Technology Education Department
Introduction to Technical Drawing
The "Alphabet of Lines" is a list of line symbols that are used on technical drawings to represent the shape and describe the size of an object. Each of the following lines is drawn at different thickness or darkness for contrast as well as according to the importance of the line. If two lines fall on top of one another (coinside), the more important line is shown. Visible lines take presidence over hidden lines and center lines; and hidden lines take presidence over center lines. The list below gives the name of the line; explains how the line is used; indicates the appropriate thickness or darkness; and provides the recommended pencil weight for drawing the line.