Bob Engelhardt fired this volley in
:

Especially using the cranks & link in place of gears
or sprockets & chain.


Especially interesting is that it wouldn't work at all without some
"work" pinched snugly between the rolls. Think what would happen if
there were no workpiece. The non-driven roll would simply stall when the
crank link hit dead-aft-center, and could not be reasonably expected to
advance or retract, no matter which way the driven roll was turned.

It _is_ interesting, because the workpiece is part of the mechanism.

LLoyd