Bar stock is a popular type of raw, pure metal used by industry to make metal parts and products. It is also known by the colloquial names blank, slug, or billet. There are numerous extrusion forms and lengths for bar stock. Round (circular cross-section), rectangular, square, and hexagonal or hexagonal forms are the most prevalent. Pipes, angle stock, and other things with variable diameter are not regarded as bar stock since a bar is distinguished by having a "enclosed invariant convex cross-section."
Bar stock is typically processed in a series of operations, including sawing, turning, milling, drilling, and grinding, to create a finished product that is frequently very different from the initial stock. Sometimes, specialized machinery that feeds the stock into the right processing unit allows the operation to be partially automated.