Detecting repaired coins
MrEureka
Posts: 24,271 ✭✭✭✭✭
Usually, all an expert needs is a quick look at a coin to detect a repair. Sometimes, with the aid of a magnifying glass. But other times, the repair is good enough that it may be suspected (because “something” looks off) but not actually seen. In such cases, what technologies, equipment and methods can be used to positively determine what, if anything, was done to the coin?
Andy Lustig
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
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Comments
my understanding is that the sniffer hardware/software is able to "fingerprint" a coin to a unique signature. the same tech can detect various compounds on the surfaces enough to give the user enough information to make a determination of an acceptable range and/or specifically identify.
i have to believe that the scanning properties can detect the "normal/average" surface striking characteristics for each type for whatever the predetermined range would be enough so that any disturbances outside of a preset range at the very minimum, can pinpoint to an area(s) enough to bring attention to it.
not sure how easy/difficult it would be to have the settings as such so that every single contact mark on a coin is not pointed out.
i think a less techie method is to rotate the coin in such a way as the disturbances kind of reflect and/or show inconsistencies in original surfaces with metal flow, luster etc. personally i've never really encountered a coin called as such (from submissions), so my personal in-hand experience is limited. any experience in-hand is with stuff that was to any average seasoned numismatist that keeps an eye out, would notice what i did, perhaps even more.
there have been plenty of images of coins posted here over the years asking the members to try and identify what, if any, tooling, repairs etc they can detect/guess at. removing the in-hand option make such things much more difficult.
my 2c
I thought I had read here that the referenced "sniffer" was short lived and is not being used today?
"Got a flaming heart, can't get my fill"
for my part i don't know 100% either way and also don't know if they have since implemented something better. so, my response was to this part of the OP inquiry. at the very least, it did exist, therefore, either it still exists or can exist again.
where's Schrödinger where you need him. lol
"In such cases, what technologies, equipment and methods can be used to positively determine what, if anything, was done to the coin?"
i do recall some members using some scientific equip and also medical equip on some coins a while back. don't really recall what came about from it but i'm sure there is plenty of tech to aid with altered numismatics.
there is auto-detect (for lack of a better designation) software that identifies stamps/coins and within a range of accuracy, can tell you what you have. i'm sure something like that could aid as well.
as applied to TPGs, the question is for the bulk but still valuable material, can it be done cost-effectively, including factoring in buy-backs/resubs etc. - i think for expensive coins, it would be a good idea to have something like that around to work with knowledgable/experienced numismatists to decrease buy-back risk/brand protection.
what does those few around here today think?
Expensive early coins have had holes plugged (usually at the 12:00 position) and skillfully re-engraved and some are virtually undetectable. If a repair is suspected, a XRF spectrometer metal analyzer or similar device can be used to ascertain the chemical composition of the suspected area and the results can be compared to a similar analysis of the chemical composition of the central part of the coin. If the chemical composition is the same at both locations, there probably was no plugged hole repair. Conversely, if the results are different, there is most like a plugged hole at the location being examined. I assume the major grading services have access to such equipment.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
I heard that the repair master in Kentucky buys up badly damaged early coins. He melts them down to get the metal to use for his plugs.
Of course the first mint was inconsistent with the metal alloy used in its coins, so that might not be a way to beat the XRF spectrometer.
I have seen a few repaired holes that were so darn good, that you could barely see them with a 10X glass. They are scary.
This is the one that scares me because I can't see it very well on the TrueView.
1933 Eagle Details "spooned" (tooled) Hansen
My Saint Set
>
That's not a 1/2 Eagle. That's an Eagle.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
Post repaired
My Saint Set
I remember hearing something about a blacklight (or maybe that was with stamps and currency)
A blacklight can be used to detect puttied coins.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
.
not sure if you read the heritage description or not.
https://www.pcgs.com/cert/25538477
"Heritage Auction’s Comments: In the absence of a Details grade from PCGS, we consider this attractive 1933 Indian eagle to have Uncirculated sharpness. The coin last appeared at auction in 2005, when it was raw. In that lot description, the Stack's cataloger noted "a profusion of tiny swirling hairlines" on Liberty's cheek. They are indeed faint, seen only with a loupe and under good lighting, but they are in fact tool marks -- the faint remnant of some individual's attempt to smooth out high-point abrasions on this coin in the distant past. Although unfortunate, this "repair" does not overly affect the eye appeal of the coin. Orange-gold luster glistens on each side, especially in the fields. The strike is sharp and the only mentionable abrasions are a few tiny ticks on the reverse eagle, which serve as pedigree markers."
My Saint Set
Here is an example from the "repair master in Kentucky". Before and after. Pretty easy to tell it has been repaired, even with the naked eye. If you are looking for it.
It also dropped a grade, from AU details to XF details.
these tool marks almost look like die polish
Agree. If another high grade specimen was to be found with the same exact pattern, that should change the opinion that this coin is "tooled" or otherwise messed with.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
Why mention that as a possibility, when it won’t happen? It’s not die polish.
Mark Feld* of Heritage Auctions*Unless otherwise noted, my posts here represent my personal opinions.
What if it were polish lines on the hub used to produce the die? I'm just brainstorming here.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
It seems most repairs to coins are detectable with the naked eye and good lighting. The term 'most' probably accounts for 85% (my estimate). Then magnification will pick up another group, likely 10% or more (again, my estimate). After that, sniffers, XRF, etc., come into play. If the repair/tooling/whatever escapes all of those, well, so be it. I would count it good. Cheers, RickO
Agree. A good stereo microscope with good lighting picks up most repairs.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
I'd a never knew it.
Pete
Linked from the Cert Verification page, but here's the direct link for the 2019 auction:
https://coins.ha.com/itm/indian-eagles/1933-10-surfaces-tooled-pcgs-genuine/a/1298-3916.s
Nice provenance on this:
S. Hallock Dupont; Morrison Family and Lawrence C. Licht; Poulos Family
Here's the 2005 Stack's auction:
https://auctions.stacksbowers.com/lots/view/3-FPRJE/1933-brilliant-uncirculated
with a couple dozen in the pcgs pops, is it odd this is the coin DLH has in his set?
to be on-topic.
since zoins posted the ha link, i figured i'd comp the images to CF again to see JUST in case, if this coin has a match with those markings, a small chance but alas, nothing even close.
imo between the MAX pcgs images and the full slab shots of HA, the damage to the cheekbone/cheek/ area and a little more would catch most people's attention, even if one didn't know what they were looking at.