1)
What function did the sockets serve?
1.
Oznayim la'Torah: It was to hold the boards firm to prevent them from falling 1 - due to the weight of the silver (and bearing in mind that the acacia-wood that they used to manufacture the boards was a light species of wood).
1
See Oznayim la'Torah who dismisses the suggestion that it was to prevent them from rotting in the desert, since in any event, the Amah-long prongs reached the ground - though one could differentiate between where the entire plank stood on the ground to where it was only the prongs.
