I am trying to fashion a set of drop down wheels for a cabinet. These
casters are screwed to the underside of cross piece of wood (front to
back). They will be on a hinge so that when they are down they are inside
the cabinet, when the cross piece is pushed down, they below the bottom and
raise the cabinet.

I would like to have a crank lift where I could insert a handle from outside
the cabinet into a recess that contains the end of the linkage to the crank
lift itself. If the crank is turned one direction, it meshes a gear which
drives a rod down onto the edge of the crosspiece, opposite from the hinges.
If it is turned the other direction, then the rod comes up and the weight of
the cabinet forces the casters up underneath and inside the cabinet housing.
Kind of like the old foot operated sewing machines, but using a crank lift
versus your foot to move the pedal.

Any ideas on how to do this "cheaply"? I have seen commercial solutions but
they are way toooo expensive.