Some of the types of section lines you are likely to
encounter as a welder are shown in figure 3-39.
Another use of lines is to form symbols, such as
welding symbols, that are discussed later in this chapter.
While engineers use lines to describe the shape or
form of an object, they use dimensions to provide a
complete size description. Dimensions used on draw-
ings are of two types: size and location. As implied by
their names, a size dimension shows the size of an
object or parts of an object and a location dimension
is used to describe the location of features. Examples
of both size and location dimensions are shown in
Figure 3-39.Section lines for various metals.
Figure 3-40.Elements of an orthographic drawing.