Abstract: A tool holder (10) in which coolant fluid is delivered to a driven tool (115) through a piston (220) which extends through an axial passage in the tool holder (10) and its collet or chuck (170) and is held in contact with the tool (115) by pressure of the coolant fluid. The tool holder advantageously provides an axial float in which springs mount the tool (115) to the tool holder (10) and allow the collet to follow the lead of the tool. The coolant delivery system (200), although acting in an axial direction, does not interfere with the axial "float" of the tool and collet, as the fluid pressure is chosen to be great enough to provide a face seal and small enough not to destroy the float of the tool.

Abstract: The chuck assembly and the collet for retaining an end mill tool against axial pullout. The collet includes a radially compressible body having a tapered outer surface, a central bore and a radial aperture extending from the outer surface into the central bore. The radial aperture has an undercut or larger diameter medial portion with a movable pin mounted therein, said pin being movably mounted and, adapted to extend into the bore to retain the tool. The pin has a hole drilled through with a spring bar mounted therein. The ends of the spring bar are compressed to a length smaller than the diameter of the radial aperture and inserted into the larger undercut portions where the expansion of the spring bar retains the pin. The hole in the pin is larger than the diameter of the spring bar to allow the pin to move along its axis (radially into the collet bar).

Abstract: The chuck assembly and the collet for retaining an end mill tool against axial pullout. The collet includes a radially compressible body having a tapered outer surface, a central bore and a drilled radial aperture extending from the outer surface into the central bore. The radial aperture has an undercut or larger diameter medial portion with a movable pin mounted therein, said pin being movably mounted and, adapted to extend into the bore to retain the tool. The pin has a hole drilled through with a spring bar mounted therein. The ends of the spring bar are compressed to a length smaller than the diameter of the radial aperture and inserted into the larger undercut portions where the expansion of the spring bar retains the pin. The hole in the pin is larger than the diameter of the spring bar to allow the pin to move along its axis (radially into the collet bar).