Abstract: A shaft, having a slot formed therein offset from the shaft axis, receives the terminal end of a limb within the slot. The limb end has a pointed termination, and a bight. The slot has an arcuately formed portion, in which to nest the bight, and a depression in which to receive the pointed termination. More, the shaft has threading formed thereon, adjacent the slot, with the slot traversing the threads and a shaft-end head. An internally-threaded sleeve is slidably engaged with the shaft, and overlies the slot-nested end of the limb, and threadedly fastens onto the shaft threads, to prevent the limb from removing from the shaft.