polish them up a bit first and double your return.

i would photgraph them again on a flat surface, so you don't need to prop the end up on a bottle (looks tacky). a top-quality photo will give you a better return. use a high contrast backgound, like a black velvet or wool contrsting with bright reflection from the crank and rings, like in photo one.

then closeups of the teeth (to show they're not ragged and rough) and the square hole (to show it's still square) for the smaller pics. and show the main pic with the dust caps in place, so people know they're included and correct.