THE RIGHT MAIN LANDING GEAR COLLAPSED DURING THE LANDING ROLL. THE AIRPLANE VEERED TO THE RIGHT AND THE RIGHT WING CONTACTED A RUNWAY LIGHT. POST ACCIDENT INVESTIGATION REVEALED A FATIGUE FAILURE OF THE LANDING GEAR TRUNNION ON THE LOWER FILLET OF THE WEB ON THE TRUNNION. METALLURGICAL EXAM REVEALED THE FAILURE PROPAGATED FROM GRINDING MARKS MADE DURING THE MANUFACTURING FINISHING PROCESS. A SERVICE BULLETIN WAS ISSUED IN 1985 BY THE MANUFACTURER ADDRESSING THE INSPECTION OF THIS AREA FOR CRACKS.