Selected Publications on Dimensional Metrology - Gage Blocks

The Gauge Block Handbook, Doiron, Theodore D. Dr., Beers, John S., NIST Monograph 180 with Corrections, 145 p. (2005).

Abstract: Gage blocks are the primary method used by industry to standardize the measurement of dimension. This work discusses every aspect of gage block calibration, including definitions, characteristics of gage blocks, calibration by interferometry and mechanical comparison, and statistical process control techniques to assure the consistency and accuracy of calibrations.

Contact Deformation in Gage Block Comparisons, Beers, John S., Taylor, James E., NBS Technical Note 962, 46 p. (May 1978).

Abstract: When calibrating gage blocks or when gaging objects with contact type comparators, local deformation occurs where the probe tip contacts the gaging surface. This deformation results in a measurement error only if the gage blocks or objects being compared are of different materials having different mechanical properties. This document presents formulas and monographs for determining deformation magnitude, and instructions for applying deformation corrections. The formulas and monographs are valid only for spherical probe tips. A method is given for evaluating tip geometry and it is recommended that non-spherical or flawed tips be replaced.

Preparations for Gage Block Comparison Measurements, Tucker, Clyde D., NBS Internal Report 74-523, 12 p. (July 9, 1974).

Abstract: The methods described here for the cleaning and deburring of gage blocks can be useful to those individuals who have not established formal laboratory procedures for these operations. Many individuals may employ valid methods that vary somewhat from those employed at the National Bureau of Standards.

Many of the gage block comparators that are in use have not been periodically evaluated by the user. It is the intent of this report to set forth guidelines and procedures that may be used conveniently by metrologists to aid in obtaining more meaningful comparisons of gage blocks by the use of probe-type transducers.

Intercomparison Procedures for Gage Blocks Using Electromechanical Comparators, Beers, John S., Tucker, Clyde D., NBS Internal Report 76-979, 22 p. (January 1976).

Abstract: 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.

The NIST Gage Block Calibration Software System User's Manual, Zimmerman, Jay H., NIST Internal Report 2000-6387, 228 p. (January 2000).

Abstract: The NIST Gage Block Calibration Software System is a complete calibration system with custom, integrated software to calibrate and measure high-precision, quality gage blocks as individual blocks or sets, both English and metric. The calibration system has software programs that enable the NIST technical staff to create and maintain measurement history and related information and statistical process control of NIST's and its gage block calibration customers' gage blocks. These software programs provide for measuring gage blocks using interferometric techniques and doing intercomparison using an opposed head electro-mechanical comparator with automatic data acquisition. The accessory programs enable the NIST technical staff to configure system resources, calculate or estimate elastic deformations, and edit files. This calibration system conducts calibrations and measurements that meet the requirements of MIL-STD 45662A, ANSI/NCSL Z540-1-1994, and ISO 9002-94.

Gauge Blocks—A Zombie Technology, Doiron, Theodore D. Dr., Journal of Research of the National Institute of Standards and Technology 113 (3), 10 p. (May-June 2008).

Abstract: Gauge blocks have been the primary method for disseminating length traceability for over 100 years. Their longevity was based on two things: the relatively low cost of delivering very high accuracy to users, and the technical limitation that the range of high precision gauging systems was very small. While the first reason is still true, the second factor is being displaced by changes in measurement technology since the 1980s. New long range sensors do not require master gauges that are nearly the same length as the part being inspected, and thus one of the primary attributes of gauge blocks, wringing stacks to match the part, is no longer needed. Relaxing the requirement that gauges wring presents an opportunity to develop new types of end standards that would increase the accuracy and usefulness of gauging systems.