An oil finish will do virtually nothing effective at all to seal them,
though, unless is top-coated with a non-permeable coat of varnish or
lacquer.
--dpb


Even then - there could be some expansion/contraction -
our last home had factory-made oak kitchen cupboards
that had a couple doors that would rub in summer -
and have a full 1/8 inch space in winter.
John T.