How does shelf doubling on modern coins happen?

[CoinZip]

Can anyone explain what is going on during the minting process to make this (rather cool looking) effect?

 

[Mr.Mcknowitall]

Can anyone explain what is going on during the minting process to make this (rather cool looking) effect?

 

 

I never saw that kind of "tripling" before.

 

BTW, what was this terrible Show I heard about? Was it due to the Scarsdale diet?

[RWB]

If you will look in the book From Mine to Mint you will find a discussion of how this common problem occurred prior to the introduction of horizontal presses. The same thing can happen with a horizontal press, but multiple ledges are more likely due to the speed of the press and very short stroke.

[CoinZip]

RWB I don't have your book, sorry.

 

Do you think loose parts as in the dies, collar, or some other part have anything to do with the process?

[Mr.Mcknowitall]

RWB I don't have your book, sorry.

 

Do you think loose parts as in the dies, collar, or some other part have anything to do with the process?

 

Of note, an individual had 20+ examples of the coin, with the same effect, and same finish.

 

 

[RWB]

You can borrow the book from the ANA library or your local library via ILL. Wizard Coin Supply and others sell the book.

 

The collar was a metal plate with a hole in it. In some presses it moved and in others it was fixed.

 

PS: Yep, I could give you the info. right here and now...but maybe you will pick up the book and read about a lot more than just this one tiny subject. You will have learned far more than from reading any post from me or anyone else.