|A list of the materials and parts necessary for the fabrication or
assembly of a component or system is often included on the drawing. The
list usually will be in ruled columns in which are listed the part number,
name of the part, material from which the part is to be constructed, the
quantity required, and the source of the part or material. A typical bill
of material is shown in figure 2-4. On drawings that do not have a bill
of material, the data may be indicated directly on the drawing.
On assembly drawings, each item is identified by a number in a circle or square. An arrow connecting the number with the item assists in locating it in the bill of material.