Just wanna add something here, I've found the bone crank in two different locations:
1. up against a wall
2. already attatched to one of the mechanisms that pull up corpses
so your best bet is to just check all of the cranes (i forgot what they're called), right click them and select detatch bone crank, or just look around the walls to see if it spawned there instead.
Someone mentioned that it can be found in pots as well, though i seriously doubt that because it just wouldn't make sense for it to be stored there in the first place. Also, opening the pots is gonna spawn angry ghost nords.