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.