Phil Teggart, general manager of Omaha Steel Castings Co., has purchased the privately held company from Ron Howlett, who owned the firm for about 30 years. The company at 4601 Farnam St. was founded in 1906. Teggart said it has about 250 employees and annual sales of about $25 million. Teggart, who has held his position for the past 4½ years, said the firm makes steel castings for the construction, mining,…