To provide a standard Adapter Interface and establish accuracies for different sizes of blade classification instruments to permit moment weighing of two blades which when placed 180 degrees apart in a perfect disc, will produce no appreciable static unbalance. The standard Adapter Interface will provide interchangability of adapters between instruments of different manufacturers. The moment weighing scales sizes covered by this document are intended to cover the full range of blades in common use and to detect moment variations from blade to blade when it is positioned at the same radius as in its associated wheel. To provide a standard interface adapter flange on any blade classification instrument capable of meeting the sensitivity requirements for the specific class.