A bevel protractor (Fig. below) is a tool for measuring angles within one degree. It consists of a steel rule, a blade, and a protractor head. The protractor head has a revolving turret graduated to read from 0° to 180° in opposite directions. The head may be a reversible type with shoulders on both sides of the blade or a non-reversible type with a single shoulder. Most bevel protractors contain a spirit level, which is useful when measuring angles in relation to a horizontal or vertical plane. A plain steel protractor may be more convenient to use for laying out and checking angles on some types of work.
