Jens, you may find the very first thread i posted of this forum of interest:
I have been very interested in this subject for some time. For me, the answer to why magnetize a blade is indeed "sword mysticism" kicking in. The first thing i do when i receive a new keris is to check it for magnetic polarity. Most often it is farly weak or dead, but i have received a few blades with a very strong polarity. But even if the polarity is gone i create it. It is a VERY simple process. I have a very powerful magnet that i place the tip of the keris on, and after reciting a few highly secret magickal incantations
, it is done. I hold the blade there for less that a minute, so it really does not take much. Why do this? Well, i don't use my keris to cut, at least not in the mundane sense.
Polarizing the magnetic flow of the blade increases it's effectiveness as a conduit for energy. The entire universe operates of the interaction between strong and weak magnetic fields. This is occult science gentlemen, so please feel free to roll your eyes.