I'm sure this is not an error but rather strange toning and wasn't sure where to post it for info. I found this 1971 dime today and it just looks strange to me. There are very straight lines on both sides of the coin. Rubbing across them with a toothpick they feel slightly raised. Any info would be greatly appreciated.
Opinions vary on what causes this on copper nickel clad coins. I heard that it was due to the clad layers being pulled through the blanking machine while I've also heard that its the result of friction cause by the springlike action of the rolls pf clad material as the giant rolls are unwound. These marks are referred to as striation and occur on Washingtons, Kennedys and Eisenhowers. Some are prevalent as below: Some are not so obvious.
Only for the conversation aspect. As far as I know, I;m the only one that ever paid a premium for one. Better yet, I'm the only one I know of that purchased a coin "specifically" for this condition. The 1973 IKE above was bought simply because it has striations.
I believe you're referring to the "Woody" or wood grain effect, its an improper mix of alloys, that gives the coin a streaking effect.
That would be my answer as well. However, the Lincoln Woodies do not have a physical texture to them. Meaning the surface is smooth. On these striated planchets the surfaces often have parallel grooves etched into them which causes the feeling of "ridges" as the OP pointed out.
the 1976 dollar coin looks like it has been cleaned by someone with sandpaper,probably to remove heavy corrosion. even if a planchet looked like this before being struck with the coin dies it would look smooth after being struck by the dies.
Everybody is entitled to an opinion but I somehow do not believe that PCGS would have graded it had it been sandpapered. Rmember Troy, before being minted the planchet looked much worse.
If this was really done at the mint then I'm almost certain that the dies had been heavily abraided to remove something or maybe it was unfinished dies. I have plenty of coins that have heavy polish marks like this where some major die clash marks was removed from the die, usually when a die is abraided the polish marks don't go up into the recesses of the die but I know anything can happen. another thing that could have caused this is the fact that the dies may have been starting to become clogged up with something. My opinion is that this was caused by a die problem and not a planchet problem. We have way too many goofed up coins coming from our coin mints these days and quality control has gone to heck. anyway I like your coin and thanks for letting us see it. Troy W.
These are not die polish lines nor are the abrading lines. They are fine grooves cut into the clad stip which the planchet was cut from. They run in the exact same direction, obverse and reverse and occured during the planchet creation processes. The grooves are deep enough to have not been removed during the striking of the coin. Die polish lines, on the other hand, occur in many different directions on the surface of the coin and never run parallel to each other on the obverse AND reverse.
