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Source for NIB magnets
---------- Forwarded message ----------
Date: Wed, 1 Oct 97 15:36:00 EDT
From: Gary Lau 01-Oct-1997 1508 <lau-at-hdecad.ENET.dec-dot-com>
To: tesla-at-pupman-dot-com
Subject: Source for NIB magnets
>If you are looking for very strong magnets, you might try
>Neodymium-Iron-Boron permanent magnets. They are probably the strongest
>permanent magnets you can buy. I have seen these magnets attract dollar
>bills (metallic ink) and magnetically suspend liquid oxygen, which is only
>paramagnetic.
>
>Although I am unsure of how you might direct the field (perhaps pole
>pieces), their strength is unbeatable if you can design the gap-magnet
>combination to take advantage of it.
>
>They can be bought from Edmund Scientific (overpriced, but I know they
>carry NIB magnets). They are probably available from other
>scientific/educational companies, so you might want to call Fischer
>Scientific, Central Scientific, or any other of which you know. Sorry, I
>don't currently have an Edmund Scientific catalog. I believe Edmund is
>located in New Jersey.
A cheap/free source of these magnets is from junked brick-sized hard disk
drives. The magnets are used to move the head assembly across the
surface of the disk. The bigger the drive, the bigger the magnet, though
I'm not familiar with the older drawer-sized jobs, these might be
pre-NIB-technology. The pole pieces must do a remarkably efficient job
at containing the field so as not to corrupt the disk data. Just be very
careful when trying to remove the magnets from the pole pieces. They are
glued with some very tough glue. ANY attempt at whacking them off or
even gripping them in a vice will instantly shatter the magnets, they're
brittle like ceramic. Better to try to slowly bend the pole pieces in a
vice or arbor press so they peel away from the magnets. Then, keep your
fingers out from between them!
Gary Lau
Waltham, MA