Collets and tool holder assemblies employing the same

A tool holder assembly comprising:

• a housing for connection and rotation with a spindle about an axis of rotation, the housing defining a socket;
• a collet positioned in the socket, the collet including a clamping portion having a central bore of stepped architecture comprising an inner section of first diameter, a transition section of second diameter and an outer section of third diameter;
• and
• a coupling portion of a cutting tool or cutting tool blank positioned in the central bore, wherein the surfaces of the inner section and transition section engage the coupling portion.

A method of making a cutting tool comprising:

• providing a cutting tool blank having a coupling portion and a blank portion;
• securing the coupling portion of the cutting tool blank in a clamping portion of a collet, the clamping portion having a central bore of stepped architecture comprising an inner section of first diameter, a transition section of second diameter and an outer section of third diameter;
• and
• grinding the blank portion to provide a working portion of the cutting tool having one or more cutting edges.