Fabrication of the main electrodes of the NMIA-BIPM calculable capacitor

The design of the NMIA-BIPM calculable cross capacitor includes the requirement that the main electrodes be geometrically true cylinders to within 100 nm over all but the last 50 mm at each end of their length. After much experimentation, techniques have been developed that result in the fabrication of electrodes that comfortably meet this requirement.