ISO 3070-2:2016 specifies, with reference to ISO 2301, ISO 2307 and ISO 2302, geometric tests, spindle tests and tests for checking the accuracy and repeatability of positioning by numerical control of horizontal spindle boring and milling machines having a movable column along the X-axis and also specifies the applicable tolerances corresponding to general-purpose, normal accuracy machines.

This type of machines are usually provided with sliding boring spindles and can be provided with universal spindle heads of the following types, whose test conditions are covered by ISO 175431:

- fixed or indexable heads, with accessory spindle(s) square to the Z-axis, with or without one spindle parallel to the Z-axis;

- 45 split indexable heads, with mechanical indexing of the different angular positions of the two bodies (e.g. Hirth couplings);

- 45 split continuous heads, provided with continuous positioning of the two numerically controlled axes;

- swivel heads, with two numerically controlled rotary axes perpendicular to each other.

Test conditions for accessory facing heads are specified in Annex B.

ISO 3070-2:2016 concerns machines having movement of the column on the bed (X-axis), vertical movement of the spindle head on the column (Y-axis), axial movement of the ram (Z-axis), axial movement of the boring spindle (W-axis), and, in most cases, one or more tables moving on a bed parallel to the spindle (R-axis) and rotating around a vertical axis (B-axis).

ISO 3070-2:2016 deals only with the verification of the accuracy of the machine. It does not apply to the operational testing of the machine (e.g. vibration, abnormal noise, stick-slip motion of components) nor to machine characteristics (e.g. speeds, feeds), as such checks are generally carried out before testing the accuracy.