The general purpose cast iron section line is drawn at a 45° and spaced 1.5 mm to 3 mm or more, depending on the size of the drawing. As a general rule, use 3mm spacing. Section lines are drawn as thin (.35 mm) black lines.  The section lines should be evenly spaced and of equal thickness, and should be thinner than visible lines . Also, do not run section lines beyond the visible outlines or stop them too short. The correct and incorrect method of drawing section lines are shown in figure 16.

Figure 16. Representation of section line.

Section lines should not run parallel or perpendicular to the visible outline. If the visible outline to be sectioned is drawn at 45°, the section lines are drawn at a different angle, such as 30° as shown in figure 17.

Figure 17 showing the direction of section lines with respect to the visible outline of the object.

Avoid placing dimensions or notes within the section lined areas. If the dimension or note must be placed within the sectioned area, omit the section lines in the area of the note as shown in figure 17.