Was looking at another thread that brought a question to mind that has me perplexed. I understand the minting process and have a firm understanding of how most errors come to be. What I don’t understand is how a mark from two different mints can occur on one coin. Does an engraver in San Francisco receive a die that was incorrectly punched with a Denver mark and makes an attempt to correct the err?
Interesting question. The answer may depend on the series and era. As a Morgan collector, I have read that in the case of the 1900 O/CC, the story is that when it became apparent that Carson City would not strike more Morgan's, their reverse dies went back to Philadelphia, and were reworked and sent to New Orleans.
To my understanding, that's sometimes how it works. Sometimes a coin die is punched for a mint that isn't striking any more of a coin, and the Philadelphia Mint tries to obliterate the old mintmark.
There is a certain amount of dies sent to each branch mint depending on the intended amount of coins to be produced. If there is a sudden die failure or the need for more demand. Dies will be re allocated and the need to remove and re punch a die will happen. The other scenario is that someone got over anxious and punched to many dies intended for Denver or San Fran. And the way to fix it is to try and remove it and re punch the correct branch MM.
No. The mintmarks were all punched at the Philadelphia mint. The branch mints did not have the facilities to make or harden dies - the dies were all made and punched at the mother mint. So, a worker would have had to erroneously punch and then overpunch while creating the die. San Francisco then used whatever was sent to it.
That makes sense.... Now mind you, I am not an errors guy. I do see a lot of what the error experts refer to as a “re-punched mint mark”. In that case would the dies be returned to Philadelphia to be heated, re-punched and subsequently re-tempered before being returned to the branch mint?
No. Repunched mint-marks usually happened when the mintmarks were first created. The engraver literally hits the punch with a hammer to create the mintmark - if the hammer bounced, or if the punch bounced, it would create a second image. Also, if the engraver decided he had rotated the letter too much, or put the letter in the wrong spot, he might try again. This all happened before the die was hardened.
This taken from http://doubleddie.com/58201.html "If it was necessary to have a mint mark on the coins to identify the Mint at which the coins were being produced, the mint mark was the final part of the design added to the working die. A die maker at the Mint used a thin steel rod (punch) that had the appropriate mint mark letter engraved at the one end. Holding the mint mark punch in the appropriate position on the working die he tapped the mint mark punch with a mallet to leave an impression of the mint mark on the working die. It frequently required more than one tap with the mallet to leave a satisfactory impression of the mint mark on the die, and the die maker would repeat the taps with the mallet until the mint mark impression was deemed satisfactory." I never new that the coins were heat treated again as it says this is the final step. Thanks for clearing that up @physics-fan3.14 It does make sense.
What it says is that this was the final piece of the design punched into the die. It is much easier to punch a mintmark into soft steel. However, you need hard steel to strike the coins with. So, after all of the design elements were engraved in the die, it was hardened in order to strike the coins. You can read about the entire process in Roger Burdette's book, "From Mine to Mint."
