This part of ISO 8636 specifies, with reference to ISO 230-1, ISO 230-2, and ISO 230-7, geometric tests, machining tests, and tests for checking accuracy and repeatability of positioning of numerically controlled axes for general-purpose normal accuracy bridge-type milling machines with a travelling bridge (gantry-type). This part of ISO 8636 also specifies the applicable tolerances corresponding to the above-mentioned tests. This part of ISO 8636 is applicable to machines with travelling bridge and fixed table. It does not include single-column (open sided) machines and those with fixed bridge and moving tables. This part of ISO 8636 deals only with the verification of the accuracy of the machine. It does not apply to the testing of the machine operation (vibration, abnormal noise, stick-slip motion of components, etc.) nor to machine characteristics (such as speeds, feeds, etc.), which should generally be checked before testing the accuracy. This part of ISO 8636 provides the terminology used for the principal components of the machines and the designation of the axes with reference to ISO 841.