EN ISO 6789-2:2017 PDF

Overview

EN ISO 6789-2:2017 (ISO 6789-2:2017) defines requirements for the calibration of hand torque tools and the determination of measurement uncertainty for those calibrations. It is part of the ISO 6789 series for hand torque tools and complements ISO 6789-1 by focusing on traceable calibration procedures, uncertainty budgets and reporting. The standard applies to both step‑by‑step (static) and continuous (quasi‑static) calibration methods for torque measurement devices that derive torque from elastic deformation or a proportional measured variable.

Key Topics and Requirements

• Calibration method and system requirements - procedures for calibrating torque measurement devices used to verify hand torque tools (indicating and setting types).
• Measurement uncertainty calculation - detailed method to evaluate Type A and Type B uncertainty components and combine them into a relative standard and expanded uncertainty for each tool.
• Relative measurement uncertainty interval (W') - specification of minimum requirements where a traceable calibration certificate for the torque measurement device does not already provide W'.
• Tool types covered - Type I (indicating) torque tools and Type II (setting) torque tools used for screws and nuts.
• Sources of uncertainty - guidance on typical contributors: resolution, repeatability, reproducibility, interface variations and loading point variation.
• Calibration reporting - requirements for results to be documented on a calibration certificate.
• Normative and informative annexes - worked calculation examples for indicating and setting tools (Annex A/B) and minimum requirements for calibrating torque measurement devices when no national standard calibration is available (Annex C).

Applications

• Ensuring accurate and traceable torque delivery in assembly and quality control operations.
• Calibration services in metrology and testing laboratories to support maintenance and compliance programs.
• Verification of torque tools used in critical industries such as automotive, aerospace, medical device manufacturing and industrial production.
• Supporting procurement specifications and supplier quality auditing where torque accuracy and documented uncertainty are required.

Who Should Use This Standard

• Calibration and metrology laboratories performing hand torque tool calibration.
• Tool manufacturers and product engineers validating tool performance.
• Quality managers, maintenance engineers and compliance officers responsible for torque accuracy and traceability.
• Purchasing agents specifying calibration requirements for hand torque tools.

Related Standards

• EN ISO 6789-1:2017 - design, manufacturing and declaration of conformity for hand torque tools.
• ISO/IEC 17025 - general competence requirements for testing and calibration laboratories.
• Relevant national calibration standards and laboratory procedures for torque measurement devices.

EN ISO 6789-2:2017 is essential for organizations needing robust, traceable calibration of hand torque tools with clearly defined uncertainty estimates that enable consistent, auditable torque control.