An improved method of assembling molds enables the size of successive molds to be adjusted to provide cast articles having a desired size. In practicing the method, a first or initial mold is assembled in a fixture. This initial mold is used to form a cast article. The cast article formed in the initial mold is measured to determine the extent to which the dimensions of the article deviate from predetermined design dimensions. The fixture is then adjusted to compensate for the deviations in the dimensions of the cast article from the intended or design dimensions. A second mold is then assembled in the fixture. Since the fixture has been adjusted to compensate for the inaccuracies in the first mold, a product cast with the second mold will have dimensions closer to the desired dimensions.