The connecting rod between centres being “fishbellied”. This item is one of the more complex ones, being cross-drilled, bored, turned and eventually hand shaped.
The “fishbelly” effect is really two opposing tapers of about two degrees inclusive, one end was turned and the rod flipped over for the other end. The surface was then filed in the lathe to blend the tapers together.
One end finished, the other half roughed-out ready for the yoke to be slit.
The finished con-rod complete with the crank and crank pin. This item was one of the most complicated parts of the kit. The big-end also has a bronze bush press fitted into it.