[Hallicrafters] air variable capacitors

[Ginger Harris]

Since everything is so quiet, I might as well ask a question.  Is it  
safe to assume that  in a receiver, the rotors are always centered  
between the stator blades at the factory?  Could there be an  
exception among  those big spaced capacitors of the 1920s?  It seems  
that off center spacing would increase the capacitance a little.  I  
am puzzled.  Thanks and an early Merry Christmas,   JP    KI4ZVX