Years 2005 - Now , Jefferson Nickel - Liberty Study

Thank you Silvio for the 12 Nickel rolls.
There were 105 nickels dated after 2004 out of 480 nickels. The following table is the distribution per year and per mint.


I know statically, I will not be able to conclude much but it is a start.

I was trying to find a chart showing various die states but I did not find one for the nickel.

So, I had enough of year 2000 to get good pictures of the parallel flow lines at different die state.

Can someone indicate which pictures you would consider mid (middle) die state (MDS) and late die state (LDS)?

Thank you Silvio, I will use your scale as of now when I need to describe die state.

Deterioration of the working die

Deterioration of the working die occurs due to two forces. The first is the vertical impact the working die has with the coin blank as shown in illustration below. This can occur as early as Silvio's category 1b die state!
Any weakness in the working die metal will cause fractures which eventually creates "chips", "breaks", "cracks", " Cuds", etc...
In some cases, as the working die worn out, these fractures expands and eventually forms double Die Deterioration.



The other force is due to metal flow of the coin blank as shown in illustration below. This is usually visible in later die states (Silvio's category 2b die state).
This flow acts like coarse sand paper on the working die.



The following picture shows what it looks like up close.

Based on my observations, the illustration below estimates the stresses on the different working dies. The reverse working die seems to deteriorate faster than the obverse working dies indicated by the darker red zone. I am suspecting this is due to the reverse working die having a greater curved field.

For all working dies, deterioration seems to begin at the outer rim (red zones) , and at later die state, the center gets affected (yellow zone).



Pictures below are some of the areas where noticeable deterioration was observed.

Thank you Coop for your pictures.

Doubled die on Reverse

Here is what I have found for the reverse side.

2013-P DDR-003
reference: http://www.varietyvista.com/04d%20J...3PDDR003.htm




I do not know what happened for this one!

Maybe one of you have seen this kind of doubling.

The whole right side of the building seems doubled (red arrow shows the doubling of door and small window under door) and the details are not sharp.
There are metal ripples on the wall of the building.



Reference coin vs coin in question



This is the window to the right. Notice the concave depression after the edges of the walls.

Die Clash on Reverse

Here is what I have found. The most common die clash is the one on the side of building as shown in image below (Two areas I found highlighted in red).

I have 11 coins with DC all having slightly different clash position. I only provided one picture of each DC type found.




Note: Obverse picture was flipped for this montage.

Update

After 2 weeks into online course, the simulation process is harder than I thought!

The student version of software is limited so I will not be able to simulate previous reply's 3D model :(

In the course, it is mentioned that we can simplify a model to obtain meaningful results that can be extrapolated.

So here is reduced version of Hub and Die colliding. You will notice the outer surface of die rod blank expanding during the hubbing process confirming what is seen in picture below. The simulation reports up to approximately 1.5mm diameter expansion. This might be the reason for some "play" between collar and Hub/Die.

Sorry for small animation, CC will only allow 300k file size.



source:https://www.coinnews.net/2013/09/13...oduce-coins/

Depending on the material used for the die rod blank, there could be some contraction as the piston is lifted. This depends on the elastic portion of stress-strain curve.

No problem Silvio, always glad to clarify.




Thank you for showing me the working die as it was the first time I could see one in person!

Below is a picture showing the different stages of producing a working die.
What you showed me was the hardened ("working") die ground as indicated by the blue arrow.

I was working on the struck ("working") die as indicated by the red arrow. What could have been confusing is that I have not included the shoulder on the working die blank in this simulation but in the new simulation I am attempting, it is there as shown in image below.


source:https://www.coinnews.net/2013/09/13...oduce-coins/

At first I thought it was a new DDR but closer inspection it is a die clash.

I am surprised at the amount of die clashes I find in the new rolls I purchased recently for the study!

In the montage below, I have indicated with red arrows and numbers the marks left by Jefferson's nose as it is hard to get a good picture.