5kop1790KM - nice but false

[sigistenz]

I won a nice coin at eBay but was disappointed when receiving it - the edge looked like filed down all around. See my picture above. The seller had not shown the edge. Who could have tooled the edge - and what for?

The microscope reveals the secret: there are bubbles on the edge This means it has not been filed down. We have to do with another fake. Even under a magnifying glass, the coin looks perfectly all right. Only the microscope shows the bubbles of the cast. The seller promises to take the item back for a refund.

Enjoy watching Sigi

PS: Weight is 53.1grams which is in the normal weight range for these coins

[Guest rnsdb]

One more for the forgery task. Scary, but particularly the patina. I'm not sure what limed down means, but isn't the absence of edge 1 enough to condemn it even without the bubbles? Is casting technology headed toward no bubbles at all and good edges? Or is it already here and this is an older example?

 

Your forgery analysis HERE + HERE + HERE + HERE

 

Would a useful article for a next electronic issue of JRNS be a review of the methods, sources and future evolution of forgery technology?

 

Ron

[sigistenz]

 

 

One more for the forgery task. Scary, but particularly the patina. I'm not sure what limed down means, but isn't the absence of edge 1 enough to condemn it even without the bubbles? Is casting technology headed toward no bubbles at all and good edges? Or is it already here and this is an older example?

HERE + HERE + HERE + HERE

Would a useful article for a next electronic issue of JRNS be a review of the methods, sources and future evolution of forgery technology?

Ron

Ron, I confused French and English both of which are foreign languages for me. I did want to say "filed down" but the French "limé" came into my mind. I now corrected my post above.
The absence of the edge alone may mean that somebody tooled it away. That was my first impression. Only under the microscope the bubbles appear. Yes, the color is very tempting. In hand the coin looks perfectly alright - and I have seen a lot.

Regards, Sigi

[Guest rnsdb]

Congratulations, sigi. You have unwittingly become the first volunteer. I have added the 53.1 gm weight to the database and if you can provide the size in mm of both the original and the forgery, I will add that also.

 

The forgery edge is troubling. Why would it be filed or was the edge never cast in the first place? It raises the question of whether casting technology has a vulnerability when it comes to edges.

 

Maybe some who have bought cast forgeries can shed light as to whether required edges are always there and if so, are they generally as good as the obverse and reverse.

 

Also whether casting bubbles will always show under the microscope. But even here, wouldn't the planchets used for the original stamping have been made by casting the copper and therefore show bubbles under the microscope? With the technology of the 1700's, I would think there would be even more bubbles in the originals than in modern forgeries.

 

Having collected mostly in the 80's and 90's, I never paid much attention to forgeries, although I did have a 1 rouble plate piece offered to me, supposedly found at the bottom of the Volga river, but comparing it to original pictures, even I realized it was a forgery.

 

Ron

[sigistenz]

Hello Ron, as you may know the weight standard for those coins was 51.19g. Little care was taken for the indivual pieces. The batch weight had to be correct, i.e. there had to be 320 of them per pood. Individual weight differed between about 20% above and 20% below standard. The pieces in my collection weigh between 40 and 65 grams. My two1790KM 5kop. weigh 48.7 and 48.8 grams, which is pure incidence and does not mean that the 1790KMs were lighter than standard. So weight is of little help as long as it stays around 51.19 grams.

The same applies to diameter or thickness of the planchet. My two (of course genuine as all my coins) 5kop1782KM measure 41 and 43mm across. So the diameter does not mean a thing, either.

As I said the above forgery looks absolutely convincing as to design and color. Even in my hand with my 40 years' experience no doubt arises. A fine coin in very nice shape.

Only the edge gives it away and not at first glance, either. As my close up scan showed some clear spots I took out the microscope. And only then the bubbles could be seen. I hoped my picture of the edge showed that the bubbles are not holes (as of porosity) but do stand out. That made clear that there could not have been any tooling of the edge.

The bubbles cannot be explained by the coining process either. Copper sheets were rolled to about the required thickness, then planchets were cut (stamped) out of them. For the impression of the edge design the planchet was rolled between two parallel bars. No way for outstandíng bubbles thus. BTW it happened that genuine coins missed by mistake the edge rolling pocess, plain edges occur. But no outstanding bubbles possible with planchets that had been stamped out of a rolled sheet of copper.

All this is to say that weight, diameter, pictures of both sides of this forgery don't give it away. This must be the copy of a genuine coin anyway. It is the edge. And only the edge.

I feel honored to be considered a volunteer. As such I'd insist that the true edge of a forgery be given the importance it deserves.

Pictures of only both (true looking) sides are of little help, they may even lead to confusion.

Ron, as you know English is not my mother tongue. I don't know if I appear harsh - that is not my intention. I want to be constructive.

Best, Sigi

[Guest rnsdb]

Thanks for the input. I would not thought the variance to be as wide as that. I would expect silver to be much narrower and gold variances to be almost non-existent.

 

This is a perfect example of Wiki. As a specialist in large coppers, you know this level of detail. Most of us don't but we can if the database is filled up with these kind of shared insights.

 

If you will look at the revised HERE form for the original, you will see I propose the following. Weight and size shown in the respective data fields will be the standard or typical. In the Memo description, I put your ranges for both weight and size. This may help with false positives when trying to decide original vs forgery.

 

Ron

[EugeneG]

As I can see

It is the edge. And only the edge.

So there are no "bubbles" on surface? I'm curious, how those bubbles can appear. Edge on galvano-fakes is usually being fixed manually. I never had luck to have a close look on such coins, maybe bubbles are common.

[sigistenz]

So there are no "bubbles" on surface? I'm curious, how those bubbles can appear. Edge on galvano-fakes is usually being fixed manually. I never had luck to have a close look on such coins, maybe bubbles are common.

Eugene, I don't have the coin anymore, it is on its way back to the seller. Now that you mention it, I took another closer look at my remaining scans. And yes, indeed, there seem to be very small bubbles (warts, pimples or whatever) on the sides as well but too small for a magnifying glass. In hand the coin looked pretty nice, smooth, slighly shining, nice color.

Now it's clear that it is a cast job. Better than what I've seen before. But the edge still seems to be problematic for the forgers. From now on I will aks to see the edge before bidding

Thank you for the useful question!

Sigi

 

[extant4cell]

I am not completely convinced that it is a fake, but I didn't had a chance to handle it...

[extant4cell]

Do you know what was its diameter?

[extant4cell]

OK, this was a nice "theory" that I described, which may have some sense, but now I am more inclined to say it is a fake coin. Here is an example of a forgery coin that I was shown and I just added to the database: http://www.rnumis.com/rnumis_research_0.php?db_pgtyp=db_pgtyp_rf_single&rf_id=386

 

 

It has a similar edge problem...

[STEVE MOULDING]

Is there any legitimate explanation for edges like this?

[sigistenz]

Is there any legitimate explanation for edges like this?

I don't think so. To apply the edge device, for example (//////////////) or (XXXXXXXXXXXXXX), the planchet was squeezed between the two bars of the edging machine. The two bars were then moved one opposite to the other. This turned the planchet and impressed the edge. If he planchet was not perfectly circular, portions of the edge were left unimpressed. But what we see here on Eugene's picture was removed deliberately. When copying a coin by casting, two halves of the mould are necessary, one for the averse, the other for the reverse. The molten metal is then filled into them. A more or less distinct seam between the two half moulds will remain on the edge all around. To conceal the cast, the seam has to be removed (filed away), like on Eugene's coin.

A legitimate explanation for edges like this would be wear down from circulation - Eugene's coin did not see enough circulation for an edge like this.

Sigi

[STEVE MOULDING]

Could somebody file away the edge rim on a real coin to get some 'free' copper? Unlikely, I guess...doesn't seem worth it. Just trying to make sure we thought about all possibilities

 

The close-up of your 1790KM shows a very uniform edge. Not even a hint of a seam or of two underlying halves. And would those tiny imperfections along the edge persist after a filing? (that, of course, would also be an argument against the "free copper" theory)

 

Did you see a seam trace anywhere else on the coin Sigi? (I know it's already gone back to the seller)

[extant4cell]

Both don't look like modern fakes. Most probably casting fakes. Another wild suggestion - experimenting with a ring in order to make coins more circular after edging at the time of pressing?

[extant4cell]

Here is it's sister:

• 

[sigistenz]

Could somebody file away the edge rim on a real coin to get some 'free' copper? Unlikely, I guess...doesn't seem worth it. Just trying to make sure we thought about all possibilities

 

The close-up of your 1790KM shows a very uniform edge. Not even a hint of a seam or of two underlying halves. And would those tiny imperfections along the edge persist after a filing? (that, of course, would also be an argument against the "free copper" theory)

 

Did you see a seam trace anywhere else on the coin Sigi? (I know it's already gone back to the seller)

 

 

 

With silver coins it happened that edges were filed for the metal - but I think it is unlikely with copper, it would not be worthwhile.

As to "my" edge, I think the filing was done to make disappear the seam. I have no idea how the pimples got on the edge. I only discovered them on my high resolution scan. Maybe I should have inspected it closer. I am not a metallurgist. I did not notice any other suspicious traces.

My intention was to be fast to convince the seller to accept the coin back for a refund. Now it's too late.

Sigi

[sigistenz]

Both don't look like modern fakes. Most probably casting fakes. Another wild suggestion - experimenting with a ring in order to make coins more circular after edging at the time of pressing?

Hmm - at the mint, you mean, done officially after the edgeing process? Unlikely, I think. With copper coins less care was taken than with precious metals. Their parkmeters must have had a great tolerance

Sigi

[bobh]

As to "my" edge, I think the filing was done to make disappear the seam. I have no idea how the pimples got on the edge.

Wouldn't there be bubbles hidden right underneath the surface which would appear after filing?

[sigistenz]

Wouldn't there be bubbles hidden right underneath the surface which would appear after filing?

The pimples stood out, I do not know what had be done. My only sorrow was to return the coin fast and have a fast refund. With the seller I did not enter a (lenghty) discussion if fake or not, I told him that the edge was mutilated which is uncontestable. I got my money back.

Sigi

[rsraghead]

sounds like the best thing to have done

[extant4cell]

I am glad you got your money back. One other suggestion is that this coin had lots of small corrosion cavities that were repaired with cuprite that later started to swell and sticking out like tiny copper droplets...

[sigistenz]

 

Here is it's sister:

• 

 

Hi Eugene - in fact this one is alike to "mine". Is it yours? Could you show the edge?

Thank you, Sigi

[extant4cell]

It's not mine... I was shown this coins when I discussed "yours", as an example of it not to be too exclusive. And I even argued for a sec that it was the same coin. Alas, I was quickly subdued with some cold water... Someone was selling it a while ago along with this one:

• 

truthfully calling it a copy... I am sure it would have a similar edge.

[sigistenz]

See here "my" coin and "Eugene's" coin side by side. Their imperfections are pretty alike. I think there is no more doubt that they both are fake.

Sigi