HEAD STACK ASSEMBLY AND ITS MANUFACTURING METHOD AND MAGNETIC DISK DEVICE HAVING THE HEAD STACK ASSEMBLY

PROBLEM TO BE SOLVED: To provide a head stack assembly in which deformation of base plates themselves caused by caulking and fastening is effectively prevented and its manufacturing method and to provide a magnetic disk device having the head stack assembly. SOLUTION: The manufacturing method is for the head stack assembly which has a suspension that supports a head, an arm which drives the head and base plates which mount the arm onto the suspension. The method has a step in which the base plates respectively have bosses that have openings are inserted into the through-hole of the arm and a processing member, whose size is larger than the openings, is passed through the base plates in one direction within the through-hole so as to fasten, by caulking, the base plates to the arm. Prior to the caulking and fastening step, the minimum thickness of the bosses in the through-hole at the cross section that includes the center axis of the through-hole is set equal to or less than 60% of the thickness of the base plates outside the through-hole. COPYRIGHT: (C)2007,JPO&INPIT