A torque-limiting driver is disclosed, having a handle, a body, a torque-limiting assembly and a work-piece engaging tip. The torque-limiting assembly includes an upper and lower shank that have a plurality of teeth circumferentially spaced. The teeth have a vertical face, an inclined face, and a flat peak. There is a spring for applying pressure across the upper and lower shank with multiple washers interposed between the lower shaft and spring. In some instances, there is a round-square drive with arched catches having preselected radii to assure operation over certain cycles at selected torque and to reduce nose cone damage and breakage at a predetermined measurement of inch-pounds of torque.
