This might well be the most frequently asked of all frequently asked questions and is rightly a subject of genuine concern to production and quality managers.   To answer the question, I am going to look to the standard BS EN ISO6789 – “Assembly tools for screws and nuts – Hand torque tools – Requirements and test methods for design conformance testing, quality conformance testing and recalibration procedure”. Unsurprisingly, most of us refer to it as “the torque wrench standard”!   In 1992, ISO 6789 was very much a document covering the design and manufacture of torque tools and the requirement was that the tool should be tested at maximum capacity for 5000 cycles in each direction. No guidance was given on recalibration intervals.   However, when the standard was revised to the 2003 edition, the scope was broadened to include “quality conformance testing and recalibration” and so became of relevance to people using torque wrenches ra ...

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