Bill of Materials - 8: Material Specifications
The Material column will show either:
(1) the material to be used in making a part and the specification for that material, or
(2) the specification for a purchased part, if the part is higher quality than standard commercial grade.

The material used in a machine shop will typically be some form of a metal stock. Stock is available for most of the industrial metals (steel, aluminum, titanium, copper, etc), and in a variety of sizes and shapes (round rod, square rod, angles, tubes, plates, etc).

Each of the metals is also available in different alloys and in different grades. The alloy, grade, and form of stock are all shown in the materials/specification block. It is extremely important, before beginning to machine a part, to be certain that your stock is the correct alloy and grade. In aircraft parts, for example, the safety of an airplane depends upon you using only the materials specified on the blueprint.
