David Lahti;79;of Branthoover Street (Arnold City);Belle Vernon;died Wednesday;Dec.22;1993;in his home following a short illness.  Mr.Lahti was born Feb.10;1914;in Fairhope;Washington Township;Fayette County;a son of the late John and Emmy Humony Lahti.  He was a retired carpenter and a member of Local Union No.541 of Washington;Pa.  Mr.Lahti was a U.S.Navy veteran of World War II.  He was a charter member of Veterans of Foreign Wars Post No.3557 of (Fairhope) Belle Vernon and a member of Belle Vernon American Legion Post No.659.  Surviving are his wife;Regina (Sekowski) Lahti;two sons;Dave Lahti in California and James Lahti in Connecticut;one daughter;Mrs.John K.(Diane) Boozer of Belle Vernon;a brother;Eugene Lahti in New York;a sister;Betty Seacord of Albany;Ga.;five grandchildren;three great-grandchildren;and a sister-in-law;Carmella Lahti of Belle Vernon.  Three brothers;Harry;Larry and John Lahti;and five sisters;Ella Horton;Sally Salo;Helen Erickson;Bertha Raynor and Hilda Davis;are deceased.  Friends will be received in the Howard W.McCrory Funeral Home;Fayette City;on Wednesday from 7 to 9 p.m.;Thursday from 2 to 4 and 7 to 9 p.m.and on Friday until 11 a.m.;the hour of services in the funeral home.  Burial will be in Belle Vernon Cemetery.  The Howard W.McCrory Funeral Home is handling arrangements.