metal bracket on hard drive magnets ? - Page 3

The magnets do have dual polarity with North on one half and South on the other half of the same side. You can test this if you use a regular magnet like a refrigerator magnet on each end of one side. It will attract on one end and repel on the other. Please explain your claim of one directional magnetic field though, as I can easily stick one of these magnets to my table on either side when it has no bracket.

if you hit the bracket with an xrf gun it will show up as 80 percent nickel but if you grind the coating away it shows 100% iron.

I wouldnt be so sure they are just nickel plated iron. I do agree that iron is a great magnetic flux carrying element, but thats not what the brackets are used for. Apart from being an alignment and mount for the magnet, it reduces the EMF from the back side of the magnet, affecting the other working components of the drive. Strong magnetic fields can upset the electronics in the logic board which wouldnt be a good thing for reliability.

Something I noticed was that the thicker (and thus stronger) magnets have a correspondingly thicker backing plate (excessive for just mounting). And likewise, the thinner less powerful magnets had much thinner brackets. I do believe that they act as a magnetic flux shield, reflecting the flux rather than carrying it anywhere, reducing unwanted flux leakage.

Only a few parts of hard drives are iron alloys, which is a bit of a giveaway (to me anyway) that unwanted magnetic flux transfer, induced from ferrous metals are either avoided or limited in their use.

I love proving myself wrong, and melting the brackets down will tell me a lot about what this metal really is. If its an alloy, then its melting temperature will shed some light on its composition to start with. That said, the sound they make when tapped is just too different than common steels, like comparing the ring of a crystal glass to a tomato juice bottle.

currently there is no such thing as a "mono-pole magnet" if you find one let me know, we can split the Nobel prize in physics.