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.

Dimensions

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 drawings 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 3-40.

Figure 3-39. - Section lines for various metals.

Figure 3-40. - Elements of an orthographic drawing.