1988 Lincoln cent with obverse circle

wavysteps2003 · Expert Member

For some reason I have been on a roll find things, a few which I can not explain what has happened. This is one of those times. I have any idea that it may be from the finishing lathe, but that is an outright guess.

Any ideas?

The circle is raised, so it is die related and is positioned off the center.

WAVYSTEPS2003 aka BJ Neff

coop · Expert Member

Maybe Abe has ringworm? Laughing

walkingdude · Veteran Member

or his earring fell off.. Laughing

Gabe · Senior Member

Yeah, I think it is probably due to lathe work on the die, like you said.

Very interesting find!

coop · Expert Member

Seems like I saw something like that on one of Wexlers auctions. I think he said he had no clue what it was.

eagames · Expert Member

Is the center of a coin always exactly in the center of the die, they don't shift it to allow for something like alignment pins?

Just wondering if it's not maybe that's a lathe mark from the actual center of the die.

wavysteps2003 · Expert Member

John Wexler did indeed have something similar, except it was on the reverse. Here is a picture of it.

The circle is a bit smaller in size and less complete than that of the 1988 circle, but they are nearly in the same location.

WAVYSTEPS2003 aka BJ Neff

coop · Expert Member

I thought it was him that had it on Ebay. I've got a mind like a steel trap..............RUSTED! Laughing

Steven · Expert Member

Looks like Abe is setting in a tire swing Laughing

Steven

wavysteps2003 · Expert Member

My first impression "hula-hooping Lincoln".

WAVYSTEPS2003

Earwig · Veteran Member

If it were created on the reduction lathe wouldnt it be on most 88's? I think it was prob on the planchet before the strike but who knows i know i dont Very Happy

wavysteps2003 · Expert Member

Hi Earwig - The lathe that we are talking about in this case is not the reduction lathe, which you are right in saying, that it would be on all 1988 Lincoln cent dies if it were the reduction lathe, but in this case it is the finishing lathe.

When the die is made, the extreme pressure that is used on the steel rod (the new working die) causes its sides to bulge. This bulge is taken out by the finishing lathe, which enables the die to fit into the slots on the coin press.

As far as the ring, or in fact an raised metal on the planchet, it would be negated by the strike (flatened out) so that all traces of extra metal would be eradicated. We must remember that when the planchet is struck, there is a considerable amount of metal flow, from the center of the planchet to its edge, more on the obverse than the reverse (the obverse has more area to fill than the reverse). This flow of metal is the cause that would take an anomaly, such as the ring on the 1988 Lincoln cent, and do away with it. This metal flow can be best seen when a die begins to age as radial lines near the edge of the coin. As the die increases in age, these metal flow lines intensify from die detrioration. Oddly enough, metal flow lines was at one time thought to be the cause of wavy steps and trails, but that has been disproven.

Hope that this helps.

WAVYSTEPS2003 aka BJ Neff

coppercoins · Site Admin

BJ...Just wondering, what is your source on this information. I would like to see more about it.

wavysteps2003 · Expert Member

Hi Chuck - mostly all of it came out of "Mint Errors" by Alan Herbert. The finishing lathe information was extrated from "The Dies" section. The cold metal flow is discussed in "The Striking Process" along with the differences in the obverse to reverse of the Lincoln cent, however, that was not the only source concerning the Lincoln cent. There was another article I read about cold metal flow and the percentages of flow comparing the obverse to the reverse on the Lincoln cent, but I will be darned if I can remember where it is or who wrote it.

I believe it was Ken Potter that explained the die detrioration and metal flow in a discussion I had with him concerning wavy steps and trails when we were trying to find the cause of those anomalies. Alan Herbert makes a very brief statement in the "Strike" section about metal flow over an irregular surface but nothing about die detrioration and the effects produced by this flow.

BJ

coppercoins · Site Admin

I need to get Alan's book, I guess. I don't have a copy of that one.