1987P with high plateau

MorgansRmine · Advanced Member

Not really an error, just need some help understanding this one. I've seen many of the 80s coins with ridges around them and understand many of them are die wear or just soft metal flow as I see them described. The plateau on this one is higher than the L, about half way up the I and evens out at B. In the picture you can see polishing lines on both sides of the ridge but not in it. This gives me the impression that this is an exceedingly large indentation in the die. Not a gas bubble, even a pair on metal tweezers won't compress it. Any ideas ?

Dick · Expert Member

morgansaremine, I don't know exactly what it is, but my supposition is that due to the constructiion od tjhe strip that is used to make the blank, which in turn is run thru the "upset mill", to make it a planchet, wjhich in turn is run thru the cioning press to make it into a coin. Now, my part of the theory, is that the upset mill sauses the edge of the blank to be compressed inwards, and consecuently weakens the rim area. then the planchet is made into a coin by the press. this outer area, being higher than the rest of the "disc", leaves the ridge. Not all the coins , (zincolns) are the same structure, so not all will show this ridge. I will say that I can show zincoln cents fron '82, to date, that ALL have this ridge in place. Not always in the same place, but always pressent. It is one of the on-going subjects that has been cussed, and discussed ever since the firat one was circulated. You will read many thoughts as to what causes the ridge, but mine is only one of many, and no more "gospgal", than any other. hope this makes "cents
Dick

eagames · Expert Member

I think you're both right. It shows like that on many dies from zinc cents. Probably from die wear and probably related to the way zinc wears the dies. I've never seen it on copper cents.

Look at this one, Bobs pics show it very well going through TRUST. It's the same sort of raised area along the rim:

http://coppercoins.com/lincoln/diestate.php?date=1984&die_id=1984p1do004&die_state=mds

coop · Expert Member

It could be a die gouge.

I was thinking about the gas bubble, cut plating exposure, But with it unmovable with the tweezers, I'm thinking die gouge.

Dick · Expert Member

On the 2009-D cents? I have a few, and the ridge is present. I still think it is bulging , caused by the ypset mill. It is only on the rim, and most often found on the OBV. I don't recall seeing one on the REV. Not all have it, but those that do have it usually in the areas with few devices. I have never seen a ridge go around the bottom of the coin. I think the base of the bust is too big to allow it to remain, after the strike. IMHO Jist a thought.
Dick

MorgansRmine · Advanced Member

Hi Dick, this one attaches to the coat on the left side and starts again on the right side and continues just past the date.

Not sure what this circle is.

coop · Expert Member

It's from a drop of something that evaporated on it. Probably water.