Question on terminology: Lamination vs Strike Through
renomedphys
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Okay, so I get what “strike through” means. It could be anything: hair, grease, a paperclip, whatever. But when another piece of metal, like a shard from leftover planchet stock gets struck through then it’s called a lamination? The way I understand it is a lamination could be a lot of things too, just with only metal being sandwiched into the planchet (pre-strike) or the coin (during strike). Is this also the term used when the planchet stock is not uniformly formed, and a gas bubble or impurity in the planchet results in a void that presents like a split or a flake on the surface?
On another side question, do we ever see bimetallic laminations, like a silver coin with a piece of copper “laminated” onto the surface?
Can both terms be interchangeable under certain circumstances?
Comments
You're pretty close overall.
Laminations form in the alloy when there is some sort of impurity that causes the metal to separate when the ingots are rolled out. This causes pieces of metal to peel on the finished product (whether that's the sheet of metal or finished coin).
Strike thrus are exclusive to the striking process, when something foreign comes between the coin and die. For example, grease, or a shard of wood, or fibers.
Coin Photographer.
Go here and near the top for various examples and definitions of laminations and then below for more planchet errors.
https://www.error-ref.com/part-v-planchet-errors/
And here for struck through errors which are more than half way down the long list of striking errors.
https://www.error-ref.com/part-vi-striking-errors/
https://youtube.com/watch?v=wwmUMvhy-lY - Pink Me And Bobby McGee
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https://youtube.com/watch?v=D0FPxuQv2ns - Ruby Starr (from 'Go Jim Dandy') Maybe I'm Amazed
RLJ 1958 - 2023
They are not interchangeable, but they are not mutually exclusive either. I think part of the confusion is that the same defect can be both a lamination and a strike through, and this is little-acknowledged within the community.
I remember my newbie days and PEELING OFF a pretty large lam from a Morgan..
If the lamination was peeled back or detached prior to striking, the die would strike through the detached lamination would be my take, creating a lamination and strike through on the same coin.
Also, before learning the reason, apiece of burnt wood from another Morgan
...and scraps of different metal.
I don't believe it. An example please. A struck thru was never a part of the original planchet. If the foreign object breaks away, it is not a lamination, but I guess as a very big stretch you can say it delaminated since it became a part of the coin but I don't know if that would be professional. What do the experts say?
I guess this would be an example after all - proving pigs can fly.
Not really a lamination, but occasionally you get a retained strike through in which the debris that came between the die and the planchet remains trapped in the surface of the coin. If the debris was something soft like a copper fragment, and it was stuck through and retained on a silver planchet, you can get that bi-metallic effect.
Or, if the debris is harder, you can get something like a staple embedded in a coin.
A coin can be struck through a lamination from a different coin. It looks like it was struck through a small fragment or something, but includes an incuse bit of the design, maybe reversed, maybe not, depending on how the lamination fragment landed on the planchet before striking. This is usually referred to as struck through struck fragment.
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
If a piece from a lamination/delamination somehow splits off a planchet a split second before striking and is then struck into the coin, I still see that as a struck-through.
In any case, I don't see any way to prove otherwise, as the void caused by the delamination would be obliterated and eliminated when the coin was struck.
Laminations are usually due to a planchet impurity just below the surface. This won't look or strike the same as the unaffected part of the planchet and would probably not bond to the coin very well if it detached before striking.
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
Am not sure but seem to recall occluded gas coins can eventually "pop" and result in a lamination or split type condition. Regardless, it is a planchet defect. At least this is what CW collectors clearinghouse commented on with the 1947 cent I had submitted to them in 1971. Was Ed Fleischmanns diagnosis. Still have it and has yet to "pop"/crack.
I've seen Lincoln cents with gold colored flakes and silver colored flakes. I have both an Indian cent and a Lincoln with tiny silver impurities struck into them. Both were found in the bins dealers throw low grad cents into.
That sounds reasonable but my point was that the spot where the lamination peeled off the planchet woukd presumably by obliterated by the dies when struck. And detached piece would just be a struck-through, retained or not. So, I think (?) it would be hard to diagnose a struck-through as a delamination from that same planchet.
It's all just theoretical, though, as I think the chance of that scenario occurring is slim, to say the least.