1975 D lincoln cent

On the reverse top right of memorial is what looks like a rockwell test mark.

 

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And in other breaking news, today is Tuesday!

 

Nope.. Not it.

 

Today is Twosday.

 

So you're say it's double died?

 

I've seen the Rockwell Test unit
at the West Point Mint, about
10 years ago.

You cannot see the Test Mark impression
on a struck coin, based on what I saw,
and also what they told me.

It is a genuine 'Test', but to verify the
hardness of the planchets before they
are struck.

 

according to the online stuff, which is what OP is probably reading, one can see it
https://conecaonline.org/rockwell-hardness-test-marks-on-lincoln-cents/

duplicated/reiterated here
http://www.error-ref.com/rockwell-test-mark-in-planchet/

Personally I don't fully understand it. If done to a planchet the metal gets moved/compressed during the strike so it shouldn't be noticeable. On a working die it would be of course, but then it would be one possibly hundred of thousands of coins.

 

I knew Lonesome John Devine very well,
as we lived about 20 minutes from each other.

I am convinced that John was wrong about that
Lincoln Cent reverse coin in the photos.

The test mark is perfectly round, and would
disappear when the coin was struck over it.

In the photo, the 'indent' is over the design
of the Lincoln Memorial.

Those pages referenced above are incorrect about
the cent, not the overview of the process.

 

Thanks, just looking at metal flow marks, and the consequence would obliterate a fixed planchet/blank surface indent. So that link above I didn't understand "how". But if you say it's wrong I'd have to concur (from a nobody).

 

I've seen the RTM (Rockwell Test Mark) at
the West Point Mint, and I believe there is
no way that small indent would survive
65 tons of pressure for a Cent, or up to 85
Tons of pressure for higher denominations.

It's an urban legend that coins exist with them,
in my opinion, and I note that the 2nd link even
mentions Dies with RTM's....never heard of Dies
having this done to them anywhere, any Mint.

Just my opinion

 

Thanks again everyone!

 

Where in the OP's photo is this mark, supposedly?

 

This from CONECA website. "While this paper focuses on Rockwell Tests on planchets, it should be acknowledged that Rockwell Tests are also performed on dies and on master hubs. “A die that is too hard will be brittle and have a tendency to fail prematurely. A die that is too soft will deform and deteriorate too quickly.” (Diamond, Page 16) A die which has had a Rockwell Test will leave a raised bump on the coin. This same source shows a photo of a 2000 Lincoln Cent with a small, circular indentation just above Lincoln’s bow tie. It has been proposed that this is from a Rockwell Test on a Master Hub since the same mark can be seen in preceding and subsequent years without change in position. However, it should be noted that neither such a circular indentation from a Test on a Master Hub nor a raised bump from a Test on a Die will leave a “mirror image” of the indentations on planchets being discussed here. The shapes of these indentations will be different. (See a discussion of this in Appendix A).

Planchets with Rockwell Test Marks are very rare to extremely rare. (Harper and Miller, Page 62.) “Dies and planchets tested in this fashion are supposed to be discarded, since they are blemished once the procedure is completed. If they are not discarded, then you have a desirable die error and planchet error, respectively.” (Diamond, Page 16)

There is a notable lack of consensus in the Numismatic Community over whether there are actually any legitimate Rockwell Test Marks on coins. Absolute certainty requires that the test itself be witnessed and the planchet followed through the complete minting process!

 

This is the 4th or 5th thread in almost as many days about the Rockwell Test. Did UTube crank out another phony video?

 

I think it's the same OP posting those.

edit: a couple people .. https://www.cointalk.com/search/4169507/?q=rockwell&o=date

 

I haven't seen it, but JB Coins is my guess. He knows nothing and educates people with misinformation. He would go through a roll of brand new dimes and pull out 20 doubled dies with his microscope. I tried to tell him it was doubling, but not valuable doubling, and then I gave up.

 

Yes! It is! I gave him this...….



…...but he wouldn't accept it.

Chris

 

How do you know who is informed and who's not.

 

From a Metallurgy/Materials Science standpoint, I could never come to grips with a Rockwell Test Mark being visible after striking. Your observations and exceptional knowledge of the minting process add a strong piece of data to my belief that this not a legitimate error.

In addition, how many planchets are actually sampled for the Rockwell test? 0.001% or 0.0001% of a delivered order? Assuming the supplier has a good quality system and does not allow defective parts to reach the mint, I would suspect the sampling would be extremely small.

 

WOW, JB Coins you say. Thanks good to know. I always thought he was slightly off bubble. I guess I need to stay away from him then, thanks.