The building and operation of Big Science organisations relies extensively on the construction of large and complex mechanical systems such as magnet components, accelerating structures, support systems, shielding structures, and vacuum components. The needs for mechanical parts vary in terms of materials, sizes, volume, and degree of complexity; but the following technical areas are of particular relevance to most Big Science organisations: manufacturing of high to very high precision mechanical components, large machined components, pressure vessels and high temperature reactors, complex welded structures; as well as assembly, installation, validation and testing of the above components.