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Information request - Class 9 Doubled Dies - Definition
Here is a great explanation that includes snippets on annealing and their purpose. It is important to also remember that the dies were annealed inbetween hubbings as well as the coin blanks/planchets.
If after reading this you have specific questions, let me know and I will do my best to address them.
Thank you very much Bob! This informative article answers my question about how the blanks are annealed, but the order in which that happens is totally different from what I was imagining and I have one part of the process that I am not understanding (the very last part).
So the order is like this (for Copper coin production - I am assuming since I thought I read that copper plated zinc cents do not go through the annealing process)
1. Blanks are punched from the coil of metal
2. The blanks are conveyed to an annealing furnace and heated to around 1700 degrees
3. The blanks are "quenched" which is described as "pickled" passivated (lightly coated) in dilute sulphuric acid prior to the Oakite and soap chip wash. This process takes 1 to 1.5 hours depending on the metal and denomination size
4. The blanks are dried and burnished to a high luster to prevent water spots and to smooth the coin surfaces
5. Then the blanks are fed down a path to the upset mill where the rim is formed and at which point the blank becomes a planchet and is then fed down to the striking chamber. At this point the planchet is still a bit warm.
... then the article says... "If the planchet is destined to be a cent, it is at this point that the copper coating is put onto it" - that loses me, I thought the article was referring to 95% copper 5% zinc alloy metal. I thought that the 97.5% zinc 2.5% copper (Copper Coated Zinc) planchets that come from an outside source (which are not annealed) are already copper coated.
Thank you very much Bob! This informative article answers my question about how the blanks are annealed, but the order in which that happens is totally different from what I was imagining and I have one part of the process that I am not understanding (the very last part).
So the order is like this (for Copper coin production - I am assuming since I thought I read that copper plated zinc cents do not go through the annealing process)
1. Blanks are punched from the coil of metal
2. The blanks are conveyed to an annealing furnace and heated to around 1700 degrees
3. The blanks are "quenched" which is described as "pickled" passivated (lightly coated) in dilute sulphuric acid prior to the Oakite and soap chip wash. This process takes 1 to 1.5 hours depending on the metal and denomination size
4. The blanks are dried and burnished to a high luster to prevent water spots and to smooth the coin surfaces
5. Then the blanks are fed down a path to the upset mill where the rim is formed and at which point the blank becomes a planchet and is then fed down to the striking chamber. At this point the planchet is still a bit warm.
... then the article says... "If the planchet is destined to be a cent, it is at this point that the copper coating is put onto it" - that loses me, I thought the article was referring to 95% copper 5% zinc alloy metal. I thought that the 97.5% zinc 2.5% copper (Copper Coated Zinc) planchets that come from an outside source (which are not annealed) are already copper coated.
I agree, something doesn't jive here. Copper plated zinc planchets arrive at the Mint pre-manufactured. This information is pretty old. Maybe the way they do things has changed.
All opinions expressed are not necessarily shared by willbrooks or his affiliates. Taking them may result in serious side effects. Results may vary. Offer not valid in New Jersey.
I agree, something doesn't jive here. Copper plated zinc planchets arrive at the Mint pre-manufactured. This information is pretty old. Maybe the way they do things has changed.
Maybe so Will, but could there be some confusion here because the writer of this article said he knew that TN produced planchets for the Mint and the process is the same but takes place in a different location.
And by saying this, the writer appears to be stating that the copper plated zinc planchets go through the same "annealing" process at the TN location where they are manufactured.
I wanted to go back and study the different classes of hub doubling before I jumped in here and have kind of caught up. Besides the class nine, I also have a problem wrapping my head around class 5, pivoted. Can someone explain the actual strike and how the coin is constricted from movement and is there a similar or different process for the hubbing. I know there is a collar for the actual coin strike but how is the hubbing constricted? This is what is giving me a problem with the pivoted doubling, I would think this would require quite a bit of movement between the hub and die.
The cent blanks/planchets are annealed at the location where they are made prior to the copper plating being applied.
So, are you guys saying that with cents, that the entire process is now contracted and the only thing actually done at the mint is the actual strike?
No Jon. The designing die making and hubbing is also (still) done at the mint. The only thing not done there is the production of the copper coated zinc planchets.
Bob Piazza
Former Lincoln Cent Attributer Coppercoins.com
Jon ....hubbing includes the impression of the coins design into the blank die. Ater the initial impression, the die is annealed to make it a bit softer for the subsequent impression. If everything is not aligned perfectly for the second hubbing by use of keyways then this is where the doubled die happens. The second hubbing is not perfectly aligned with the first hubbing. In the case of the Class 5, the second hubbing is pivoted one way or the other from the first hubbing. This pivot point is near the rim versus the center of the hub. This will leave the secondary impression which in some cases can be major. This info is available from multiple places including Wikipedia:
Class 1, Rotated--A class I doubled die results when the die receives an additional hubbing that is misaligned in a clockwise or counterclockwise direction. Class 2, Distorted--A class 2 doubled die results when the hub's design moves toward the rim between hubbings. Class 3, Design--A class 3 doubled die results when a hub bearing a different design stamps a die bearing another design. Class 4, Offset--A class 4 doubled die results when the die receives an additional hubbing that is misaligned in an offset direction. Class 5, Pivoted--A class 5 doubled die results when the die receives an additional hubbing that was misaligned via rotation with a pivot point near the rim. Class 6, Distended--A class 6 doubled die results when the die receives an additional hubbing from a hub that was distended. Class 7, Modified--A class 7 doubled die results when the hub is modified between the die's hubbings (e.g., a design element was chiseled off). Class 8, Tilted--A class 8 doubled die results when a die and/or hub is tilted during a hubbing.
Jon ....hubbing includes the impression of the coins design into the blank die. Ater the initial impression, the die is annealed to make it a bit softer for the subsequent impression. If everything is not aligned perfectly for the second hubbing by use of keyways then this is where the doubled die happens. The second hubbing is not perfectly aligned with the first hubbing. In the case of the Class 5, the second hubbing is pivoted one way or the other from the first hubbing. This pivot point is near the rim versus the center of the hub. This will leave the secondary impression which in some cases can be major. This info is available from multiple places including Wikipedia:
Class 1, Rotated--A class I doubled die results when the die receives an additional hubbing that is misaligned in a clockwise or counterclockwise direction. Class 2, Distorted--A class 2 doubled die results when the hub's design moves toward the rim between hubbings. Class 3, Design--A class 3 doubled die results when a hub bearing a different design stamps a die bearing another design. Class 4, Offset--A class 4 doubled die results when the die receives an additional hubbing that is misaligned in an offset direction. Class 5, Pivoted--A class 5 doubled die results when the die receives an additional hubbing that was misaligned via rotation with a pivot point near the rim. Class 6, Distended--A class 6 doubled die results when the die receives an additional hubbing from a hub that was distended. Class 7, Modified--A class 7 doubled die results when the hub is modified between the die's hubbings (e.g., a design element was chiseled off). Class 8, Tilted--A class 8 doubled die results when a die and/or hub is tilted during a hubbing.
Thank you Bob for answering both questions. I understand the concept of the pivoted doubling but do not understand how this could happen, I guess because I do not know how they are aligned for the second hubbing. Where the pivot point is at the edge, that would mean it was extremely out of line at the 1/4 point above and below the pivot. I just would have thought there would be something to constrict the die and hub during this process, you mentioned a keyway.
I apologize if I did not state the question well Bob, I'm good at doing that. Sometimes I don't say exactly what I'm thinking when I type it out and don't understand when I don't get the response I was looking for. I spent the last couple of days going over the different classes and they make sense to me short of class 5 and class 9. The only other class that does not occur inside the radius of the two parts, the die and the hub, is the class 4. It just seems odd on the class 5, that the amount of movement (pivot) is extreme for what I would think should be allowable, unless there are no confines between the two (die and hub). I guess the confines are what I am asking about.
In reality, the amount of movement is very very small. A Bar L is a class 5, and on some of those, it is really minor. The keyway is something a lot of folks don't know about. The keyways were used as alignment keys during the hubbing process. If the keyways began to wear with use, it could indeed lead to a small misalignment, especially considering how much pressure is used. There was a point in the process when keyways were supposedly eliminated. However, the instances of doubled dies increased and they went back to using them. I so not know much more about that issue. Take a look at this photo from John Wexler's site and you can see the keyways I am talking about.
Die varieties such as doubled dies, Repunched mint marks (RPMs), Over Mint Marks (OMMs), Repunched Dates, Overdates, coin design varieties, as well as regular coins and error coins.
Bob Piazza
Former Lincoln Cent Attributer Coppercoins.com
In reality, the amount of movement is very very small. A Bar L is a class 5, and on some of those, it is really minor. The keyway is something a lot of folks don't know about. The keyways were used as alignment keys during the hubbing process. If the keyways began to wear with use, it could indeed lead to a small misalignment, especially considering how much pressure is used. There was a point in the process when keyways were supposedly eliminated. However, the instances of doubled dies increased and they went back to using them. I so not know much more about that issue. Take a look at this photo from John Wexler's site and you can see the keyways I am talking about.
In reality, the amount of movement is very very small. A Bar L is a class 5, and on some of those, it is really minor. The keyway is something a lot of folks don't know about. The keyways were used as alignment keys during the hubbing process. If the keyways began to wear with use, it could indeed lead to a small misalignment, especially considering how much pressure is used. There was a point in the process when keyways were supposedly eliminated. However, the instances of doubled dies increased and they went back to using them. I so not know much more about that issue. Take a look at this photo from John Wexler's site and you can see the keyways I am talking about.
Ah, the grooves and lugs are the "keyways" you refer to. This is a very educational thread. If only I can retain it. Think I'll start a notebook for all this stuff.
Ah, the grooves and lugs are the "keyways" you refer to. This is a very educational thread. If only I can retain it. Think I'll start a notebook for all this stuff.
Good idea
It is overwhelming how much information there is to know. I have multiple 3 ring binders of info I have saved.
All opinions expressed are not necessarily shared by willbrooks or his affiliates. Taking them may result in serious side effects. Results may vary. Offer not valid in New Jersey.
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