Squares (tool)

geometry device used for technical drawing

thumb|Drafting board with a T-square and set square 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 , , , and .

woodworking or a metal working tool used for marking 90° angles and measuring a piece of wood

handtools for marking and checking 90° and 45° angles

flat tool used in carpentry to mark right angles and calculate angles

measuring and marking tool