On Apr 20, 16:04, Chuck McManis wrote: (The Zinc isn't a hard metal and it's only weakly ferromagnetic (doesn't stick to a magnet). The nuts you found are zinc-plated steel, probably what we call BZP (bright zinc plated). Soft iron sometimes has quite a high carbon content, and a very variable silicon content (which affects its magnetic permeability). The composition of "soft iron" varies quite a lot, whereas although different types of steel have different compositions, the composition of any given type is fairly standard (and in some cases very precisely controlled), and usually quite low in silicon. -- Pete Peter Turnbull Dept. of Computer Science University of York