Measuring method and measuring system for measuring drilled holes, and precision machine tool with a measuring system

A measuring method for measuring the geometry of a drilled hole in a workpiece with the use of a measuring system which has a measuring unit which, in the state which is set up ready for operation, has a measuring mandrel which can be moved bidirectionally along a travel path parallel to a measuring mandrel axis by means of a linear drive;

• the measuring mandrel being calibrated at least once with the use of a reference device by way of at least one reference element of defined internal dimensions, by the measuring mandrel being moved by means of the linear drive into a calibrating location, in which a measuring sensor of the measuring mandrel is arranged in the region of the reference element, wherein, during measuring operation, the reference device is arranged in a neutral location outside the travel path of the measuring mandrel in such a way that the measuring mandrel can be introduced into the drilled hole to be measured without dipping through the reference element;
• the reference device is moved, in order to carry out a calibration operation, out of the neutral location into a calibrating location, in which the reference element is arranged in a calibration position coaxially with respect to the measuring mandrel axis;
• the measuring mandrel is moved by means of the linear drive into a calibrating location, in which a measuring sensor of the measuring mandrel is arranged in the region of the reference element;
• and, in the calibrating location, a calibration measurement for calibrating the measuring mandrel is carried out.