Glenarvon
Executioner
About alternative crucifixion tools...
This "nail" is an unusual relic conserved in Milan. He's a complex object with a central nail and many rings.
Local tradition tells it's a nail of Jesus cross. Of course, it's not so, but it's probably a roman tool of II-III century, perhaps used for crucifixions.
I think basically it functions as a belt buckle. The nail (actually a sort of blade) must be inserted in the back of the hand, but body's weight is mainly supported by the cuff.