This sector comprises establishments primarily engaged in manufacturing industrial and commercial machinery. These establishments assemble parts into components, subassemblies, and complete machines. They may purchase the parts or make them themselves, using general metalworking processes. Establishments primarily engaged in rebuilding machinery are included in the same industry as establishments manufacturing the particular type of new machinery. Unless otherwise specified, establishments primarily engaged in manufacturing parts designed for use solely or principally with a particular machine are classified in the same industry as establishments manufacturing that type of machinery.