Cutting tool holder

In a cutting tool assembly, a clamping arrangement for clamping a cutting insert to a tool holder wherein said tool holder is formed at an end thereof with an insert seat defined by a base surface and a transverse side surface;

• a mounting pin secured to said tool holder and extending out of said base surface so as to have mounted thereon a centrally apertured cutting insert;
• a ball guide groove formed in said tool holder;
• a plurality of clamping balls located in said groove;
• an upper opening of said groove extending along the length thereof in an upper surface of the tool holder adjacent to the insert seat so as to allow for ready introduction of said clamping balls into said groove;
• a first inner end of said groove constituting a bearing surface for an innermost of said clamping balls;
• a second outer end of said groove opening into said transverse side surface and having a transverse dimension less than the diameter of an outermost of said clamping balls;
• a groove base spaced from said upper surface in the region of said first end by a first amount less than the diameter of the innermost clamping ball and, in the region of said second end, by a second amount greater than the first amount;
• a ball displacing member articulated to said tool holder and juxtaposed with respect to said groove so as to bear on said innermost clamping ball and displacing means for displacing said member towards said tool holder so as to displace said outermost clamping ball into displacing said innermost clamping ball outwardly with respect to said side surface, whereby an insert mounted on said pin and resting on said base surface is clampingly pressed against said pin and is pivoted into clamping engagement with said side and base surfaces.