using a screwdriver is:

*P = Pitch of screw (The distance between two adjacent screw threads is called the pitch.)
*C = Circumference of the head $MA = C / P.$

The same formula can be used when using a screwdriver, but with:

*C = Circumference of the screwdriver handle.

Examples

* Lead screw and ball screw are specialized screws for translating rotational to linear motion.
* Automated garage door, where a motor drives a long finely threaded shaft at relatively high speed and lifts the heavy door at a slower rate.
* Archimedes' screws and worm gears are examples of this machine.

ee also

* Screw (disambiguation)
* Screw - the threaded fastener
* Archimedes' screw

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### Look at other dictionaries:

• simple machine — n. any of the basic mechanical devices, including the lever, wheel and axle, pulley, wedge, screw, and inclined plane, one or more of which are essential to any more complex machine …   English World dictionary

• Simple machine — This article is about the concept in physics. For the Internet forum software, see Simple Machines Forum. Table of simple mechanisms, from Chambers Cyclopedia, 1728.[1] Simple machines provide a vocabulary for understanding more complex machine …   Wikipedia

• simple machine — noun Date: circa 1704 any of various elementary mechanisms formerly considered as the elements of which all machines are composed and including the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw …   New Collegiate Dictionary

• simple machine — /sɪmpəl məˈʃin/ (say simpuhl muh sheen) noun one of the six (sometimes more) elementary mechanisms: the lever, wheel and axle, pulley, screw, inclined plane, and wedge …   Australian-English dictionary

• Screw (disambiguation) — The term screw may refer to:* Screw (simple machine) ** Archimedes screw a simple machine for transporting water to a higher elevation * Screw threaded fastener related articles **Screw threaded fastener with external threads ** Leadscrew used to …   Wikipedia

• screw — screwable, adj. screwer, n. screwless, adj. screwlike, adj. /skrooh/, n. 1. a metal fastener having a tapered shank with a helical thread, and topped with a slotted head, driven into wood or the like by rotating, esp. by means of a screwdriver. 2 …   Universalium