Method and apparatus for mechanically balancing the disk pack of a hard disk drive

At least one mechanical counterbalance for use in balancing a disk pack includes a spindle motor rigidly coupled and aligned by at least two open screw holes with a disk clamp, comprising:

• a cylindrical shaft rigidly coupled to a latching assembly, both centered about a primary axis, and a balance weight;
• wherein said latching assembly includes a compressible latch rigidly coupled to a latch gap zone, both centered about said primary axis;
• wherein said balance weight is rigidly coupled to said latch gap zone;
• wherein said cylindrical shaft is rigidly coupled to said compressible latch;
• wherein for each of said open screw holes, when said mechanical counterbalance is inserted into said open screw hole to lock said mechanical counterbalance,
• said cylindrical shaft fits into said open screw hole,
• said compressible latch compresses when pressed away from said cylindrical shaft in said open screw hole, and
• said compressible latch expands when pressed further away from said cylindrical shaft in said open screw hole to lock said mechanical counterbalance against a member of a locking plate collection based upon said latch gap zone;
• wherein said locking plate collection comprises said disk clamp and said spindle motor;
• wherein said mechanical counterbalance has a total mass provided at essentially said primary axis when used in said disk pack;
• and
• wherein said balance weight includes an interior face aligned toward members of said locking plate collection when said mechanical counterbalance is inserted into said open screw hole.