Benchmark device for adjusting posture of machine tool spindle

The invention discloses a benchmark device for adjusting the posture of a machine tool spindle. The benchmark device comprises a mandrel and a connecting block. The connecting block comprises a transition plate, a self-aligning plate and a posture adjusting plate. The self-aligning plate is connected with the transition plate through translational pre-tightening screws. The self-aligning plate isconnected with the posture adjusting plate through posture adjusting screws. The benchmark device further comprises a plurality of translational adjustment screws. One of the self-aligning plate and the posture adjusting plate is provided with a ball head and the other is provided with a groove body. A plurality of posture adjusting screws are arranged and are annularly distributed around the matching surface. The mandrel is fixed on the posture adjusting plate, and the ball center of the ball head falls on the axis of the mandrel. The benchmark device can effectively solve the problem of establishing a measurement be