Publishing and copyright information

The BSI copyright notice displayed in this document indicates when the document was last issued.

The following BSI references relate to the work on this document:
Committee reference ISE/101/1
Draft for comment 18/30342602 DC

Foreword

Publishing information

This British Standard is published by BSI Standards Limited, under licence from The British Standards Institution, and came into effect on 31 December 2018. It was prepared by Panel ISE/101/1/2, Torque measuring and testing, under the authority of Subcommittee ISE/101/1, Uniaxial testing, and Technical Committee ISE/101, Test methods for metals. A list of organizations represented on these committees can be obtained on request to their secretary.

Supersession

BS 7996:2018 supersedes BS 7996:2009, which is withdrawn.

Information about this document

This British Standard describes a method of calibration and classification only and should not be used or quoted as a specification.

This revision introduces the relative measurement uncertainty interval, the range in which the expected error is likely to lie, calculated as the sum of the absolute relative deviation and the expanded uncertainty.

Use of this document

It has been assumed in the drafting of this British Standard that the execution of its provisions is entrusted to appropriately qualified and competent people.

Presentational conventions

The provisions of this standard are presented in roman (i.e. upright) type. Its requirements are expressed in sentences in which the principal auxiliary verb is “shall”.

Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.

Contractual and legal considerations

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

1 Scope

This British Standard specifies a method for the calibration and classification of torque measuring devices using continuous torque application where the inertial effects are minimal. This includes torque measuring devices used for the calibration of torque tools.

The information to be given on the certificate of calibration is also specified in this standard.

Annex A provides diagrams of the continuous application of torque, and examples for the calibration of torque measuring devices. Annex B gives an example of determining uncertainty of the calibration results of the torque measuring device. Annex C shows how to calculate mechanical and electronic bandwidth.

2 Normative references

3 Terms, definitions, abbreviations and symbols

4 Preparation for calibration

4.1 Reference standard

4.2 Condition and identification of a torque measuring device

4.3 Resolution of the indicator

4.4 Lower limit of calibration, T_min

4.5 Rate of applied torque

4.6 Number of calibration orientations (see Annex A)

5 Preliminary procedure

5.1 Alignment

5.2 Temperature considerations

5.3 Instrumentation set-up

5.4 Preloading procedure

6 Calibration procedure

6.1 Selection of calibration torques

6.2 Application of calibration torques

6.3 Torque application rate validation

7 Calculation of results

7.1 Determination of deflection, d

7.2 Determination of relative repeatability, R₁

7.3 Determination of relative reproducibility, R₂

7.4 Determination of relative errors of interpolation, E_it and E_itd

7.5 Determination of relative residual deflection, R₀

7.6 Determination of relative reversibility, R₃

7.7 Determination of relative errors of indication, E_i and E_id

7.8 Determination of uncertainty of measurement and relative measurement uncertainty interval

8 Classification of torque measuring devices

8.1 General

8.2 Determination of a classification and its range

9 Calibration certificate

Bibliography

BS 7996:2018

Torque measuring devices. Calibration and classification using continual torque application. Method

Current

Published:

31 Dec 2018