Uncertainty of Calibration of Instruments, a Simple Example in Dimensional Metrology

How is the calibration of a micrometer using gage blocks different from using a micrometer to calibrate gage blocks? In the measurement community there seems to be a lot of confusion about which characteristics of an instrument go into the uncertainty budget for calibrating that instrument. This talk will discuss this issue for a standard hand micrometer and show that given a set of gage blocks and micrometer readings, the uncertainty is exceedingly different depending on which is the standard and which is the instrument under test.