This document specifies, with reference to ISO 230-1 and ISO 230-2, geometric tests and tests for checking the accuracy and repeatability of positioning of numerically controlled axes for general purpose, normal accuracy, bridge-type milling machines with a fixed bridge (portal type). This document also specifies the applicable tolerances corresponding to the above-mentioned tests.

This document is applicable to machines with moving tables and fixed double columns. It does not include single-column (open sided) machines and those with fixed tables and moving columns.

This document 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 are generally checked before testing the accuracy.

This document provides the terminology used for the principal components of the machine and the designation of the axes with reference to ISO 841.