Hammer
Overview
 
A hammer is a tool
Tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...

 meant to deliver an impact to an object. 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, such as steam hammer
Steam hammer
A steam hammer is a power-driven hammer used to shape forgings. It consists of a hammer-like piston located within a cylinder. The hammer is raised by the pressure of steam injected into the lower part of a cylinder and falls down with a force by removing the steam. Usually, the hammer is made to...

s.

The hammer may be the oldest tool for which definite evidence exists.
Encyclopedia
A hammer is a tool
Tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...

 meant to deliver an impact to an object. 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, such as steam hammer
Steam hammer
A steam hammer is a power-driven hammer used to shape forgings. It consists of a hammer-like piston located within a cylinder. The hammer is raised by the pressure of steam injected into the lower part of a cylinder and falls down with a force by removing the steam. Usually, the hammer is made to...

s.

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

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
Caplock mechanism
The caplock mechanism or "percussion" lock was the successor of the flintlock mechanism in firearm technology, and used a percussion cap struck by the hammer to set off the main charge, rather than using a piece of flint to strike a steel frizzen....

 of firearm
Firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

s.

History

The use of simple tools dates to about 2,400,000 BCE when various shaped stones were used to strike wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

, 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
Paleolithic
The Paleolithic Age, Era or Period, is a prehistoric period of human history distinguished by the development of the most primitive stone tools discovered , and covers roughly 99% of human technological prehistory...

. 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
Ball-peen hammer
A ball-peen hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It is distinguished from a point-peen hammer or chisel-peen hammer by having a hemispherical head...

 and the cow hammer. Some upholstery hammers have a magnetized appendage, to pick up tacks. In the hatchet
Hatchet
A hatchet is a single-handed striking tool with a sharp blade used to cut and split wood...

 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:
  • Ball-peen hammer
    Ball-peen hammer
    A ball-peen hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It is distinguished from a point-peen hammer or chisel-peen hammer by having a hemispherical head...

    , or mechanic's hammer
  • Carpenter's hammers (used for nailing), such as the framing hammer
    Framing hammer
    Framing hammers, used for framing wooden houses, are heavy duty rip hammers with a straight claw. The hammer heads typically weigh from 20 to 32 ounces for steel heads, and 12 to 16 ounces for titanium heads...

     and the claw hammer
    Claw hammer
    A claw hammer is a tool primarily used for pounding nails into, or extracting nails from, some other object. Generally, a claw hammer is associated with woodworking but is not limited to use with wood products...

  • Construction hammers, including the sledgehammer
    Sledgehammer
    A sledgehammer is a tool consisting of a large, flat head attached to a lever . The head is typically made of metal. The sledgehammer can apply more impulse than other hammers, due to its large size. Along with the mallet, it shares the ability to distribute force over a wide area...

  • Cross-peen hammer, or Warrington hammer
  • Drilling hammer - a lightweight, short handled sledgehammer
  • Gavel
    Gavel
    A gavel is a small ceremonial mallet commonly made of hardwood, typically fashioned with a handle and often struck against a sound block to enhance its sounding qualities. It is a symbol of the authority and right to act officially in the capacity of a chair or presiding officer. It is used to call...

    , used by judges and presiding authorities in general
  • Geologist's hammer
    Geologist's hammer
    A geologist's hammer, rock hammer, rock pick or geological pick is a hammer used for splitting and breaking rocks. In field geology, they are used to obtain a fresh surface of a rock in order to determine its composition, nature, mineralogy, history and field estimate of rock strength...

     or rock pick
  • Knife-edged hammer, its properties developed to aid a hammerer the act of slicing whilst bludgeoning
  • Lump hammer
    Lump hammer
    A lump hammer or club hammer is a heavy one-handed hammer with a double-faced head. It is useful for light demolition work, driving masonry nails, and for use with a steel chisel when cutting stone or metal. In this last application, its weight drives the chisel more deeply into the material being...

    , or club hammer
  • Mallet
    Mallet
    A mallet is a kind of hammer, usually of rubber,or sometimes wood smaller than a maul or beetle and usually with a relatively large head.-Tools:Tool mallets come in different types, the most common of which are:...

    s, including the rubber hammer and dead blow hammer
    Dead blow hammer
    A dead blow hammer is a specialized mallet helpful in minimizing damage to the struck surface and in controlling striking force with minimal rebound from the striking surface...

  • Soft-faced hammer
  • Splitting maul
  • Stonemason's hammer
    Stonemason's hammer
    A Stonemason's hammer has one flat traditional face and a short or long chisel-shaped blade. It can thus be used to chip off edges or small pieces of stone without using a separate chisel...

  • Tinner's Hammer
  • Upholstery hammer
    Upholstery hammer
    An upholstery hammer is a lightweight hammer used for securing upholstery fabric to furniture frames using tacks or small nails....



Mechanically-powered hammers

Mechanically powered hammers often look quite different from the hand tools, but nevertheless most of them work on the same principle. They include:
  • Hammer drill
    Hammer drill
    A hammer drill, also known as a "Hammer drill", "roto-drill" or "hammering drill", is a rotary drill with a hammering action. The hammering action provides a short, rapid hammer thrust to pulverize relatively brittle material and provide quicker drilling with less effort...

    , that combines a jackhammer-like mechanism with a drill
    Drill
    A drill or drill motor is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of...

  • Jackhammer
    Jackhammer
    A jackhammer is a pneumatic tool that combines a hammer directly with a chisel that was invented by Charles Brady King. Hand-held jackhammers are typically powered by compressed air, but some use electric motors. Larger jackhammers, such as rig mounted hammers used on construction machinery, are...

  • Steam hammer
    Steam hammer
    A steam hammer is a power-driven hammer used to shape forgings. It consists of a hammer-like piston located within a cylinder. The hammer is raised by the pressure of steam injected into the lower part of a cylinder and falls down with a force by removing the steam. Usually, the hammer is made to...

  • Trip hammer
    Trip hammer
    A trip hammer, also known as a helve hammer, is a massive powered hammer used in:* agriculture to facilitate the labor of pounding, decorticating and polishing of grain;...



In professional framing
Framing (construction)
Framing, in construction known as light-frame construction, is a building technique based around structural members, usually called studs, which provide a stable frame to which interior and exterior wall coverings are attached, and covered by a roof comprising horizontal ceiling joists and sloping...

 carpentry
Carpenter
A carpenter is a skilled craftsperson who works with timber to construct, install and maintain buildings, furniture, and other objects. The work, known as carpentry, may involve manual labor and work outdoors....

, the hammer has almost been completely replaced by the nail gun
Nail gun
A nail gun, nailgun or nailer is a type of tool used to drive nails into wood or some other kind of material. It is usually driven by electromagnetism, compressed air , highly flammable gases such as butane or propane, or, for powder-actuated tools, a small explosive charge...

. In professional upholstery
Upholstery
Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word upholstery comes from the Middle English word upholder, which referred to a tradesman who held up his goods. The term is equally applicable to domestic,...

, its chief competitor is the staple gun
Staple gun
A staple gun or powered stapler is a hand-held machine used to drive heavy metal staples into wood, plastic, or masonry. Staple guns are used for many different applications and to affix a variety of materials, including insulation, house wrap, roofing, wiring, carpeting, upholstery, and hobby and...

.

Tools used in conjunction with hammers

  • Masonry star drill
  • Anvil
    Anvil
    An anvil is a basic tool, a block with a hard surface on which another object is struck. The inertia of the anvil allows the energy of the striking tool to be transferred to the work piece. In most cases the anvil is used as a forging tool...

  • Chisel
    Chisel
    A chisel is a tool with a characteristically shaped cutting edge of blade on its end, for carving or cutting a hard material such as wood, stone, or metal. The handle and blade of some types of chisel are made of metal or wood with a sharp edge in it.In use, the chisel is forced into the material...

  • Punch
  • Woodsplitting maul - can be hit with a sledgehammer for splitting wood.
  • Woodsplitting wedge - hit with a sledgehammer for splitting wood.

Hammer as a force amplifier

A hammer is basically a force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

 amplifier
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...

 that works by converting mechanical work
Mechanical work
In physics, work is a scalar quantity that can be described as the product of a force times the distance through which it acts, and it is called the work of the force. Only the component of a force in the direction of the movement of its point of application does work...

 into kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

 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 muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

s 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
Anvil
An anvil is a basic tool, a block with a hard surface on which another object is struck. The inertia of the anvil allows the energy of the striking tool to be transferred to the work piece. In most cases the anvil is used as a forging tool...

, 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 (). While the energy delivered to the target increases linearly with mass, it increases geometrically with the speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...

 (see the effect of the handle, below). High tech titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 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.

Effect of gravity

Gravity will exert a force on the hammer head. If hammering downwards gravity will increase the acceleration during the hammer stroke and increase the energy delivered with each blow. If hammering upwards gravity will reduce the acceleration during the hammer stroke and therefore reduce the energy delivered with each blow. Some hammering methods rely entirely on gravity for acceleration on the down stroke.

War hammers

A war hammer is a late medieval weapon
Weapon
A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...

 of war
War
War is a state of organized, armed, and often prolonged conflict carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political...

 intended for close combat
Close combat
*Close combat is a generic term for both Close Quarters Battle and Hand to hand combat.*Mêlée generally refers to disorganized close combat.*CQB is an acronym for Close Quarters Battle, such as that which occurs in urban warfare....

 action.

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
Hammer and sickle
The hammer and sickle is a part of communist symbolism and its usage indicates an association with Communism, a Communist party, or a Communist state. It features a hammer and a sickle overlapping each other. The two tools are symbols of the industrial proletariat and the peasantry; placing them...

, which was the symbol of the former Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 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
Norse mythology
Norse mythology, a subset of Germanic mythology, is the overall term for the myths, legends and beliefs about supernatural beings of Norse pagans. It flourished prior to the Christianization of Scandinavia, during the Early Middle Ages, and passed into Nordic folklore, with some aspects surviving...

, Thor
Thor
In Norse mythology, Thor is a hammer-wielding god associated with thunder, lightning, storms, oak trees, strength, the protection of mankind, and also hallowing, healing, and fertility...

, 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.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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