At 16:33 10/1/2004, Gnarlodious wrote:
>  What you get is a torus shaped magnet of any size you can scrounge, some
>huge, some small. The largest is 4 inches in diameter. I have several in my
>van for keeping track of things, including a homemade cupholder stuck to the
>dash.

There are a couple of small but *extremely* serious magnets in every modern
hard drive -- you'll find them stuck to the inside of the steel cage
surrounding the "voice coil" attached to the head arm.  They used to glue
them on, but I don't think they typically bother anymore, having them stay
put is really not an issue.  In fact they may well be holding the whole
cage together.  Couple of those inside a Kleenex box will nail it right
down....

The ones in notebook drives are probably about 3/4 x 3/8 x 1/8 or so,
curved to match the sweep of the coil.  Nickel plated or coated with epoxy
or some such, as they really don't want little magnet chips getting loose.

T-6 or maybe T-5 driver is pretty likely for getting the notebook drives
apart.  Nokia  5100/6100 phones are T-6 so places that sell customizing
gear for them will have T-6 drivers for sale (and Home Depot has two Husky
(house brand) combination drivers -- Red top is #1, 0, 00, 000 Phillips and
1/16, 5/64, 3/32, 1/8 flat; Black top is T4, 5, 6, 7, 8, 9, 10,
15.  Excellent, if you modify them by tossing out the internal divider so
all four bits can stow inside.  Not free, but perfectly reasonable for the
quality.

Also -- the platters on any hard drive are *extremely* flat -- the head
flies a few micro-inches off the surface -- and have hard reflective
sputtered surfaces*.  Modern ones are quite likely glass as aluminum wasn't
stiff enough.  Also the rings separating the platters are excellent small
parallels (as are wheel bearings on a larger scale).  The couple notebook
drives I've opened had steel rings, a lot more durable than aluminum.

* Early ('80s) drives had platters spin-coated with iron oxide in varnish
just like a tape or floppy.

david

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"