Beers, J.; Tucker, C.
NBS Internal Report 76-979; 22p. January 1976.
Calibration; comparator; gage blocks; length; measurement process.
The widely used procedures for calibrating gage blocks by comparison with blocks of know length generally lack the redundancy needed to evaluate measurement uncertainty or the controls needed to monitor the process on a continuing basis. A detailed description is given here for the systematized intercomparison of groups of four nominally equal gage blocks using an electromechanical comparator. Two of the blocks are unknowns and two are standards. The process provides the redundancy needed for evaluating uncertainty and for continuous monitoring. Gage block thermal effects, equalization time, handling techniques, and observation sequence are described.