20 Super-Powerful NEODYMIUM Magnets for Experiments Start Price USD 7.99 Current Price USD 8.50 Time Left - Bid Count 2 Buy It Now Price - Reserve Price - Start Time Monday, November 17, 2008 End Time Monday, November 24, 2008 Location Acton, MA See more about '20 Super-Powerful NEODYMIUM Magnets for Experiments ' Description   Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 20 Super-Powerful Neodymium Magnets   Description: This auction is for 10 sets of 2 Neodymium magnets.  The magnets are from server hard-drives, so they are much higher quality and strength than normal hard-drive magnets.  They are all from identical model hard-drives, so the magnets themselves are also identical making them much easier to work with and set up experiments with.  These magnets are about the strongest magnets possible.  They are made to extremely tight specifications to compact the highest possible field energy into the smallest space.   Consequently, each magnet has a field of about 1 Tesla, which is just amazing.    These are great conversation pieces. These magnets are used to control the movement of the Hard Drive reader arms, which have a small electromagnet in the back.  The stronger the magnet, the less likely kinetic energy will move the arm away from where it should be.  The magnets are actually split in two and have two of each pole.  Incidentally, the metal that the magnets are attached to is called Mu-metal.  It’s an alloy of 75% Nickel and 25% Copper with a small amount of Molybdenum.  It is anodized in a special process with elemental Hydrogen to make all of the grains arrange in the same direction giving it its unusual properties.  It is mildly magnetic, but it is one of the best magnetic shielding materials in existence.  For this reason, the magnetic field does not extend out of the hard-drive and cause stuff to stick to your laptop.  This also means that even though there is a powerful magnet on each side of the metal, the magnetic assemblies don’t really stick together well and are easily separated.     Just a few warnings.  These are extremely powerful magnets.   They will pinch skin that is caught between them.  They can also easily erase the hard drive of a computer so don’t let them get within 5 feet of a computer or CRT.      I would also not suggest giving these to kids just to be safe, plus they require a fair amount of force to separate so they probably would find them much fun anyways.      In the picture I have taken apart one magnet assembly to show what it looks like inside.  The magnet assemblies are held together only by the magnetic force and can be carefully separated with a screwdriver. I will ship them attached in their assemblies so they don’t stick the box to the floor of the mail truck.  Good luck bidding!   Shipping: I guarantee FAST SHIPPING with all my auctions.   If you pay using PayPal the Monday after the auction ends, they will be in the mail Tuesday to get them to you as fast as possible.   These need to be shipped in a thick box so they don’t stick to anything so the final weight will be about 4 pounds.  If you live outside the continental United States please email me so I can figure out shipping beforehand.  I will combine shipping on multiple items to save cost.    Payment: I prefer PayPal.  Due to an increase in non-paying bidders, if you have less than 10 feedback, you must email me first to confirm that you will pay.   Place a Bid!