Method of assembling a head arm stack for a magnetic disk drive

A method of assembling a head stack on a pivot bearing for use in a head positioning mechanism of a disk drive in which a plurality of different head stack components are clamped on the bearing comprises providing a plurality of head stack components, each having an opening for receiving the bearing. The head stack assembly includes two pairs of head arms, spacers and a flat coil member. A caddy positions the components with their respective openings disposed on a common axis. The head arm assemblies are positioned in the caddy with the openings biased against each other and disposed on the common axis. The flat coil member is placed between the pairs of arm assemblies with its opening on the common axis. The head stack components in the caddy are angularly aligned on the common axis. A threaded end of the bearing is inserted through the openings and receives a clamping nut which is tightened to clamp the components on the bearing for conjoint movement with the flat coil component. The caddy is then removed.