Indian Head vs Copper Lincoln Mystery

Iron Buzz

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1864 - 1909 Indian Head Penny : 95% copper, 5% zinc, 3.11 grams
1909 - 1982 Copper Lincoln Cent : 95% copper, 5% zinc, 3.11 grams
1982 - 2014 Zinc Lincoln Cent: 97.5% zinc, 2.5% copper, 2.5 grams

So... why do those Indian Heads ring up with the same ID as a zinc penny? On my XP Deus at 18K, a copper Linc reads 90-91. An Indian Head and a Zincoln both read 85-87. Why?
 

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TerryC

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Simply because the display is only a selling point and cannot be trusted. Its only best guess is it will tell you iron from silver. If you put too much trust in the display, you will be missing some good targets. TTC
 

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Iron Buzz

Iron Buzz

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Simply because the display is only a selling point and cannot be trusted. Its only best guess is it will tell you iron from silver. If you put too much trust in the display, you will be missing some good targets. TTC
Thanks, but that really doesn't answer my question. I don't rely too much on the ID. I'm wondering why two coins with apparently identical composition and mass would report a different electronic signature, one being identical to a coin with a radically different composition and mass.
 

TerryC

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Sorry. The outer skin of the Zincoln is copper as is the IH. Their diameter is the same. Your detector is mainly telling you that the size of the two coins is the same. I cannot speak for all detectors but most will home in on the size first. That is why crushed wine bottle caps will display the same as quarters... most of the time. Brass cartridge casing will ring in as a penny. TTC
 

TerryC

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Further, I don't know why the copper penny rings different than the zincoln. I really don't use the display.... because it can't be trusted.... we have run full circle. TTC
 

bigscoop

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Run a 10K white gold ring and see what it reads, let us know? Then do the same with a 10K class ring. Do they read the same? They are both .385 gold.

VDI is way over-rated and it really only has a couple of practical applications. The first being in areas where the number of holes has to be kept to an absolute minimum, and the second, the guy who is just shooting for silver coins. The internet is full of videos where hunters are constantly getting fooled by VDI.

In fact, the other day I was a present when a CTX hunter began to realize this very same thing and I was thinking of doing a video on that outing and what was learned that day, and why.
 

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foiler

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V D I = Very Dubious Information.
 

bigscoop

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I think your inquiry is actually revealing the cold hard truth behind VDI, this making your concern sort of a moot point. If you want the Wheaties and Indian Heads you're still going to have to dig those lousy zincs. If this wasn't the case, just as with the broad VDI range of gold items, then many of us wouldn't still be hunting with an Excal or Sov. Gt., etc., we would have switched over to a good VDI machine long ago. I truly wish the tech age could offer us more accurate ID because there are many days when I really get tired of digging pull tabs and zincs, etc. :laughing7:
 

cudamark

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Wheaties don't read the same as copper memorials either. I was always curious about that myself. Maybe the amount of corrosion and/or length of time in the ground? Personally, I'm glad there is a different reading!
 

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Iron Buzz

Iron Buzz

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Further, I don't know why the copper penny rings different than the zincoln. I really don't use the display.... because it can't be trusted.... we have run full circle. TTC

I don't totally trust the TID either, but kind of like when my phone rings... I don't have to look at the screen to know that it rang, but I do like to look to see what the number is.
 

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Iron Buzz

Iron Buzz

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Wheaties don't read the same as copper memorials either. I was always curious about that myself. Maybe the amount of corrosion and/or length of time in the ground? Personally, I'm glad there is a different reading!
They do, in my experience.

I still don't see anybody really addressing what I am asking. For all practical purposes, the only differences between an IH and a copper Lincoln is the image stamped on it. OK, and the age/patina, perhaps. They are the exact same of metal. All copper Lincs ring up essentially the same, because they are the exact same metal. Zincolns ring up differently because they are not... they have a different conductivity than either the IHs or the Lincs. (for me, Wheaties also ring up the same as a copper Lincoln, BTW).

Your MD doesn't have any idea what picture is stamped on that piece of metal. It knows the conductivity. The conductivity is based upon the composition and the mass.

I'm not trying to be difficult here... but I am looking for an explanation that makes sense to me, and simply dissing the TID is insufficient for me. The TID is consistent given the same conditions.

Still looking for an answer that makes sense to me.
 

Eleven Cents

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Maybe the amount of corrosion and/or length of time in the ground?

Corrosion definitely has strange effects. On my low end BH, a new steel bottle cap rings low, but a rusty one sometimes rings high like copper or silver, especially if it's flattened.
 

l.cutler

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Ever tried non dug examples in an air test? Might be interesting to see if it has something to do with having been in the ground longer, maybe something to do with the zinc leaching out?
 

digger27

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It has nothing to do with VDI's, whether I use my Fisher screen units or my no screen Tesoros they act the same.
It has all to do with conductivity readings which is what all detectors go by.

Indian Heads....
Value1 cent (0.01 US dollars)
Mass(1859—1864) 4.67 g,
(1864—1909) 3.11 g
Diameter19.05 mm (0.750 in)
EdgePlain
Composition(1859—1864) 88% copper, 12% nickel
(1864—1909) 95% copper, 5% tin or zinc
Zinc cents...
Mass2.5 g (0.080 troy oz)
Diameter19.05 mm (0.750 in)
Thickness1.52 mm (0.0598 in)
EdgePlain
Composition1982—present copper-plated zinc
97.5% Zn, 2.5% Cu
Even though the modern cents are made differently than all Indians to our detectors, despite their composition, they seem almost the same...sort of.
Might be an actual scientific explanation but I don't know it, you need to find a good metallurgist and ask them, all I know is they just do.
Also IH's as a lot are just weird...I have air tested several from the late 1800's to the early 1900's, all in the relatively same condition and they all seem to be slightly different and not exactly the same.

Silver war nickels are another strange coin...they can come in just slightly higher than a regular nickel to much higher for some reason.

I quit asking why about these things long ago, in sites that might have older coins I just dig signals and hope for the best.
 

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l.cutler

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I did a quick unscientific trial on three non dug cents. A 1908 Indian, 1956 wheat 1981 Lincoln and a 2009 zinc Lincoln with my T2. The Indian came in at 79, the 1956 at 83, the 1981 at 83, and the Zinc at 78. Really odd, no idea why.
 

b3y0nd3r

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My CTX:

12-26-29 indian
12-41 Wheat
12-38-43 copper memorial
12-30-36 zinc memorial

When you are looking at TID(target identification) number, you are seeing a reading that is based on the phase shift of the detection field from the zero point. Believe it or not, the amount of material in each coin is not exact and certain material affect the phase shift dramatically and some material very little.

An Example:

Last year I dug quite a lot of co-mingled coins. On the CTX:

separate:
Wheat 12-41
Nickel 12-14

Together(co-mingled) was a TID of 12-30

So we can see that the nickel brought the TID of the wheat penny down 11 points and brought it's TID up 16 points.

Well the same is true with these pennys:

With the Indian, the tin in the coin brings down the TID

Same with the zinc penny, the massive amount of zinc brings it's TID down compared to the copper cent but slightly higher than the indian.

Now here is the tricky part. It's the amount of that .050 tin/zinc ratio that affects the phase. I would say in indians, there is more tin than zinc and in wheats, there is more zinc than tin. Also, from 1959-1962 the composition of this memorial coin was the same as wheats and on my CTX they read like them.

I hope that helps
 

bigscoop

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But you've already answered your own question. The bottom line is simply this, "due to the many variables that come into play, the technology isn't nearly as precise as advertised, or nearly as precise as many want to believe." If it was then a silver ring wouldn't read the same as a silver coin, the ring being hollow, etc. Pulltabs wouldn't read like gold rings, the shapes and densities being very noticeably different, etc. The processor is simply gathering various, and limited, data points and then making a best guess.

To help explain this a bit better let's compare a high end "sound only" machine to a high end "TID" machine. The sound only machine returns "a complete sound wave" that the ear can evaluate, yet the best TID machine is only returning, at most, a summation from just a handful of data points within that entire sound wave. In essence, there is far more data in the complete sound wave then there is in the TID return, "if the ear can actually accept and dissect that data", which it can't. This is why TID was developed, to offer users an additional visual means of trying to make some sense of it all. So the bottom line is that the technology isn't nearly as precise as many wish it to be, your own comparisons actually serving to solidify that fact. Here, in a nutshell, rest your answer.
 

cudamark

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My CTX:

12-26-29 indian
12-41 Wheat
12-38-43 copper memorial
12-30-36 zinc memorial

When you are looking at TID(target identification) number, you are seeing a reading that is based on the phase shift of the detection field from the zero point. Believe it or not, the amount of material in each coin is not exact and certain material affect the phase shift dramatically and some material very little.

An Example:

Last year I dug quite a lot of co-mingled coins. On the CTX:

separate:
Wheat 12-41
Nickel 12-14

Together(co-mingled) was a TID of 12-30

So we can see that the nickel brought the TID of the wheat penny down 11 points and brought it's TID up 16 points.

Well the same is true with these pennys:

With the Indian, the tin in the coin brings down the TID

Same with the zinc penny, the massive amount of zinc brings it's TID down compared to the copper cent but slightly higher than the indian.

Now here is the tricky part. It's the amount of that .050 tin/zinc ratio that affects the phase. I would say in indians, there is more tin than zinc and in wheats, there is more zinc than tin. Also, from 1959-1962 the composition of this memorial coin was the same as wheats and on my CTX they read like them.

I hope that helps

Except that the later wheats (1944-58) have no tin, just like the '62-82 Memorials.....but they read different (lower) on all my White's detectors and my Minelabs. The percentage of tin vs. zinc on the Indians and early wheats is probably the difference in readings for those and I guess the composition of the '82-up Zincolns is just a matter of similar conductivity that makes them sound and read like an Indian cent even though their composition is totally different. Now if we can just get a detector that can tell a pull tab and gold with 100% accuracy, we'll have something!
 

Kurios1

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Do you think your thinker is thinking too much here maybe? As much as I too wonder about VDI's and tones and all at the end of it I just hear a tone check the VDI and dig it. Time and experience has led me to know the language whichever machine I am using is speaking to me pretty well. I try to avoid thinking about all the inconsistencies with the technology and just dig the targets. I spare racking my brain on more serious issues. Have fun and dig that beep.:wave:
 

Electricfrontporch

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At least with the IH cent you only have zincolns for trash competition.
Gold jewelry is far more moody. Comes in anywhere between a 1/2 a ketchup pack
And that zinc cent. In the end regardless of the technology a lot of trash
equals a little treasure. DIG IT ALL!

Noah
 

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