An employee was repairing a misaligned cable on the left side of a warehouse door. He was using a wrench, held in his left hand, to loosen two screws at the left side of the spring tension rod area. When the screws were loosened, the right side of the metal spring wheel (where his right hand was resting) began spinning. His right-hand fingers were turned part of the way around the wheel, causing a dislocation of the middle finger and a partial amputation of the ring finger.