T-square

{{Short description|Technical drawing instrument}}

{{other uses|T-square (disambiguation)}}

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{{more citations needed|date=September 2014}}{{One source|date=November 2023}}

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File:Drafting board with T Square.jpg]]

A T-square is a technical drawing instrument used by draftsmen primarily as a guide for drawing horizontal lines on a drafting table. The instrument is named after its resemblance to the letter T, with a long shaft called the "blade" and a short shaft called the "stock" or "head". T-squares are available in a range of sizes, with common lengths being {{convert|18|inch}}, {{convert|24|inch}}, {{convert|30|inch}}, {{convert|36|inch}} and {{convert|42|inch}}.{{Citation needed|date=September 2010}}

In addition to drawing horizontal lines, a T-square can be used with a set square to draw vertical or diagonal lines.{{cite book | last = United States War Department | title = Topographic Drafting | publisher = U..S. Government Printing Office | date = 1940 | pages = 27–28 | url = https://books.google.com/books?id=3y-7iT046m8C&pg=PA27}} The T-square usually has a transparent edge made of plastic which should be free of nicks and cracks in order to provide smooth, straight lines.

T-squares are also used in various industries, such as construction. For example, drywall T-squares are typically made of aluminum and have a {{convert|48|inch|cm|adj=mid|-long}} tongue, allowing them to be used for measuring and cutting drywall. In woodworking, higher-end table saws often have T-square fences attached to a rail on the front side of the table, providing improved accuracy and precision when cutting wood.