Whats your preferred method of putting the magnet in a chop cup.  The only way I can think of is to double skin the whole cup. I know you can crimp it in with a copper disk but that gives that tell tale line around the top of the cup. I am trying to chop a Gazzo cup and I think a thin copper cup should be partially spun the magnet seated and and outer skin spun over the lot. The rolled edge will make this invisible. Its a costly way to do it But I cannot think of a better way. Prehaps Bill Palmer will know.

I like the ones where the inner disc is spun in and extends down into the first ring. That way it "locks" in, and the inside is smooth except for a thin line where nobody can see it anyway. To make it even better, I'd spin all three cups with this disc so they all work and feel the same.

My old Morrissey Combos had a disc spun in this way. They didn't do the other two though so the one chopped cup is obviously heaver and balances differently. If I pass them out for examination I have space them out to be sure only one person gets one cup.

An outer skin sounds ideal, but seems like a lot of extra work to me. This is skinned before rolling the beads I assume? I suppose the bead on the mouth can serve to lock the whole thing in place, maybe with only the one layer being rolled to cover up edge of the skin.

What about putting in a false bottom with magnet underneath?

If you did this, without the magnet in the other two cups, they'd all look alike.

Gary,

I'm pretty sure that Jim Riser has employed this technique.  I know that he made the Ramsey cups in a similar way.

http://www.jamesriser.com/Magic/JohnRamsay/Cup.html

I can't go to the site at the moment because the drool makes a mess of the keyboard...

The trouble with false bottoms is the line between the false bottom and the rest of the cup. Gluing them in is always a problem. Spinning them in so they "lock" into a groove is more secure, but they still have to be tight enough not to rotate inside the cup. Adding false bottoms to all three would definitely help for consistency. You might even want to add a dummy plug to take the place of the magnet in the other two cups so the weight and balance is the same.

Thanks for that, the spun bit down to the first bead sounds a goer. I'll have a play with that and see how it looks. Can you get nice curved disc magnets I wonder.