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 Woodworking is the skill of making items from wood, and includes cabinetry, furniture making, wood carving, joinery, carpentry, and woodturning. History Along with stone, clay and animal parts, wood was one of the first materials worked b ...

metalworking Metalworking is the process of shaping and reshaping metals in order to create useful objects, parts, assemblies, and large scale structures. As a term, it covers a wide and diverse range of processes, skills, and tools for producing objects on e ...

construction Construction are processes involved in delivering buildings, infrastructure, industrial facilities, and associated activities through to the end of their life. It typically starts with planning, financing, and design that continues until the a ...

and

technical drawing Technical drawing, drafting or drawing, is the act and discipline of composing drawings that visually communicate how something functions or is constructed. Technical drawing is essential for communicating ideas in industry and engineering. ...

. Some squares incorporate a scale for measuring distances (a

ruler A ruler, sometimes called a rule, scale, line gauge, or metre/meter stick, is an instrument used to make length measurements, whereby a length is read from a series of markings called "rules" along an edge of the device. Usually, the instr ...

) or for calculating angles.

Terminology

Many squares are made of two parts, a ''stock'' and a straight ''blade'' or ''tongue''. 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 A drawing board (also drawing table, drafting table or architect's table) is, in its antique form, a kind of multipurpose desk which can be used for any kind of drawing, writing or impromptu sketching on a large sheet of paper or for reading a la ...

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

Wooden try squares have survived from

Ancient Egypt Ancient Egypt () was a cradle of civilization concentrated along the lower reaches of the Nile River in Northeast Africa. It emerged from prehistoric Egypt around 3150BC (according to conventional Egyptian chronology), when Upper and Lower E ...

and

Ancient Rome In modern historiography, ancient Rome is the Roman people, Roman civilisation from the founding of Rome, founding of the Italian city of Rome in the 8th century BC to the Fall of the Western Roman Empire, collapse of the Western Roman Em ...

and can be seen in art from the time. From the 18th century squares began to be manufactured in

factories A factory, manufacturing plant or production plant is an industrial facility, often a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process each item into another. Th ...

, prior to that they were typically made from wood and were often made by the

tradesmen A tradesperson or tradesman/tradeswoman is a skilled worker that specialises in a particular trade. Tradespeople (tradesmen/women) usually gain their skills through work experience, on-the-job training, an apprenticeship program or formal educat ...

themselves. Some woodworkers continue to make their own squares.

Types of square

There are a number of different types of square used for a variety of different industries and purposes:

Accuracy

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 British Standards (BS) are the standards produced by the BSI Group which is incorporated under a royal charter and which is formally designated as the national standards body (NSB) for the UK. The BSI Group produces British Standards under th ...

BS 939:2007 for engineering squares, and BS 3322 for try squares. 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. 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 upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)) Sandpaper, also known as coated abrasive or emery paper, is a type of material that consists of sheets of paper or cloth with an abrasive substa ...

. Framing squares can be adjusted using a hammer and a punch.

Symbolism

The square is incorporated into the most common

Freemasonry Freemasonry (sometimes spelled Free-Masonry) consists of fraternal groups that trace their origins to the medieval guilds of stonemasons. Freemasonry is the oldest secular fraternity in the world and among the oldest still-existing organizati ...

symbol, the Square and Compasses. Historically squares have also been used by woodworkers, such as joiners and

carpenters Carpentry is a skilled trade and a craft in which the primary work performed is the cutting, shaping and installation of building materials during the construction of buildings, ships, timber bridges, concrete formwork, etc. Carpenters trad ...

, as symbols in signs and

heraldry Heraldry is a discipline relating to the design, display and study of armorial bearings (known as armory), as well as related disciplines, such as vexillology, together with the study of ceremony, Imperial, royal and noble ranks, rank and genealo ...

to represent their trade. The square as a symbol is also seen in artistic representations of the Christian saints

Thomas the Apostle Thomas the Apostle (; , meaning 'the Twin'), also known as Didymus ( 'twin'), was one of the Twelve Apostles of Jesus according to the New Testament. Thomas is commonly known as "doubting Thomas" because he initially doubted the resurrection of ...

and

James the Less James the Less ( ) is a figure of early Christianity. He is also called "the Minor", "the Little", "the Lesser", or "the Younger", according to translation, James is styled "the Less" to distinguish him from the Apostle James the Great (also ca ...

References

{{Authority control Woodworking measuring instruments Metalworking measuring instruments Dimensional instruments Woodworking hand tools Technical drawing tools