The Z=38 coupling box, code 08.10.201, operates when the clutch 08.10.203 is energized with 24 V. By generating an electromagnetic field, it closes and locks the drive plates. The fins on the outer plates, once clamped, engage with the slots of the coupling box, transmitting the rotation of the threading spindle. Activation is controlled via a feeler/probe, which also sets the threading depth to be carried out on the workpiece. Threading is performed by chasing (follow threading), and the spindle always rotates in the same counterclockwise direction both when the threading tool enters and when it exits.