Abstract: A present invention is for a device and method for measuring and calibrating the rotary motion of a rotatable machine member, such as a pivotable swivel member (2b) of a spindle (2) of a five-axis machine tool (1). The device includes an arm (110) mounted to the spindle, a housing (120) mounted to the arm, an optical encoder mounted internal to the arm and positioned therein to measure rotation about an axis extending lengthwise along the housing, which such axis is parallel to the axis about which the swivel member rotates. The device also includes a rotary table (170) mounted to the housing opposite the arm, the rotary table comprising a stator (171) fixedly mounted to the housing and a rotor (172) clampedly affixed to a shaft passing through the housing. The shaft is coupled to an input shaft of the encoder such that rotary movement of the rotor can be measured by the encoder. An electronic level (190) fixedly secured to the rotor, such as by a bracket (180).

Abstract: A present invention is for a device and method for measuring and calibrating the rotary motion of a rotatable machine member, such as a pivotable swivel member (2b) of a spindle (2) of a five-axis machine tool (1). The device includes an arm (110) mounted to the spindle, a housing (120) mounted to the arm, an optical encoder mounted internal to the arm and positioned therein to measure rotation about an axis extending lengthwise along the housing, which such axis is parallel to the axis about which the swivel member rotates. The device also includes a rotary table (170) mounted to the housing opposite the arm, the rotary table comprising a stator (171) fixedly mounted to the housing and a rotor (172) clampedly affixed to a shaft passing through the housing. The shaft is coupled to an input shaft of the encoder such that rotary movement of the rotor can be measured by the encoder. An electronic level (190) fixedly secured to the rotor, such as by a bracket (180).