Patent ID: 8413477

Claim:
A calibration tool for fabricating disk springs, said calibration tool comprising: a circular cylindrical tool body that includes a circular opening having an insertion bevel at an upper face end portion for receiving and centering a workpiece within an inner circumferential enveloping surface of the tool body opening, and a tool surface at the inner circumferential enveloping surface for aligning the workpiece relative to a movable die disposed within the inner circumferential enveloping surface, wherein the tool surface includes a first surface portion having an inner diameter that increases in size along the axial longitudinal direction of movement of the movable die into the tool body, and a second surface portion having an inner diameter that decreases in size along the axial longitudinal direction of movement of the movable die into the tool body, whereby no radially inwardly oriented force loading of the workpiece occurs during movement of the movable die into the tool body to form the disk spring and cause internal stress within the workpiece that results in warping of the workpiece.