Gearhart Industries said it signed a definitive settlement with Smith International relating to the previously reported understanding to resolve the disputes between them, including the disengagement of Smith's interest in Gearhart . . . Burlingame, Calif.-based GTE Sprint Communications said it will begin offering its long-distance telephone service to the United Kingdom beginning April 1 . . . Greyhound Corp., Phoenix, said its previously reported purchase of Lakewood-based Purex Industries' consumer products division, for $264 million, has been made final.