Torque Wrench
Calibrate torque wrenches to ISO 6789 for precision assembly requiring controlled bolt torque.
Standards
ISO 6789-1, ISO 6789-2, ISO/IEC 17025
Typical Interval
12 months or every 5,000 cycles
Uncertainty Range
±2–4% of reading
What Is Torque Wrench?
Torque wrenches apply precise fastening torque — critical in automotive, aerospace, and industrial assembly to prevent under-torquing (joint slippage) or over-torquing (fastener damage). ISO 6789 calibration tests at 20%, 60%, and 100% of rated capacity, 5 repetitions per point.
Applicable Standards
Primary standards: ISO 6789-1, ISO 6789-2, ISO/IEC 17025
ISO/IEC 17025-accredited laboratories must maintain an unbroken traceability chain from the calibration result back to NIMT (Thailand's national metrology institute) or another internationally recognised NMI.
Typical Measurement Uncertainty
Expanded uncertainty is typically ±2–4% of reading, depending on the measurement range, reference equipment used, and environmental conditions. The actual uncertainty will be stated on your calibration certificate.
Recommended Calibration Interval
A calibration interval of 12 months or every 5,000 cycles is generally recommended. The appropriate interval for your specific instrument depends on usage frequency, environmental exposure, and any applicable regulatory or customer requirements.
What Your Calibration Certificate Will Include
- Calibration results — instrument indication vs. reference value at each test point
- Error and expanded uncertainty (U) at k=2 (95% confidence level)
- Traceability chain to NIMT or a recognised NMI
- Environmental conditions during calibration (temperature, humidity)
- Calibration date, certificate number, and authorised signature
Find a Torque Wrench Calibration Lab in Thailand
ThaiLabHub lists ISO 17025-accredited calibration laboratories across Thailand. Search our directory to find labs that offer torque wrench services, with scope details, location, and contact information.
For Labs: Manage Torque Wrench Jobs with LabSync
LabSync helps Thai calibration laboratories manage jobs, issue traceable certificates, calculate GUM uncertainty budgets, and generate Thai tax reports (PP30 + WHT) — all in one system.
Frequently Asked Questions
Why is it important to calibrate a Torque Wrench?+
Weight and force measurements affect product quality, legal trade, and structural safety. An uncalibrated Torque Wrench can accumulate bias across thousands of measurements. Calibration corrects systematic error to within ±2–4% of reading per ISO 6789-1, ISO 6789-2, ISO/IEC 17025.
How often should a Torque Wrench be calibrated?+
Most Torque Wrenchs should be calibrated every 12 months or every 5,000 cycles under normal operating conditions. High-use environments, harsh conditions (vibration, temperature extremes), or regulatory requirements (FDA, GMP, ISO 17025) may necessitate more frequent calibration. Always follow the manufacturer's recommended interval as a baseline and consult your lab's quality plan.
What does a Torque Wrench calibration certificate show?+
A calibration certificate issued under ISO/IEC 17025 includes: the instrument identification (make, model, serial number), the reference standards used (with their own traceability chain), the measurement points tested, before/after correction values, the expanded measurement uncertainty (±2–4% of reading), the environmental conditions during calibration, the calibration date and next-due date, and the signature of the authorized calibration engineer. This certificate is the evidence required for audits and accreditation.
Related Calibration Services
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