Precision squares

Precision squares are rigid squares, machined to tight tolerances, for checking and marking out right angles in the workshop, in engineering and in fine woodworking. They are used where a builder's square is not accurate enough, for example to check a part before assembly or to mark out a precise cut.

The try square has a stock that rests against the edge of the workpiece, useful for marking out and checking. The bevel-edge square has a bevelled edge that makes the scale easier to read. The plain galvanised steel square is for general workshop use. Choose according to how the workpiece sits and how important it is to read the graduation clearly.

Choose the length according to the workpiece to be checked: a short blade is more practical on small parts, while a long blade is needed to check larger surfaces and angles. In the catalogue the squares are available in many lengths, up to very long models. Choose a size that covers the largest piece in your work.

The granite master square is a reference for checking angles, to be placed on a flat surface to check other pieces. Granite is a stable material that is little subject to deformation over time. It must be handled with care, because the edges can chip if it is dropped or knocked against the bench.

Galvanised steel protects the square from rust and suits general workshop use, even in damp environments. The hardened square has a harder surface, designed for jobs where the reference edge must stay intact for longer. For frequent marking out on metal, the hardened version is the recommended choice.

Check that the square is not bent, dented or damaged along the edges, because even slight damage will throw off the marking out. To check it, mark an angle on a sheet of paper, then turn the square over and repeat the marking: if the line coincides, the angle is correct. Store the square in a case or hung up, to avoid knocking the edges.

In the catalogue the precision squares are from the Fervi and Metrica brands. Fervi includes bevel-edge squares, 90-degree squares and granite master squares; Metrica includes try squares, flanged squares and plain squares. Choose according to the type of work and the shape you need, rather than the brand.

In the workshop you need squares to check the assembly of mechanical parts and to verify right angles on work surfaces. A steel try square is useful for resting against an edge, while a hardened square withstands repeated use better. For finer checks it is worth adding a granite master square.