Method of making an expandable mandrel having a thin cylindrical sleeve and a pair of thick wall arcular ends

摘要

A method of making a workpiece holding device having an expandable mandrel including the step of melting copper ring seals around the bore next to the ends of the expandable mandrel to maintain the mandrel rigidly in place. The holding device includes an expandable sleeve of generally cylindrical shape having a thin outer shell with a pair of opposed thick wall circular ends integral with the shell extending radially inward to form a bore. An elongated generally circular central body with a central bore for containing pressure and adapted to be mounted on a machine tool having an outside diameter engageable with the bore. A pair of opposed arcuate undercut grooves are formed at an intersection of the outer shell and the circular ends to prevent the formation of destructive stress concentration at the intersection. Chamfers are formed at the outer edges of the bore and copper rings are inserted therein and melted to form a seal between the bore and mount the expandable sleeve to the central body.