According to the situation that the PDS database is American English system,this paper makes a change it to metric system, and also provides detail methods for all data files related to English and metric system, that is piping materials class data files, piping specification data files, piping job specification database and p.

Adopting special lantern gear to minify the drive error of the screw drive chain on CA6140 lathe,high-precision inch-system lead screw and modulus lead screw can be processed.

Unification of cotton yarn count conversion factor between English count and tex system;