Good quality try squares, mitre squares, bevels, marking and mortice gauges should be made from top quality hardwood of which rosewood is traditionally preferred, being considered to be stable, comfortable in use and high quality in appearance.
The metal blades should be treated against rust with a process which often produces a blued steel blade. This also has the advantage of providing a dull matt finish against which it is easy to read in the day light when using the square.
An essential feature of a top quality square is that the blade should be secured to the stock so that it holds the right angle and does not wobble. This is best achieved by the use of steel rivets which bond securely to the blade and brass washers which provide a firm anchor in the stock.
The combination set consists of a number of parts, the square head and blade to which can be added a bevel, protractor and scriber.
The cheaper squares have die-cast stocks and printed blades.
Better quality squares usually have cast iron stocks which are heavy and more stable than other materials and deep etched blades graduated on both edges of both sides of the blade so that the graduations do not wear out.
The try and mitre square sets right angles but can also set and check 45° angles.
The try square is used for setting and checking right angles.