square (tool)
{{short description|Handtools for marking and checking 90° and 45° angles}}
{{Infobox tool|name=Square|types=Combination square
Framing square
Engineer's square
Mitre square
Set square
Speed square
Try square
T-square|image=vinkli.jpg|classification=Marking and measuring hand tools|title=Square (tool)|used_with=Pens, pencils, scribes, drawing boards, and plum bobs}}
A square is a tool used for marking and referencing a 90° angle, though mitre squares are used for 45° angles. Squares see common use in woodworking, metalworking, construction and technical drawing.{{Cite book |last=Salaman |first=R. A. |url=https://archive.org/details/dictionaryoftool0000sala |title=Dictionary of Tools Used in the Woodworking and Allied Trades, c. 1700-1970 |publisher=Scribner |year=1975 |isbn=978-0-684-14535-8 |location=New York, US |pages=472–479 |author-link=Raphael Salaman |via=Internet Archive}} Some squares incorporate a scale for measuring distances (a ruler) or for calculating angles.
Terminology
Many squares are made of two parts, a stock and a straight blade or tongue.{{Sfn|Salaman|1975|p=472}} The stock is usually thicker than the blade, with the blade being fixed into or onto the stock. The blade typically has parallel edges. The stock is usually held against the edge of a workpiece or drawing board and the tongue is then used as a straight edge for making a mark, or as a reference to check the accuracy of an angle.
History
File:Carpenter's_Square_MET_20.3.90.jpeg wooden try square from the 20th century BC.]]
Wooden try squares have survived from Ancient Egypt and Ancient Rome and can be seen in art from the time. From the 18th century squares began to be manufactured in factories, prior to that they were typically made from wood and were often made by the tradesmen themselves.{{Sfn|Salaman|1975|p=472}} Some woodworkers continue to make their own squares.{{Cite web |date=2015-09-28 |title=Make Wooden Try Squares |url=https://www.popularwoodworking.com/article/make-wooden-try-squares/ |url-status=live |archive-url=https://web.archive.org/web/20201018140751/https://www.popularwoodworking.com/article/make-wooden-try-squares/ |archive-date=2020-10-18 |access-date=2020-10-17 |website=Popular Woodworking Magazine |language=en-US}}
Types of square
There are a number of different types of square used for a variety of different industries and purposes:
Accuracy
File:Testing_a_try_square_for_accuracy.png for accuracy against itself.]]
Different industries and applications have different requirements for the accuracy of squares. Some squares are manufactured to meet regulated standards of accuracy, such as British Standards BS 939:2007 for engineering squares, and BS 3322 for try squares.{{Cite web|title=BS 939:2007 - Engineers' squares (including cylindrical and block squares). Specification – BSI British Standards|url=https://shop.bsigroup.com/ProductDetail/?pid=000000000030163790|access-date=2020-10-17|website=shop.bsigroup.com|archive-date=2020-10-20|archive-url=https://web.archive.org/web/20201020070415/https://shop.bsigroup.com/ProductDetail/?pid=000000000030163790|url-status=live}}{{Cite web|title=BSI - BS 3322 - Specification for Carpenters' Squares and Bevels {{!}} Engineering360|url=https://standards.globalspec.com/std/157385/BS%203322|access-date=2020-10-17|website=standards.globalspec.com|archive-date=2020-10-18|archive-url=https://web.archive.org/web/20201018162249/https://standards.globalspec.com/std/157385/BS%203322|url-status=live}}
A square can become inaccurate over time through common use and abuse, such as the edges becoming worn or the square being dropped or mistreated. The materials, most notably wood, can also vary with changes in temperature and humidity. Squares can be checked for accuracy against a known reference, such as a square or piece of machinery that is known to be accurate or against a cylindrical square. A bright light or feeler gauges can be used to check for gaps between the square and the object being referenced.
Through symmetry, squares can also be checked against themselves. One method for L-shaped squares (illustrated) is to hold the square against a reliable known straight edge. A line is struck using a marking knife or sharp pencil; the square is then flipped over, and from the same point another line is struck. If the square is accurate, only a single line should be visible.{{Cite web |last=Stanley |first=Jenny |date=17 October 2017 |title=Check if a Square is Square |url=https://www.familyhandyman.com/article/check-if-a-square-is-square/ |url-status=live |archive-url=https://web.archive.org/web/20220710175525/https://www.familyhandyman.com/article/check-if-a-square-is-square/ |archive-date=2022-07-10 |access-date=2020-10-18 |website=The Family Handyman |language=en-US}}{{Cite web |last=Sellers |first=Paul |author-link=Paul Sellers |date=14 December 2011 |title=Checking your square's squareness |url=https://paulsellers.com/2011/12/checking-your-squares-squareness/ |url-status=live |archive-url=https://web.archive.org/web/20201018053207/https://paulsellers.com/2011/12/checking-your-squares-squareness/ |archive-date=18 October 2020 |access-date=18 October 2020 |website=Paul Sellers - A Lifestyle Woodworker |language=en-US}}
There are a number of methods for correcting an inaccurate square by hand. For example, wooden blades can be corrected using a hand plane and sandpaper, while metal blades can be corrected using a file, emery cloth, or sandpaper.{{Cite web|title=How to correct an engineer's square that is not square?|url=https://www.wonkeedonkeetools.co.uk/engineers-squares/how-to-correct-an-engineer-s-square-that-is-not-square|access-date=2020-10-17|website=Wonkee Donkee Tools|language=en-GB|archive-date=2020-10-17|archive-url=https://web.archive.org/web/20201017234715/https://www.wonkeedonkeetools.co.uk/engineers-squares/how-to-correct-an-engineer-s-square-that-is-not-square|url-status=live}}{{Cite web |last=Sellers |first=Paul |author-link=Paul Sellers |date=2014-06-13 |title=On Woodworking Squares and Working Wood |url=https://paulsellers.com/2014/06/on-woodworking-squares-and-working-wood/ |url-status=live |archive-url=https://web.archive.org/web/20201015201256/https://paulsellers.com/2014/06/on-woodworking-squares-and-working-wood/ |archive-date=2020-10-15 |access-date=2020-10-17 |website=Paul Sellers' Blog |language=en-US}} Framing squares can be adjusted using a hammer and a punch.{{Cite web|date=1996-09-01|title=Tuning a framing square|url=https://www.finehomebuilding.com/1996/09/01/tuning-a-framing-square|access-date=2020-10-18|website=Fine Homebuilding|language=en-US|archive-date=2020-10-18|archive-url=https://web.archive.org/web/20201018182902/https://www.finehomebuilding.com/1996/09/01/tuning-a-framing-square|url-status=live}}
Symbolism
File:Square_and_compasses2.JPG symbol used by Freemasons.]]
File:Thomas the Apostle Helsinki Cathedral.jpg of Thomas the Apostle holding a square.]]
The square is incorporated into the most common Freemasonry symbol, the Square and Compasses.{{Cite web|title=SQUARE AND COMPASSES - Freemasonry's Logo|url=https://www.masonic-lodge-of-education.com/square-and-compasses.html|access-date=2020-10-17|website=www.masonic-lodge-of-education.com|archive-date=2020-10-18|archive-url=https://web.archive.org/web/20201018105529/https://www.masonic-lodge-of-education.com/square-and-compasses.html|url-status=live}} Historically squares have also been used by woodworkers, such as joiners and carpenters, as symbols in signs and heraldry to represent their trade.{{Cite web |last=Schwarz |first=Christopher |author-link=Christopher Schwarz |date=29 May 2014 |title=Melencolia Square, Part 4: Look for a Sign |url=https://blog.lostartpress.com/2014/05/29/melencolia-square-part-4-look-for-a-sign/ |url-status=live |archive-url=https://web.archive.org/web/20201018042004/https://blog.lostartpress.com/2014/05/29/melencolia-square-part-4-look-for-a-sign/ |archive-date=18 October 2020 |access-date=17 October 2020 |website=Lost Art Press |language=en-US}} The square as a symbol is also seen in artistic representations of the Christian saints Thomas the Apostle and James the Less.{{Cite book |last=Hardon |first=John A. |url=http://archive.org/details/na00john |title=Modern Catholic Dictionary |publisher=Doubleday |year=1980 |isbn=978-0-385-12162-0 |edition=1st |location=Garden City, NY |pages=83 |language=en |chapter=Carpenter's square |author-link=John Hardon |via=Internet Archive}}
{{Commons|Category:Squares (tool)|squares (tool)}}
References
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{{Measuring and alignment tools}}
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Category:Woodworking hand tools