A minor quibble with D. L. Bullock's adjustment procedure.  The
screws with the slotted washers (proper name: Belleville washer)
should be considered the "adjustment" screw.  The screws outboard
of those (without washers) simply lock the assembly in place after
the rotational adjustment is correct.

John Grant

 [ My 1917 Pianola has a shoulder screw which holds the Belleville
 [ spring washer against the moveable piece, so it's actually an
 [ axle for rotation.  The 100-year-old washer has lost most of
 [ its springiness so I should replace it someday...  -- Robbie