Machine tool
Overview
 
A machine tool is a machine
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

, typically powered other than by human muscle (e.g., electrically, hydraulically, or via line shaft
Line shaft
A line shaft is a power transmission system used extensively during the Industrial Revolution. Prior to the widespread use of electric motors small enough to be connected directly to each piece of machinery, line shafting was used to distribute power from a large central power source to machinery...

), used to make manufactured parts (components) in various ways that include cutting or certain other kinds of deformation. All machine tools involve some kind of fundamental constraining and guiding of movement provided by the parts of the machine, such that the relative movement between workpiece and cutting tool
Cutting tool
In the context of machining, a cutting tool is any tool that is used to remove material from the workpiece by means of shear deformation. Cutting may be accomplished by single-point or multipoint tools. Single-point tools are used in turning, shaping, plaining and similar operations, and remove...

 (which is called the toolpath) is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or "freehand".
Encyclopedia
A machine tool is a machine
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

, typically powered other than by human muscle (e.g., electrically, hydraulically, or via line shaft
Line shaft
A line shaft is a power transmission system used extensively during the Industrial Revolution. Prior to the widespread use of electric motors small enough to be connected directly to each piece of machinery, line shafting was used to distribute power from a large central power source to machinery...

), used to make manufactured parts (components) in various ways that include cutting or certain other kinds of deformation. All machine tools involve some kind of fundamental constraining and guiding of movement provided by the parts of the machine, such that the relative movement between workpiece and cutting tool
Cutting tool
In the context of machining, a cutting tool is any tool that is used to remove material from the workpiece by means of shear deformation. Cutting may be accomplished by single-point or multipoint tools. Single-point tools are used in turning, shaping, plaining and similar operations, and remove...

 (which is called the toolpath) is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or "freehand". Machine tools archetypically perform conventional machining
Machining
Conventional machining is a form of subtractive manufacturing, in which a collection of material-working processes utilizing power-driven machine tools, such as saws, lathes, milling machines, and drill presses, are used with a sharp cutting tool to physical remove material to achieve a desired...

 or grinding
Grinding (abrasive cutting)
Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.A wide variety of machines are used for grinding:* Hand-cranked knife-sharpening stones * Handheld power tools such as angle grinders and die grinders...

 on metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 (that is, metal cutting by shear deformation, producing swarf
Swarf
Swarf, also known as turnings, chips, or filings, are shavings and chippings of metal — the debris or waste resulting from metalworking operations including milling and grinding. It can usually be recycled, and this is the preferred method of disposal due to the environmental concerns regarding...

), but the definition can no longer be limited to those elements, if it ever could, because other processes than machining may apply, and other workpiece materials than metal are common. The precise definition of the term varies among users, as detailed in the "Nomenclature and key concepts" section. It is safe to say that all machine tools are "machines that help people to make things", although not all factory machines are machine tools.

Nomenclature and key concepts, interrelated

Many historians of technology
History of technology
The history of technology is the history of the invention of tools and techniques, and is similar in many ways to the history of humanity. Background knowledge has enabled people to create new things, and conversely, many scientific endeavors have become possible through technologies which assist...

 consider that true machine tools were born when the toolpath first became guided by the machine itself in some way, at least to some extent, so that direct, freehand human guidance of the toolpath (with hands, feet, or mouth) was no longer the only guidance used in the cutting or forming process. In this view of the definition, the term, arising at a time when all tools up till then had been hand tool
Hand tool
A hand tool is a device for performing work on a material or a physical system using only hands. The hand tools can be manually used employing force, or electrically powered, using electrical current...

s, simply provided a label for "tools that were machines [instead of hand tools]". Early lathes, those prior to the late medieval period, and modern woodworking lathes and potter's wheel
Potter's wheel
In pottery, a potter's wheel is a machine used in asma of round ceramic ware. The wheel may also be used during process of trimming the excess body from dried ware and for applying incised decoration or rings of color...

s may or may not fall under this definition, depending on how one views the headstock spindle
Spindle (tool)
In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer to the entire rotary unit, including not only the shaft itself, but its bearings...

 itself; but the earliest lathe with direct mechanical control of the cutting tool's path was a screw-cutting lathe dating to about 1483. This lathe "produced screw threads out of wood and employed a true compound slide rest".

The mechanical toolpath guidance grew out of any of various root concepts:
  • First is the spindle
    Spindle (tool)
    In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer to the entire rotary unit, including not only the shaft itself, but its bearings...

     concept itself, which constraints workpiece or tool movement to rotation around a fixed axis
    Rotation around a fixed axis
    Rotation around a fixed axis is a special case of rotational motion. The fixed axis hypothesis exclude the possibility of a moving axis, and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation around more than one axis at the same...

    . This ancient concept predates machine tools per se; the earliest lathes and potter's wheel
    Potter's wheel
    In pottery, a potter's wheel is a machine used in asma of round ceramic ware. The wheel may also be used during process of trimming the excess body from dried ware and for applying incised decoration or rings of color...

    s incorporated it for the workpiece, but the movement of the tool itself on these machines was entirely freehand.
  • The machine slide, which has many forms, such as dovetail ways, box ways, or cylindrical column ways. Machine slides constrain tool or workpiece movement linearly. If a stop is added, the length of the line can also be accurately controlled. (Machine slides are essentially a subset of linear bearings, although the language used to classify these various machine element
    Machine element
    Machine elements are basic mechanical parts used as the building blocks of most machines. Most are standardized to common sizes, but customs are also common for specialized applications.-Types:*Shafts**Couplings*Keys*Splines*Bearings**Roller bearings...

    s includes connotative
    Connotation
    A connotation is a commonly understood subjective cultural or emotional association that some word or phrase carries, in addition to the word's or phrase's explicit or literal meaning, which is its denotation....

     boundaries; some users in some contexts would contradistinguish elements in ways that others might not.)
  • Tracing, which involves following the contours of a model or template and transferring the resulting motion to the toolpath.
  • Cam
    Cam
    A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path...

     operation, which is related in principle to tracing but can be a step or two removed from the traced element's matching the reproduced element's final shape. For example, several cams, no one of which directly matches the desired output shape, can actuate several vector
    Vector
    Vector, a Latin word meaning "carrier", may refer in English to:-In computer science:*A one-dimensional array**Vector , a data type in the C++ Standard Template Library...

    s of the toolpath.


Abstractly programmable toolpath guidance began with mechanical solutions, such as in musical box
Musical box
A music box is a 19th century automatic musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb. They were developed from musical snuff boxes of the 18th century and called carillons à musique...

 cams and Jacquard loom
Jacquard loom
The Jacquard loom is a mechanical loom, invented by Joseph Marie Jacquard in 1801, that simplifies the process of manufacturing textiles with complex patterns such as brocade, damask and matelasse. The loom is controlled by punched cards with punched holes, each row of which corresponds to one row...

s. The convergence
Technological convergence
Technological convergence is the tendency for different technological systems to evolve towards performing similar tasks. Convergence can refer to previously separate technologies such as voice , data , and video that now share resources and interact with each other synergistically.The rise of...

 of programmable mechanical control with machine tool toolpath control was delayed many decades, in part because the programmable control methods of musical boxes and looms lacked the rigidity for machine tool toolpaths. Later, electromechanical solutions (such as servos
Servomechanism
thumb|right|200px|Industrial servomotorThe grey/green cylinder is the [[Brush |brush-type]] [[DC motor]]. The black section at the bottom contains the [[Epicyclic gearing|planetary]] [[Reduction drive|reduction gear]], and the black object on top of the motor is the optical [[rotary encoder]] for...

) and soon electronic solutions (including computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

s) were added, leading to numerical control and computer numerical control
Numerical control
Numerical control refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to controlled manually via handwheels or levers, or mechanically automated via cams alone...

.

When considering the difference between freehand toolpaths and machine-constrained toolpaths, the concepts of accuracy and precision
Accuracy and precision
In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...

, efficiency
Efficiency
Efficiency in general describes the extent to which time or effort is well used for the intended task or purpose. It is often used with the specific purpose of relaying the capability of a specific application of effort to produce a specific outcome effectively with a minimum amount or quantity of...

, and productivity
Productivity
Productivity is a measure of the efficiency of production. Productivity is a ratio of what is produced to what is required to produce it. Usually this ratio is in the form of an average, expressing the total output divided by the total input...

 become important in understanding why the machine-constrained option adds value
Value (economics)
An economic value is the worth of a good or service as determined by the market.The economic value of a good or service has puzzled economists since the beginning of the discipline. First, economists tried to estimate the value of a good to an individual alone, and extend that definition to goods...

. After all, humans are generally quite talented in their freehand movements; the drawings, paintings, and sculpture
Sculpture
Sculpture is three-dimensional artwork created by shaping or combining hard materials—typically stone such as marble—or metal, glass, or wood. Softer materials can also be used, such as clay, textiles, plastics, polymers and softer metals...

s of artists such as Michelangelo
Michelangelo
Michelangelo di Lodovico Buonarroti Simoni , commonly known as Michelangelo, was an Italian Renaissance painter, sculptor, architect, poet, and engineer who exerted an unparalleled influence on the development of Western art...

 or Leonardo da Vinci
Leonardo da Vinci
Leonardo di ser Piero da Vinci was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance...

, and of countless other talented people, show that human freehand toolpath has great potential. The value
Value (economics)
An economic value is the worth of a good or service as determined by the market.The economic value of a good or service has puzzled economists since the beginning of the discipline. First, economists tried to estimate the value of a good to an individual alone, and extend that definition to goods...

 that machine tools added to these human talents is in the areas of rigidity (constraining the toolpath despite thousands of newtons (pounds
Pound-force
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...

) of force fighting against the constraint), accuracy and precision
Accuracy and precision
In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...

, efficiency
Efficiency
Efficiency in general describes the extent to which time or effort is well used for the intended task or purpose. It is often used with the specific purpose of relaying the capability of a specific application of effort to produce a specific outcome effectively with a minimum amount or quantity of...

, and productivity
Productivity
Productivity is a measure of the efficiency of production. Productivity is a ratio of what is produced to what is required to produce it. Usually this ratio is in the form of an average, expressing the total output divided by the total input...

. With a machine tool, toolpaths that no human muscle could constrain can be constrained; and toolpaths that are technically possible with freehand methods, but would require tremendous time and skill to execute, can instead be executed quickly and easily, even by people with little freehand talent (because the machine takes care of it). The latter aspect of machine tools is often referred to by historians of technology as "building the skill into the tool", in contrast to the toolpath-constraining skill being in the person who wields the tool. As an example, it is physically possible to make interchangeable
Interchangeable parts
Interchangeable parts are parts that are, for practical purposes, identical. They are made to specifications that ensure that they are so nearly identical that they will fit into any device of the same type. One such part can freely replace another, without any custom fitting...

 screws, bolts, and nuts entirely with freehand toolpaths. But it is economically practical to make them only with machine tools.

In the 1930s, the U.S. National Bureau of Economic Research (NBER) referenced the definition of a machine tool as "any machine operating by other than hand power which employs a tool to work on metal".

The narrowest colloquial sense of the term reserves it only for machines that perform metal cutting—in other words, the many kinds of [conventional] machining
Machining
Conventional machining is a form of subtractive manufacturing, in which a collection of material-working processes utilizing power-driven machine tools, such as saws, lathes, milling machines, and drill presses, are used with a sharp cutting tool to physical remove material to achieve a desired...

 and grinding
Grinding (abrasive cutting)
Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.A wide variety of machines are used for grinding:* Hand-cranked knife-sharpening stones * Handheld power tools such as angle grinders and die grinders...

. These processes are a type of deformation that produces swarf
Swarf
Swarf, also known as turnings, chips, or filings, are shavings and chippings of metal — the debris or waste resulting from metalworking operations including milling and grinding. It can usually be recycled, and this is the preferred method of disposal due to the environmental concerns regarding...

. However, economist
Economist
An economist is a professional in the social science discipline of economics. The individual may also study, develop, and apply theories and concepts from economics and write about economic policy...

s use a slightly broader sense that also includes metal deformation of other types that squeeze the metal into shape without cutting off swarf, such as rolling, stamping with dies
Die (manufacturing)
A die is a specialized tool used in manufacturing industries to cut or shape material using a press. Like molds, dies are generally customized to the item they are used to create...

, shearing, swaging, rivet
Rivet
A rivet is a permanent mechanical fastener. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the buck-tail. On installation the rivet is placed in a punched or pre-drilled hole, and the tail is upset, or bucked A rivet...

ing, and others. Thus presses
Machine press
A machine press, commonly shortened to press, is a machine tool that changes the shape of a workpiece.-Servomechanism:A servomechanism press, also known as a servo press or a electro press, is a press driven by an AC servo motor. The torque produced is converted to a linear force via a ball screw....

 are usually included in the economic definition of machine tools. For example, this is the breadth of definition used by Max Holland
Max Holland
Max Holland is a journalist, author, and the editor of Washington Decoded, an online newsletter from the nation's capital that began publishing March 11, 2007...

 in his history of Burgmaster and Houdaille, which is also a history of the machine tool industry in general from the 1940s through the 1980s; he was reflecting the sense of the term used by Houdaille itself and other firms in the industry. Many reports on machine tool export
Export
The term export is derived from the conceptual meaning as to ship the goods and services out of the port of a country. The seller of such goods and services is referred to as an "exporter" who is based in the country of export whereas the overseas based buyer is referred to as an "importer"...

 and import
Import
The term import is derived from the conceptual meaning as to bring in the goods and services into the port of a country. The buyer of such goods and services is referred to an "importer" who is based in the country of import whereas the overseas based seller is referred to as an "exporter". Thus...

 and similar economic topics use this broader definition.

The colloquial sense implying [conventional] metal cutting is also growing obsolete because of changing technology over the decades. The many more recently developed processes labeled "machining", such as electrical discharge machining
Electrical discharge machining
Electric discharge machining , sometimes colloquially also referred to as spark machining, spark eroding, burning, die sinking or wire erosion, is a manufacturing process whereby a desired shape is obtained using electrical discharges...

, electrochemical machining, electron beam machining
Electron beam machining
Electron-beam machining is a process where high-velocity electrons concentrated into a narrow beam are directed toward the work piece, creating heat and vaporizing the material. EBM can be used for very accurate cutting or boring of a wide variety of metals...

, photochemical machining, and ultrasonic machining, or even plasma cutting
Plasma cutting
Plasma cutting is a process that is used to cut steel and other metals of different thicknesses using a plasma torch...

 and water jet cutting
Water jet cutter
A water jet cutter, also known as a waterjet, is a tool capable of slicing into metal or other materials using a jet of water at high velocity and pressure, or a mixture of water and an abrasive substance. The process is essentially the same as water erosion found in nature but greatly accelerated...

, are often performed by machines that could most logically be called machine tools. In addition, some of the newly developed additive manufacturing
Additive manufacturing
Additive manufacturing is defined by ASTM as the "process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies, such as traditional machining...

 processes, which are not about cutting away material but rather about adding it, are done by machines that are likely to end up labeled, in some cases, as machine tools.

The natural language
Natural language
In the philosophy of language, a natural language is any language which arises in an unpremeditated fashion as the result of the innate facility for language possessed by the human intellect. A natural language is typically used for communication, and may be spoken, signed, or written...

 use of the terms varies, with subtle connotative
Connotation
A connotation is a commonly understood subjective cultural or emotional association that some word or phrase carries, in addition to the word's or phrase's explicit or literal meaning, which is its denotation....

 boundaries. Many speakers resist using the term "machine tool" to refer to woodworking machine
Woodworking machine
A Woodworking machine is a machine that is intended to process wood. These machines are usually powered by electric motors and are used extensively in woodworking...

ry (joiners, table saws, routing stations, and so on), but it is difficult to maintain any true logical dividing line, and therefore many speakers are fine with a broad definition. It is common to hear machinists refer to their machine tools simply as "machines". Usually the mass noun
Mass noun
In linguistics, a mass noun is a noun that refers to some entity as an undifferentiated unit rather than as something with discrete subsets. Non-count nouns are best identified by their syntactic properties, and especially in contrast with count nouns. The semantics of mass nouns are highly...

 "machinery" encompasses them, but sometimes it is used to imply only those machines that are being excluded from the definition of "machine tool". This is why the machines in a food-processing plant, such as conveyors, mixers, vessels, dividers, and so on, may be labeled "machinery", while the machines in the factory's tool and die department are instead called "machine tools" in contradistinction. As for the 1930s NBER definition quoted above, one could argue that its specificity to metal is obsolete, as it is quite common today for particular lathes, milling machines, and machining centers (definitely machine tools) to work exclusively on plastic cutting jobs throughout their whole working lifespan. Thus the NBER definition above could be expanded to say "which employs a tool to work on metal or other materials of high hardness". And its specificity to "operating by other than hand power" is also problematic, as machine tools can be powered by people if appropriately set up, such as with a treadle
Treadle
A treadle [from OE tredan = to tread] is a part of a machine which is operated by the foot to produce reciprocating or rotary motion in a machine such as a weaving loom or grinder...

 (for a lathe
Lathe
A lathe is a machine tool which rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.Lathes are used in woodturning,...

) or a hand lever (for a shaper
Shaper
A shaper is a type of machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical...

). Hand-powered shapers are clearly "the 'same thing' as shapers with electric motors except smaller", and it is trivial to power a micro lathe
Micro lathe
A micro lathe is a machine tool used for the complex shaping of metal and other solid materials. Micro lathes are related to lathes but are distinguished by their small size and differing capabilities, application, use, and locations...

 with a hand-cranked belt pulley instead of an electric motor. Thus one can question whether power source is truly a key distinguishing concept; but for economics purposes, the NBER's definition made sense, because most of the commercial value of the existence of machine tools comes about via those that are powered by electricity, hydraulics, and so on. Such are the vagaries of natural language
Natural language
In the philosophy of language, a natural language is any language which arises in an unpremeditated fashion as the result of the innate facility for language possessed by the human intellect. A natural language is typically used for communication, and may be spoken, signed, or written...

 and controlled vocabulary
Controlled vocabulary
Controlled vocabularies provide a way to organize knowledge for subsequent retrieval. They are used in subject indexing schemes, subject headings, thesauri, taxonomies and other form of knowledge organization systems...

, both of which have their places in the business world.

History

Machine tools filled a need created by textile machinery during the Industrial Revolution in England in the middle to late 1700s. Until that time machinery was made mostly from wood, including gearing and shafts.

James Watt
James Watt
James Watt, FRS, FRSE was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world.While working as an instrument maker at the...

 was unable to have an accurately bored cylinder for his first steam engine, trying for several years until John Wilkinson
John Wilkinson (industrialist)
John "Iron-Mad" Wilkinson was an English industrialist who pioneered the use and manufacture of cast iron and cast-iron goods in the Industrial Revolution.-Early life:...

 invented a suitable boring machine in 1774, boring Boulton & Watt's first commercial engine in 1776.

The first machine tools offered for sale (i.e., commercially available) were constructed by Matthew Murray
Matthew Murray
Matthew Murray was an English steam engine and machine tool manufacturer, who designed and built the first commercially viable steam locomotive, the twin cylinder Salamanca in 1812...

 in England around 1800. Others, such as Henry Maudslay
Henry Maudslay
Henry Maudslay was a British machine tool innovator, tool and die maker, and inventor. He is considered a founding father of machine tool technology.-Early life:...

, James Nasmyth
James Nasmyth
James Hall Nasmyth was a Scottish engineer and inventor famous for his development of the steam hammer. He was the co-founder of Nasmyth, Gaskell and Company manufacturers of machine tools...

, and Joseph Whitworth
Joseph Whitworth
Sir Joseph Whitworth, 1st Baronet was an English engineer, entrepreneur, inventor and philanthropist. In 1841, he devised the British Standard Whitworth system, which created an accepted standard for screw threads...

, soon followed the path of expanding their entrepreneurship from manufactured end products and millwright
Millwright
A millwright is a craftsman or tradesman engaged with the construction and maintenance of machinery.Early millwrights were specialist carpenters who erected machines used in agriculture, food processing and processing lumber and paper...

 work into the realm of building machine tools for sale.

Important early machine tools included the slide rest lathe, screw-cutting lathe
Screw-cutting lathe
A screw-cutting lathe is a machine capable of cutting very accurate screw threads via single-point screw-cutting, which is the process of guiding the linear motion of the tool bit in a precisely known ratio to the rotating motion of the workpiece...

, turret lathe
Turret lathe
The turret lathe is a form of metalworking lathe that is used for repetitive production of duplicate parts, which by the nature of their cutting process are usually interchangeable...

, milling machine
Milling machine
A milling machine is a machine tool used to machine solid materials. Milling machines are often classed in two basic forms, horizontal and vertical, which refers to the orientation of the main spindle. Both types range in size from small, bench-mounted devices to room-sized machines...

, pattern tracing lathe (shaper) and metal planer
Planer (metalworking)
A planer is a type of metalworking machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical...

, which were all in use before 1840. With these machine tools the decades old objective of interchangeable parts
Interchangeable parts
Interchangeable parts are parts that are, for practical purposes, identical. They are made to specifications that ensure that they are so nearly identical that they will fit into any device of the same type. One such part can freely replace another, without any custom fitting...

 was finally realized.

Forerunners of machine tools included bow drills and potter's wheels, which had existed in ancient Egypt prior to 2500 BCE, and lathes are known to have existed in multiple regions of Europe since at least 1000 to 500 BCE. But it was not until the later Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

 and the Age of Enlightenment
Age of Enlightenment
The Age of Enlightenment was an elite cultural movement of intellectuals in 18th century Europe that sought to mobilize the power of reason in order to reform society and advance knowledge. It promoted intellectual interchange and opposed intolerance and abuses in church and state...

 that the modern concept of a machine tool—a class of machines used as tools in the making of metal parts, and incorporating machine-guided toolpath—began to evolve. Clock makers of the middle ages and renaissance men
Polymath
A polymath is a person whose expertise spans a significant number of different subject areas. In less formal terms, a polymath may simply be someone who is very knowledgeable...

 such as Leonardo da Vinci
Leonardo da Vinci
Leonardo di ser Piero da Vinci was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance...

 helped expand humans' technological milieu toward the preconditions for industrial machine tools. During the 18th and 19th centuries, and even in many cases in the 20th, the builders of machine tools tended to be the same people who would then use them to produce the end products (manufactured goods). However, from these roots also evolved an industry of machine tool builders as we define them today, meaning people who specialize in building machine tools for sale to others.

The demand for machine tools has been driven by various manufacturing industries over the centuries. The human desire for firearms (from small arms
Small arms
Small arms is a term of art used by armed forces to denote infantry weapons an individual soldier may carry. The description is usually limited to revolvers, pistols, submachine guns, carbines, assault rifles, battle rifles, multiple barrel firearms, sniper rifles, squad automatic weapons, light...

 through artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...

) was the earliest, and it has lasted as a top driver through the present. Lathes and boring machines for boring cannon barrels led the way. The next major impetus of machine tool development was the building of textile machinery during the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

 in England. Historians of machine tools often focus on a handful of major industries that most spurred machine tool development. In order of historical emergence, they have been firearms (small arms and artillery); clocks
Horology
Horology is the art or science of measuring time. Clocks, watches, clockwork, sundials, clepsydras, timers, time recorders and marine chronometers are all examples of instruments used to measure time.People interested in horology are called horologists...

; textile machinery; steam engines (stationary
Stationary steam engine
Stationary steam engines are fixed steam engines used for pumping or driving mills and factories, and for power generation. They are distinct from locomotive engines used on railways, traction engines for heavy steam haulage on roads, steam cars , agricultural engines used for ploughing or...

, marine
Marine steam engine
A marine steam engine is a reciprocating steam engine that is used to power a ship or boat. Steam turbines and diesel engines largely replaced reciprocating steam engines in marine applications during the 20th century, so this article describes the more common types of marine steam engine in use...

, rail
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...

, and otherwise
History of steam road vehicles
The history of steam road vehicles describes the development of vehicles powered by a steam engine for use on land and independent of rails; whether for conventional road use, such as the steam car and steam waggon, or for agricultural or heavy haulage work, such as the traction engine.The first...

; the story of how Watt
James Watt
James Watt, FRS, FRSE was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world.While working as an instrument maker at the...

's need for an accurate cylinder spurred Boulton's boring machine is discussed by Roe (1916)); sewing machine
Sewing machine
A sewing machine is a textile machine used to stitch fabric, cards and other material together with thread. Sewing machines were invented during the first Industrial Revolution to decrease the amount of manual sewing work performed in clothing companies...

s; bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

s; automobile
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

s; and aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

. Others could be included in this list as well, but they tend to be connected with the root causes already listed. For example, rolling-element bearing
Rolling-element bearing
A rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing round elements between the two pieces...

s are an industry of themselves, but this industry's main drivers of development were the vehicles already listed—trains, bicycles, automobiles, and aircraft; and other industries, such as tractors, farm implements, and tanks, borrowed heavily from those same parent industries.

Drive power sources

Machine tools can be powered from a variety of sources. Human and animal power are options, as is energy captured through the use of waterwheels. However, modern machine tools began to develop only after the development of the steam engine
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

, which led to the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

. Since electrification
Electrification
Electrification originally referred to the build out of the electrical generating and distribution systems which occurred in the United States, England and other countries from the mid 1880's until around 1940 and is in progress in developing countries. This also included the change over from line...

 of industry after 1900, most machine tools are powered by electricity; however, hydraulic and pneumatic power can be used, but this is uncommon.

Automatic control

Machine tools can be operated manually, or under automatic control. Early machines used flywheel
Flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...

s to stabilize their motion and had complex systems of gears and levers to control the machine and the piece being worked on. Soon after World War II, the numerical control
Numerical control
Numerical control refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to controlled manually via handwheels or levers, or mechanically automated via cams alone...

 (NC) machine was developed. NC machines used a series of numbers punched on paper tape or punched card
Punched card
A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...

s to control their motion. In the 1960s, computers were added to give even more flexibility to the process. Such machines became known as computerized numerical control (CNC) machines. NC and CNC machines could precisely repeat sequences over and over, and could produce much more complex pieces than even the most skilled tool operators.

Before long, the machines could automatically change the specific cutting and shaping tools that were being used. For example, a drill
Drill
A drill or drill motor is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of...

 machine might contain a magazine with a variety of drill bit
Drill bit
Drill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes....

s for producing holes of various sizes. Previously, either machine operators would usually have to manually change the bit or move the work piece to another station to perform these different operations. The next logical step was to combine several different machine tools together, all under computer control. These are known as machining centers, and have dramatically changed the way parts are made.

From the simplest to the most complex, most machine tools are capable of at least partial self-replication
Self-replicating machine
A self-replicating machine is an artificial construct that is theoretically capable of autonomously manufacturing a copy of itself using raw materials taken from its environment, thus exhibiting self-replication in a way analogous to that found in nature. The concept of self-replicating machines...

, and produce machine parts as their primary function.

Examples

Examples of machine tools are:
  • Broaching machine
    Broach (metalwork)
    Broaching is a machining process that uses a toothed tool, called a broach, to remove material. There are two main types of broaching: linear and rotary. In linear broaching, which is the more common process, the broach is run linearly against a surface of the workpiece to effect the cut...

  • Drill press
  • Gear shaper
    Gear shaper
    A gear shaper is a machine tool for cutting the teeth of internal or external gears. The name shaper relates to the fact that the cutter engages the part on the forward stroke and pulls away from the part on the return stroke, just like the clapper box on a planer shaper.The cutting tool is also...

  • Hobbing machine
    Hobbing machine
    Hobbing is a machining process for making gears, splines, and sprockets on a hobbing machine, which is a special type of milling machine. The teeth or splines are progressively cut into the workpiece by a series of cuts made by a cutting tool called a hob...

  • Hone
    Hône
    Hône is a town and comune in the Aosta Valley region of north-western Italy.-Twin towns:twin towns with the year of its establishing:# Nora Municipality, Sweden...

  • Lathe
  • Screw machine
    Screw machine
    A screw machine may refer to a:* Screw machine , a small- to medium-sized automatic lathe that is mechanically automated via cams...

    s
  • Milling machine
    Milling machine
    A milling machine is a machine tool used to machine solid materials. Milling machines are often classed in two basic forms, horizontal and vertical, which refers to the orientation of the main spindle. Both types range in size from small, bench-mounted devices to room-sized machines...

  • Shear (sheet metal)
    Shear (sheet metal)
    -Bench shear:A bench shear, also known as a lever shear, is a bench mounted shear with a compound mechanism to increase the mechanical advantage. It is usually used for cutting rough shapes out of medium sized pieces of sheet metal, but cannot do delicate work. For the small shear, it mostly...

  • Shaper
    Shaper
    A shaper is a type of machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical...

  • Saws
    SAWS
    SAWS may refer to:*Peace be upon him , abbreviated as SAWS, phrase that Muslims often say after saying the name of a prophet of Islam*State Administration of Work Safety, government agency of the People's Republic of China...

  • Planer
    Planer (metalworking)
    A planer is a type of metalworking machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical...

  • Stewart platform
    Stewart platform
    A Stewart platform is a type of parallel robot that incorporates six prismatic actuators, commonly hydraulic jacks. These actuators are mounted in pairs to the mechanism's base, crossing over to three mounting points on a top plate. Devices placed on the top plate can be moved in the six degrees...

     mills
  • Grinding machine
    Grinding machine
    A grinding machine, often shortened to grinder, is a machine tool used for grinding, which is a type of machining using an abrasive wheel as the cutting tool...

    s


When fabricating or shaping parts, several techniques are used to remove unwanted metal. Among these are:
  • Electrical discharge machining
    Electrical discharge machining
    Electric discharge machining , sometimes colloquially also referred to as spark machining, spark eroding, burning, die sinking or wire erosion, is a manufacturing process whereby a desired shape is obtained using electrical discharges...

  • Grinding (abrasive cutting)
    Grinding (abrasive cutting)
    Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.A wide variety of machines are used for grinding:* Hand-cranked knife-sharpening stones * Handheld power tools such as angle grinders and die grinders...

  • Multiple edge cutting tools
  • Single edge cutting tools


Other techniques are used to add desired material. Devices that fabricate components by selective addition of material are called rapid prototyping
Rapid prototyping
Rapid prototyping is the automatic construction of physical objects using additive manufacturing technology. The first techniques for rapid prototyping became available in the late 1980s and were used to produce models and prototype parts. Today, they are used for a much wider range of applications...

 machines.

See also

:Category:Machine tool builders
  • Epoxy granite
    Epoxy granite
    Epoxy granite, also known as synthetic granite, is a mixture of epoxy and granite commonly used as an alternative material for machine tool bases...

  • Four slide machine
  • Self-replicating machine
    Self-replicating machine
    A self-replicating machine is an artificial construct that is theoretically capable of autonomously manufacturing a copy of itself using raw materials taken from its environment, thus exhibiting self-replication in a way analogous to that found in nature. The concept of self-replicating machines...

  • Machine tool dynamometer
  • Machining vibrations
    Machining vibrations
    Machining vibrations, also called chatter, correspond to the relative movement between the workpiece and the cutting tool. The vibrations result in waves on the machined surface. This affects typical machining processes, such as turning, milling and drilling, and atypical machining processes, such...

  • Machinist calculator
    Machinist calculator
    A machinist calculator is a hand-held calculator programmed with built-in formulas making it easy and quick for machinists to establish speeds, feeds and time without guesswork or conversion charts. Formulas may include revolutions per minute , surface feet per minute , inches per minute , feed per...

  • Metalworking
    Metalworking
    Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...

  • Multimachine
    Multimachine
    The multimachine is an all-purpose open source machine tool that can be built inexpensively by a semi-skilled mechanic with common hand tools, from discarded car and truck parts, using only commonly available hand tools and no electricity. Its size can range from being small enough to fit in a...

     - an open source machine tool
  • Swarf
    Swarf
    Swarf, also known as turnings, chips, or filings, are shavings and chippings of metal — the debris or waste resulting from metalworking operations including milling and grinding. It can usually be recycled, and this is the preferred method of disposal due to the environmental concerns regarding...

  • Tool bit
    Tool bit
    The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, shapers, and planers. Such cutters are also often referred to by the set-phrase name of single-point cutting tool. The cutting edge is ground to suit a particular machining operation and may be resharpened or...

  • Tool wear
    Tool wear
    Tool wear describes the gradual failure of cutting tools due to regular operation. It is a term often associated with tipped tools, tool bits, or drill bits that are used with machine tools.Types of wear include:...


History of machine tools

A memoir that contains quite a bit of general history of the industry.. A monograph with a focus on history, economics, and import and export policy. Original 1976 publication: LCCN 75-046133 , ISBN 0521212030. One of the most detailed histories of the machine tool industry from the late 18th century through 1932. Not comprehensive in terms of firm names and sales statistics (like Floud focuses on), but extremely detailed in exploring the development and spread of practicable interchangeability, and the thinking behind the intermediate steps. Extensively cited by later works. One of the most detailed histories of the machine tool industry from World War II through the early 1980s, relayed in the context of the social impact of evolving automation via NC and CNC. A seminal classic of machine tool history. Extensively cited by later works. A biography of a machine tool builder that also contains some general history of the industry.
  • Ryder, Thomas and Son, Machines to Make Machines 1865 to 1968, a centenary booklet, (Derby: Bemrose & Sons, 1968). Collection of previously published monographs bound as one volume. A collection of seminal classics of machine tool history.

Machine shop practice

. A widely used training text, in two volumes, for machinist apprentices and other trainees, as well as a reference book for the shelf of the journeyman-level machinist. Multiple editions.. Public domain (copyright expired) and thus available with free full-text access online. Quite dated, yet still can acquaint a reader with most of the fundamental concepts of machine tools.

External links

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