I am guessing that these parallel lines are from the rollers of a coin counting machine but would like verification. What do you think caused these? Am I correct?
They look like heavy planchet striations to me. Those are the heaviest I have seen. That doesn't look like PMD to me.
My best guess would be that the lines were created by the rollers that thin the metal strips to the correct thickness. Mostly due to the fact that both sides run parallel to each other. I do not think that a counting machine could make such marks all the way across both sides, with the fields included. I think that a counting machines has a rubber wheel that only makes contact with the highest part of the relief.
Wouldn't such lines be "pressed out" though when the coin was made? I've come across lots of pennies that had such but it was more color not actual high/low surface. Interesting.
Since the lines run over and through the design, I don't think that it could be the surface of the planchet. The die would have obliterated and/or smoothed any lines on the planchet inside the design elements
With roller lines/planchet striations they exist because of the density of one area vs the next. These do not get fully removed from the planchet upon strike. They are grooved into the planchet. It is like a rough planchet where the roughness doesn't get struck out and smoothed.
The lines or striations have a different density from each other , Then if a planchet is not softened enough in the annealing process (hard planchet) the striking of the coin may not remove all the lines on the planchet. A hard planchet can make a coin look like it recieved a weak strike. I really do not believe that there is simply one factor that made the op's look the way it does, otherwise I think they would be more commonly found. JMO
I got this coin out of a mint sewn bag along with about a dozen others. If that helps anyone figure out the actual cause.
They are too strait, and parallel. The lines are in the planchet surface, they have nothing to do with PMD.
