Re: Magnetic Field in a Flat Spiral

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "David Sharpe by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <sccr4us-at-erols-dot-com>
> 
> Paul N., All
> 
> NIB - Neodymium-Iron-Boron Rare Earth Magnets.
> One supplier is Edmund Scientifics in USA. Used
> them as a suppler for work, recommended.
> 
> <http://www.scientificsonline-dot-com/>http://www.scientificsonline-dot-com/
> 
> Relatively inexpensive for the extreme power of these
> magnets.  Edmunds stocks various sizes and shapes
> most prevalent are rectangular or disc shaped.

	Edmunds has a good stock, but at very high prices.  Wondermagnet
(www.wondermagnet-dot-com) has a good selection too, at much lower prices. 
They have some interesting things like small spherical magnets, again at
pretty good prices.  Their web site has interesting links and also
possible experiments which can be performed with magnets.  I haven't
bought anything from them, but my friends who have report complete
satisfaction.  All Electronics (www.allcorp-dot-com) often has some good
magnet buys too, and I have a lot of their magnets around the shop
here.  Another source of really cheap magnets is swap meets, but that
takes more work on your part.  Finally, Radio Shack has some need little
disks which are great for static magnetic levitation demonstrators. 
Less than a buck each.

> Watch the warning(s) on these magnets, they nearly
> 10X more powerful then old school alnico magnets!
> They can destroy credit cards, FD's, and with higher
> power units, can remove skin from fingers/or cause
> blood blisters, when contacting magnetic steel.  Some
> units removed from old HD are so powerful they can
> not be pulled normally apart, they must be slid apart.

	How true!  There has been one of the head drive magnets from a very old
IBM head drive stuck to my Mosler safe for a couple of years, and even
stayed there during a 20 mile move!  Will eventually have to slide it
off, but that's hard because of the rough finish on the safe, and there
will be ugly scratches when the deal is done.  King Kong might be able
to pull it off with his fingers, but I don't think there's a man alive
who could.

> Wear safety glasses, they are brittle and can shatter
> like glass.  Having a super magnet sliver in your eye
> is something I don't want to ponder...and has
> happened to other folks in the past.  Consider what
> happens in that event when you walk by a steel door
> trying to get medical assistance...enough said.

	The dust is highly flammable in addition to the mechanical problems
with the splinters.
 
> <<Off topic shield down Terry!!!>>   :^)
> 
> Regards
> Dave Sharpe, TCBOR
> Chesterfield, VA. USA

Ed

P.S. To perhaps get this by Terry, I suspect that some of these magnets
could be used as very effective magnetic blow out devices for spark
gaps, and would sure like to encourage someone to give it a try and
report the results here.  Should be reasonably easy and cheap to get at
least a couple of thousand gauss across a 1" gap.