Editing Pantograph

{{Short description|Mechanical linkage used for copying drawings}}
{{About|the duplication instrument|the electrical device used above trains or trams|Pantograph (transport)|other uses|}}
[[File:Pantograph in action.svg|thumb|Drafting pantograph in use]]
[[File:Pantograph animation.gif|thumb|Pantograph used for scaling a picture. The red shape is traced and enlarged.]]
[[File:Pantograph01.jpg|thumb|Pantograph 3d rendering]]

A '''pantograph''' ({{ety|el|παντ-|all, every||γραφ-|to write}}, from their original use for copying writing) is a [[Linkage (mechanical)|mechanical linkage]] connected in a manner based on [[parallelogram]]s so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line drawing is traced by the first point, an identical, enlarged, or miniaturized copy will be drawn by a pen fixed to the other. Using the same principle, different kinds of pantographs are used for other forms of duplication in areas such as [[sculpting]], [[Mint (facility)|minting]], [[engraving]], and [[Milling (machining)|milling]].

== History ==
[[File:Eidographe2.svg|thumb|left|Diagram illustrating the principles used by William Wallace's eidograph]]

The ancient Greek engineer [[Hero of Alexandria]] described pantographs in his work ''Mechanics''.<ref>{{cite book| last = Ceccarelli| first = Marco | title = Distinguished Figures in Mechanism and Machine Science: Their Contributions and Legacies| url = https://books.google.com/books?id=UmBnVMA5ri4C| publisher = [[Springer Science+Business Media|Springer]]|date=2007| page = 230| isbn = 978-1-4020-6366-4}}</ref>

In 1603,<ref name=GPscheiner>{{Cite web|url=http://galileo.rice.edu/Catalog/NewFiles/scheiner.html|title=The Galileo Project — Scheiner, Christoph" (history)|first=Albert|last=Van Helden|publisher=Galileo Project, [[Rice University]]|date=1995|access-date=24 March 2020|url-status=live|archive-url=https://web.archive.org/web/20040709143818/http://galileo.rice.edu/Catalog/NewFiles/scheiner.html|archive-date=9 July 2004}}</ref> [[Christoph Scheiner]] used a pantograph to copy and scale diagrams, and wrote about the invention over 27 years later, in ''"Pantographice seu Ars delineandi res quaslibet per parallelogrammum lineare seu cavum"'' (Rome 1631). One arm of the pantograph contained a small pointer, while the other held a drawing implement, and by moving the pointer over a diagram, a copy of the diagram was drawn on another piece of paper. By changing the positions of the arms in the linkage between the pointer arm and drawing arm, the scale of the image produced can be changed.

In 1821, Professor [[William Wallace (mathematician)|William Wallace]] (1768–1843) invented the eidograph to improve upon the practical utility of the pantograph.<ref>{{cite journal|title=Transactions of the Royal Society of Edinburgh. - Edinburgh, Dickson 1788-1905|journal=Transactions of the Royal Society of Edinburgh|date=1836|volume=13|pages=418–439, 637|url=https://books.google.com/books?id=paBbAAAAcAAJ&q=Account%20of%20the%20Invention%20of%20the%20pantograph%20and%20a%20description%20of%20the%20eidograph%2C%20a%20copying%20instrument%20invented%20by%20William%20Wallace&pg=PA418|publisher=Dickson}}</ref> The eidograph relocates the fixed point to the center of the parallelogram and uses a narrow parallelogram to provide improved mechanical advantages.

== Uses ==
[[File:Pantograph etching mechanism.JPG|thumb|Pantograph etching mechanism]]
[[File:Francis Galton's pantograph.jpg|thumb|Francis Galton's pantograph]]

=== Drafting ===

The original use of the pantograph was for copying and [[scaling (geometry)|scaling]] [[technical drawing|line drawings]]. Modern versions are sold as technical toys.

=== Sculpture and minting ===

Sculptors use a three-dimensional version of the pantograph,<ref>{{Cite web|url=https://www.britishpathe.com/video/an-unfinished-symphony-in-stone|title=An Unfinished Symphony In Stone: A video with sculptor CS Jagger using a three-dimensional pantograph|publisher=[[Pathé News|British Pathé]]|language=en-GB|at=1 min. 7 sec.|access-date=24 March 2020|date=28 January 1935 }}</ref> usually a large boom connected to a fixed point at one end, bearing two rotating pointing needles at arbitrary points along this boom. By adjusting the needles different enlargement or reduction ratios can be achieved. This device, now largely overtaken by [[Computer-aided manufacturing|computer guided]] [[CNC Router|router]] systems that [[3D scanner|scan]] a [[Scale model|model]] and can produce it in a variety of materials and in any desired size,<ref name="castro2003">{{Cite journal|url=https://www.sculpture.org/documents/scmag03/janfeb03/cronin/cronin.shtml|title=Making the Personal Monumental: A Conversation with Patricia Cronin|first=Jan Garden |last=Castro|access-date=23 August 2017|publisher=[[International Sculpture Center]]|journal=[[Sculpture (magazine)|Sculpture]]|volume=22|date=January–February 2003|issue=1|archive-url=https://web.archive.org/web/20191001223724/https://www.sculpture.org/documents/scmag03/janfeb03/cronin/cronin.shtml|archive-date=1 October 2019|url-status=live }}</ref> was invented by inventor and steam pioneer [[James Watt]] and perfected by [[Benjamin Cheverton]] in 1836. Cheverton's machine was fitted with a rotating cutting bit to carve reduced versions of well-known sculptures.<ref>{{cite web|url=http://writeantiques.com/the-man-who-brought-marble-sculpture-down-to-size/|title=The man who brought marble sculpture down to size - WriteAntiques|website=writeantiques.com|access-date=23 August 2017|archive-url=https://web.archive.org/web/20170823073907/http://writeantiques.com/the-man-who-brought-marble-sculpture-down-to-size/|archive-date=23 August 2017|url-status=dead|df=dmy-all}}</ref> A three-dimensional pantograph can also be used to enlarge sculpture by interchanging the position of the model and the copy.<ref>{{cite web|url=http://www.keropiansculpture.com/enlarging_machine.html|title=Enlarging and Reducing Sculpture|website=www.keropiansculpture.com|access-date=23 August 2017}}</ref><ref>{{cite web|url=http://www.terraz.org/liberty/article.php3?id_article=20|archive-url=https://web.archive.org/web/20040716025123/http://www.terraz.org/liberty/article.php3?id_article=20|url-status=dead|archive-date=16 July 2004|title=Enlarging a copy of the Statue of Liberty (French) by means of a 3d-pantograph with a scanning wheel and a cutting edge, in clay.|access-date=23 August 2017}}</ref>

Another version is still very much in use to reduce the size of large [[relief]] designs for [[coin]]s down to the required size of the coin.<ref>{{cite web|url=http://www.fleur-de-coin.com/articles/moderncoinminting.asp|title=Designing and minting coins|first=Ioannis|last=Androulakis|website=www.fleur-de-coin.com|access-date=23 August 2017}}</ref>

=== Acoustic cylinder duplication ===
{{Unreferenced section|date=July 2018}}

One advantage of [[phonograph]] and gramophone discs over cylinders in the 1890s&mdash;before electronic amplification was available—was that large numbers of discs could be stamped quickly and cheaply. In 1890, the only ways of manufacturing copies of a master cylinder were to mold the cylinders (which was slow and, early on, produced very poor copies), or to acoustically copy the sound by placing the horns of two phonographs together or to hook the two together with a rubber tube (one phonograph recording and the other playing the cylinder back). Instead of copying a master cylinder, the other alternative was to record a performance to multiple gramophones simultaneously,  over and over again, making each cylinder a master copy. [[Thomas Edison|Edison]], [[Gianni Bettini|Bettini]], [[Leon Douglass]] and others solved this problem (partly) by mechanically linking a cutting stylus and a playback stylus together and copying the "hill-and-dale" grooves of the cylinder mechanically. When molding improved somewhat, molded cylinders were used as pantograph masters. This was employed by Edison and [[Columbia Records|Columbia]] in 1898, and was used until about January 1902 (Columbia brown waxes after this were molded). Some companies like the [[United States Phonograph Company]] of [[Newark, New Jersey]], supplied cylinder masters for smaller companies so that they could duplicate them, sometimes pantographically. Pantographs could turn out about 30 records per day and produce up to about 150 records per master. In theory, pantograph masters could be used for 200 or 300 duplicates if the master and the duplicate were running in reverse and the record would be duplicated in reverse. This, in theory, could extend the usability of a pantograph master by using the unworn/lesser worn part of the recording for duplication. [[Pathé]] employed this system with mastering their vertically cut records until 1923; a {{convert|5|in|mm|adj=mid|-diameter}}, {{convert|4|or|6|in|mm|adj=mid|-long}} master cylinder, rotating at a high speed, would be recorded on. This was done as the resulting cylinder was considerably loud and of very high fidelity. Then, the cylinder would be placed on the mandrel of a duplicating pantograph that would be played with a stylus on the end of a lever, which would transfer the sound to a wax disc master, which would be electroplated and be used to stamp copies out. This system resulted in some fidelity reduction and rumble, but relatively high quality sound. [[Edison Disc Record|Edison Diamond Disc Records]] were made by recording ''directly'' onto the wax master disc.

=== Milling machines ===
{{Unreferenced section|date=July 2018}}
[[File:Pantograph milling machine 001.jpg|thumb|upright|A small pantograph milling machine]]
[[File:Pantograph mill table.jpg|thumb|Detail of the table of a larger pantograph milling machine]]

Before the advent of control technologies such as [[numerical control]] (NC and CNC) and [[programmable logic controller|programmable logic control]] (PLC), duplicate parts being milled on a [[milling machine]] could not have their contours mapped out by moving the [[milling cutter]] in a "connect-the-dots" ("by-the-numbers") fashion. The only ways to control the movement of the cutting tool were to dial the positions by hand using dexterous skill (with natural limits on a human's [[accuracy and precision]]) or to trace a cam, template, or model in some way, and have the cutter mimic the movement of the tracing stylus. If the milling head was mounted on a pantograph, a duplicate part could be cut (and at various scales of magnification besides 1:1) simply by tracing a template. (The template itself was usually made by a [[tool and die maker]] using [[toolroom]] methods, including milling via dialing followed by hand sculpting with [[file (tool)|files]] and/or [[die grinder]] points.) This was essentially the same concept as reproducing documents with a pen-equipped pantograph, but applied to the [[machining]] of hard materials such as metal, wood, or plastic. Pantograph [[router (woodworking)|routing]], which is conceptually identical to pantograph milling, also exists (as does CNC routing). The Blanchard lathe, a [[Thomas Blanchard (inventor)#Machine tools for gun making and pattern copying lathe|copying lathe developed by Thomas Blanchard]], used the same essential concept.

The development and dissemination throughout industry of NC, CNC, PLC, and other control technologies provided a new way to control the movement of the milling cutter: via feeding information from a program to actuators ([[Servomotor|servos]], [[selsyn]]s, [[leadscrew]]s, machine slides, [[spindle (tool)|spindles]], and so on) that would move the cutter as the information directed. Today most commercial machining is done via such programmable, computerized methods. Home machinists are likely to work via manual control, but computerized control has reached the home-shop level as well (it is just not yet as pervasive as its commercial counterparts). Thus pantograph milling machines are largely a thing of the past. They are still in commercial use, but at a greatly reduced and ever-dwindling level. They are no longer built new by machine tool builders, but a small market for used machines still exists. As for the magnification-and-reduction feature of a pantograph (with the scale determined by the adjustable arm lengths), it is achieved in CNC via mathematic calculations that the computer applies to the program information practically instantaneously. Scaling functions (as well as mirroring functions) are built into languages such as [[G-code]].

=== Other uses ===

In another application similar to drafting, the pantograph is incorporated into a pantograph engraving machine with a revolving cutter instead of a pen, and a tray at the pointer end to fix precut lettered plates (referred to as 'copy'), which the pointer follows and thus the cutter, via the pantograph, reproduces the 'copy' at a ratio to which the pantograph arms have been set. The typical range of ratio is Maximum 1:1 Minimum 50:1 (reduction) In this way machinists can neatly and accurately [[engraving|engrave]] numbers and letters onto a part. Pantographs are no longer commonly used in modern engraving, with computerized  laser and rotary engraving taking favor.

The device which maintains electrical contact with the [[overhead line|contact wire]] and transfers power from the wire to the [[railway electric traction#Unit types|traction unit]], used in [[electric locomotive]]s and [[tram]]s, is also called a "[[Pantograph (transport)|pantograph]]".

[[Herman Hollerith]]'s [[Keypunch|"Keyboard punch"]] used for the [[1890 United States census|1890 U.S. Census]] was a pantograph design and sometimes referred to as "The Pantograph Punch".<ref>{{cite book |author1-link=Leon E. Truesdell | last = Truesdell | first = Leon E. | title = The Development of Punch Card Tabulation in the Bureau of the Census: 1890-1940 | publisher = US GPO | year = 1965 }}</ref>

An early 19th-century device employing this mechanism is the [[Polygraph (duplicating device)|polygraph]], which produces a duplicate of a letter as the original is written.

In 1886, [[Eduard Selling]] patented a prize-winning calculating machine based on the pantograph, although it was not commercially successful.<ref>{{cite book|author=Selling, E.|title=Eine neue Rechenmaschine|year=1887|publisher=Springer|location=Berlin|doi=10.3931/e-rara-18446}}</ref>

[[Longarm quilting]] machine operators may trace a pantograph, paper pattern, with a laser pointer to stitch a custom pattern onto the quilt.{{Citation needed|date=February 2010}} Digitized pantographs are followed by computerized machines.{{Citation needed|date=March 2013}}

[[Linn Boyd Benton]] invented a pantographic engraving machine for type design,<ref>{{cite book|author=Cost, Patricia.|title=The Bentons: How an American Father and Son Changed the Printing Industry|year=2011|location=Rochester, NY|isbn=978-1-933360-42-3}}</ref> which was capable not only of scaling a single font design pattern to a variety of sizes, but could also condense, extend, and slant the design (mathematically, these are cases of [[affine transformation]], which is the fundamental geometric operation of most systems of digital typography today, including [[PostScript]]).<ref name="Linotype2022">{{cite web|url=https://www.linotype.com/2382/linn-boyd-benton.html|website=www.linotype.com|title=Font Designer-Linn Boyd Benton|year=2022|author=Linotype|access-date=8 October 2022}}</ref>

[[Richard Feynman]] used the analogy of a pantograph as a way of scaling down tools to the nanometer scale in his talk "[[There's Plenty of Room at the Bottom]]".

== See also ==

* {{annotated link|Autopen}}
* {{annotated link|Lettering guide}}
* {{annotated link|Parallel motion linkage}}
* {{annotated link|Spirograph}}

== References ==

{{reflist}}

== External links ==
{{commons category|Pantographs (instrument)}}

* [https://web.archive.org/web/20070224124851/http://www.ies.co.jp/math/java/geo/panta/panta.html Pantograph Java applet]
* [http://mathworld.wolfram.com/Pantograph.html Pantograph] at mathworld.wolfram.com
* [http://www.peter.com.au/articles/pantograph.html How to build a pantograph]
* [http://www.rostek-uk.com/html/building_maintenance_units.html Pantograph Cradle used in Building Facade Access System] {{Webarchive|url=https://web.archive.org/web/20140101092404/http://rostek-uk.com/html/building_maintenance_units.html |date=2014-01-01 }}
* [http://www.galleyrack.com/images/artifice/letters/pantocut/general-pantographs/schwamb-merrill-2ed-1915-elements-of-mechanism-pp-120-124-pantograph-0600greyjpg.pdf Mechanism of a pantograph]
* [http://www.engraversjournal.com/article.php/2207/index.html R&I Industry Scrapbook Part 2: The Pantograph Era by Kristin Huff]

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[[Category:Art and craft toys]]
[[Category:Linkages (mechanical)]]
[[Category:Technical drawing tools]]
[[Category:Copying]]