EMPLOYEE'S CO-WORKER BROKE A DRILL STEEL OFF IN THE OPPOSITE SIDE CHUCK. EMPLOYEE ATTEMPTED TO HELP GET IT OUT AND DECIDED TO TIE A NYLON ROPE TO THE MAST AND DRILL STEEL AND ATTEMPTED TO LOWER THE CHUCK. EMPLOYEE REACHED TO SECURE THE ROPE WHEN HIS THUMB BECAME TRAPPED BETWEEN THE ROPE AND THE DRILL STEEL.