  With observations of the EP Cru system, we continue our series of
measurements of spin-orbit angles in eclipsing binary star systems, the BANANA
project (Binaries Are Not Always Neatly Aligned). We find a close alignment
between the sky projections of the rotational and orbital angular momentum
vectors for both stars (beta_p = -1.8+-1.6 deg and |beta_s|<17 deg). We also
derive precise absolute dimensions and stellar ages for this system. The EP Cru
and DI Her systems provide an interesting comparison: they have similar stellar
types and orbital properties, but DI Her is younger and has major spin-orbit
misalignments, raising the question of whether EP Cru also had a large
misalignment at an earlier phase of evolution. We show that tidal dissipation
is an unlikely explanation for the good alignment observed today, because
realignment happens on the same timescale as spin-orbit synchronization, and
the stars in EP Cru are far from syncrhonization (they are spinning 9 times too
quickly). Therefore it seems that some binaries form with aligned axes, while
other superficially similar binaries are formed with misaligned axes.
