A sensing and positioning device adapted to be mounted on a spindle of a machine tool including: a fixing element; and at least three sensing elements adapted to be connected operationally to a programmable control unit of a machine tool. The sensing and positioning device is adapted to be used with a machining tool mounted on the spindle. A machine tool including a workpiece table, a machining head, and movement means adapted to move the machining head above the workpiece table. The machine further includes the device described above. An associated machining method is also described.