An automatic measurement setup for outer diameter of inner conductor in coaxial air lines

An automatic measurement setup for measuring outer diameter of the inner conductor (ODIC) of coaxial air lines is introduced. The setup is used to measure ODIC of air lines with precision connectors, including N, 7mm, 3.5mm, 2.92mm, 2.4mm, 1.85mm, 1.0mm. Multiple needle gauges are used to achieve measurement uncertainties better than 0.3μm. As an example, the measurement results of 2.92 mm and 1.85mm connector air lines are shown.