Abstract
A nut runner accessory for a power-driven tool is provided. The nut runner accessory can include a gear assembly received in a housing. The gear assembly transfers an externally generated force to a driver head of the nut runner accessory. The driver head can include a plurality of stepped pockets that can receive and engage different sizes and/or configurations of nuts to be threaded onto/off of a threaded rod. The driver head can be counterweighted, to counteract imbalance generated due to an offset between a center of mass of the driver head and a center of rotation of the driver head.