Rockwell test mark?

I know all too well of the stary eyed dreamer that is convinced he has the special cheerios golden dollar!!! Or 4 92 close am's!!! Or a 69s double die that will lead to retirement. Well today, I am that dreamer!!! Ok, maybe not but if I dont ask Ill always wonder...1983 Lincoln cent. Poor ole Abe looks like hes about to be hit in the face by a baseball!!!! But hes not. Its a little round depression right in front of his forehead. Rockwell test mark??? Now this COULD be a penny I shot with my bb gun 30 years ago coming back to me, or it could be something else. Its very clean and appears " part" of the coin. Like its always been there. I see no deformity on the reverse to show it was hammered in. So does anyone have any information to support a yes, jackpot or a no, go spend it? Thank you all as always that answer my neverending list of questions!!!!

 

Log in or Sign up to hide this ad.

this item was brought up in another thread recently. Actually many threads.
I brought up the link to a specific website and Fred W gave his input into it. Fred's input made sense.

Just search Rockwell test and you'll find those threads as they were fairly recent.

such as
https://www.cointalk.com/threads/1975-d-lincoln-cent.336219/#post-3447950

 

Yea, ive gone and researched this at a few different sites but as far as I can gather, theres nothing that i understand to disqualify this cent OR to verify it. That seems to be an issue with these it seems. Thank you for the link, Ill check out the threads.

 

Yeah, maybe ask an expert then?

 

Absolutely not.

 

Don't you think it's at least odd, that the indentation has different toning than the surrounding surface ?

If this was done at the "factory" per se right after production, over time wouldn't the toning be the same ?

 

If I can do it at home, it isn't an error.

 

This falls under the , yes, i know theres a 99.9% chance it is not what im asking about. BUT what would make feel REALLY dumb is NOT putting it out there and getting rid of it only to discover later that it WAS something rare that I was unqualified to identify correctly even after reading multiple sources on the occurance. And Id feel even WORSE if I passed it along because I was told that it was nothing by a sourse that was just sick and tired, understandably, of debunking frivolous posts about DD's, rarities, etc....SO....yes, it is most 99.9% likely its a dent by a BB or something. But it is NOT toned differently, just looks that way in the pic, theres no distortion on the reverse or noticeable push up like with a crater. One of these will be found one day by someone. Hopefully they will be able to id it. Thanks guys!!!!!

 

In my opinion, a Rockwell Test coin will
never be found in circulation.

Yes, post the coin and ask if that's what it is....
no problem there......

 

(a) then learn to take better, more realistic photos. We can only reply to what we see.

(b) It's too small to push metal out the back side. You yourself can experiment with things like this at home. For instance, take a ball bearing and hammer it a tad on a cent and see what happens. Compare against post and pre 1982, use different size bearings, etc. Compare to using a vice for the compression, with a hard back surface or a surface to distribute the pressure, etc.

 

Btw....#1...My pics BITE!!!! I am anxiously awaiting the arrival of a coin microscope camera doo dad. Not so much to find those minor minor errors but to hopefully take better pics..
#2...Serious question.....a Rockwell test dent is intentional. Just not intended for the planchet to be used. How WOULD one ID a legit Rockwell test mark? A legit one would look for the most part identical to a mark that could be "made at home". The error is the use and release not the product, being the mark
#3.... This will for now go into my "POOR ABE" series. I will call this one. Poor Abe...about to eat a baseball.....I like it!!! Itll go good with "speared", black eye, mutant black eye" and " angry Abe"!!!!
Thanks boys

 

I've said this before, but it needs to be said again:

In 2004 I took a special, 2-person Floor Tour of the West Point Mint.

(I was there in 1973 when it was the West Point Depository, examining
the CC dollars for Error coins, on behalf of the GSA)

During my 2004 Tour, (with Dave Camire of NGC), we saw the entire
Mint's operation - including a small room with the Rockwell Test
machinery.

Basically, it's a metal pointed tip that drops onto the surface of the
planchet, to help determine hardness of the planchet so it's correct
and not too hard or brittle, which would shorten die life, among other
factors.

The indentation that is left from the Rockwell Test is small, and the
WP Mint employee told us that they destroyed those pieces tested,
but that if one somehow got struck, the striking pressure during
minting (65 to 85 tons of pressure, depending on denomination)
would ENTIRELY eliminate the small indentation.

That's why none have ever been found, and those that are pictured
on some of the good Error websites are not RTP's, in my opinion.

I know that "Lonesome" John Devine identified a coin as a RT coin,
and although I knew John very very well, I believe he was mistaken
on the coin pictured and listed on a few websites.

So, yes, the Rockwell Test Machine exists, and I've seen it in person,
but in my opinion, any coins touted as RT pieces simply are not, as
they would not exist (the indention) after such planchets are struck
with such tonnage of striking pressure.

My opinion.

 

Well that mark had to be made post strike. You can see on the left edge of the mark how the metal has been pushed up higher than the field. If it was pre strike the edge would be no higher than the surrounding field and the mark would have pretty well have been wiped out completely by the strike.

So what would the point be to doing a Rockwell hardness test on the coin after it has been struck? I might see a hardness strist pre strike to make sure the planchets had been annealed properly before they were sent to the press, but that typically isn't the case with the zinc cents anyway. You might do one on a die, but that would create a raised lump on the coin so the die wouldn't be used anyway. If you did a test on a die I don't think you would do it on the die face you would do it on the body of the die. Or in the case of a die blank pre hubbing you would do it toward the edge where it would be removed by the lathe post hubbing.

 

Fred has mentioned in past posts (other threads) that they cannot exist because the hardness test is done before striking. The minting of the planchet, which squeezes and pushed the metal around, would totally obliterate any Rockwell test. If seen, it would be totally deformed at best.

Additionally, This excerpt from metal testing information about hardness testing Confirms that it is completed before and after annealing on planchets. Thus it won't ever be found.







Additionally, the Rockwell test machines are generally available and used in metal testing by the metal industry. One could obtain one and start their own production line if they wanted ...

There's more info out there ... just a google or two away.

 

I did some very very quick and dirty calculations. It appears that the test ball is 1/16". In order to get a 60 hardness measurement (listed in @Clawcoins post above) the depth of the penetration would only be 0.005". I didn't do the math but the dia of the mark would be pretty small as well. I would expect a mark that small to be completely obliterated during the striking process, as Fred mentioned above.

It might be a good idea for one of the metallurgical guys to check my math. I've done Vickers Indentation tests but never did Rockwell on metals. The small penetration depth makes sense, however.

 

BTW, the rockwell test is to confirm metal striking and flow test. Thus it is done before striking.

If the material was well outside of the test confirmation parameters, then the metal (planchet) would not strike and flow properly based on the strike tonnage. Thus the planchet would not have any sharp details formed on the metal. So if the test itself still existed after striking, then the formation of everything else would be weak to nonexistent.

 

Hi
I found your thread quite interesting.so I did a quick research on the Rockwell test.
And found this bit of interesting information...
(Such planchets are supposed to be discarded. If a planchet with a Rockwell test mark is struck by coinage dies, the pit is not erased. The pit’s originally circular outline may, however, be distorted into a slight oval as the coin expands beneath the impact of the dies.)

http://www.error-ref.com/?s=rockwell

Also on cc they were talking about it on there site as well.
One person was claiming it was only done at the san Francisco mint. Not sure if that is completely accurate. If Fred says he was at west point in 73 and it was there.
Well I’d have to go with Fred.

 

The odd part, if you look at the pictures you'll see one of their "rockwell test" in a design element. So did the test mark RAISE with the striking and wasn't moved or distorted much. how to do you take into account the striking pressure which supposedly raised everything around the testmark, including the test mark, but didn't erase the mark itself ?




The test itself does not increase the metal strength in that area to a point that striking would not do anything to it.

Think of the pressure to move the metal into devices, etc. And this pressure bypassed the test mark? Also think of all the metal flow marks you get on coin fields. This gives you an idea of metal flow and movement. And yet, somehow a test mark would not be affected?

If you look at the above picture, the lower part of the crater has the raised section pushed down by looks of the metal itself. So this mark occurred after striking IMHO and allowed the device to shift up.

Fred also mentioned in another thread that those pages are incorrect.

I forgot to mention the rockwell test in normal industry can have various bearing sizes for testing, with 1/16th being the smallest for their machines, at least from what I have read.

 

Hi
So if yours was a Rockwell test coin . Then that would be a perfect strike. With no extra indentation from a slightly miss strike.
On the Error reference if you scroll down a bit till you get to...
PART IV. Die Errors:
Rockwell Test Mark Left in the Die

You will find this...
The pit is oval, rather than circular, but this can be attributed to distortion produced by the strike.