The Try Square
: THE USES OF THE COMPASS AND THE SQUARE
In the use of the ordinary large metal square it is necessary to lay the short limb of the square on the face of the work, and the long limb must, therefore, rest against the work side or edge of the timber, so that the scribing edge of the short limb does not rest flat against the work. As such a tool is defective in work requiring accuracy, it brought into existence what is called the try square, which has a rectangular handle, usually of wood, into which is fitted at one end a metal blade, which is at right angles to the edge of the handle. The handle, therefore, always serves as a guide for the blade in scribing work, because it lies flat down on the work.
The T-Square is another modification of the try square, its principal use being for draughting purposes.