Hammer

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This article is about the tool. Hammer_sentence_0

For other uses, see Hammer (disambiguation). Hammer_sentence_1

A hammer is a tool consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. Hammer_sentence_2

This can be, for example, to drive nails into wood, to shape metal (as with a forge), or to crush rock. Hammer_sentence_3

Hammers are used for a wide range of driving, shaping, and breaking applications. Hammer_sentence_4

The modern hammer head is typically made of steel which has been heat treated for hardness, and the handle (also known as a or ) is typically made of wood or plastic. Hammer_sentence_5

The claw hammer has a "claw" to pull nails out of wood, and is commonly found in an inventory of household tools in North America. Hammer_sentence_6

Other types of hammer vary in shape, size, and structure, depending on their purposes. Hammer_sentence_7

Hammers used in many trades include sledgehammers, mallets, and ball-peen hammers. Hammer_sentence_8

Although most hammers are hand tools, powered hammers, such as steam hammers and trip hammers, are used to deliver forces beyond the capacity of the human arm. Hammer_sentence_9

There are over 40 different types of hammers that have many different types of uses. Hammer_sentence_10

History Hammer_section_0

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, who while excavating a site near Kenya's Lake Turkana discovered a very large deposit of various shaped stones including those used to strike wood, bone, or other stones to break them apart and shape them. Hammer_sentence_11

The first hammers were made without handles. Hammer_sentence_12

Stones attached to sticks with strips of leather or animal sinew were being used as hammers with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age. Hammer_sentence_13

The addition of a handle gave the user better control and less accidents. Hammer_sentence_14

The hammer became the number one tool. Hammer_sentence_15

Used for building, food and protection. Hammer_sentence_16

The hammer's archaeological record shows that it may be the oldest tool for which definite evidence exists of its early existence. Hammer_sentence_17

Hammer_unordered_list_0

  • Hammer_item_0_0
  • Hammer_item_0_1
  • Hammer_item_0_2
  • Hammer_item_0_3
  • Hammer_item_0_4

Construction and materials Hammer_section_1

A traditional hand-held hammer consists of a separate head and a handle, which can be fastened together by means of a special wedge made for the purpose, or by glue, or both. Hammer_sentence_18

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). Hammer_sentence_19

If wood is used for the handle, it is often hickory or ash, which are tough and long-lasting materials that can dissipate shock waves from the hammer head. Hammer_sentence_20

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. Hammer_sentence_21

A loose hammer head is hazardous because it can literally "fly off the handle" when in use, becoming a dangerous uncontrolled missile. Hammer_sentence_22

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 for attachment. Hammer_sentence_23

Some hammers are one-piece designs made mostly of a single material. Hammer_sentence_24

A one-piece metallic hammer may optionally have its handle coated or wrapped in a resilient material such as rubber, for improved grip and to reduce user fatigue. Hammer_sentence_25

The hammer head may be surfaced with a variety of materials including brass, bronze, wood, plastic, rubber, or leather. Hammer_sentence_26

Some hammers have interchangeable striking surfaces, which can be selected as needed or replaced when worn out. Hammer_sentence_27

Designs and variations Hammer_section_2

A large hammer-like tool is a maul (sometimes called a "beetle"), a wood- or rubber-headed hammer is a mallet, and a hammer-like tool with a cutting blade is usually called a hatchet. Hammer_sentence_28

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. Hammer_sentence_29

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. Hammer_sentence_30

Some upholstery hammers have a magnetized face, to pick up tacks. Hammer_sentence_31

In the hatchet, the flat hammer head may be secondary to the cutting edge of the tool. Hammer_sentence_32

The impact between steel hammer heads and the objects being hit can create sparks, which may ignite flammable or explosive gases. Hammer_sentence_33

These are a hazard in some industries such as underground coal mining (due to the presence of methane gas), or in other hazardous environments such as petroleum refineries and chemical plants. Hammer_sentence_34

In these environments, a variety of non-sparking metal tools are used, primarily made of aluminium or beryllium copper. Hammer_sentence_35

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. Hammer_sentence_36

Hand-powered Hammer_section_3

Hammer_unordered_list_1

  • Ball-peen hammer, or mechanic's hammerHammer_item_1_5
  • Boiler scaling hammerHammer_item_1_6
  • Brass hammer, also known as non-sparking hammer or spark-proof hammer and used mainly in flammable areas like oil fieldsHammer_item_1_7
  • Bricklayer's hammerHammer_item_1_8
  • Carpenter's hammer (used for nailing), such as the framing hammer and the claw hammer, and pinhammers (ball-peen and cross-peen types)Hammer_item_1_9
  • Cow hammer – sometimes used for livestock slaughter, a practice now deprecated due to animal welfare objectionsHammer_item_1_10
  • Cross-peen hammer, having one round face and one wedge-peen face.Hammer_item_1_11
  • Dead blow hammer delivers impact with very little recoil, often due to a hollow head filled with sand, lead shot or pelletsHammer_item_1_12
  • Demolition hammerHammer_item_1_13
  • Drilling hammer – a short handled sledgehammer originally used for drilling in rock with a chisel. The name usually refers to a hammer with a 2-to-4-pound (0.91 to 1.81 kg) head and a 10-inch (250 mm) 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.Hammer_item_1_14
  • Electrician's hammerHammer_item_1_15
  • Engineer's hammer, a short-handled hammer, was originally an essential components of a railroad engineer'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.Hammer_item_1_16
  • Gavel, used by judges and presiding authorities to draw attentionHammer_item_1_17
  • Geologist's hammer or rock pickHammer_item_1_18
  • Joiner's hammer, or Warrington hammerHammer_item_1_19
  • Knife-edged hammer, its properties developed to aid a hammerer in the act of slicing whilst bludgeoningHammer_item_1_20
  • Lathe hammer (also known as a lath hammer, lathing hammer, or lathing hatchet), a tool used for cutting and nailing wood lath, which has a small hatchet blade on one side (with a small, lateral nick for pulling nails) and a hammer head on the otherHammer_item_1_21
  • Lump hammer, or club hammerHammer_item_1_22
  • Mallets, including versions made with hard rubber or rolled sheets of rawhideHammer_item_1_23
  • Railway track keying hammerHammer_item_1_24
  • Magnetic double-head hammerHammer_item_1_25
  • Magnetic tack hammerHammer_item_1_26
  • Rock climbing hammerHammer_item_1_27
  • Rounding hammer, Blacksmith or farrier hammer. Round face generally for moving or drawing metal and flat for "planishing" or smoothing out the surface marks.Hammer_item_1_28
  • Shingler's hammerHammer_item_1_29
  • SledgehammerHammer_item_1_30
  • Soft-faced hammerHammer_item_1_31
  • Splitting maulHammer_item_1_32
  • Strike Tack hammerHammer_item_1_33
  • Stonemason's hammerHammer_item_1_34
  • Tinner's hammerHammer_item_1_35
  • Upholstery hammerHammer_item_1_36
  • Welder's chipping hammerHammer_item_1_37

Mechanically powered Hammer_section_4

Mechanically powered hammers often look quite different from the hand tools, but nevertheless, most of them work on the same principle. Hammer_sentence_37

They include: Hammer_sentence_38

Hammer_unordered_list_2

In professional framing carpentry, the manual hammer has almost been completely replaced by the nail gun. Hammer_sentence_39

In professional upholstery, its chief competitor is the staple gun. Hammer_sentence_40

Associated tools Hammer_section_5

Hammer_unordered_list_3

  • AnvilHammer_item_3_43
  • ChiselHammer_item_3_44
  • Pipe drift (Blacksmithing - spreading a punched hole to proper size and/or shape)Hammer_item_3_45
  • Star drillHammer_item_3_46
  • PunchHammer_item_3_47
  • Woodsplitting maul – can be hit with a sledgehammer for splitting wood.Hammer_item_3_48
  • Woodsplitting wedge – hit with a sledgehammer for splitting wood.Hammer_item_3_49

Physics Hammer_section_6

As a force amplifier Hammer_section_7

A hammer is a simple force amplifier that works by converting mechanical work into kinetic energy and back. Hammer_sentence_41

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. Hammer_sentence_42

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. Hammer_sentence_43

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. Hammer_sentence_44

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. Hammer_sentence_45

In this way, great strength is not needed to produce a force strong enough to bend steel, or crack the hardest stone. Hammer_sentence_46

Effect of the head's mass Hammer_section_8

Effect of the handle Hammer_section_9

The handle of the hammer helps in several ways. Hammer_sentence_47

It keeps the user's hands away from the point of impact. Hammer_sentence_48

It provides a broad area that is better-suited for gripping by the hand. Hammer_sentence_49

Most importantly, it allows the user to maximize the speed of the head on each blow. Hammer_sentence_50

The primary constraint on additional handle length is the lack of space to swing the hammer. Hammer_sentence_51

This is why sledgehammers, largely used in open spaces, can have handles that are much longer than a standard carpenter's hammer. Hammer_sentence_52

The second most important constraint is more subtle. Hammer_sentence_53

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. Hammer_sentence_54

Most designs are a compromise between practicality and energy efficiency. Hammer_sentence_55

With too long a handle, the hammer is inefficient because it delivers force to the wrong place, off-target. Hammer_sentence_56

With too short a handle, the hammer is inefficient because it doesn't deliver enough force, requiring more blows to complete a given task. Hammer_sentence_57

Modifications have also been made with respect to the effect of the hammer on the user. Hammer_sentence_58

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. Hammer_sentence_59

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. Hammer_sentence_60

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. Hammer_sentence_61

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. Hammer_sentence_62

Effect of gravity Hammer_section_10

Gravity exerts a force on the hammer head. Hammer_sentence_63

If hammering downwards, gravity increases the acceleration during the hammer stroke and increases the energy delivered with each blow. Hammer_sentence_64

If hammering upwards, gravity reduces the acceleration during the hammer stroke and therefore reduces the energy delivered with each blow. Hammer_sentence_65

Some hammering methods, such as traditional mechanical pile drivers, rely entirely on gravity for acceleration on the down stroke. Hammer_sentence_66

Ergonomics and injury risks Hammer_section_11

A hammer may cause significant injury if it strikes the body. Hammer_sentence_67

Both manual and powered hammers can cause peripheral neuropathy or a variety of other ailments when used improperly. Hammer_sentence_68

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. Hammer_sentence_69

Additionally, striking metal objects with a hammer may produce small metallic projectiles which can become lodged in the eye. Hammer_sentence_70

It is therefore recommended to wear safety glasses. Hammer_sentence_71

War hammers Hammer_section_12

Main article: War hammer Hammer_sentence_72

A war hammer is a late medieval weapon of war intended for close combat action. Hammer_sentence_73

Symbolism Hammer_section_13

The hammer, being one of the most used tools by man, has been used very much in symbols such as flags and heraldry. Hammer_sentence_74

In the Middle Ages, it was used often in blacksmith guild logos, as well as in many family symbols. Hammer_sentence_75

The hammer and pick are used as a symbol of mining. Hammer_sentence_76

In mythology, the gods Thor ( Norse) and Sucellus (Celtic and Gallo-Roman), and the hero Hercules ( Greek), all had hammers that appear in their lore and carried different meanings. Hammer_sentence_77

Thor, the god of thunder and lightning, wields a hammer named Mjölnir. Hammer_sentence_78

Many artifacts of decorative hammers have been found, leading modern practitioners of this religion to often wear reproductions as a sign of their faith. Hammer_sentence_79

In American folklore, the hammer of John Henry represents the strength and endurance of a man. Hammer_sentence_80

A political party in Singapore, Workers' Party of Singapore, based their logo on a hammer to symbolize the party's civic nationalism and social democracy ideology. Hammer_sentence_81

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. Hammer_sentence_82

The hammer in this symbol represents the industrial working class (and the sickle represents the agricultural working class). Hammer_sentence_83

The hammer is used in some coats of arms in former socialist countries like East Germany. Hammer_sentence_84

Similarly, the Hammer and Sword symbolizes Strasserism, a strand of National Socialism seeking to appeal to the working class. Hammer_sentence_85

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. Hammer_sentence_86

In Pink Floyd – The Wall, two hammers crossed are used as a symbol for the fascist takeover of the concert during "In the Flesh". Hammer_sentence_87

This also has the meaning of the hammer beating down any "nails" that stick out. Hammer_sentence_88

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. Hammer_sentence_89

Judah Maccabee was nicknamed "The Hammer", possibly in recognition of his ferocity in battle. Hammer_sentence_90

The name "Maccabee" may derive from the Aramaic maqqaba. Hammer_sentence_91

(see Judah Maccabee § Origin of Name "The Hammer".) Hammer_sentence_92

The hammer in the song "If I Had a Hammer" represents a relentless message of justice broadcast across the land. Hammer_sentence_93

The song became a symbol of the civil rights movement. Hammer_sentence_94

Image gallery Hammer_section_14

Hammer_unordered_list_4

  • Hammer_item_4_50
  • Hammer_item_4_51
  • Hammer_item_4_52
  • Hammer_item_4_53
  • Hammer_item_4_54
  • Hammer_item_4_55
  • Hammer_item_4_56
  • Hammer_item_4_57
  • Hammer_item_4_58
  • Hammer_item_4_59
  • Hammer_item_4_60
  • Hammer_item_4_61
  • Hammer_item_4_62
  • Hammer_item_4_63
  • Hammer_item_4_64
  • Hammer_item_4_65
  • Hammer_item_4_66
  • Hammer_item_4_67

See also Hammer_section_15

Hammer_unordered_list_5


Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Hammer.