Wire chamfering, like threading, is accomplished by cutting or rolling. Cut chamfers remove the metal from the corner of the part leaving an angular transition between the two planes. Rolled chamfer pushes the material from the outer diameter in towards the part's centerline creating a "cup" shaped projection on the end of the part.
Advantages of Rolled Wire Chamfers
Disadvantage of Rolled Wire Chamfers
Cut chamfer although more expensive are better suited for parts assembled by customers or where it will project beyond the surface of their mating part leaving the end exposed.