I'm not very knowledgeable about coining presses. Are there such things as coining presses that are specifically designed to press details into medals/coins that impart lettering, especially if along the rim of a coin? I found this in my research on South Korean commemorative coin production at the South Korean Mint: "In order to improve the quality of the large denomination coins, a letter imprinter was introduced on May 31, 1986 by Schuler, Germany." Just wondering...
Along the edge? The Presidential Dollars have edge lettering and they use a device such as: FYI, the US MINT does use Schuler equipment too. Here is a singular page that can help you in understanding the minting process http://www.coinnews.net/2013/09/20/...-makes-coins-for-circulation/#photosandvideos
Edge devices can be applied DURING strike or AFTER strike. To apply them during the strike, they need to be in the collar (inverted just like the die) - this is how the reeding gets applied to US coins, via a reeded collar. They can also pass - after the strike - through an edge lettering device (as @Clawcoins shows) that applies the lettering as the coin rolls over it under pressure. US Dollar coins are lettered this way and that's why the lettering can be right-side-up or up-side-down.
Is this how no edge lettering varieties are created? A US Mint employee forgot to place them into the machine?
No, it's not because somebody forgot something. The system is all automated and things move quickly so when mistakes happen it's typically because of mechanical failure of one kind or another. It could be a momentary pressure issue, a few coins simply didn't get picked up by the machine or any other of a long list of possibilities.
But when they are applied during the strike, the collar has to be segmented so that it can open up and release the coin after the strike and then reset for the next coin. This is how the lettered edge is applied to the proof president and NA dollar coins.
No... Along the inside RIM of the coins, on the obverses and reverses of the coins, surrounding the central devices.
the lettering is a normal part of a Die .. one for the Obverse, another for the Reverse. Then a Collar around the edge. Normally a planchet falls into the cavity which has the Reverse (anvil) die, Then the Obverse (hammer) die strikes it. This slightly expands it and it also takes form of the Collar. Then it gets ejected.
I think we might not be understanding what you are asking. Are you asking, "Is there a standardized set of letter punches used to create the letters?" The answer to that is - there used to be. There were letter punches, and each die was hand crafted. This is not the case today - today in the US, dies are created on the computer and then a machine cuts them. The font used may be designed by the sculptor - there is no standard font on US coins.
I just don't know what (literally) "letter engraving machine" (original text: "문자각인기)" means. And no, Korean people don't know what this is. Only specialists familiar with minting operations in Korea would know exactly what this word is in the Korean language. I thought that maybe this same device would be used in minting operations elsewhere. Perhaps this is reference to a type of reducing lathe (pantograph)?
Can you give us some more context of where you encountered this term? (I also don't know Korean, so that doesn't really help me....) A Janvier reducing lathe was used by the US mint until 2008, so it's entirely possible the Korean mint purchased one in the 1980's.
I encountered this quote (in Korean, but translated here): "In order to improve the quality of the large denomination commemorative coins, a letter engraving machine was introduced on May 31, 1986 from Schuler, Germany." This quote is from the South Korean Mint's "50th Anniversary of the Mint" official history. It's from the section of this official history that relates to the developments at the Mint in the 1980s. It mentioned that the Mint installed new minting machinery, including two reducing lathes from Britain (I wonder what British company manufactures pantographs?), as well as several new HME proof-class presses to manufacture the 1988 Seoul Olympics commemorative coins. Then at the end of the paragraph, there is this part about the "letter engraving machine (문자각인기)" 문자 [moon ja]: Letter, 각인 [gak in]: Engraving, 기 [kee] Machine
mlov - To the best of my knowledge every mint in the world uses hubs to make their dies, and has done so for over a century. There may be a few exceptions but I have't heard of any. My point here would be that the letter engraving machine you are talking about is used to make the hubs - not the dies themselves. And there are master hubs as well as working hubs - master hubs are used to make the working hubs. All of that is somewhat immaterial, merely a technicality, in regard to the intent of your question of - what is an engraving machine. In simple terms it's a programmable cutting machine that uses cutting blades to cut the letters, and the coin's design, into the metal itself. That's really all there is to it. In reality they are very common machine shop tools. You can go to any machine shop and see tools that do the same basic things that the machines the mints use - they cut metal. That's all there is to it.
This must be a lathe of some sort that cuts into the matrix die (original die), then? That machine might possibly be a coining-specific piece of machinery if it is made/distributed by Schuler GmbH. Don't you think?
Are the "lettering" hubs cut separately from "central device" hubs, and then hubbed together to make a master hub? Like this (if you can make sense of my poor illustration)?
No, not exactly. And, remember this changed many times over the years. With early US coinage, the engraver made a die. Each letter was its own punch, and the device was a punch. Each detail was hand punched into its own unique die, and then that die was used directly to make a coin. With the reducing lathe, now the engraver would usually work with a plaster mold. The engraver would create the letters, devices, and layout of the coin on a large plaster disc. They would make a metal electrotype, and then the reducing lathe would then reduce that to the size of the coin to make the master hub. This lathe basically had a pin that traced out the entire surface of the plaster mold, and then the machine engraved that in steel. With this technique, the entire hub was created all at the same time. They wouldn't make an individual hub for the letters, or devices. This Master Hub was then used to make a Master Die. (Remember - a hub has raised relief like the coin, a die is inverted) The Master Die then made Working Hubs, and then the Working Hubs made Working Dies. These working dies actually struck the coins. Throughout much of the 20th century, the date and mintmark was left off the Master Hub. A new Master Die was made each year (or, possibly several depending on demand). The date was added to the master die. Mintmarks were then added individually to each working die, as required. I strongly suspect the piece of equipment you are referring to is a reducing lathe, as I've described. Throughout most of the 20th century, this was the standard practice for making coins throughout much of the world.
Watch the video here for a demonstration: http://www.royalmintmuseum.org.uk/e...ies/how-coins-are-made/design-die-making.html
You could perhaps take a look at the line of Schuler minting equipment, to see if anything matches what you are looking for: https://www.schulergroup.com/major/...ing/download_minting/minting_broschuere_e.pdf
Thanks so much for your kind and informative response! I also believe that the piece of machinery that the Korean Mint history document is referring to is a pantograph. Cheers!
