hammer

1 the part of a gunlock that strikes the percussion cap when the trigger is pulled [syn: cock]

2 a hand tool with a heavy rigid head and a handle; used to deliver an impulsive force by striking

3 an athletic competition in which a heavy metal ball that is attached to a flexible wire is hurled as far as possible [syn: hammer throw]

4 the ossicle attached to the eardrum [syn: malleus]

5 a heavy metal sphere attached to a flexible wire; used in the hammer throw

6 a striker that is covered in felt and that causes the piano strings to vibrate

7 a power tool for drilling rocks [syn: power hammer]

8 the act of pounding (delivering repeated heavy blows); "the sudden hammer of fists caught him off guard"; "the pounding of feet on the hallway" [syn: pound, hammering, pounding]

1 beat with or as if with a hammer; "hammer the metal flat"

2 create by hammering; "hammer the silver into a bowl"; "forge a pair of tongues" [syn: forge]

see Hammer

English

Etymology

Old English hamor < Germanic *hamara-. Cognate with Dutch hamer, German Hammer, Swedish hammare.

Pronunciation

• /ˈhæmə/, /"h

History

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 and 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.

Popular hand-powered variations include:

• carpenter's hammers (used for nailing), such as the framing hammer and the claw hammer
• upholstery hammer
• construction hammers, including the sledgehammer
• drilling hammer - a lightweight, short handled sledgehammer
• Ball-peen hammer, or mechanic's hammer
• cross-peen hammer, or Warrington hammer
• mallets, including the rubber hammer and dead blow hammer.
• Splitting maul
• stonemason's hammer
• Geologist's hammer or rock pick
• lump hammer, or club hammer
• gavel, used by judges and presiding authorities in general
• Tinner's Hammer

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

• jackhammer
• steam hammer
• trip hammer
• hammer drill, that combines a jackhammer-like mechanism with a drill

Tools used in conjunction with hammers

• Woodsplitting wedge - hit with a sledgehammer for spiting wood.
• Woodsplitting maul - can be hit with a sledgehammer for splitting wood.
• Masonry star drill
• Chisel
• Punch
• Anvil

The physics of hammering

Hammer as a force amplifier

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

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=). 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. But clearly, it's unreasonable to use a sledge hammer to drive upholstery tacks. 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. 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.

Symbolic hammers

The hammer is associated with West Ham United, who are nicknamed 'The Hammers' and have a symbol of two crossed hammers on the team crest. The origin of this goes back to the club's beginning in the 19th Century, when the Thames Ironworks company football team turned professional in 1895, and became renamed as West Ham United. Two hammers crossed is a mining symbol.

The song If I Had a Hammer has been a top ten hit and was considered an anthem of the Civil Rights Movement. It has been recorded by many artists, including Peter, Paul, and Mary, Trini Lopez, and Leonard Nimoy. The song begins:

If I had a hammer I'd hammer in the morning

I'd hammer in the evening all over this land

I'd hammer out danger, I'd hammer out warning

I'd hammer out love between my brothers and my sisters

All over this land

External links

• Hammer types images and descriptions.
• The Hammer Museum The world's only museum about the place of the hammer in human history.