Method for manufacturing a one-piece torsional vibration damper retainer plate

A method for manufacturing a one-piece torsional vibration damper retainer plate having an annular periphery curled into a generally C-shaped channel for retaining at least one spring, said method comprising the steps of:

• partially curling the annular periphery to receive the spring;
• disposing the spring about the annular periphery of the retainer plate;
• completing curling of the annular periphery about the spring and forming the generally C-shaped channel after the step of partially curling to substantially surround the spring to prevent the spring from being removed from the C-shaped of the retainer plate during operation of the retainer plate;
• and
• said method characterized by heat treating the surface of the C-shaped channel to change physical properties of the retainer plate between the step of partially curling the annular periphery and the step of completing the curling of the annular periphery thereby creating a wear resistant surface layer for contact with the spring disposed within the C-shaped channel.