How to Use a T Square. T squares are used in technical drawing which is also known as drafting. Technical drawing requires precise drawings and T squares are an essential drafting instrument. T squares provide the foundation from which good renderings are created. T Squares are also used in the construction trades.

Make the distinction between the T square used for technical drawing, such as architectural plans, and the T square used for construction. The technical drawing T square used by professionals like engineers, draftsmen and architects is used along with a drawing board. The construction T square is used by bricklayers, carpenters and home builders.

Place the T square at right angles to the edges of the drawing board. T squares are movable straightedges. T squares are used to hold other tools such as squares and triangles. Slide the T square up the surface of the table to the desired location on the paper.

Secure the T square in place. T squares should not slide around across the surface of the paper. On a slanted drafting table, T squares are often mounted with a type of pulley system or that is mounted on both sides of the drafting table.

Use the T square to draw parallel lines by simply tracing along its edge. Place squares and triangles on the T square to precisely draw angles. "French curves" are used to draw curved shapes and templates are used to draw reoccurring shapes.

Place a T square at the edge of a wall or cabinet to determine the angle. Lay a T square in a corner to establish if it the edges form a right angle. T squares, along with a level, are used in bricklaying to keep the line true vertically.