Editing Hammer (section)

{{Short description|Tool}}
{{About|the tool}}
{{pp-semi-indef}}
{{Use dmy dates|date=June 2021}}
[[File:Claw-hammer.jpg|thumb|right|upright=1.3|A modern [[claw hammer]] suited to drive and remove [[nail (fastener)|nails]]]]
[[File:Cartwheel mallets.JPG|thumb|Cartwheel [[mallet]]s with heads of felt held between steel washers for use with [[timpani]] drums]]
[[File:OHM - Streithammer.jpg|thumb|Detail of the head of a [[war hammer]]]]
[[File:Turonian Jerusalem Stone 031612.JPG|thumb|right|A [[geologist's hammer]] used to break up rocks, as seen in [[archaeology]] and [[prospecting]]]]

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A  '''hammer''' is a [[tool]], most often a [[hand 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. This can be, for example, to drive [[nail (fastener)|nails]] into [[wood]], to shape [[metal]] (as with a [[forge]]), or to crush [[Rock (geology)|rock]].<ref>{{Cite web|url=https://dictionary.cambridge.org/dictionary/english/hammer|title=hammer Meaning in the Cambridge English Dictionary|website=dictionary.cambridge.org|language=en|access-date=2018-06-09}}</ref><ref name="claw">{{Cite web|url=http://www.madehow.com/Volume-4/Hammer.html|title=How hammer is made - material, making, history, used, components, structure, steps|website=madehow.com|language=en|access-date=2018-08-21}}</ref> Hammers are used for a wide range of driving, shaping, breaking and non-destructive striking applications. Traditional disciplines include [[carpentry]], [[blacksmithing]], [[war hammer|warfare]], and [[mallet percussion|percussive]] musicianship (as with a [[gong]]).

'''Hammering''' is use of a hammer in its strike capacity, as opposed to [[pry bar|prying]] with a secondary claw or [[grappling]] 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 a lengthy downward [[plane (geometry)|planar]] arc—downward to add [[kinetic energy]] 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]] must adapt the hammer stroke to the location and orientation of the target, which can necessitate a [[club (weapon)|clubbing]] or [[golf swing|golfing]] motion with a two-handed grip.

The modern hammer head is typically made of [[steel]] which has been [[heat treating|heat treated]] for hardness, and the handle (also known as a [[wikt:haft#Noun|haft]] or [[wikt:helve#Noun|helve]]) is typically made of wood or [[plastic]].

Ubiquitous in [[framing (construction)|framing]], 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]]. Other types of hammers vary in shape, size, and structure, depending on their purposes. Hammers used in many [[tradesman|trades]] include [[sledgehammer]]s, [[mallet]]s, and [[ball-peen hammer]]s. Although most hammers are hand tools, [[power hammer|powered hammers]], such as [[steam hammer]]s and [[trip hammer]]s, are used to deliver [[force]]s beyond the capacity of the human arm. There are over 40 different types of hammers that have many different types of uses.<ref>{{cite web |last1=Akins |first1=Ricky |title=40 Different Types of Hammers and Their Uses |url=https://www.garagetooladvisor.com/hand-tools/different-types-of-hammers-and-their-uses/ |website=Garage tool advisor |access-date=2018-10-29|date=2018-09-06 }}</ref>

For hand hammers, the grip of the shaft is an important consideration. Many forms of hammering by hand are heavy work, and [[perspiration]] can lead to slippage from the hand, turning a hammer into a dangerous or destructive uncontrolled projectile. Steel is highly [[Elasticity (physics)|elastic]] and transmits [[shock (mechanics)|shock]] and [[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, [[Damped vibration|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]].

In terms of [[human physiology]], many uses of the hammer involve coordinated [[ballistic movement]]s under intense muscular forces which must be planned in advance at the [[motor system|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]], clubbing, and hammering precipitated aspects of [[brain evolution]] in early [[hominid]]s.<ref name=Calvin2004>{{cite book 
   |last=Calvin 
   |first=William H. 
   |author-link=William H. Calvin 
   |date=2004 
   |title=A Brief History of the Mind: From Apes to Intellect and Beyond 
   |publisher=[[Oxford University Press]]
   |page=47 
   |isbn=0-19-515907-1
}}</ref>