How to Select Squares
Squares are used to indicate, by visual comparison, whether two surfaces are perpendicular. Most products consist of a simple, fixed standard and a beam and blade with a mutual orientation of 90degrees.
Types of Squares
A wide variety of squares are available that vary in construction and application.
- Precision squares or solid squares consist of a short, ground blade and a beam or handle that forms an L-shape. They are precision-ground and normally do not have any rulings. Precision squares have reliefs on the inside corners or outside edges to facilitate fillets or radii on cast or machined parts. The beam of a precision square is thicker than the blade, which facilitates the use of the square on an edge. Precision squares are used for precision marking and measuring, and for checking the squareness of machined components.
- Cylindrical squares have a hollow, cylindrical shape and are used to check other squares in machine shop or inspection room settings. Some cylindrical squares provide graduations to indicate variation from square.
- Bevel squares can be adjustable, universal, sliding, combination, or T-bevels. Typically, bevels do not have any graduations.
- Adjustable die makers' squares are used to measure small, angular variations (10 degrees) from square. They are used for measuring angles, die clearances, and pattern drafts. They are often equipped with different attachments, such as offset, bevel, or ruled blades.
- Angle squares consist of a square with angular graduations along the longest face or hypotenuse.
- Double-precision squares have a square head which slides onto a blade or rule. This square head has two square surfaces and comes with a variety of optional blade types. Blade choices for double-precision squares include bevel blades, drill point angle blades, and ruled blades.
- Try squares consist of a short blade and a beam or handle that forms an L-shape. The beam is thicker than the blade, which facilitates location of the square on an edge.
- L squares are used for general shop marking and measuring, and for checking the squareness of components.
- T squares or dry-all squares have a long blade and a beam or handle section that forms the top of the "T” shape. They are used for marking, measuring, and checking the squareness of large flat sheets of materials such as drywall. T squares are available in both fixed and folding versions.
- Combination squares measure length, center, and angularity or squareness. They often have transfer or marking capabilities. These multiple tasks are possible because combination squares have a series of optional heads.
Important Selection Properties
When selecting squares, the user must consider the application for which the tool is being used. Blade length, width, thickness, and material type are all important specifications to consider, as they determine the suitability of the square for different tasks.