Dimensional Measurements

Complex Dimensional Standards

Technical Contacts:
Dennis Everett (12010C - 12070S)
Tel: 301/975-5272
E-mail: dennis.everett@nist.gov

Eric S. Stanfield (11050S)
Tel: 301/975-4882
E-mail: eric.stanfield@nist.gov

John Stoup (12060S)
Tel: 301/975-3476
E-mail: john.stoup@nist.gov

Theodore D. Doiron
Tel: 301/975-3472
E-mail: theodore.doiron@nist.gov

Do not ship instruments or standards to the mailing address listed below. Contact the technical staff for the shipping address.

Mailing Address:
National Institute of Standards and Technology
100 Bureau Drive, Stop 8211
Gaithersburg, MD 20899-8211

back to top | back to index of dimensional measurements

API Threaded Plug and Ring Gages (12010C-12033C)

NIST provides calibration and certification services for (1) API threaded plug and ring gages, (2) API casing, tubing and line pipe plug and ring gages, and (3) API sucker rod gages. NIST is the custodian of the American Petroleum Institute (API) Grand Master rotary thread gages. These Grand Master gages are maintained and have been recalibrated at NIST for more than 60 years. They can be considered an international standard since all API Regional Master Gages throughout the world are referenced to NIST. Foreign product manufacturers can have their Reference Master Gages calibrated by NIST or by one of the other national standard laboratories listed below:

• National Physical Laboratory, Teddington, England
  
• National Research Laboratory of Metrology, Ibaraki, Japan
  
• National Measurement Laboratory, Lindfield, N.S.W., Australia
  
• Laboratory National d'Essais, Paris, France
  
• Instituto Nacional de Technologia Industrial, Buenos Aires, Argentina
  
• National Institute of Metrology, Beijing, People's Republic of China

As required, the API laboratory is temperature controlled at 20 °C. Parameters measured for plug gages are length of plug, taper, pitch diameter, major diameter, thread lead, lead and following thread half-angles, depth of thread, pitch line width, and radius of curvature.

Parameters measured for ring gages are length of ring, taper, thread lead, minor diameter, lead and following thread half-angles, counter bore, depth of thread, pitch line width, radius of curvature, and standoff.

Elements of rotary gages, buttress gages, extreme line casings, and large casing and tubular gages are measured on a coordinate measuring machine with an expanded uncertainty of 2.5 µm (0.0001 inch) for diameters under 254 mm, increasing to 5.0 µm (0.0002 inch) as the gage diameter increases to 500 mm. Profile measurements are made on a contour tracing machine with an expanded uncertainty of 12.5 µm (0.0005 inch).

All gages received must be marked with the API monogram and the API registration number. If not marked, the gages will be returned to the customer uncalibrated. Gages that meet the specifications are marked as specified in the API Standards. All thread gages must be submitted in sets of plug and ring. The name of the gage owner should be given for inclusion in the Report of Calibration.

back to top | back to index of dimensional measurements

Special Tests of Threaded Plug and Ring Gages (12050S)

NIST provides special tests of threaded plug and ring gages in the areas listed for API gages (12010C). The accuracy of these calibrations is determined substantially by the quality of the artifact, but high quality artifacts yield uncertainties approximately the same as API gages.

back to top | back to index of dimensional measurements

Special Tests of Two- and Three-Dimensional Gages (12060S, 11050S)

NIST provides special tests of two-dimensional gages, ball plates or grid plates, with dimensions up to 600 mm 600 mm 600 mm (24 inch 24 inch 24 inch ). The accuracy of the calibration depends substantially on the quality of the gage, but expanded uncertainties of 1 µm or less are obtainable for high quality artifacts. NIST has a wide variety of state-of-the-art metrology equipment and provides services associated with dimensional quality control as special tests in addition to the regular and special tests described above. A three-dimensional measuring machine is available for calibration of two- and three-dimensional ball plates, two-dimensional grid plates, and other artifacts of complex shape. Please consult with the technical contacts listed.

back to top | back to index of dimensional measurements

Special Complex Dimensional Tests, by Prearrangement (12070S)

NIST can provide other special tests for complex dimensions. For requirements not covered by the services described above, special arrangements may be made by contacting Ted Doiron 301/975-3472.

back to top | back to index of dimensional measurements

References-Complex Dimensional Standards

On Characterizing Measuring Machine Geometry , R. J. Hocken and B. Borchardt, Natl. Bur. Stand. (U.S.), NBSIR 79-1752 (1979).

Three Dimensional Metrology , R. J. Hocken, et al., Annals of the CIRP, 26/2 (1977).

back to top | back to index of dimensional measurements

Sieves

Theodore D. Doiron
Tel: 301/975-3472
E-mail: theodore.doiron@nist.gov

Do not ship instruments or standards to the mailing address listed below. Contact the technical staff for the shipping address.

Mailing Address:
National Institute of Standards and Technology
100 Bureau Drive, Stop 8211
Gaithersburg, MD 20899-8211

Special Tests of Sieves (10060S)

NIST provides special testing for measuring sieves using a high accuracy optical projector. The average wire diameter of both the warp and shoot wires are determined by measuring 20 or more wires at five different positions along the diameter of the sieve. The average opening is found by measuring the average pitch of the wires and subtracting the average wire diameter. These results are compared with the tolerances in the ASTM E-11 specifications. The frame dimensions are also checked. The technical contact(s) must be consulted before this special test is requested.

back to top | back to index of dimensional measurements

Algorithm Testing and Evaluation

Technical Contact:
Craig M. Shakarji
Tel: 301/975-3545
E-mail: craig.shakarji@nist.gov

Do not ship instruments or standards to the mailing address listed below. Contact the technical staff for the shipping address.

Mailing Address:
National Institute of Standards and Technology
100 Bureau Drive, Stop 8260
Gaithersburg, MD 20899-8260

back to top | back to index of dimensional measurements

General Information (10070S-10082S)

NIST provides a suite of special tests to evaluate the performance of data analysis software used in coordinate measuring systems (CMSs). These tests use the Algorithm Testing and Evaluation Program for Coordinate Measuring Systems (ATEP-CMS). Tested software is treated as a filter that transforms point coordinate data into feature parameters according to a defined transfer function. NIST evaluates the accuracy of the filter under conditions typical of those found in industrial practice. NIST independently compares the output of the software under test to predetermined corresponding reference values. NIST uses orthogonal-distance least squares algorithms and supports the following geometry types: circle, line, plane, sphere, cylinder, cone and torus. In these Special Tests, the reported measurement uncertainty is determined by the effects of computational roundoff and convergence settings used to generate the reference fits, the propagation of these effects through the comparison algorithms, and sampling uncertainty dependent on the number of data sets used to perform the test.

back to top | back to index of dimensional measurements

Special Test of CMS Software: NIST-Generated Data Sets (10070S-10072S)

In this special test, NIST provides NIST-generated data sets to be used to evaluate customer software. The customer and NIST agree on general guidelines for determining the ranges of parameters (geometry types, form errors, measurement errors, sampling plans) to be used in defining the customer's test experiments. NIST then provides the customer with NIST-generated data sets based on these guidelines. The customer produces fit results from their data analysis software using the NIST-generated data sets. NIST generates fit results from the same data sets using the ATEP-CMS reference algorithms. The two sets of fit results are then compared by NIST. NIST then provides the customer with a Report of Special Test containing results of the test and the combined standard uncertainty.

back to top | back to index of dimensional measurements

Special Test of CMS Software: Customer-Generated Data Sets (10080S-10082S)

In this special test, NIST uses customer-generated data sets and corresponding fit results from the data analysis software to be tested. NIST then generates fit results from the same data sets using the ATEP-CMS reference algorithms. The two sets of fits are then compared by NIST. NIST then provides the customer with a Report of Special Test containing results of the test and the combined standard uncertainty.

back to top | back to index of dimensional measurements

References-Algorithm Testing and Evaluation

Methods for Performance Evaluation of Coordinate Measuring System Software, ASME B89.4.10-2000, ASME, New York, NY (2002).

Algorithm Testing and Evaluation Program for Coordinate Measuring Systems: Testing Methods , C. Diaz, Natl. Inst. Stand. Technol., NISTIR 5686 (1995).

Evaluation of Software for Coordinate Measuring Systems , C. Diaz and T. Hopp, Proc. 1995 SME Clinic, CMMs Week, June 5-8, Soc. of Manuf. Eng., Dearborn, MI; also in Proc. 1995 Interface Symp., June 21-24, Interface Foundation of North America, Carnegie Mellon Univ., Pittsburgh, PA (June 1995).

Testing Coordinate Measuring Systems Software , C. Diaz and T. H. Hopp, Proc. 1994 Natl. Conf. Stand. Lab. Ann. Workshop and Symp. (Aug. 1994).

Concept for an Algorithm Testing and Evaluation Program at NIST , C. Diaz, Natl. Inst. Stand. Technol., NISTIR 5366 (Jan. 1994).

Computational Metrology , T. H. Hopp, Manufacturing Review 6 (4), 295-304, ASME, NY (1993).

back to top | back to index of dimensional measurements