Abstract: A method and apparatus for producing a casting having a curved internal passage includes die or mould means and core means including at last three parts, said parts being dimensioned and arranged to abut one another so that at least part of the joint line on the surface of the curved passage lies on a surface of revolution accessible from one end of said passage, two of said parts being capable of withdrawal along their respective axes from the ends of the passage, the third core part being of metal, and being arranged to define the inside portion of the curve of the passage, and being dimensioned so that its width is less than the diameter of the curved portion of the passage, whereby said third core part may be withdrawn from said passage.