Honest Question: What causes these deep flow lines? (UNC 1976 P Ike T2)

Good morning. I have an honest question about a coin. I'm assuming it's not valuable nor special - but I'd just like to know what causes the super deep radial flow lines on some coins, but not others? Again, this is purely for my own education/knowledge (plus anyone else who happens to see it) so I am perfectly happy with a detailed answer.

More information is better, in other words.

I'm looking at this 1976 P Type 2 Eisenhower Dollar as an example. Here is a shot of the entire coin:



I just pulled it from the original Mint Cello, which gave it the lovely caramel butter patina you see, so it's definitely uncirculated. However, when you take a closer look at the fields, there are radial flow lines emanating from the bust and moving out to the edges.

It's easiest to see in this closeup of "In God We Trust" here:



It's the same on the other side, but is also accompanied by some copper-colored specks that look like maybe the alloy mix of the planchet wasn't quite fully mixed properly:



Now, this doesn't happen on all the 1976 P T2 Ikes in this batch - just a few so far. So I'm curious - what is the difference between this coin and the others? Just a really beat up die? Some sort of planchet issue? A striking pressure or temperature variance during some stage of the process?

Thanks, I'll stop guessing and listen.

 

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It looks like die deterioration to me. You can also see how the letters have been affected by doubling from die deterioration (DDD).

 

I agree with Chris. It looks like that die was on its last legs.

 

Thank you for the response, Chris - just a quick followup (so I can visualize what's happening a little better):

The die is deteriorating to the point of being unusable for striking recognizable coins. The details on the lettering, portrait, all the raised details is getting mushier and mushier. I can see that part. What's happening to the flat parts (the fields) that causes these abnormally deep lines?

 

Coin metal flows outward toward the rim. As it does, it scrapes against the die steel causing the parallel striations.

 

Thank you for that. As I was waiting to hear back, I was trying to visualize it and (surprisingly) that's what I was speculating.

Appreciate your help (as well as @furryfrog02 for confirming) gentlemen.

 

I think it was @GDJMSP who pointed out that, counterintuitively, the metal must flow inward -- toward the places where the coin is thicker (i.e. the portrait or other devices), and away from where it's thinner.

 

You're quite welcome!

 

You may be right. I wonder if Doug @GDJMSP can give us a link to that information.

 

Wow...that is a great question and indeed there are others interested, like me. Not sure I've ever noticed it on too many MS coins, but have indeed seen this on several older coins, particularly some large cents and bust halves...always thought it was a red flag for some aspect of cleaning, whizzing, etc. For as long as I've been collecting, I'm not as read or experience with certain stuff...this one for sure...as others, so as they say, you're never too old to learn (or ask)...!

 

Great question stldanceartist. I am interested in the answers also, thanks.

 

These striations can be found on MS coins, too! Like cracks and chips, they do not affect the grade.

 

The metal of each coin struck is moving against the die surface as it fills in the deeper parts, normally located at the centre of the coin,(bust etc). This constant movement slowly wears the die surface until it becomes extreme like yours shows. It is a classic "tell" of a severely worn die. Also to fill the deeper centre, the metal flows from out to in, or there would not be enough metal to fill the incuse area sufficiently.

 

Good eye to notice. I'll look at my Ike's now.

 

Your comments in the second link make sense, but why isn't there support of this from other specialists?

Doug's Quote
"Pick up almost any book on coins, read any of a multitude of articles, and you'll find that same basic statement. But the part of it that is wrong - is that when a coin is struck the metal flows towards the rims. Not only is this not true - it cannot even be true ! But yet it is one of the most often repeated ideas there is in numismatics.

Start with why planchets are run through the upset mill. That is done to make sure there is enough metal to form the rim of the coin when the planchet is struck. And it is specifically done because the people at the mint know for a fact that when a coin is struck the vast majority of the metal flows inwards towards the center of the coin - not outwards towards the rim !

On almost all coins the single largest part of the die that must be filled is the central device, in the center of the coin. And that is where the vast majority of the metal flows to - to fill that portion of the die."

 

Older post before single squeeze method, but thorough to say the least.
https://www.cointalk.com/threads/what-you-need-to-know-about-strike.102246/

 

I think, just theory, the reason "experts" get this wrong is that when you look at the coins the striations appear to radiate outward. It is an optical illusion, but our minds just naturally see it that way. On the other hand, I have some ancients with this and the letters seem to leave "shadows" as the striations radiate outward. In this case I believe the metal did flow outward because ancient coins were often struck with a planchet smaller in diameter than the dies and without collars so that, if struck with sufficient force, the metal would flow out to fill the full diameter of the coin.