Hi Bob, the hook on the middle casting looks like it might be a latch, similar to latching an end housing shut on a SB 9 or Dalton 6 lathe ( to cover/ protect the bull and idling gears on the left side of the headstock). However, the third casting seems to be an articulated handle of some sort, with a machined flat surface for grabbing around some part. Very mysterious. The owner has passed and none of his descedants are machinists... So no background at all.