"Please take a number and queue up before answering"
You pose a very interesting question on blade magnetism.
I have for the last week or so been testing my wootz daggers for magnetic fields. One I call the Mysore dagger has some very unusual properties (at least to me that is ) starting at he hilt end of the blade a compass will change direction four times! with the needle pointing N then S then N and then S again at the tip of the 12" blade. I have no idea as to how this magnetic properties were "added" to the blade or for what reason if in fact it was done knowingly at all. I have two Wootz ingots that are original ( not forged into a blade ) that show no such magnetic properties, which would lead one to believe that the magnetic properties were "added" after the blade was completed.
I am in the process of working up a visual display of the magnetic fields on this dagger and will post pictures when and if it works out.
Again you pose a very interesting subject/question, you do have a tendency to ask hard questions.