ISO 13041-8:2004 specifies, with reference to ISO 230-3, the tests which apply for the evaluation of thermal distortions of the machine structure and positioning system, up to 2 000 mm in length, of numerically controlled (NC) turning machines and turning centres. ISO 13041-8:2004 defines three tests which are: the environmental temperature-variation error test, the test for thermal distortion caused by a rotating spindle, and the test for thermal distortion caused by moving linear axes