  Suspended nanowires are shown to provide mechanically-controlled coherent
mixing/splitting of the spin states of transmitted electrons, caused by the
Rashba spin-orbit interaction. The sensitivity of the latter to mechanical
bending makes the wire a tunable nano-electro-mechanical (NEM) weak link
between reservoirs. When the reservoirs are populated with misbalanced "spin
up/down" electrons, the wire becomes a source of split spin currents, which are
not associated with electric charge transfer and which do not depend on
temperature or driving voltages. The mechanical vibrations of the bended wires
allow for additional tunability of these splitters by applying a magnetic field
and varying the temperature. Clean metallic carbon nanotubes of a few microns
length are good candidates for generating spin conductance of the same order as
the charge conductance (divided by $e^2$) which would have been induced by
electric driving voltages.
