2012 Jefferson Nickels: Machine Doubling Identification, Attempt #2.

Some more pictures of the 2012-D and the reference 2010-P with different lighting and two angles. You can clearly see that the second 2 on the 2012 does not exhibit the same phenomenon as the other three date numbers.

Hopefully this helps to distinguish the 3D effect from the actual phenomenon in question here.

Funny post this.

@ Brandmeister: If you want to understand well MD (is generic name in numismatics), you have to study:

1. Strike Doubling (die)
2. Machine Doubling (striking)
3. Mechanical Doubling (ejecting)

Those are the three forms included in generic name MD.

@ Brandmeister:

I can tell you, Ken Potter, Favas, Stanton (RIP), Herbs (RIP), Wexler, Mike Diamond and here COOP wrote about this subject. If you want to go deep an understand and achieve more structured way I suggest you ANA Academy. I do not come here to teach but to give opinions and to show the path someone to take. It is no short way to learn this hobby, and if you expect someone will give on the plate everything's you can forgot this hobby. Those peoples I mention before they studies this hobby for decades and even all theirs life. Many books was wrote and many publications, so just studying and practice will made you achieve your goals.

@Brandmeister, thank you for the extra pictures much appreciated.




Read the topic (link given on page 1 of this post) and you will see that I have tried this.
The best way to figure out if it is MD or not is by comparing a normal coin with one that has a doubling to determine if the device is larger or reduced.




Not too long ago, on the CC's Canadian Discussion forum, O'connor asked the same questions as you about doubled die. Compiled sufficient knowledge and just released his first book on Canadian Doubled dies.
https://www.mcddv.ca/

So yes, with perseverance you can "enjoy a good round of golf" ;)

Many of the finer details that distinguish one coin anomaly from another become apparent only by angling that coin and observing light reflecting off the critical areas. Such details are difficult to express in words. Even a video can't fully show them because video is a projection onto a flat screen, whereas a coin is, of course, three dimensional. When drilling down to the level of detail you want, Brandmeiter, there is no substitute for practice with actual coins. The questions you've been asking demonstrate you've been making progress, good job!

I have been doing a lot of reading on Machine Doubling. My summary, some conclusions, and then questions.

I think we all agree that this is not a real doubled die example. (Actually, I don't think anyone ever proposed that, but I am being 100% clear). The question here is: what specific kind of Machine Doubling happened to this coin? We have correctly proportioned devices accompanied by a thin duplicate shelf in a single uniform direction.

This does not appear to be Die Deterioration Doubling. DDD examples on Error-ref.com look soft, rounded, and mushy. Our specimen is sharp, flat, shelf-like. The overall obverse coin strike looks pretty clear.

Error-ref.com lists three sub-types of Machine Doubling during striking. Rim-restricted doubling is not relevant here. Slide doubling, which smears the design as the die drags across the newly struck coin, also doesn't seem to be a candidate. The ER description of Push Doubling matches a lot of Coop's examples in the #1-30 range. But that's the complete Machine Doubling entry at Error-ref.com. ER also lists flat field doubling for twice struck proofs (not relevant here), and ejection doubling, which produces effects like Sacagawea's extra eyes (also not relevant here).

I note that visually the effect here is very similar to flat field doubling on proof coins, but that's obviously excluded from the possibilities.

The problem I have with a push doubling conclusion is that the devices here do not seem to be cut into a shelf by a subtractive process. Everything is basically the correct size and outline, with a thin duplicate shelf underneath. Numidian has showed that quite well with his overlays.

Approaching #100 in the Coop slide deck, we encounter "die movement doubling". It's a term I had not heard before on any site like ERef. The device appears correctly struck, but a shelf edge has been "pushed". That looks pretty darn close to my nickel.

However, the term "die movement doubling" produces no results on Google. Obviously it's a phenomenon separate from the subtractive Push Doubling process. Is there a formal term for DMD? What is the cause? It doesn't seem like DMD can have the same cause as PD because PD relies on cutting some of the device metal into a shelf, which thins the devices. Nor does DMD seem that it can be caused by Slide Doubling because that process smears the metal.

So what is Die Movement Doubling, what specifically causes that, and is that what happened on this nickel?

In re-examining the nickel vs. the reference coin, I am now noticing that the strike seems shallower and less distinct than the second coin. I had initially assumed that was circulation wear, but maybe that is a sign of some Die Deterioration or polishing?

It's a fair question.

I am an engineer. The science of things matters to me. When I do a root-cause analysis, I get to a satisfactory explanation or I keep digging. I have very much enjoyed this discussion so far, even if the coin is worthless.

I think people here give an answer of Machine Doubling (really meaning push doubling) far too easily. If the cause does not correctly explain the effect, then the scientific method requires further investigation. The term Machine Doubling itself seems to encompass a large number of common and uncommon scenarios that are not identical in formation or result. If we cannot point to a specific type of error from a specific cause, then that is guessing, not knowing with confidence.

Also, the doubling question seems to arrive often from newcomers to this site. True die doubling is probably 1% of those cases. The various forms of MD/DDD and other manufacturing flaws are 99% of those cases. So all we have to do is guess Machine Doubling every single time, and we are likely to be correct with a 99% record. If we are looking for a valuable and rare 1%, then that is not a very useful strategy. I could throw out every tiny transparent mineral in my prospecting pan, but that guarantees I will never find a diamond. I would, however, be correct 99.99% of the time. Does that represent a mastery of diamond prospecting, or merely describe a basic grasp of probability? It seems quite possible to be 99.99% correct and achieve a result of $0.

It is also worth asking the question in reverse. If I am sure that a coin has true die doubling, then I must first rule out worthless forms of doubling. Some of the legitimate forms of doubling like distended hub doubling seem to look very much like MD/DDD. How can I be trusted to identify a diamond if I cannot immediately dismiss quartz, glass, and other lookalike minerals? This seems especially important for doubled die coins, because the odds of finding one are tiny. A collector seems much more likely to purchase such a coin. You don't buy a Rolex if you can't identify a Rolex. I guess you can buy a Rolex from a certified dealer, but then you're just "buying the slab, not the coin".

If I had found a different type of interesting error in a roll of nickels, I would be doing a deep dive on that subject instead of this one. =)