OK, make a 'U" shaped piece of steel, kind of like an old horseshoe type magnet. And place one of the magnets on the inside of each leg of the 'U'. After placing the first magnet you'll probably need to put a piece thin wood or plastic (paint stick?) on it to allow the second one to be put in.


Kind of like this, where the red is the magnet;

ll ll
l_ l

 

My current fixture is actually made of paint sticks, and glued up with Elmer's carpenter glue, so it won't come apart without breaking. I can salvage the magnets, but I'll have to build another fixture, so it will take some time. Thanks for the input.

 

I can't follow. Are these disk magnets polarized along the central axis? That's the "normal" arrangement and you can stack them as you say without concern for their rotation about that axis. If you turn one pancake over, then it repels. Is that right?

That's correct. Of course, I am not using the disks, but the hard drive magnets that I am using are made the same way as to their polarization.

ETA: Further experimentation indicates that the curved magnets actually have four poles; see the next post.

 

Here's some more information about the magnets that I have available. See the attached photos.

As you can see, the four magnets are curved; I have three different sizes. Each magnet seems to have four poles: a north and a south on one end, and a south and a north on the other end. This makes them stack or arrange themselves to each other in a particular way, and it makes it hard for me to know how they should be arranged for best performance in my project.

 

Put cr1 and cr2 end-to-end to make a sort of horseshoe shape. Then send the coin between them. Just remember to think of magnetic fields as electric circuits (it needs a return path that is narrowly defined (like a spark plug). Otherwise it will make its own diffuse return path. Iron is great at inducing a magnetic field to travel a specific path.

The more concentrated your magnetic field is, the more lines of flux you will have and more eddy current you will create in your conductor.

Also, the faster the conductor breaks lines of magnetic flux, the more current will flow (and stronger eddy currents).

Finally, the better conductor will result in more current, more eddy current.

 

Here's some more information about the magnets that I have available.

Hmmm... I think you'll have better luck with better magnets, something like these for instance.

 

Tracecom,

Don't mean to distract you from your current train of thought and project, but I just searched for other sorting methods. I don't know exactly how it works but this video is very interesting. I am guessing it is an inductive method, just a little more refined than a paint stick shoot (no offense intended, this guy really put some time into it though).

YouTube Penny sorting video

 

Tracecom,

Don't mean to distract you from your current train of thought and project, but I just searched for other sorting methods. I don't know exactly how it works but this video is very interesting. I am guessing it is an inductive method, just a little more refined than a paint stick shoot (no offense intended, this guy really put some time into it though).

YouTube Penny sorting video

I saw that and wondered how he is sorting. I thought it might be by weight; a zinc penny weights 2.5 grams compared to a copper penny, which weighs 3.11 grams. I don't see any wires going to the drop mechanism to indicate inductive testing. Notice that he has some nuts that may be used as balance adjustments.


ETA: Yes, it's by weight. Here's the manual. http://www.jmdaniel.com/owner's_manuel.htm And attached is a picture of his balance beam; I think I could make that out of paint sticks or something similar.

 

ETA: Yes, it's by weight. Here's the manual. http://www.jmdaniel.com/owner's_manuel.htm And attached is a picture of his balance beam; I think I could make that out of paint sticks or something similar.

Ok, I gave him too much credit. From the photo in your link, it looks very much like also built a paint-stick project.

 

Actually, I like it...and it seems to work.

 

Actually, I like it...and it seems to work.

I like it too. I just thought it was much more "refined". I am just surprised it really works with the paint-stick seesaw method. It is so simple and seems to work really well with little effort from the user.

 

Mankind has been using relative balances for longer than recorded history. They work!