  The possibility for double-wall carbon nanotube to operate as the bolt and
nut pair is studied. The barriers for relative motions of walls along the
helical "thread" line and for jumps on neighbour helical lines are calculated
as functions of wall lengths for the set of double-wall carbon nanotubes. The
dynamics of relative motion of carbon nanotube walls along the helical line
under the action of external forces is considered. Perforated nanodrill,
variable nanoresistor and other principally new nanotube based mechanical
nanodevices using these motion are proposed. Possible operation modes of
proposed nanodevices are discussed.
