@Bert: In the original source, the hero, Sigurd the Volsung, tests and breaks two other swords. Finally he brings the fragments of his father's sword to the dwarven blacksmith Regin who's also his foster father (and made the first two swords) and then when that one, the broken sword, is reforged, he tests by dropping a piece of wool into a river and the sword cuts the wool.

I don't really want a suggestion on how to adapt it so much as how to go about adapting it following Grishka's advice, which is good btw.