A method of repairing a generator blower hub assembly (12) and rotor blade (10) removed from the generator blower hub assembly (12) where the rotor blade (10) has fatigued material in threads of a threaded blade root (14). The method may include removing (32) at least a portion of the fatigued material to form the blade root (14) to a first or new diameter. Threads may be formed (36) on the diameter of the blade root (14) using a roll forming process. A collar (20) may be secured within a threaded hole (16) formed in the generator blower hub assembly (12) where the collar (20) includes internal threads (35) for receiving the threads formed on the diameter of the blade root (14), which may be threaded into the collar (20). Collar (20) may be fabricated of steel alloy and include relief groove (40) for improving the fatigue resistance of the threaded blade root (14) when reassembled into the generator blower hub assembly (12).