BS 2558_Supplement No.1 is a British Standard that discusses tubular box spanners. BS 2558 provides an immediate guide to the overall metric sizes of fastening tools.
BS 2558_Supplement No.1 on metric sizes for tubular box spanners is useful for:
It is recognized that because fasteners are now being manufactured according to the appropriate metric British Standards, it is important to have available standards for the associated fastening tools.
BS 2558_Supplement No.1 provides the best industry guidance on dimensions for ISO metric hexagons along with recommendations for size combinations for double-ended flat spanners. This assists in manufacturing highly efficient and durable tubular box spanners.