Abstract: The present invention is a tool holder and quick change adaptor which permits very tight tolerances to be kept when operations are being performed while at the same time permitting quick change of the tool holder. The tool holder and quick change adaptor of the present invention employs a cone and conical recess which are dimensioned such that the two mate with surface to surface contact without locking and provide limited deflection of the tool for precise tool operation.

Abstract: In a quick change spindle adapter including a power rotated spindle having a bore adapted to receive a tool holder, a body secured upon the spindle and a retractable spring biased sleeve mounted on the body having a tapered inner wall. A tool holder mounting a tool projects into the body and has a shank loosely positioned within the spindle. A tapered collar on the tool holder extends into the body and is retainingly engaged by a series of spaced balls in the body with the balls projecting into engagement with the sleeve tapered wall retaining the tool holder and shank upon the spindle. The improvement comprises a conical recess within the end of the spindle defining an axial bearing and a centering cone on the tool holder is in snug engagement and axial registry with the bearing maintaining a self-alignment of the tool holder and spindle.