The cross section (true shape) of a struc­tural metal shape is often shown on a view by a revolved section. As the name implies, a revolved section of a shape is a cross section that has been turned (revolved) 90°.

When the metal is of such a shape and length that break lines are not necessary, the revolved section appears as a view placed on top of another, Figure 8.4.

A revolved section can be placed in a space between break lines when break lines are used to indicate a reduced length. A revolved section may also be shown in a space between break lines when the structural shape is not uniform in size, Figure 8.5. In this case, break lines are not necessarily used to signify a reduced length, but may be used to indicate where the revolved section applies.

Although it is not always necessary to include a revolved section, it is often shown

to aid print interpretation. nonuniform structural shapes.

When a structural member of a weldment has several different cross-sectional shapes, these shapes can be shown on a print by as many revolved sections as are needed to describe the object. Figure 8.6 illustrates several revolved sections for a single structural member.

ASSEMBLY SECTIONS

An assembly section is achieved in the same manner as a full section or half section. However, in this case, the interior details of assembled parts are represented.

The section lines used in assembly sections are shown running in different directions so that one part can be differentiated from another.

Surfaces of thin materials shown in section are not indicated by section lines; rather, they are shown as solid black lines. When several thin materials are shown adjoining one another, a thin space is allowed between the solid lines to show their separation.

Figure 8.7 illustrates a section of an assembled part. Note the difference in the directions of the section lining.