Combine flour, salt, and baking powder; stir well. Cut in shortening with a pastry blender until the mixture resembles coarse crumbs. Stir in milk, and mix well. Turn dough out onto a floured board and knead about three minutes. Divide dough into 10 equal portions. Press each flat in a greased tortilla press. Heat an ungreased skillet over medium heat; cook tortillas about two minutes on each side or until lightly browned, being careful not to let tortillas wrinkle. Tickle tortillas lightly with your fingers while browning the second side to make them puff.