Conder mentioned that the hammer die is often the obverse die; this implies that the reverse die could be the hammer die as well and it got me thinking... question: Is this something that only mint employees would know or is there verified examples of this happening and what would be the reasoning of switching places of the hammer and anvil dies?
Anvil Die: "I'm fed up with you beating on me all the time. It's my turn! How do you like that?" Hammer Die: "Ouch! Ouch! I'm calling the cops. That's domestic violence." Chris
Then you haven't been paying close enough attention, I do mess up sometimes. Usually a given series will have the dies installed the same way for the whole series or at least for a given year in that series. There are times when the obv/rev, hammer/anvil relationship does change during a series run. It is possibly to tell which way the dies are placed in the press. For the series by looking for misaligned die coins. The anvil die can never be misaligned by more than just a very small amount because it is restrained inside the collar. The hammer die on the other hand can be noticeable (and sometimes far) off. On individual coins you look at the edge of the coin. The collars are typically NOT completely smooth and after striking, when the coin is pushed up out of the collar, any irregularities on the surface of the collar will result in scrape marks on the edge of the coin going in the direction on the side that is the anvil die. On coins with reeded edges this will also often result in little ridges or rolls of metal on the anvil die side along the bottom and edges of the reeds. As to why they would change the positioning, I don't know, but I would suspect it would be done after a change in the hub or die relief in an attempt to get better filling of the dies.
Would changing die positions also extend the lifespan of the dies? For instance, Hammer die starting to deteriorate from too many strikes; by making hammer into anvil, give that die more serviceable lifespan as opposed to it staying as hammer until it fails? Inquiring mind wants to know.
No because the two are not interchangable. A die made to be used as the anvil die can not be used as a hammer die and vice versa. The necks of the two are different lengths. The anvil die has to have a longer neck because it stays inside the collar at all times but has to push the coin up out of the collar at the end of the strike. The hammer die has a shorter neck so it can come completely out of the way to let the feed fingers pass between it and the collar to push the struck coin away. If you put a hammer die in the anvil position, after the strike when it raised up the coin would not be completely out of the collar and would be damaged when the fingers tried to push it out of the way. An anil die in the hammer position would not leave enough room for the figers to operate, and might not even come completely out of the collar.