Conical tool holder for precision balancer

A machine for determining dynamically a residual unbalance in a workpiece having a conical surface is provided with a plurality of support elements, such as roller elements, that communicate with the workpiece at the conical surface thereof. The roller elements are arranged circumferentially equidistant about the workpiece and may have cylindrical or conical configurations. Further support elements, such as roller elements, can be applied against an annular surface of the workpiece, such as on a flange portion thereof. At least one of the support rollers that communicates with the conical surface is arranged to rotate about an adjustable axis of rotation that can be oriented with respect to the workpiece to achieve good rotative communication therebetween. The rollers are arranged to rotate at different speeds from the workpiece, whereby an unbalance signal associated with the workpiece can readily be isolated from a composite signal having unbalance information related to a residual unbalance of the workpiece combined with residual unbalances of the rollers.