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Pillar of the Community
 United States
3331 Posts |
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That is an outstanding write-up Pete!
Excellent work and I'm glad you had fun with it too. Thank you! |
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Pillar of the Community
 United States
6554 Posts |
Excellent research, as usual.
You might just be able to file a FOIA request with a direct question.
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Pillar of the Community
United States
3331 Posts |
Quote:
Excellent research, as usual.
You might just be able to file a FOIA request with a direct question. Thank you! The mint used to respond to my questions, but no longer. I don't know if they blocked me as a pest, or if government cutbacks nixed that. FOIA requires $ I am not excited to spend and a time frame I am not anxious to endure, so I have never tried. I have also found them to be most jealous of proprietary information! |
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Pillar of the Community
United States
1791 Posts |
Great article! As someone that once worked with CNCs on a larger scale, all that with the tooling is extremely accurate and the cutting direction matters. a profile can't be cut in one direction and then done again in the opposite direction. They won't match up. There is always some "slop" when reversing directions so all profiling must be done from the same direction.
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Pillar of the Community
United States
3331 Posts |
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Great article! As someone that once worked with CNCs on a larger scale, all that with the tooling is extremely accurate Thank you! I may send you a message with some CNC questions! |
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Pillar of the Community
 United States
5785 Posts |
Excellent article and it looks like you had fun writing it. I've wondered for a long time whether computer glitches could have been responsible for all the DDR varieties on the 2015 homestead headquarters. Words of encouragement are one of the major food groups.
We need to consume them regularly to thrive and grow.
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Pillar of the Community
United States
3331 Posts |
Quote:Excellent article and it looks like you had fun writing it. I've wondered for a long time whether computer glitches could have been responsible for all the DDR varieties on the 2015 homestead headquarters. Thank you. The only way I can see for computer involvement would be at the master die level and that would be through CNC Doubling (CNCD), not hub doubling of the master die. If a specific example were on ALL examples, then perhaps. Even most examples, then it could be possible, since there could be more than one master die - but I know of no way (yet) to make such attribution! |
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Pillar of the Community
United States
2738 Posts |
Fun read Pete!
Next week on Law & Order: Special Varieties Unit "The Case of the Missing Master Hub"
Ice-T voice over: "They thought they could hide the evidence in a CNC machine. they were wrong."
"Pride is yoked with callous behavior, as humility is with compassion." St. Gregory Palamas Top Finds - 1969-S 1c FS-101 http://goccf.com/t/477681 1976 D WQ FS-101 http://goccf.com/t/382777 - 1968 D 1c FS-801 http://goccf.com/t/422254Cool clashed dies - 1972 D 1c http://goccf.com/t/429855&SearchTerms=CCLStruck-In Rim Burr - 1969 S 1c http://goccf.com/t/425587&SearchTerms=burrFloating (Type II) Counterclash - 1978 D 1c http://goccf.com/t/434991&SearchTerms=1978 |
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Pillar of the Community
United States
3331 Posts |
The Mint is now moving beyond CNC milled Master Dies to Laser Engraved Master Dies. The 2024 American Liberty silver medals and the 2025 American Liberty gold coins (resurrecting the 1794-dollar designs) are the first to incorporate this technology. The 2025 Laser Engraved American Eagle One Ounce Silver Proof Coin is the first American Eagle Silver Proof Coin (with a laser-engraved privy mark) minted using laser-engraved master dies.
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Pillar of the Community
United States
3331 Posts |
I have been attempting to think through some of the implications of the Master Die being produced via CNC milling. One implication, of course, is with respect to the appearance of what Master Die Doubling looks like when produced via the CNC process. (CNCD) Examples of how CNCD might happen: • We know that the absence of a fillet in CNC machining can result in tool deviation, tool deflection, vibration, and dimensional inaccuracies. A slight outline around a small section of a device might be a result. (A fillet in CNC machining is a rounded transition (radius) applied to the intersection of a device with the field of the die. The purpose is to eliminate sharp corners which produce stress concentrations, improve fatigue strength, and enhance aesthetics.) • We know that a "phantom channel" on a die may be caused by tool deflection/spring-back from the cutting tool being under lateral load, backlash in the Machine Axes, or G-code/CAM Post-Processor Error. A "phantom channel" = a short additional outline following the contours of a device such as an eye, a hand/finger, number/letter, or edge of a structure. I would submit that the following examples of Master Die Doubling could easily be the result of CNC Doubling. (CNCD). An attendant question RE: this comment at the following listing: "Comments: WMDO-001 is known on 2022-P Angelou, Ride, Mankiller, and Wong quarters. It is expected, but unconfirmed, on Otero-Warren quarters. Most, if not all, of Angelou and Ride quarters show this master die doubling. It is less common on Mankiller and Wong." If it is master die doubling, how can it be less common on some examples? Surely all are not examples of die wear or weak strikes? Is this a clue that there is more than one master die for these issues, as that possibility is implied in Mint documents? COMMENTS WELCOME!  Edited by Pete2226
03/29/2026 11:51 am
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Moderator
United States
189340 Posts |
Very interesting and thank you for sharing!  |
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Pillar of the Community
United States
3331 Posts |
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Pillar of the Community
United States
2738 Posts |
Maybe an asterisk could be a temporary solution for the attribution sites?
Something like: WMDO-001 (under review / possible CNCD)
Description: Doubling to the north on the last T in TRUST and the first 2 in the date. Slight doubling to the south inside the nostril.
Note: This feature appears on most, if not all, 2022-P Angelou and Ride quarters, but is noticeably less common on Mankiller and Wong quarters. Traditional master die doubling from a single shared master die should be consistent across all designs. The frequency variation suggests it may instead be CNC-induced doubling (CNCD) from multiple master dies or milling artifacts rather than classic master die doubling.
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Pillar of the Community
United States
3331 Posts |
Quote:
Maybe an asterisk could be a temporary solution for the attribution sites?
Something like: WMDO-001 (under review / possible CNCD)
Description: Doubling to the north on the last T in TRUST and the first 2 in the date. Slight doubling to the south inside the nostril.
Note: This feature appears on most, if not all, 2022-P Angelou and Ride quarters, but is noticeably less common on Mankiller and Wong quarters. Traditional master die doubling from a single shared master die should be consistent across all designs. The frequency variation suggests it may instead be CNC-induced doubling (CNCD) from multiple master dies or milling artifacts rather than classic master die doubling. That might work! But nobody listens!  |
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Pillar of the Community
United States
3331 Posts |
Another snippet RE: Master Dies (from an article on Mint Directors since 1793) "Joseph F. Menna: The 13th and current chief engraver, Joseph F. Menna, joined the coinage bureau in 2005 as a medallic sculptor. Since 2006, the Mint mothballed plaster models in favor of digital sculpting in the tooling process for directly producing master dies and working dies. Menna was named chief engraver in February 2019 by Mint Director David J. Ryder." Coin World April 6, 2026, "From presidential appointee to Mint Director's choice", by Paul Gilkes, Coin World Senior Editor, page 33ff. |
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Posted 03/27/2026 3:14 pm
