JHi John,
My old one broke - the rollers would not mesh, as the fixing points failed; so I went looking for anew one.
Here it is - I live in England but it will hopefully give you an idea
The picture is upside down to show how it fits into the vice! get the vice in a location where both handles can be turned together, and hopefully some of the horizontal part in the vice as well.
The jaws are 4.5 inches wide, and I now use the foil that is used in aluminum food - its slightly softer than the soda pop cans, so hopefully the machine will last longer. The two handles are a must to assist in keeping the foil straight, my sheets are about 3.25 x 2.5 inches - a bit small, but I can live with that! Anything that is longer is likely to lift in the center, and will fail quicker. We don't have as far as I know any 'gear stock' here that I can buy, if it is steel it will be stronger but I am not sure about the depth of the corrugations.
This one is an
Xcut Mini Paper Crimper XCU2682100
the cost (converted is about $10.
Hope the above helps