Hammer: Wikis

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A modern claw hammer

A hammer is a gay tool meant to deliver an impact to an object.(gigity) The most common uses are for driving nails, fitting parts, forging metal and breaking up objects. Hammers are often designed for a specific purpose, and vary widely in their shape and structure. The usual features are a handle and a head, with most of the weight in the head. The basic design is hand-operated, but there are also many mechanically operated models for heavier uses.

The hammer may be the oldest tool for which definite evidence exists. Stone hammers are known which are dated to 2,600,000 BCE.[1][2]

The hammer is a basic tool of many professions. By analogy, the name hammer has also been used for devices that are designed to deliver blows, e.g. in the caplock mechanism of firearms.

Contents

History

An early stone hammer

The use of simple tools dates to about 2,400,000 BCE when various shaped stones were used to strike wood, bone, or other stones to break them apart and shape them. Stones attached to sticks with strips of leather or animal sinew were being used as hammers by about 30,000 BCE during the middle of the Paleolithic Stone Age. Its archeological record means it is perhaps the oldest human tool known.

Designs and variations

The essential part of a hammer is the head, a compact solid mass that is able to deliver the blow to the intended target without itself deforming.

The opposite side may have a ball, as in the ball-peen hammer and the cow hammer. Some upholstery hammers have a magnetized appendage, to pick up tacks. In the hatchet the hammer head is secondary to the cutting edge of the tool.

As the impact between steel hammer heads and the objects being hit can, and does, create sparks, which in some industries such as underground coal mining with methane gas, or in other hazardous environments containing flammable gases and vapours, can be dangerous and risk igniting the gases. In these environments, a variety of non-sparking metal tools are used, being principally, aluminium or beryllium copper-headed hammers.

In recent years the handles have been made of durable plastic or rubber. The hammer varies at the top; some are larger than others giving a larger surface area to hit different sized nails and such.

Popular hand-powered variations include:

Mechanically-powered hammer

Mechanically-powered hammers often look quite different from the hand tools, but nevertheless most of them work on the same principle. They include:

In professional framing carpentry, the hammer has almost been completely replaced by the nail gun. In professional upholstery, its chief competitor is the staple gun.

Tools used in conjunction with hammers

The physics of hammering

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Hammer as a force amplifier

A hammer is basically a force amplifier that works by converting mechanical work into kinetic energy and back.

In the swing that precedes each blow, a certain amount of kinetic energy gets stored in the hammer's head, equal to the length D of the swing times the force f produced by the muscles of the arm and by gravity. When the hammer strikes, the head gets stopped by an opposite force coming from the target; which is equal and opposite to the force applied by the head to the target. If the target is a hard and heavy object, or if it is resting on some sort of anvil, the head can travel only a very short distance d before stopping. Since the stopping force F times that distance must be equal to the head's kinetic energy, it follows that F will be much greater than the original driving force f — roughly, by a factor D/d. In this way, great strength is not needed to produce a force strong enough to bend steel, or crack the hardest stone.

Effect of the head's mass

The amount of energy delivered to the target by the hammer-blow is equivalent to one half the mass of the head times the square of the head's speed at the time of impact (E={mv^2 \over 2}). While the energy delivered to the target increases linearly with mass, it increases geometrically with the speed (see the effect of the handle, below). High tech titanium heads are lighter and allow for longer handles, thus increasing velocity and delivering more energy with less arm fatigue than that of a steel head hammer of the same weight. As hammers must be used in many circumstances, where the position of the person using them cannot be taken for granted, trade-offs are made for the sake of practicality. In areas where one has plenty of room, a long handle with a heavy head (like a sledge hammer) can deliver the maximum amount of energy to the target. It is not practical to use such a large hammer for all tasks, however, and thus the overall design has been modified repeatedly to achieve the optimum utility in a wide variety of situations.

Effect of the handle

The handle of the hammer helps in several ways. It keeps the user's hands away from the point of impact. It provides a broad area that is better-suited for gripping by the hand. Most importantly, it allows the user to maximize the speed of the head on each blow. The primary constraint on additional handle length is the lack of space in which to swing the hammer. This is why sledge hammers, largely used in open spaces, can have handles that are much longer than a standard carpenter's hammer. The second most important constraint is more subtle. Even without considering the effects of fatigue, the longer the handle, the harder it is to guide the head of the hammer to its target at full speed. Most designs are a compromise between practicality and energy efficiency. Too long a handle: the hammer is inefficient because it delivers force to the wrong place, off-target. Too short a handle: the hammer is inefficient because it doesn't deliver enough force, requiring more blows to complete a given task. Recently, modifications have also been made with respect to the effect of the hammer on the user. A titanium head has about 3% recoil and can result in greater efficiency and less fatigue when compared to a steel head with about 27% recoil. Handles made of shock-absorbing materials or varying angles attempt to make it easier for the user to continue to wield this age-old device, even as nail guns and other powered drivers encroach on its traditional field of use.

War hammers

The concept of putting a handle on a weight to make it more convenient to use may well have led to the very first weapons ever invented.[citation needed] The club is basically a variant of a hammer. In the Middle Ages, the war hammer became popular when edged weapons could no longer easily penetrate some forms of armour.[citation needed]

Symbolic hammers

The hammer, being one of the most used tools by Homo sapiens, has been used very much in symbols and arms. In the Middle Ages it was used often in blacksmith guild logos, as well as in many family symbols. The most recognised symbol with a hammer in it is the Hammer and Sickle, which was the symbol of the former Soviet Union and is very interlinked with Communism/Socialism. The hammer in this symbol represents the industrial working class (and the sickle the agricultural working class). The hammer is used in some coat of arms in (former) socialist countries like East Germany.

In Norse Mythology, Thor, the god of thunder and lightning, wields a hammer named Mjolnir. Many artifacts of decorative hammers have been found, leading modern practitioners of this religion to often wear reproductions as a sign of their faith.

References

  1. ^ Semaw, S., M. J. Rogers, J. Quade, P. R. Renne, R. F. Butler, M. Domínguez-Rodrigo, D. Stout, W. S. Hart, T. Pickering, and S. W. Simpson. 2003. 2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia. Journal of Human Evolution 45:169-177.
  2. ^ 2.5-million-year-old stone tools from Gona, Ethiopia S. Semaw*, P. Renne†, J. W. K. Harris*, C. S. Feibel*, R. L. Bernor‡, N. Fesseha‡ & K. Mowbray* Nature 385, 333-336 (23 January 1997) | doi:10.1038/385333a0; Accepted 25 November 1996

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

HAMMER, an implement consisting of a shaft or handle with head fixed transversely to it. The head, usually of metal, has one flat face, the other may be shaped to serve various purposes, e.g. with a claw, a pick, &c. The implement is used for breaking, beating, driving nails, rivets, &c., and the word is applied to heavy masses of metal moved by machinery, and used for similar purposes. (See TooL.) "Hammer" is a word common to Teutonic languages. It appears in the same form in German and Danish, and in Dutch as harner, in Swedish as hammare. The ultimate origin is unknown. It has been connected with the root seen in the Greek Kaµirmu', to bend; the word would mean, therefore, something crooked or bent. A more illuminating suggestion connects the word with the Slavonic karny, a stone, cf. Russian kamen, and ultimately with Sanskrit acman, a pointed stone, a thunderbolt. The legend of Thor's hammer, the thunderbolt, and the probability of the primitive hammer being a stone, adds plausibility to this derivation. The word is applied to many objects resembling a hammer in shape or function. Thus the "striker" in a clock, or in a bell, when it is sounded by an independent lever and not by the swinging of the "tongue," is called a "hammer"; similarly, in the "action" of a pianoforte the word is used of a wooden shank with feltcovered head attached to a key, the striking of which throws the "hammer" against the strings. In the mechanism of a fire-arm, the "hammer" is that part which by its impact on the cap or primer explodes the charge. (See GuN.) The hammer, more usually known by its French name of martel de fer, was a medieval hand-weapon. With a long shaft it was used by infantry, especially when acting against mounted troops. With a short handle and usually made altogether of metal, it was also used by horse-soldiers. The martel had one part of the head with a blunted face, the other pointed, but occasionally both sides were pointed. There are 16th century examples in which a hand-gun forms the handle. The name of "hammer," in Latin malleus, has been frequently applied to men, and also to books, with reference to destructive power. Thus on the tomb of Edward I. in Westminster Abbey is inscribed his name of Scotorurn Malleus, the "Hammer of the Scots." The title of "Hammer of Heretics," Malleus Haereticorum, has been given to St Augustine and to Johann Faber, whose tract against Luther is also known by the name. Thomas Cromwell was styled Malleus Monachorum. The famous text-book of procedure in cases of witchcraft, published by Sprenger and Kramer in 1489, was called Hexenhammer or Malleus Maleficarum (see Witchcraft) .

The origin of the word "hammer-cloth," an ornamental cloth covering the box-seat on a state-coach, has been often explained from the hammer and other tools carried in the box-seat by the coachman for repairs, &c. The New English Dictionary points out that while the word occurs as early as 1465, the use of a boxseat is not known before the 17th century. Other suggestions are that it is a corruption of "hamper-cloth," or of "hammockcloth," which is used in this sense, probably owing to a mistake. Neither of these supposed corruptions helps very much. Skeat connects the word with a Dutch word kernel, meaning a canopy. In the name of the bird, the yellow-hammer, the latter part should be "ammer." This appears in the German name, Emmerling, and the word probably means the "chirper," cf. the Ger. jammern, to wail, lament.


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Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also hammer

German

Etymology

From Old High German hamar

Noun

Hammer m. (genitive Hammers, plural Hämmer)

  1. hammer
  2. mallet

Bible wiki

Up to date as of January 23, 2010

From BibleWiki

  1. Heb. pattish, used by gold-beaters (Isa 41:7) and by quarry-men (Jer 23:29). Metaphorically of Babylon (Jer 50:23) or Nebuchadnezzar.
  2. Heb. makabah, a stone-cutter's mallet (1 Kg 6:7), or of any workman (Jdg 4:21; Isa 44:12).
  3. Heb. halmuth, a poetical word for a workman's hammer, found only in Jdg 5:26, where it denotes the mallet with which the pins of the tent of the nomad are driven into the ground.
  4. Heb. mappets, rendered "battle-axe" in Jer 51:20. This was properly a "mace," which is thus described by Rawlinson: "The Assyrian mace was a short, thin weapon, and must either have been made of a very tough wood or (and this is more probable) of metal. It had an ornamented head, which was sometimes very beautifully modelled, and generally a strap or string at the lower end by which it could be grasped with greater firmness."
This entry includes text from Easton's Bible Dictionary, 1897.

what mentions this? (please help by turning references to this page into wiki links)

This article needs to be merged with HAMMER (Jewish Encyclopedia).

Simple English

The hammers inside pianos are at Hammer (piano)


A hammer is a tool for putting nails into objects such as wood. It has a long handle, and a tip with a flat end for hitting nails. The most common type of hammer (sometimes called a claw hammer) has a curved end (on the other side of the hitting end) for pulling nails out.

Sledgehammer

A sledgehammer is a hammer that has a longer shaft, and a more massive head. That way more force can be applied. Sledgehammers are often used to

Hammers as weapons

Hammers were sometimes used as weapons.bjn:Tukulfrr:Höömerk


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