Ask Jeeves - S10-E6
Trivia: This episode is a nod to the game Clue. Each weapon appears in a shot. Dash grabs the revolver. Dean grabs the candlestick, wrench, lead pipe and rope. Phillip was stabbed by the knife. Also there is six people invited to the party, three men and three women, referencing the guests who usually attend the Clue game party.
Answer: Angel blades come from angels. It's their angelic magic that makes it special. Therefore, an archangel blade is made magical with the powers of an archangel. They couldn't have just created one or used one, as none of them are archangels.