Rigid Connection of Bones This crank linkage works, except I need to constrain the larger bone to the bone labeled "crank" so they behave as a solid link. When I add rigging to the tail of the larger bone, the larger bone is able to pivot at the juncture of the three bones. Parenting (Ctrl-P) doesn't seem to help...
I figured out a solution and it's really simple. Since the big bone has the same movement as the bone labeled "crank", I really don't need it. I made a link object the length of both "crank" and the big bone and made that a child of "crank". Then I made the origin of the link object at the top of where the big bone was and I built the second armature (not shown) off that point. Then I made the connecting bone copy the location of the link object.