Primary-level calibration of pitch and runout artifacts require quantifying the measurement uncertainty on the artifact
being calibrated by a method that does not rely on a transfer comparison. The measurement decomposition method,
developed jointly by National Institute of Standards and Technology (NIST) and Oak Ridge Metrology Center (ORMC)
personnel, is used to determine the uncertainty of each component of the measurement task. Once quantified, these
components are added in quadrature according toNIST TechnicalNote 1297, 1994 Edition’). Verification of this method
was accomplished by inter-comparison between ORMC and NIST using high precision coordinate measurement
machines and rotary tables. The results were also compared with data obtained using the circle closure principle.