Unlocking the Die Manufacturing Process

Discussion in 'Coin Chat' started by justafarmer, Apr 13, 2017.

  1. justafarmer

    justafarmer Senior Member

    In 1836 the Mint acquired the French Portrait Lathe. Prior to this time the die manufacturing process did not originate from reducing a galvano to create a Master Hub. General consensus is the process began every year with the Mint engraving a new Master Die containing only the central elements of the coin design. This hand engraved Master Die was used to create Working Hubs which in turn was used to create Working Dies. These Working Dies only contained the central design and therefore had to be hand-engraved and/or punched individually with the remaining design elements (date, mintmark, motto, etc) before being used to strike coins.

    This train of thought may hold true for the earliest years of the Mint’s operation. Coin production was a brand new endeavor and coin designs were untested. But engraving a die by hand takes a lot of time, man hours and tedious work. The mint’s primary function was to produce coins and seigniorage not dies. Although seigniorage represents little more than chump change for the Us Government today; early on it was a major source of revenue..

    I am of the opinion the Mint soon realized that a Hub produced from the hand engraved Master Die could easily act as a Master Hub. The Mater Die and Hub it produced only contained the central elements, there were no design aspects transferred to the hub that would prevent it from serving as a Master going forward into subsequent coinage years.. Based on my own personal observations of coinage from this early period the uniformity as to size, detail and etc of the central design in subsequent years is very exacting. No doubt there are deviations from one year to the next in the central design of early coinage. But I am of the opinion these deviations can be explained and attributed as additional engraving of a die or hub.

    So the idea I am throwing out is it was well before 1836 when the Mint adopted the practice of utilizing a hub for carrying a coin’s central design forward into subsequent coinage years.

    The following three images of this post consist of

    1. A CAD tracing of an 1820 Large Cent large date variety also containing the date.

    2. An image of a 1820 Large Cent large date variety with the 1820 CAD tracing overlaid in light blue.

    3. An image of a 189 Large Cent with the 1820 CAD tracing overlaid in blue.

    Both coins selected were minted in subsequent years prior to the introduction of the French Portrait Lathe. The date is not part of the central design – it was hand punched into the working die in a separate step of the die manufacturing process

    Looking at the images of the 1819 and 1820 large cents you can see there are deviations in the central design from one year to the next. But these differences are not of the same magnitude as the deviation in the placement of the date. The date was also a design element hand engraved/punched individually into a die. Why would one hand engraving process be accomplished with such exacting detail from one die to the next while the other hand-worked process didn’t? My guess is because creation of the central design for the two different years was accomplished through a hubbing process bringing an established design forward instead of originating from two different brand new engraved Master Dies.

    No matter which school of thought you agree with. It doesn’t change the fact that prior to the introduction of the French Portrait Lathe the die manufacturing process originated from a hand engraved master as opposed to a Hub reduced from a galvano. Untitled - 2.jpg Untitled - 3.jpg Untitled - 4.jpg
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  3. calcol

    calcol Supporter! Supporter

    I don't know what was actually done in the U.S. mint, but initially creating a master hub might have some advantages over initially creating a master die. The hand-engraving would be to produce relief rather than incuse devices which might be simpler and less error-prone, especially creation of lettering. Working dies could then be produced from the master hub or a master die could be produced from the master hub. Then working hubs and dies would follow.

    Hubs have been used since at least Roman Republican times. A number of ancient hubs have been discovered For example, see: A Hub from Ancient Spain by M. P. Garcia-Bellido and S. Rovira, The Numismatic Chronicle, Vol. 146 (1986), pp. 76-84, and The Hub from Ancient Spain Reconsidered by C. Stannard, The Numismatic Chronicle Vol. 148 (1988), pp. 141-143.

  4. justafarmer

    justafarmer Senior Member

    I considered the idea of the die manufacturing process originating from a hub. I lean against it because an on an engraved hub it would also be necessary to establish the field through engraving. Which I think would create a high probability of establishing an irregular field. This irregular field would transfer and establish an irregular die face.

    When engraving a die - the die face can be established with high precision grinding methods before the engraving process begins. Just my thoughts.
  5. calcol

    calcol Supporter! Supporter

    You could be right. I don't know enough about metal engraving to know how hard it would be to produce flat fields on a hub. Personally, I could do a better job of that than creating devices, but I'm a better machinist than artist. :) The fields wouldn't have to be perfect on the hub. The dies could be polished to achieve that. I think dies were and still are polished after forming with a hub. I've looked in a few references on the early mint and didn't see any pertinent details about hub and die production. Hopefully there is a historical record somewhere.

  6. Conder101

    Conder101 Numismatist

    At the US Mint dies created thru the use of a punch for the central device with the other features being added by individual punches began in 1793. The chain cent obverses were hand cut into the dies but by the time they got to the 1793 half cents and the wreath cent they were already using a positive relief punch for the central bust and hand finishing the hair detail. It is believed that some of the first experiments trying to use a hub (A punch that contains multiple design elements. I consider a punch that contains a single design element to be just that, a punch not a hub. About the only exception to that rule is a four digit logotype punch. Yes it has multiple elements, but I still consider the full date punch to be a punch.) took place with the reverse of a couple of the 1793 cap cents. Using a punch for the bust and central figure of the rev was well established by 1794. The next major experiment on the use of full hubs took place in 1798. The reverse dies of roughly half of the 1798 cents and all of the 1799 and 1800 large cents were made using a hub that contained ALL of the reverse design. But the hubbing presses were not powerful enough and much hand work still had to be done to the dies (adding stems to the berries, some of the leaf stems, reworking the wreath stems and sometimes repunching/strengthening the lettering etc. After those experiments they went back to just punching the central devices and then hand punching the other features.

    It was the steam press that provided the mint with enough power to successfully do full hubbing of the dies. The portrait lathe allowed them to create exact copies of the master hubs, so that when one wore out or broke an exact duplicate could be made. Today we use a single master hub to make master dies, then the master dies to make working hubs, and finally working hubs to make working dies. This allows us to make thousands of working dies from a single master hub. But from 1836 to 1868 we made working dies directly from the master hub and multiple master hubs might be needed in a single year.
  7. calcol

    calcol Supporter! Supporter

    Thank you very much for that info. I'm curious if there are good articles or books on the technical aspects of early U.S. coinage. I'd like to read them.

    It sounds as though once the mint started engraving essentially entire designs by hand, it was the hubs that were created first, then dies. Have I got that right?

  8. justafarmer

    justafarmer Senior Member

    I have always thought of a punch as a tool which utilized a striking force to transfer a design element and a Hub as using a squeezing force. Thanks for the info.
  9. Conder101

    Conder101 Numismatist

    As I mentioned the obv of the chain cents had the busts hand engraved directly into the dies themselves. For the 1793 half cents, wreath cents and Liberty caps they were using a punch that contained the profile and part of the hair. I don't know if they cut that punch by hand as a relief positive or if they hand cut an incuse image and then used that to create the punch. Once they had the bust punch they used it to create the working dies with the hair work then being mostly done by hand engraving into the dies. But even with the chain cents the lettering, chain etc were created using punches. I don't think hand work on the hair ended until the 1795 caps, possibly the 1794 exact head of 95.
  10. red_spork

    red_spork Triumvir monetalis Supporter

    I wouldn't quite go as far as to suggest that the Romans were using hubs. Stannard, in the paper you cite, argued the hub was in fact a forger's tool and nothing more and would have been inadequate for use as a hub by a Roman mint. The Romans' well documented use and abuse of some obverse dies well after they've begun to break suggests to me that the process of creating new dies was a process that could take quite some time and was not as simple as the modern process of using a hub for the job.
  11. calcol

    calcol Supporter! Supporter

    Still, a hub is a hub, whether used by a mint or a forger. I doubt the forger came up with the idea of a hub on his own. I think we still don't know for sure whether and to what extent hubs were used by ancient mints for coin production. See article by David Vagi: "What we still don’t know: Mysteries abound with ancient coins. Ancients Today: Still more unknowns and guesses than solid facts", Coin World, 01/26/17. He believes hubs were used in production of dies for Syracusian decadrachms, far in advance of the Roman Empire.

  12. GDJMSP

    GDJMSP Numismatist Moderator

    Not long ago I asked the question of when a "hubs" (defined as containing the entire coin design) first began to be used by the US Mint. The answer I got was that it was not until the 1870's that that happened.

    Now different people are going to use different definitions as to what is a hub and what isn't a hub. For me, for it to be considered a hub it has to be the whole thing (the entire design) or it's still just a punch. That's because if you have to use more than 1 punch, and couple in hand work, to make a die - then you just can't call it a hub. And it doesn't matter whether you struck that punch with a hammer or used a press of some kind, a punch was still just a punch, even if it contained multiple design elements. And yes, these punches and gang punches that were used hundreds of years before the US existed still exist today. So we know the methodology with certainty.

    The process that Conder describes goes back centuries before the US Mint ever existed. Mints were using punches and gang punches, and hand work, to make each and every die. And it took time, a lot of time. So much time in fact that when a King or ruler died, coins bearing the - bust and name both - of the new King were sometimes delayed for as much as a year, or more - just so new dies could be made and distributed. Sometimes they would even use the previous King's bust and just change the name on the dies - merely to speed things up a bit because they still had to mint coins. Waiting was not an option. And that was the case until the late 1800's, at the most advanced mints in the world.

    And it is for reasons like that that I define a hub as I do. For it was only with the invention of hubbing that problems like this were able to be overcome. And yeah, sure they knew about the process of hubbing, had for hundreds of years, they just couldn't make it work until then.
  13. calcol

    calcol Supporter! Supporter

    So, even the mint mark has to be there to fit your definition of a hub?

  14. justafarmer

    justafarmer Senior Member

    I am not trying to change definitions. All I am saying is it never occurred to me that a requirement of a Hub is it had to contain the whole design. But I have always considered the date as part of the design and that element wasn't added to US coinage Master Hubs until the 1900s and only part of it then. So I just always incorrectly associated the difference between a hub and a punch being how they transferred their design elements to the die as opposed to what design elements were transferred.
  15. GDJMSP

    GDJMSP Numismatist Moderator

    No, nor does the date. Both of those change so they were quite intentionally left off of hubs for many, many years once hubbing became the general practice of die making.

    My point is that using a punch that has the entire bust on it for example is not a hub. Nor is a punch that has a left, right, or both sides of a wreath, nor any other portion of the design. They are still punches, not hub.

    One of the other factors that helps define hubbing is that hubbing is done by machine - not by hand. That is because it is incapable of being done by hand, and as Conder pointed out, it was even incapable of being done by crude machines. Even after steam presses were invented in the late 1830's it was still another 30 or more years before hubbing was incorporated into the die making process for it took them that long to get hubbing to work properly.

    Now if people want to call using gang punches hubbing, or bust punches, or partial design punches hubbing - fine call it what ya want. But it isn't hubbing, it's still just using punches.
  16. TheMont

    TheMont Well-Known Member


    You gave and excellant explanation of the die production method used by the U.S. Mint. May i have your permission to reprint it on my Coin Club website's monthly Blog?
  17. calcol

    calcol Supporter! Supporter

    I think we're pretty much in agreement about the definition of a hub. I'm not so sure dies could not have been created from hubs before the 19th century. Starting backward from the planchet, a die has to be of significantly tougher material than the planchet. If the planchet is hot silver or gold, the die could be bronze, and pounding the dies between a hammer and anvil would be enough force for striking a coin. For creating a die from a hub, the hub has to be of significantly tougher material than the die at the time the hub impresses the die material. Could the ancients harden an iron/steel hub sufficiently to create a die in a heated slug of bronze with the force from a slinging sledge hammer? I dunno, but they could certainly create bronze coins by slinging a sledge on (presumably iron) dies with a heated bronze planchet between them. So why couldn't they use an iron hub to create bronze dies?

    It's also possible that bronze dies could have been created by a casting molten bronze on to an iron "hub". However, I would not consider the process to be hubbing.

  18. justafarmer

    justafarmer Senior Member

    Mont - thanks for the compliment.

    I don’t mind you using my post for your coin club newsletter but I would advise against it. It is based on a flawed assumption taken on my part as to the difference of a Hub vs a Punch. Therefore the manner it disseminates the die manufacturing process information is incorrect.

    I have always differentiated a Hub from a Punch by how the different tools transferred their design elements to the opposing die. I made the assumption a Hub was a tool that utilized a pressing/squeezing force to transfer design elements and a punch utilized a striking/hammering force to transfer a design element.

    I have now learned the difference between the two is based on the extent, how much, of the coin design they transfer to the opposing die.

    Cloud in a later post of this thread gave a good explanation on the Mint’s use of a punch for carrying the central design forward into successive years. If the tool was designed to be installed into the screw press for the purpose of squeezing the design into the opposing die, then I was incorrectly making the assumption it was a hubbing tool. If the tool was designed to be struck by another tool as the means for transferring the design to the opposing die, I was classifying it as a punching tool. But as it turns out none of this matters – either way both are punches.

    But I do think the images do a good job of illustrating how much a coin design can deviate not only year to year but working die to working die.
  19. halfcent1793

    halfcent1793 Active Member

    It's a bit of a chicken and egg question as to whether the Mint began with a hub or a master die in 1793. So few 1793 cent hand half cent dies were created that it may not have been worthwhile to create a master die and then try to make hubs from that. The engraver may just have created a hub like a cameo. We just can't be sure. The quality of the die steel was poor. However, Robert Scot wrote in 1795 that his procedure was to engrave a master die and make hubs from that. So, there is no question that hubs and master dies were in use WAY before 1836.

    With respect to the overlays in the original post, my experience is that overlays of photos that were not taken at the same time with the same lighting can be hard to align, but that isn't evidence the dies were not created from hubs/master dies.
  20. Conder101

    Conder101 Numismatist

    I think what Scot was doing was making device punches (even though he called them hubs. You have to be careful with terms because sometimes they did call punches hubs.) because no full design hubs were used for sure before 1798.
  21. WFN

    WFN New Member

    Chief Engraver Robert Scot wrote a four page report to Congress in late 1794 (probably submitted 12/20/1794 with the Treasurer's report) that describes the die making process. Scot's report was the most comprehensive engraving description in the first thirty years of the US Mint - very little engraving process data was actually recorded. This report was mentioned by Don Taxay, but was first published in full in my article in the August 2012 John Reich Journal. I also have the full text in my Scot biography Robert Scot: Engraving Liberty.

    Here is an excerpt, courtesy of the National Archives in Philadelphia, from my research in 2010. The "original die" (master die) and "hubb" had just the central device (Miss Liberty and Eagle on silver and gold), while the lettering, date numerals, stars, dentils, and a few other elements were engraved or punched in the working die - with the exception of a few experiments. Scot also described the great difficulty in the annealing, hardening, and tempering processes, which often cracked dies before any coins were struck. The original die had to be hardened, and the hubb blank annealed (softened) in order for the steel to steel design transfer to occur.

    Robert Scot to the Congressional Committee on the Mint:

    "Before a Die to strike money can be made, the previous step is to Engrave an Original one first. The execution of that of the head of the Cent will take four or five days, and if it is hardened with success, a Hubb is struck out of it (that is an impression in steel) but if otherways, which is not unfrequent; it is to begin de novo. The Original Die being compleat, and Hubb struck; by failure in hardening it, it becomes useless immediately, or very soon so. On the success of these processes and that of a good clear and distinct impression in striking the Hubb, depends on the celerity with which the Dies that strike the money can be finished, for they are struck with the Hubb previously thereto."

    I will try to post an image of the actual letter for this excerpt in a day or two.
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