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A hammer is a
tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment. Although many animals use tool use by animals, simple tools, only human beings, whose use of stone tools dates back Paleolithic, hun ...

tool
, most often a
hand tool A hand tool is any tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment. Although many animals use simple tools, only human beings, whose use of stone tool A stone tool is, in ...
, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into
wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. ...

wood
, to shape
metal A metal (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appro ...

metal
(as with a
forge A forge is a type of hearth A hearth is the place in a home where a fire is or was traditionally kept for home heating and for cooking, usually constituted by at least a horizontal hearthstone and often enclosed to varying degrees by an ...

forge
), or to crush
rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition and the way in w ...
. Hammers are used for a wide range of driving, shaping, breaking and non-destructive striking applications. Traditional disciplines include
carpentry Carpenters in an Indian village Carpentry is a skilled trade A tradesman, skilled tradesman, or tradie refers to a skilled worker who specializes in a particular occupation that requires work experience, on-the-job training, and often fo ...

carpentry
,
blacksmithing
blacksmithing
,
warfare War is an intense armed conflict between State (polity), states, governments, Society, societies, or paramilitary groups such as Mercenary, mercenaries, Insurgency, insurgents, and militias. It is generally characterized by extreme violenc ...
, and
percussive A percussion instrument is a musical instrument that is sounded by being struck or scraped by a beater (percussion), beater including attached or enclosed beaters or Rattle (percussion beater), rattles struck, scraped or rubbed by hand or ...
musicianship (as with a
gong A gongFrom Indonesian language, Indonesian and ms, gong; jv, ꦒꦺꦴꦁ ; zh, c=鑼, p=luó; ja, , dora; km, គង ; th, ฆ้อง ; vi, cồng chiêng; as, কাঁহ is a percussion instrument originating in East Asia, East ...

gong
). Hammering is use of a hammer in its strike capacity, as opposed to
prying
prying
with an secondary claw or
grappling Grappling, in hand-to-hand combat Hand-to-hand combat (sometimes abbreviated as HTH or H2H) is a physical confrontation between two or more persons at short range (grappling Grappling, in hand-to-hand combat Hand-to-hand combat (some ...
with a secondary hook. Carpentry and blacksmithing hammers are generally wielded from a stationary stance against a stationary target as gripped and propelled with one
arm In human anatomy, the arm is the part of the upper limb The upper Limb (anatomy), limbs or upper extremities are the forelimbs of an upright posture, upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and incl ...

arm
, in a lengthy downward
planar Planar may refer to: Science and technology * Planar (computer graphics) In computer graphics, planar is the method of arranging pixel data into several '' bitplanes'' of RAM. Each bit in a bitplane is related to one pixel on the screen. Unlike ...
arc—downward to add
kinetic energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular ...
to the impact—pivoting mainly around the shoulder and elbow, with a small but brisk wrist rotation shortly before impact; for extreme impact, concurrent motions of the torso and knee can lower the shoulder joint during the swing to further increase the length of the swing arc (but this is tiring). War hammers are often wielded in non-vertical planes of motion, with a far greater share of energy input provided from the legs and hips, which can also include a lunging motion, especially against moving targets. Small mallets can be swung from the wrists in a smaller motion permitting a much higher cadence of repeated strikes. Use of hammers and heavy mallets for
demolition Demolition, also known as razing, cartage, and wrecking is the and in safely and efficiently tearing down of s and other artificial s. Demolition contrasts with , which involves taking a building apart while carefully preserving valuable el ...
must adapt the hammer stroke to the location and orientation of the target, which can necessitate a clubbing or
golfing Golf is a club-and-ball sport Sport pertains to any form of Competition, competitive physical activity or game that aims to use, maintain or improve physical ability and skills while providing enjoyment to participants and, in some cases ...
motion with a two-handed grip. The modern hammer head is typically made of
steel Steel is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appe ...

steel
which has been heat treated for hardness, and the handle (also known as a
haft Haft may refer to: * Haft, another name for the hilt The hilt (rarely called a haft or shaft) of a knife A knife (plural knives; from Old Norse'' knifr'', "knife, dirk") is a tool or weapon with a cutting edge or blade, often attached to a ...

haft
or
helve
helve
) is typically made of wood or
plastic Plastics are a wide range of syntheticA synthetic is an artificial material produced by organic chemistry, organic chemical synthesis. Synthetic may also refer to: In the sense of both "combination" and "artificial" * Synthetic chemical or s ...

plastic
. Ubiquitous in framing, the
claw hammer Claw Hammer was an American indie rock Indie rock is a genre of rock music that originated in the United States and United Kingdom in the 1970s. Originally used to describe independent record label An independent record label (or indie labe ...
has a "claw" to pull nails out of wood, and is commonly found in an inventory of household tools in
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
. Other types of hammer vary in shape, size, and structure, depending on their purposes. Hammers used in many
trades
trades
include
sledgehammer A sledgehammer is a with a large, flat, often head, attached to a long handle. The long handle combined with a heavy head allows the sledgehammer to gather momentum during a swing and apply a large compared to hammers designed to drive nails. ...

sledgehammer
s,
mallet A mallet is a tool used for imparting force on another object, often made of rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polymer ...

mallet
s, and
ball-peen hammer A ball-peen or ball pein hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. It is distinguished from a cross-peen hammer, diagonal-peen h ...
s. Although most hammers are hand tools, powered hammers, such as
steam hammer
steam hammer
s and
trip hammer The trip hammer of the St. Michael's Furnace property, at the Museum of Iron in Saint-Hubert (Belgium). A trip hammer, also known as a tilt hammer or helve hammer, is a massive powered hammer. Traditional uses of trip hammers include pounding, w ...
s, are used to deliver
force In physics, a force is an influence that can change the motion (physics), motion of an Physical object, object. A force can cause an object with mass to change its velocity (e.g. moving from a Newton's first law, state of rest), i.e., to acce ...

force
s beyond the capacity of the human arm. There are over 40 different types of hammers that have many different types of uses. For hand hammers, the grip of the shaft is an important consideration. Many forms of hammering by hand are heavy work, and
perspiration Perspiration, also known as sweating, is the production of fluids secreted by the sweat gland Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin Skin is the layer of usually soft, fl ...
can lead to slippage from the hand, turning a hammer into a dangerous or destructive uncontrolled projectile. Steel is highly elastic and transmits shock and
vibration Vibration is a mechanical phenomenon whereby oscillation Oscillation is the repetitive variation, typically in time Time is the indefinite continued sequence, progress of existence and event (philosophy), events that occur in an apparentl ...

vibration
; steel is also a good conductor of heat, making it unsuitable for contact with bare skin in frigid conditions. Modern hammers with steel shafts are almost invariably clad with a synthetic polymer to improve grip, dampen vibration, and to provide thermal insulation. A suitably contoured handle is also an important aid in providing a secure grip during heavy use. Traditional wooden handles were reasonably good in all regards, but lack strength and durability compared to steel, and there are safety issues with wooden handles if the head becomes loose on the shaft. The high elasticity of the steel head is important in energy transfer, especially when used in conjunction with an equally elastic
anvil An anvil is a metalworking Metalworking is the process of shaping and reshaping metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fr ...

anvil
. In terms of
human physiology The human body is the structure of a human being Humans (''Homo sapiens'') are the most populous and widespread species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an ...

human physiology
, many uses of the hammer involve coordinated
ballistic movement Ballistic movement can be defined as muscle contractions that exhibit maximum velocities and accelerations over a very short period of time. They exhibit high firing rates, high force production, and very brief contraction times. Physiology Muscle ...
s under intense muscular forces which must be planned in advance at the neuromuscular level, as they occur too rapidly for conscious adjustment in flight. For this reason, accurate striking at speed requires more practice than a tapping movement to the same target area. It has been suggested that the cognitive demands for pre-planning, sequencing and accurate timing associated with the related ballistic movements of
throwing Throwing is the launching of a ballistic projectile by hand. This action is only possible for animals with the ability to grasp objects with their hands (mainly primate A primate ( ) (from Latin , from 'prime, first rank') is a eutherian ...
, clubbing, and hammering precipitated aspects of brain evolution in early
hominid The Hominidae (), whose members are known as great apes or hominids (), are a taxonomic family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose ...
s.


History

The use of simple hammers dates to around 3.3 million years ago according to the 2012 find made by Sonia Harmand and Jason Lewis of
Stony Brook University The State University of New York at Stony Brook (SUNY at Stony Brook), more commonly known as Stony Brook University (SBU), is a public university, public research university in Stony Brook, New York. It is one of four university centers of the S ...
, who while excavating a site near
Kenya ) , national_anthem = "Ee Mungu Nguvu Yetu "Ee Mungu Nguvu Yetu" (, ) is the national anthem of Kenya. History "Ee Mungu Nguvu Yetu"'s lyrics were originally written in Swahili language, Kiswahili, the national language of Kenya ...

Kenya
's
Lake Turkana Lake Turkana (), formerly known as Lake Rudolf, is a lake in the Great Rift Valley, Kenya, Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's ...

Lake Turkana
discovered a very large deposit of various shaped stones including those used to strike
wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. ...

wood
,
bone A bone is a rigid tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North America * ''Triphosa dubit ...

bone
, or other stones to break them apart and shape them. The first hammers were made without handles. Stones attached to sticks with strips of
leather Leather is a strong, flexible and durable material obtained from the tanning Tanning may refer to: *Tanning (leather), treating animal skins to produce leather *Sun tanning, using the sun to darken pale skin **Indoor tanning, the use of arti ...

leather
or
animal sinew
animal sinew
were being used as hammers with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age. The addition of a handle gave the user better control and less accidents. The hammer became the number one tool. Used for building, food and protection. The hammer's archaeological record shows that it may be the oldest tool for which definite evidence exists. File:StoneHammerDoverMN.JPG, A stone hammer found in Dover Township, Minnesota dated to 8000–3000 BCE, the North American Archaic period File:Hammer stone tapping.jpg, Stone tapping hammer File:Hammer stone head.jpg, Perforated hammer head of stone File:Sacrificial hammer Dodona Louvre Br1183 n2.jpg, Ancient Greek bronze sacrificial hammer, 7th century BCE, from
Dodona Dodona (; : Δωδώνα, ''Dōdṓnā'', and : Δωδώνη, ''Dōdṓnē'') in in northwestern was the oldest oracle, possibly dating to the according to . The earliest accounts in describe Dodona as an oracle of . Situated in a remote r ...
File:Melencolia I (Durero) hammer crop.jpg, 16th-century claw hammer; detail from 's ''
Melencolia I ''Melencolia I'' is a 1514 engraving '' (1514), an engraving by Northern Renaissance master Albrecht Dürer Engraving is the practice of incising a design onto a hard, usually flat surface by cutting grooves into it with a Burin (engravi ...
'' (c. 1514)


Construction and materials

A traditional hand-held hammer consists of a separate head and a handle, which can be fastened together by means of a special
wedge A wedge is a triangular A triangle is a polygon In geometry Geometry (from the grc, γεωμετρία; ''wikt:γῆ, geo-'' "earth", ''wikt:μέτρον, -metron'' "measurement") is, with arithmetic, one of the oldest branche ...

wedge
made for the purpose, or by
glue Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantag ...
, or both. This two-piece design is often used to combine a dense metallic striking head with a non-metallic mechanical-shock-absorbing handle (to reduce user fatigue from repeated strikes). If wood is used for the handle, it is often
hickory Hickory is a common name for trees In botany Botany, also called , plant biology or phytology, is the science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method ...

hickory
or
ash Ash or ashes are the solid remnants of fire BBQ. Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Fire is hot because th ...
, which are tough and long-lasting materials that can dissipate
shock wave of an attached shock on a sharp-nosed supersonic F/A-18F Super Hornet in transonic flight Flight or flying is the process by which an object (physics), object motion (physics), moves through a space without contacting any planetary surfac ...
s from the hammer head. Rigid fiberglass resin may be used for the handle; this material does not absorb water or decay but does not dissipate shock as well as wood. A loose hammer head is considered hazardous due to the risk of the head becoming detached from the handle while being swung becoming a dangerous uncontrolled projectile. Wooden handles can often be replaced when worn or damaged; specialized kits are available covering a range of handle sizes and designs, plus special wedges and spacers for secure attachment. Some hammers are one-piece designs made mostly of a single material. A one-piece metallic hammer may optionally have its handle coated or wrapped in a
resilient Resilience, resilient, resiliency, or ''variation'', may refer to: Science Ecology * Ecological resilience In ecology, resilience is the capacity of an ecosystem to respond to a perturbation or disturbance by resisting damage and recovering ...
material such as
rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polymer (; Greek ''poly- Poly, from the Greek :wikt:πολύς, πολύς meaning "many" or "much" ...
for improved grip and to reduce user fatigue. The hammer head may be surfaced with a variety of materials including
brass Brass is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appea ...

brass
,
bronze Bronze is an alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appear ...

bronze
, wood, plastic, rubber, or leather. Some hammers have interchangeable striking surfaces, which can be selected as needed or replaced when worn out.


Designs and variations

A large hammer-like tool is a ''maul'' (sometimes called a "beetle"), a wood- or rubber-headed hammer is a ''
mallet A mallet is a tool used for imparting force on another object, often made of rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polymer ...

mallet
'', and a hammer-like tool with a cutting blade is usually called a ''
hatchet A hatchet (from the Old French Old French (, , ; Modern French French ( or ) is a Romance language The Romance languages, less commonly Latin or Neo-Latin languages, are the modern languages that evolved from Vulgar Latin Vu ...
''. The essential part of a hammer is the head, a compact solid mass that is able to deliver a blow to the intended target without itself deforming. The impacting surface of the tool is usually flat or slightly rounded; the opposite end of the impacting mass may have a ball shape, as in the
ball-peen hammer A ball-peen or ball pein hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. It is distinguished from a cross-peen hammer, diagonal-peen h ...
. Some upholstery hammers have a
magnet A magnet is a material or object that produces a magnetic field A magnetic field is a vector field In vector calculus and physics, a vector field is an assignment of a vector to each point in a subset of space. For instance, a ve ...

magnet
ized face, to pick up tacks. In the hatchet, the flat hammer head may be secondary to the cutting edge of the tool. The impact between steel hammer heads and the objects being hit can create sparks, which may ignite
flammable , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = German language, German , demonym = Germans, German , g ...
or
explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion An explosion is a rapid expansion in volume Volume is a expressing the of enclosed by a . ...

explosive
gas Gas is one of the four fundamental states of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space ...

gas
es. These are a
hazard A hazard is a potential source of harm. Substances, events, or circumstances can constitute hazards when their nature would allow them, even just theoretically, to cause damage to health, life, property, or any other interest of value. The probabil ...

hazard
in some industries such as underground coal mining (due to the presence of
methane Methane (, ) is a chemical compound with the chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes a ...
gas), or in other hazardous environments such as petroleum refineries and
chemical plant A chemical plant is an industrial process Industrial processes are procedures involving chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemic ...

chemical plant
s. In these environments, a variety of non-sparking metal tools are used, primarily made of
aluminium Aluminium (aluminum in and ) is a with the  Al and  13. Aluminium has a density lower than those of other common , at approximately one third that of . It has a great affinity towards , and of on the surface when exposed to air ...

aluminium
or
beryllium copper Beryllium copper (BeCu), also known as copper beryllium (CuBe), beryllium bronze and spring copper, is a with 0.5–3% and sometimes other elements. Beryllium copper combines high strength with non-magnetic and non-sparking qualities. It has ...
. In recent years, the handles have been made of durable plastic or rubber, though wood is still widely used because of its shock-absorbing qualities and repairability.


Hand-powered

*
Ball-peen hammer A ball-peen or ball pein hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. It is distinguished from a cross-peen hammer, diagonal-peen h ...
,''British Standard BS 876:1995 Specification for Hand Hammers'' or mechanic's hammer * Boiler scaling hammer * Brass hammer, also known as non-sparking hammer or spark-proof hammer and used mainly in flammable areas like oil fields * Bricklayer's hammer * Carpenter's hammer (used for nailing), such as the
framing hammer Image:Framing hammer.jpg, 250px, 22-ounce wooden-handled framing hammer with milled head and "straight" claw Framing hammers, used for Platform framing, framing wooden houses, are heavy duty rip hammers with a straight claw. The hammer heads typic ...

framing hammer
and the
claw hammer Claw Hammer was an American indie rock Indie rock is a genre of rock music that originated in the United States and United Kingdom in the 1970s. Originally used to describe independent record label An independent record label (or indie labe ...
, and pinhammers (ball-peen and cross-peen types) * Cow hammer – sometimes used for livestock slaughter, a practice now
deprecated In several fields, deprecation is the discouragement of use of some terminology, feature, design, or practice, typically because it has been superseded or is no longer considered efficient or safe, without completely removing it or prohibiting its ...
due to
animal welfare Animal welfare is the well-being of non-human animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as ...
objections * Cross-peen hammer, having one round face and one wedge-peen face. *
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 struck surface. The minimal rebound is helpful in avoiding accidental damage to precis ...

Dead blow hammer
delivers impact with very little recoil, often due to a hollow head filled with sand,
lead shot Shot is a collective term for small balls or pellets, often made of lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than ...
or pellets * Demolition hammer * Drilling hammer – a short handled sledgehammer originally used for drilling in rock with a chisel. The name usually refers to a hammer with a head and a handle, also called a "single-jack" hammer because it was used by one person drilling, holding the chisel in one hand and the hammer in the other. In modern usage, the term is mostly interchangeable with "engineer's hammer", although it can indicate a version with a slightly shorter handle. * Engineer's hammer, a short-handled hammer, was originally an essential components of a
railroad engineer Inside the train driver's cab of a German Intercity-Express, ICE train A train driver, engine driver or locomotive driver, commonly known as an engineer in the United States and Canada, and also as a locomotive handler, locomotive operator, train ...
's toolkit for working on steam locomotives. Typical weight is 2–4 lbs (0.9–1.8 kg) with a 12–14-inch (30–35 cm) handle. Originally these were often cross-peen hammers, with one round face and one wedge-peen face, but in modern usage the term primarily refers to hammers with two round faces. *
Gavel A gavel is a small ceremonial mallet A mallet is a tool used for imparting force on another object, often made of rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produ ...

Gavel
, used by judges and presiding authorities to draw attention *
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 to determine its composition, bedding orientation, nature, min ...
or rock pick * Joiner's hammer, or * Knife-edged hammer, its properties developed to aid a hammerer in the act of slicing whilst bludgeoning * (also known as a lath hammer, lathing hammer, or lathing hatchet), a tool used for cutting and nailing wood
lath A lath or slat is a thin, narrow strip of straight-grain A grain is a small, hard, dry seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warn ...

lath
, which has a small hatchet blade on one side (with a small, lateral nick for pulling nails) and a hammer head on the other * Lump hammer, or club hammer *
Mallet A mallet is a tool used for imparting force on another object, often made of rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polym ...

Mallet
s, including versions made with hard rubber or rolled sheets of rawhide * Railway track keying hammer * Magnetic double-head hammer * Magnetic tack hammer *
Rock climbing hammer Rock climbing hammers, also known as wall hammers, big wall hammers, or aid hammers, are a type of specialty hammer used mainly in aid climbing Aid climbing is a style of climbing Climbing is the activity of using one's hands, feet, or any ...
* Rounding hammer, Blacksmith or farrier hammer. Round face generally for moving or drawing metal and flat for "planishing" or smoothing out the surface marks. * Shingler's hammer *
Sledgehammer A sledgehammer is a with a large, flat, often head, attached to a long handle. The long handle combined with a heavy head allows the sledgehammer to gather momentum during a swing and apply a large compared to hammers designed to drive nails. ...

Sledgehammer
* Soft-faced hammer * Spiking hammer * Splitting maul * Strike Tack hammer * Stonemason's hammer * Tinning, Tinner's hammer * Upholstery hammer * Welding, Welder's chipping hammer


Mechanically powered

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, that combines a jackhammer-like mechanism with a drill * High Frequency Impact Treatment hammer – for after-treatment of weld transitions * Jackhammer * Steam hammer * Trip hammer * Nail gun * Staple gun


Associated tools

* Anvil * Chisel * Pipe drift (Blacksmithing - spreading a punched hole to proper size and/or shape) * Star drill * Punch (engineering), Punch * Splitting maul, Woodsplitting maul – can be hit with a sledgehammer for splitting wood. * Wedge (mechanical device), Woodsplitting wedge – hit with a sledgehammer for splitting wood.


Physics


As a force amplifier

A hammer is a simple
force In physics, a force is an influence that can change the motion (physics), motion of an Physical object, object. A force can cause an object with mass to change its velocity (e.g. moving from a Newton's first law, state of rest), i.e., to acce ...

force
amplifier that works by converting mechanical work into
kinetic energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular ...
and back. In the swing that precedes each blow, the hammer head stores a certain amount of kinetic energy—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 is stopped by an opposite force coming from the target, 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 An anvil is a metalworking Metalworking is the process of shaping and reshaping metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fr ...

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'' is 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=). While the energy delivered to the target increases linearly with mass, it increases quadratically 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 the same energy with less arm fatigue than that of a heavier steel head hammer. A titanium head has about 3% Deflection (physics), recoil energy and can result in greater efficiency and less fatigue when compared to a steel head with up to 30% recoil.
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 struck surface. The minimal rebound is helpful in avoiding accidental damage to precis ...

Dead blow hammer
s use special rubber or steel shot to absorb recoil energy, rather than bouncing the hammer head after impact.


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 to swing the hammer. This is why sledgehammers, 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. With too long a handle, the hammer is inefficient because it delivers force to the wrong place, off-target. With too short a handle, the hammer is inefficient because it doesn't deliver enough force, requiring more blows to complete a given task. Modifications have also been made with respect to the effect of the hammer on the user. 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. 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 sledgehammer) 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 gravity

Gravity exerts a force on the hammer head. If hammering downwards, gravity increases the acceleration during the hammer stroke and increases the energy delivered with each blow. If hammering upwards, gravity reduces the acceleration during the hammer stroke and therefore reduces the energy delivered with each blow. Some hammering methods, such as traditional mechanical pile drivers, rely entirely on gravity for acceleration on the down stroke.


Ergonomics and injury risks

A hammer may cause significant injury if it strikes the body. Both manual and powered hammers can cause peripheral neuropathy or a variety of other ailments when used improperly. Awkward handles can cause repetitive stress injury (RSI) to hand and arm joints, and uncontrolled shock waves from repeated impacts can injure nerves and the skeleton. Additionally, striking metal objects with a hammer may produce small metallic projectiles which can become lodged in the eye. It is therefore recommended to wear safety glasses.


War hammers

A war hammer is a late medieval weapon of war intended for close combat action.


Symbolism

The hammer, being one of the most used tools by Homo sapiens, man, has been used very much in symbols such as flags and heraldry. In the Middle Ages, it was used often in blacksmith guild logos, as well as in many family symbols. The hammer and pick are used as a symbol of mining. In mythology, the gods Thor (Norse mythology, Norse) and Sucellus (Ancient Celtic religion, Celtic and Gallo-Roman religion, Gallo-Roman), and the hero Hercules (Greek mythology, Greek), all had hammers that appear in their lore and carried different meanings. Thor, the god of thunder and lightning, wields a hammer named Mjölnir. Many artifacts of decorative hammers have been found, leading modern practitioners of this religion to often wear reproductions as a sign of their faith. In Folklore of the United States, American folklore, the hammer of John Henry (folklore), John Henry represents the strength and endurance of a man. A political party in Singapore, Workers' Party (Singapore), Workers' Party of Singapore, based their logo on a hammer to symbolize the party's civic nationalism and social democracy ideology. A variant, well-known symbol with a hammer in it is the Hammer and Sickle, which was the symbol of the former Soviet Union and is strongly linked to communism and early socialism. The hammer in this symbol represents the industrial working class (and the sickle represents the agricultural working class). The hammer is used in some coats of arms in former socialist countries like East Germany. Similarly, the Hammer and Sword symbolizes Strasserism, a strand of Nazism, National Socialism seeking to appeal to the working class. Another variant of the symbol was used for the North Korean party, Workers' Party of Korea, incorporated with an ink brush on the middle, which symbolizes both Juche and Songun ideologies. In Pink Floyd – The Wall, two hammers crossed are used as a symbol for the fascist takeover of the concert during "In the Flesh (Pink Floyd song), In the Flesh". This also has the meaning of the hammer beating down any "nails" that stick out. The gavel, a small wooden mallet, is used to symbolize a mandate to preside over a meeting or judicial proceeding, and a graphic image of one is used as a symbol of legislative or judicial decision-making authority. Judah Maccabee was nicknamed "The Hammer", possibly in recognition of his ferocity in battle. The name "Maccabee" may derive from the Aramaic ''maqqaba''. (see .) The hammer in the song "If I Had a Hammer" represents a relentless message of justice broadcast across the land. The song became a symbol of the civil rights movement.


Image gallery

File:Buck Knives Hammer (5075278861).jpg,
Ball-peen hammer A ball-peen or ball pein hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. It is distinguished from a cross-peen hammer, diagonal-peen h ...
File:Stockhammer.JPG, Bush hammer File:Hammer2.jpg, Claw hammer File:Hammer-1.jpg, Cross-peen hammer File:Hammer dog-head.jpg, Dog-head hammer (blacksmithing) File:Framing hammer.jpg, Framing hammer File:BrokenConcretion22.jpg,
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 to determine its composition, bedding orientation, nature, min ...
File:Hifit-hammer.jpg, High-frequency impact treatment, HiFIT-hammer for aftertreatment of weld transitions File:Hammer Long cross-face.jpg, Long cross-face hammer (blacksmithing) File:Sledgehammer.jpg, Post maul File:Climbing Hammer.png,
Rock climbing hammer Rock climbing hammers, also known as wall hammers, big wall hammers, or aid hammers, are a type of specialty hammer used mainly in aid climbing Aid climbing is a style of climbing Climbing is the activity of using one's hands, feet, or any ...
File:Gummihammer.png, Rubber mallet File:Sledgehammers-1.jpg,
Sledgehammer A sledgehammer is a with a large, flat, often head, attached to a long handle. The long handle combined with a heavy head allows the sledgehammer to gather momentum during a swing and apply a large compared to hammers designed to drive nails. ...

Sledgehammer
s File:Hammer straight pane sledge.jpg, Straight pane
sledgehammer A sledgehammer is a with a large, flat, often head, attached to a long handle. The long handle combined with a heavy head allows the sledgehammer to gather momentum during a swing and apply a large compared to hammers designed to drive nails. ...

sledgehammer
File:Hammer twist.jpg, Twist hammer (blacksmithing) File:Hammer tapissier.jpg, Upholstery hammer File:Mallet menuisier.jpg, Wooden
mallet A mallet is a tool used for imparting force on another object, often made of rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymer A polymer ...

mallet


See also

*Hammer Museum (Haines, Alaska) *Mjölnir


References


External links


Types of Hammers
(images and descriptions)
"Choosing a Hammer".
''Popular Science'', June 1960, pp. 164–167. {{Authority control Hammers, * Woodworking hand tools Metalworking tools