A few years ago i dabbled in watchmaking.
After buying a cheap chinese de-magnetizer that i determined would work far better in 240vac countries, I realized that it's the exact same thing as a bulk tape eraser, and dug out of a closet an eraser i bought at a thrift store ages ago because it looked useful. It was designed for reel-to-reel tape. Big electro-magnet. Basically an EI-core transformer that is missing the I and the secondary coil.
this sounds like i am just telling stories at this point, but here goes:
The method is to have a field that is strong enough to magnetize the metal, get the metal right near the source of the field - almost touching. then draw it away slowly.
The concept is that the electromagnet has to be strong enough to magnetize the part, and then you magnetize it. But since this is a coil on alternating current, it switches polarity 60 times a second (in north america and some other regions). So then you pull it further and further away from the source of the field, slowly, so that the magnetization is weaker and weaker.
I use an orienteering-style see-through compass to verify that a given item no longer has significant magnetism.
Once i got a hang of the method, I was able to demagnetize objects as large as a finishing hammer.
A whole rod, though - yeah, start calling machine shops.
Topic: Magnetic conecting rod (Read 2719 times)
