ET,
nope. I've tested more than 45 knives against the SAME computer monitor. Different kinds of steel (you know the types that Spyderco use...), different models, etc. Only SOME of the knives show this phenomenon. But I've not yet seen a NEW blade with this property... (Anyone out there with a Just-Out-Of-The-Box, unused Spydie that sees the magnetic effects? PLEASE post if so, it will support the explanation given later in this post!!)
I've spoken to a metallurgic expert working in the same company as I. He suggests that the knive where we see the magnetic effects, MIGHT have come like that from the factory... It might even have been a property of the ORIGINAL blanks used for the blades.
He says that the higher the Rc (Rockwell hardness, C-scale) of the blade, the higher the magnetic retention ability of the metal. We all know that Spyderco blades lie in the order of 58 to 62 Rc, which is at the top end as far as knives are concerned. He also says that during the manufacturing process of the steel, certain so-called "magnetic particle crack tests" are performed to check for cracks in the steel (due to various reasons). In order to do these tests, the metal is magnetized, the test performed, and afterwards the metal is de-magnetized. He feels that the de-magnetization process might possibly not be good enough, and that stray magnetization is left in the steel. All this is BEFORE they even start making a blade out of the steel... And usually only spot-checks are performed...
This method is also used AFTER production. Now, I don't know whether Spyderco tests for cracks in the production pieces using this method. I would think that SPOT CHECKS are carried out, which might explain the frequency of the reports that we see in this thread concerning Spydies with (partially) magnetized blades...
Frankly, I couldn't come up with ANY better explanation myself.
Once again, we'll need to get Sal's inputs on this issue.... Sal? Any ideas? Please shed some light on this interesting 'phenomenon'!
