1.1 This specification is intended to be a means of calling out finished machined parts ready for aerospace use. Such parts may also find use in selected commercial applications where there are clear benefits derived from the use of parts with known or This specification establishes the requirements for parts intended for aerospace use and machined from polychlorotrifluoroethylene (PCTFE) homopolymers. This specification, however, does not cover parts machined from PCTFE copolymer, PCTFE film or tape