Hammer - Razor Robotics Used with Construction A hammer is a tool or device that delivers a blow (a sudden impact) to an object. Most hammers are hand tools used to drive nails, fit parts, forge metal, and break apart objects. Hammers vary in shape, size, and structure, depending on their purposes. Hammers are basic tools in many trades. The usual features are a head (most often made of steel) and a handle (also called a helve or haft). Most hammers are hand tools, however, powered versions exist, known as powered hammers. Types of power hammer include steam hammers and trip hammers, often for heavier uses, such as forging. Some hammers have other names, such as sledgehammer, mallet and gavel. The term "hammer" also applies to big von devices that deliver blows, such as the hammer of a firearm or the hammer of a piano or the hammer ice scraper. History The use of simple hammers dates to about 2,600,000 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 with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age. The hammer's archeological record shows that it may be the oldest tool for which definite evidence exists of its early existence. A stone hammer found in Dover Township, Minnesota dated to 8000–3000 BCE, the North American Archaic period Stone tapping hammer Perforated hammer head of stone Ancient Greek bronze sacrificial hammer, 7th century BCE, from Dodona 16th-century claw hammer; detail from Dürer's Melencolia I (c. 1514) Construction and materials A traditional hand-held hammer consists of a separate head and a handle, fastened together by means of a special wedge made for the purpose, or by glue, 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 or ash, which are tough and long-lasting materials that can dissipate shock waves 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 hazardous because it can literally "fly off the handle" when in use, becoming a dangerous uncontrolled missile. 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. Some hammers are one-piece designs made primarily of a single material. A one-piece metallic hammer may optionally have its handle coated or wrapped in a resilient material such as rubber, for improved grip and reduced user fatigue. The hammer head may be surfaced with a variety of materials, including brass, 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 The parts of a hammer are the face, head (includes the bell and neck, which are not labelled), eye (where the handle fits into), peen (also spelled pein and pane). The side of a hammer is the cheek and some hammers have straps that extend down the handle for strength. Shown here are: A. Ball-peen hammer B. Straight-peen hammer C. Cross-peen hammer The claw of a carpenter's hammer is frequently used to remove nails. 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. 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. Some upholstery hammers have a magnetized 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 or explosive gases. 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. In these environments, a variety of non-sparking metal tools are used, primarily made of aluminium or beryllium copper. 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 hammers Woodsplitting maul – can be hit with a sledgehammer for splitting wood. Woodsplitting wedge – hit with a sledgehammer for splitting wood. 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. 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, 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 2 {\displaystyle E={mv^{2} \over 2}} ). 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% recoil energy and can result in greater efficiency and less fatigue when compared to a steel head with up to 30% recoil. Dead blow hammers 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 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.

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 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 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 You can help by adding to it. (July 2015) 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. War hammers A war hammer is a late medieval weapon of war intended for close combat action. Symbolic hammers The hammer, being one of the most used tools by Homo sapiens, 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 is used as a symbol of mining. A well known 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 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 coat of arms in (former) socialist countries like East Germany. Similarly, the Hammer and Sword symbolizes Strasserism, a strand of National Socialism seeking to appeal to the working class. 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. In Norse mythology, 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. Judah Maccabee was nicknamed "The Hammer", possibly in recognition of his ferocity in battle. The name "Maccabee" may derive from the Aramaic maqqaba. (see ‹See Tfd›Judah Maccabee § Origin of Name "The Hammer"). In American folkore, the hammer of John Henry represents the strength and endurance of a man.

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 American Civil Rights movement. Image gallery HiFIT-hammer for aftertreatment of weld transitions Long cross-face hammer (blacksmithing) Hammer : Map (The Full Wiki) The Full Wiki Map showing all locations mentioned on Wikipedia article: A modern claw hammer A hammer is a tool meant to deliver an impact to an object. The most common uses are for driving nail , 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 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 . History 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 principallly 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: construction hammers, including the sledgehammer drilling hammer - a lightweight, short handled sledgehammer Ball-peen hammer , or mechanic's hammer Soft-faced hammer lump hammer , or club hammer gavel , used by judges and presiding authorities in general Tinner's Hammer image:hammer2.jpg| Claw hammer Image:Framing hammer.jpg| Framing hammer Image:BrokenConcretion22.jpg| Geologist's hammer Image:Hammer tapissier.jpg| Upholstery hammer Image:Hammer-1.jpg| Cross-peen hammer Image:Ball-peen hammer 380mm.JPG| Ball-peen hammer Image:Mallet.jpg|Rubber malletImage:Wooden mallet.jpg|Wooden mallet Image:Sledgehammer.jpg| Sledgehammer image:Hammer stone tapping.jpg|Stone tapping hammerImage:Hammer stone head.jpg|Perforated hammer head of stoneImage:Hammer Long cross-face.jpg|Long cross-face hammer (blacksmithing)Image:Hammer twist.jpg|Twist hammer (blacksmithing)Image:Hammer dog-head.jpg|Dog-head hammer (blacksmithing)Image:Hammer ball pane.jpg| Ball pane hammer Image:Hammer straight pane s

ledge.jpg|Straight pane sledgehammer Image:Stockhammer.JPG| Bush hammer 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: trip hammer hammer drill , that combines a jackhammer-like mechanism with a drill 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 Woodsplitting wedge - hit with a sledgehammer for splitting wood. Woodsplitting maul - can be hit with a sledgehammer for splitting wood. Masonry star drill 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. 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. 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, 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. External links Hammer Hammer Construction A hammer is a tool or device that delivers a blow (a sudden impact) to an object. Most hammers are hand tools used to drive nails , fit parts, forge metal, and break apart objects. Hammers vary in shape, size, and structure, depending on their purposes. Hammers are basic tools in many trades . The usual features are a head (most often made of steel ) and a handle (also called a helve or haft). Most hammers are hand tools, however, powered versions exist, known as powered hammers . Types of power hammer include steam hammers and trip hammers , often for heavier uses, such as forging . Some hammers have other names, such as sledgehammer , mallet and gavel .

The term “hammer” also applies to big von devices that deliver blows, such as the hammer of a firearm or the hammer of a piano or the hammer ice scraper. Contents 12 External links History The use of simple hammers dates to about 2,600,000 BCE [1] [2] 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 with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age . The hammer’s archeological record shows that it may be the oldest tool for which definite evidence exists of its early existence. [1] [2] A stone hammer found in Dover Township, Minnesota dated to 8000–3000 BCE, the North American Archaic period Stone tapping hammer Perforated hammer head of stone Ancient Greek bronze sacrificial hammer, 7th century BCE, from Dodona 16th-century claw hammer; detail from Dürer ‘s Melencolia I (c.

1514) Construction and materials A traditional hand-held hammer consists of a separate head and a handle, fastened together by means of a special wedge made for the purpose, or by glue, 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 or ash , [3] which are tough and long-lasting materials that can dissipate shock waves 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 hazardous because it can literally “fly off the handle” when in use, becoming a dangerous uncontrolled missile. 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. Some hammers are one-piece designs made primarily of a single material. A one-piece metallic hammer may optionally have its handle coated or wrapped in a resilient material such as rubber, for improved grip and reduced user fatigue.

[4] The hammer head may be surfaced with a variety of materials, including brass , 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 The parts of a hammer are the face, head (includes the bell and neck, which are not labelled), eye (where the handle fits into), peen (also spelled pein and pane). The side of a hammer is the cheek and some hammers have straps that extend down the handle for strength. Shown here are: A. Ball-peen hammer B. Straight-peen hammer C. Cross-peen hammer The claw of a carpenter’s hammer is frequently used to remove nails. 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 . 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 . Some upholstery hammers have a magnetized 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 or explosive gases. 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. In these environments, a variety of non-sparking metal tools are used, primarily made of aluminium or beryllium copper . 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 hammers Woodsplitting maul – can be hit with a sledgehammer for splitting wood. Woodsplitting wedge – hit with a sledgehammer for splitting wood. 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.

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 , 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 2 {\displaystyle E={mv^{2} \over 2}} ).

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. [10] A titanium head has about 3% recoil energy and can result in greater efficiency and less fatigue when compared to a steel head with up to 30% recoil. Dead blow hammers 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 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. 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 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 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 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. War hammers A war hammer is a late medieval weapon of war intended for close combat action. Symbolic hammers The hammer, being one of the most used tools by Homo sapiens , 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 is used as a symbol of mining. A well known 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 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 coat of arms in (former) socialist countries like East Germany . Similarly, the Hammer and Sword symbolizes Strasserism , a strand of National Socialism seeking to appeal to the working class. 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. In Norse mythology , 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. Judah Maccabee was nicknamed “The Hammer”, possibly in recognition of his ferocity in battle. The name “Maccabee” may derive from the Aramaic maqqaba.

(see ‹See Tfd› Judah Maccabee § Origin of Name “The Hammer” ). In American folkore , the hammer of John Henry represents the strength and endurance of a man. 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 American Civil Rights movement . Image gallery HiFIT-hammer for aftertreatment of weld transitions Long cross-face hammer (blacksmithing) Hammer - Wikipedia, Photos and Videos Hammer NEXT GO TO RESULTS [51 .. 100] WIKIPEDIA ARTICLE This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed. (December 2009) Construction A hammer is a tool or device that delivers a blow (a sudden impact) to an object. Most hammers are hand tools used to drive nails , fit parts, forge metal, and break apart objects. Hammers vary in shape, size, and structure, depending on their purposes. Hammers are basic tools in many trades . The usual features are a head (most often made of steel ) and a handle (also called a helve or haft ).

Although most hammers are hand tools, powered versions exist; they are known as powered hammers . Types of power hammer include steam hammers and trip hammers , often for heavier uses, such as forging . Some hammers have other names, such as sledgehammer , mallet and gavel . The term "hammer" also applies to big von devices that deliver blows, such as the hammer of a firearm or the hammer of a piano or the hammer ice scraper. Contents History[ edit ] The use of simple hammers dates to about 2,600,000 BCE [1] [2] 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 with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age . The hammer's archeological record shows that it may be the oldest tool for which definite evidence exists of its early existence.

[1] [2] A stone hammer found in Dover Township, Minnesota dated to 8000–3000 BCE, the North American Archaic period Stone tapping hammer Perforated hammer head of stone Ancient Greek bronze sacrificial hammer, 7th century BCE, from Dodona 16th-century claw hammer; detail from Dürer 's Melencolia I (c. 1514) Construction and materials[ edit ] A traditional hand-held hammer consists of a separate head and a handle, fastened together by means of a special wedge made for the purpose, or by glue, 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 or ash , [3] which are tough and long-lasting materials that can dissipate shock waves 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 hazardous because it can literally "fly off the handle" when in use, becoming a dangerous uncontrolled missile. 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. Some hammers are one-piece designs made primarily of a single material. A one-piece metallic hammer may optionally have its handle coated or wrapped in a resilient material such as rubber, for improved grip and reduced user fatigue. [4] The hammer head may be surfaced with a variety of materials, including brass , 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[ edit ] The parts of a hammer are the face, head (includes the bell and neck, which are not labelled), eye (where the handle fits into), peen (also spelled pein and pane). The side of a hammer is the cheek and some hammers have straps that extend down the handle for strength. Shown here are: A. Ball-peen hammer B. Straight-peen hammer C.

Cross-peen hammer The claw of a carpenter's hammer is frequently used to remove nails. 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 . 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 . Some upholstery hammers have a magnetized 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 or explosive gases. 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. In these environments, a variety of non-sparking metal tools are used, primarily made of aluminium or beryllium copper .

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. Woodsplitting maul – can be hit with a sledgehammer for splitting wood. Woodsplitting wedge – hit with a sledgehammer for splitting wood. Physics of hammering[ edit ] Hammer as a force amplifier[ edit ] 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, 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 , 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[ edit ] 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 2 {\displaystyle E={mv^{2} \over 2}} ). 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. [10] A titanium head has about 3% recoil energy and can result in greater efficiency and less fatigue when compared to a steel head with up to 30% recoil. Dead blow hammers use special rubber or steel shot to absorb recoil energy, rather than bouncing the hammer head after impact. Effect of the handle[ edit ] 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 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. 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 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 gravity[ edit ] 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[ edit ] This section needs expansion. You can help by adding to it . (July 2015) 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. Symbolic hammers[ edit ] The hammer, being one of the most used tools by Homo sapiens , 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 is used as a symbol of mining. A well known 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 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 coat of arms in (former) socialist countries like East Germany . Similarly, the Hammer and Sword symbolizes Strasserism , a strand of National Socialism seeking to appeal to the working class. 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.

In Norse mythology , 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. Judah Maccabee was nicknamed "The Hammer", possibly in recognition of his ferocity in battle. The name "Maccabee" may derive from the Aramaic maqqaba. (see Judah Maccabee § Origin of Name "The Hammer" ). In American folkore , the hammer of John Henry represents the strength and endurance of a man. 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 American Civil Rights movement . Hammer - iSnare Free Encyclopedia Hammer This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed. (December 2009) Construction A hammer is a tool or device that delivers a blow (a sudden impact) to an object. Most hammers are hand tools used to drive nails , fit parts, forge metal, and break apart objects.

Hammers vary in shape, size, and structure, depending on their purposes. Hammers are basic tools in many trades . The usual features are a head (most often made of steel ) and a handle (also called a helve or haft ). Although most hammers are hand tools, powered versions exist; they are known as powered hammers . Types of power hammer include steam hammers and trip hammers , often for heavier uses, such as forging . Some hammers have other names, such as sledgehammer , mallet and gavel . The term "hammer" also applies to big von devices that deliver blows, such as the hammer of a firearm or the hammer of a piano or the hammer ice scraper. Contents 12 External links History The use of simple hammers dates to about 2,600,000 BCE [1] [2] 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 with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age .

The hammer's archeological record shows that it may be the oldest tool for which definite evidence exists of its early existence. [1] [2] A stone hammer found in Dover Township, Minnesota dated to 8000–3000 BCE, the North American Archaic period Stone tapping hammer Perforated hammer head of stone Ancient Greek bronze sacrificial hammer, 7th century BCE, from Dodona 16th-century claw hammer; detail from Dürer 's Melencolia I (c. 1514) Construction and materials A traditional hand-held hammer consists of a separate head and a handle, fastened together by means of a special wedge made for the purpose, or by glue, 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 or ash , [3] which are tough and long-lasting materials that can dissipate shock waves 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 hazardous because it can literally "fly off the handle" when in use, becoming a dangerous uncontrolled missile. 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. Some hammers are one-piece designs made primarily of a single material. A one-piece metallic hammer may optionally have its handle coated or wrapped in a resilient material such as rubber, for improved grip and reduced user fatigue. [4] The hammer head may be surfaced with a variety of materials, including brass , 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 The parts of a hammer are the face, head (includes the bell and neck, which are not labelled), eye (where the handle fits into), peen (also spelled pein and pane). The side of a hammer is the cheek and some hammers have straps that extend down the handle for strength. Shown here are: A.

Ball-peen hammer B. Straight-peen hammer C. Cross-peen hammer The claw of a carpenter's hammer is frequently used to remove nails. 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 . 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 . Some upholstery hammers have a magnetized 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 or explosive gases. 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.

In these environments, a variety of non-sparking metal tools are used, primarily made of aluminium or beryllium copper . 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 hammers Woodsplitting maul – can be hit with a sledgehammer for splitting wood. Woodsplitting wedge – hit with a sledgehammer for splitting wood. 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. 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 , 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 2 {displaystyle E={mv^{2} over 2}} ). 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. [10] A titanium head has about 3% recoil energy and can result in greater efficiency and less fatigue when compared to a steel head with up to 30% recoil. Dead blow hammers 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 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. 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 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 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 You can help by adding to it .

(July 2015) 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. War hammers A war hammer is a late medieval weapon of war intended for close combat action. Symbolic hammers The hammer, being one of the most used tools by Homo sapiens , 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 is used as a symbol of mining. A well known 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 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 coat of arms in (former) socialist countries like East Germany . Similarly, the Hammer and Sword symbolizes Strasserism , a strand of National Socialism seeking to appeal to the working class.

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. In Norse mythology , 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. Judah Maccabee was nicknamed "The Hammer", possibly in recognition of his ferocity in battle. The name "Maccabee" may derive from the Aramaic maqqaba. (see Judah Maccabee § Origin of Name "The Hammer" ). In American folkore , the hammer of John Henry represents the strength and endurance of a man. 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 American Civil Rights movement . Image gallery HiFIT-hammer for aftertreatment of weld transitions Long cross-face hammer (blacksmithing) To strike repeatedly with a hammer, some other implement , the fist , etc.

To form or forge with a hammer; to shape by beating. Dryden ( figuratively ) To emphasize a point repeatedly . (sports) To hit particularly hard. 2010 December 28, Marc Vesty, “Stoke 0 - 2 Fulham”, in BBC [1] : This time the defender was teed up by Andrew Johnson's short free-kick on the edge of the box and Baird hammered his low drive beyond Begovic's outstretched left arm and into the bottom corner, doubling his goal tally for the season and stunning the home crowd. (cycling, intransitive , slang ) To ride very fast. 2011, Tim Moore, French Revolutions: Cycling the Tour de France (page 58) Fifteen minutes later, leaving a vapour trail of kitchen smells, I hammered into Obterre. ( intransitive ) To strike internally, as if hit by a hammer. I could hear the engine’s valves hammering once the timing rod was thrown. ( transitive , figuratively , sports) To defeat (a person, a team) resoundingly We hammered them 5-0!

Hammers - The Full Wiki The Full Wiki Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles . For other uses, see Hammer (disambiguation) . 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: Advertisements 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 ( ). 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 Main article: War hammer 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 ^ 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.

^ 2.5-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 Hammer - The Full Wiki The Full Wiki Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles . Related top topics For other uses, see Hammer (disambiguation) . 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: Advertisements 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 ( ). 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 Main article: War hammer 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 ^ 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. ^ 2.5-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

Question: Sledge, tack, claw, framing, upholstery, ball-peen, twist, dog-head and bush are all types of what?
Answer: Hammer