2005 D US Nickel DDO?

Hey numidan, Glad you could find one. Just wondering, based on all the fine pics you have provided, do you have a full pic of both obverse and reverse. When asking what folks think it is important to present the entire coin. Ever part of a coin determines the die which created the coin.
Be well!

While searching for other types of doubling, I realized that it will be impossible for me to prove my point. It is like telling someone the earth is not flat.

What!!! The earth is not flat! Guards imprison this fool.

We have such a diverging opinion of what a flat, shelf-like appearance of the lowest design elements represents. For most of you, it automatically represents Mechanical Doubling.

Here is the published article, I've stumbled upon last night that made me realize it all. It analyzes the doubling of the coin shown below.


source: https://www.ngccoin.com/news/articl...ne-Doubling/




Here is my analysis: This is an example of a triple die. The illustration below shows the three location where the punch hit. The red arrow does show a slight separation between the numerals. The yellow arrows demonstrates that the last numeral looks like a single numeral but it is two overlapping ones.

I think the author was mislead by the flatter appearance of the first set of numerals (lower design elements) and the fact that the last numeral one was not tripled. If the author took some time to think how a working die forms Mechanical Doubling, he would have realized that it was impossible to create a third set of numerals by either shifting or pushing the working die.



Here are a few points not to forget:
1) The blank contains the only metal available for the minting process.
2) The press propels the working die into the blank. This forces the metal from the blank into the cavities of the die forming the coin's design.
3) Mechanical doubling will either flatten or slide the design as shown in the illustrations below. Note there is not metal left to fill up the void when the die moves sideways.
4) Do not overlook the edge geometry as shown in illustration shown below and in previous reply.



Mechanical Doubling:

source: https://www.error-ref.com/push-doubling/
Double die:

source: https://www.error-ref.com/push-doubling/

Thank you.

Don't worry for the late night, it's all about the learning.

If you not in for a quick buck, you realize that the numismatic field touches so many disciplines;

History, Arts, Mathematics/Statistic, Metallurgy/Mineralogy, Physics, Chemistry, Engineering, Photography/Lighting, Economics, etc... just to name a few.

Just one coin can amount to several hours of research and discussions over days ;) and yes, sometimes years before someone else finds a similar coin or cause.

I am so grateful that people share their stories, opinions, time, and/or expertise continuously nourishing my and hopefully other peoples' passion.

Happy hunting and learning.

P.S. During your hunting, if you find an exact copy of this coin, please add it to this post. Thanks.

Just saw this thread and haven't really had time to digest all of the replies.

I'm not a nickel guy but your image on page 1 with yellow diagonal lines shows MD, IMHO.

I have also seen devices that show erratic secondary lines someone pointed out.
I have seen dense mint grease sticking to the edges of the devices and design. This can interfere with the metal flow into the devices and can have a jagged appearance. (The overall width of any device affected in this way will be reduced, similar to MD.)

When I decided to include varieties and errors to my coin collection, I struggled to fully understand the difference between Mechanical Doubling and double die. It was inconceivable having so few double dies discovered on Canadian coins. After several lively discussions with club members and many technical exchanges with forum members (thank you Castor and SPP), I came to the conclusion that some clarification was needed. So, I decided to write an article.

I began to write a guide as shown below, and after bouncing the idea to some of my friends, I abandoned that method. The format was not unanimous and once all exceptions/images included, it would have been too overwhelming. Although I have not completed the guide, I do apply these criteria when evaluating the type of doubling. Follow the replies in this post and you will see it being applied.

Therefore, I decided to use illustrations instead (as shown throughout this post) and concentrate on the first criteria of the guide; "Examining the overall width of the upper design element". Published in "The HUB" in 2012, to sum up the article (Revising Mechanical Doubling), I concluded that all coins with Mechanical Doubling have the width of the upper design element reduced and if it was the same or enlarged, it was another type of doubling.

The main issue in applying this criteria is that when members present their findings, they rarely provide a reference (a normal coin taken under same lighting and camera conditions) to properly evaluate the width of upper design element.

Therefore, people are relying on other characteristic(s) to determine the type of doubling.

Yes it is true that when evaluating doubling on US pennies, having a flat, shelf-like doubling can automatically be considered as mechanical doubling, it is not always true for other types of coins.

Thank you for confirming what I was suspecting.
Hope you did not see a this doubling as being concave (going into the field of the coin) because it is definitely above the field as shown in image below.



I did not know there was a standard on how high the doubling must be. On the image below, the thickness of the doubling is about half of the upper design elements thickness!


Sorry for the blurry parts, it is due to the limited depth of field of my microscope.




It is normal for Mechanical Doubling. As the working die shifts, the sharp edges pushes and slides the metal causing it to look erratic.
What is nice with graphics editing programs, when you multiple a red layer with a green layer, it becomes black.
So, if you do the exercise as shown below, you can demonstrate (predict) how the edges of Mechanical Doubling will look like.

No, it is raised from the field and then has a "concave curve" ending at the higher part of the device.

The area under the yellow lines is not raised like the image you provided with the opaque "ribbon" on the "O" that demonstrated a "Doubled die".

The yellow hash area looks more like the preceding image of the Mechanical Doubling. The image of the edge looks to confirm to me.



I don't agree "erratic edges" or "weirdly shaped" devices are normal for MD, unless you and I are talking about different things.

You seem to be trying to get people to agree that this isn't MD but it looks like so many examples I have seen, especially at the yellow diagonal lines.



I'm not sure what you were trying to show with the four comparison images of the same coin.
MD can be present on a coin from any year, even similar looking MD. "... >exact alignment with small imperfections" would tend to make me lean towards MD unless there was clear doubling.

I guess I've lost sight of your reason for this thread. Is it to convince us that the doubling your 2005 is hub doubling and not MD?

Or are you asking about the "weirdly shaped " edges to some of the devices?

Or both?

ps. I've only been back into collecting for 10 years now but I'm enjoying learning new things all the time. (Some of which I actually remember on occasion. LOL)