A cutting tool apparatus having a shank and a tool support extension disposed longitudinally adjacent the shank and extending in a direction distal the shank, wherein the tool support extension includes an incurvate taper profile.

A cutting tool apparatus having a shank and a tool support extension disposed longitudinally adjacent the shank and extending in a direction distal the shank, wherein the tool support extension includes an incurvate taper profile.

A coupling device including first and second members, threaded elements mounted within one of the elements to move between open and closed position, adjacent portions of the threaded elements being provided with sloping surfaces and pin assemblies associated with the threaded elements and positioned between the sloping surfaces such that as a manually operable device is operated the threaded elements are moved longitudinally into engagement with the pin assemblies wedging the pin assemblies against the sloping surface expanding the threaded elements. There are also disclosed balls associated with the threaded elements positioned within openings within the coupling device and being moved when the threaded elements assume their open position into locking relationship.