Ever now an then you will read on here of someone's alternator rotor with the glued on permanent magnets throwing a magnet. Some have even talked out some oils messing with the glue... My opinion is forget that problem unless someone who has not a clue what he is doing hits it with a BIG hammer. I was doing some nailing out side on my fence and the wood is hard and brittle. My friend let about 6 or 7 nails get away and after looking in the grass for a while I went and got my magnet on a stick. (my lawn mower has air in it's tires--so can't be too careful. Well, my old rotor that the spline gone is lying there and I get the grand idea to just knock the magnets off and make my magnet stick a foot wider. Got my maul and a big screw driver and gave it a wack..nothing. answer wack, this time with it wedged between them. A piece broke off. After about 5 more wacks and magnet pieces flying all over the place, I rolled it over on its diameter and smacked it big time. Three magnet popped off with a fine line of it still glued on.....Just like wood glue, the bond is stronger then the material..

 

Never messed with those magnets but have pulled quite a few from old hard drives. Those are some seriously strong magnets in hard drives. I even put one on the bottom of my bike frame to help with tripping light signals at intersections.

 

I have known it to happen. Happened to a buddy of mine on his '02 Ultra. When it let go, the corner of the magnet caught the stator, sheared the four screws holding the stator in place, and spun the stator. The visible clue to what had happened was that the stator plug had disappeared inside the motor!

 

5 1/4 floppy drives..they are all gone but that is what my nail picker up is made from. Do not ever make the mistake of getting your finger between it and fridge.

 

I got ahold of a few of the real old monster IBM mainframe hard drives that where the size of a Briggs 5 hp motor , magnets in those things are unbelievable you can't pull one off flat and don't get the fingers in the way under 4 inches from steel they will pull that far away . Used 2 of them to hold a fender and the internal struts together while I welded things up when I did a strutless wide fender for a guy .

 

Now those are some serious magnets.