Errors explained?

[RChris 3]

Got these on ebay this week;

On this 1915 penny....something stuck to the die?

And this 1936....it's not camera shake! Can dies shake loose in the collar?

[RChris 3]

The reverse got the shakes too....

[Gary D 76]

The reverse got the shakes too....

The second one looks like acid damage, is it thin and under weight.The first struck through grease or someone having a laugh.

[RChris 3]

Looks normal to me - just weighed it @ 9.4g.

[Benny who 6]

The first looks like grease as Gary has mentioned,the second I would say looks like an engravers practice piece.

[Rob 3,152]

Grease on the first one, acid attack on the second. The legend has a depression surrounding the letters which is consistent with this chemical reaction. There will be stress fractures associated with metal flow where the legend was formed leading to a deeper ingress of the reactant and consequently more damage caused.

[RChris 3]

acid attack on the second.

Would you mind explaining further Rob? Acid when, where, how? Mistake during manufacture or collector cleaning attempt?

[Rob 3,152]

Or acidic soil, or in a drain somewhere, or..........

It has all the hallmarks of a chemical attack, notably the depression around the letters and the letters are sharpened giving the effect that they are honed to a knife edge.

[Peckris 579]

acid attack on the second.

Would you mind explaining further Rob? Acid when, where, how? Mistake during manufacture or collector cleaning attempt?

Neither. Dissolving coins in acid seems to have been quite a common prank in times gone by, when boys could walk into a shop and buy quite volatile ingredients for their "chemistry set" I've got a 1929 shilling that suffered this, and I have to say that acid was my first reaction on seeing your pictures.

The first one is more interesting to me, as the grease has allowed the ghost of BRITT to appear, but whatever is where GRA should be, is something else entirely.

[RChris 3]

acid attack on the second.

Would you mind explaining further Rob? Acid when, where, how? Mistake during manufacture or collector cleaning attempt?

Neither. Dissolving coins in acid seems to have been quite a common prank in times gone by, when boys could walk into a shop and buy quite volatile ingredients for their "chemistry set" I've got a 1929 shilling that suffered this, and I have to say that acid was my first reaction on seeing your pictures.

The first one is more interesting to me, as the grease has allowed the ghost of BRITT to appear, but whatever is where GRA should be, is something else entirely.

So you're saying there could have been a blob of grease next to.....? Maybe a thicker blob of grease?

I appreciate your replies chaps - but as a novice I haven't yet heard what seem to be facts, just your opinions? But maybe unless it's an obvious die crack or lamination issue, opinions are only what can be offered? For example, Rob offers a few ideas as to what may have caused the issues with this penny - and was Peckris there to witness his 1929 shilling getting an acid bath? Or has he experiemented with acid on a similar coin? Just playing devil's advocate guys, not trying to be a smartarse......but I'm hoping to learn here and have a good few more years with this hobby.

[Rob 3,152]

The above image shows the effect on a 1932 halfpenny. In order to standardise conditions as far as possible, there are three coins from the same year which should mean that they share a common master engraving before reduction, if not the same die. The two decent coins are full weight at 5.65g whilst the middle one is a miserable 2.49g. Unfortunately I got rid of it 5 or 6 years ago, so the montage had to be assembled from old images.

As seen, there is no rim, the legend is thinned compared to normal and the detail is lost. The weight of 2.49g is 44% of normal. There are also more subtle indicators of physical removal of surface metal such as the border teeth which are thin lines compared to the normal podgy fingers or the small indent near the front of George's nose just before the end which is in lower relief at this point. I standardised the images as best I could by measuring the distance from edge to edge on the thin one and matching it to the others such that the distance to the inside of the rim was the same on all three coins, as we can say for certain that there would be no lateral movement of the design. In fact the thin one is 1% larger at this dimension, but the distance from truncation tip to the top of the head on a line to the colon at 12 o'clock is roughly 1.5% less on the thin one when compared to the original version indicating that material has been lost by a sideways or at least an oblique angle attack.

I have tried to explain what would happen on this drawing.

To explain the depression around the letters and the head on your coin, assume that the flan starts with a homogenous crystal lattice. I know nothing is perfect and as an alloy is involved with different sizes of atoms this is inherently so, but some things are more perfect than others. When a coin is struck, metal flows into the recesses of the die and forms the features seen. This will disrupt the lattice structure at the flow points leading to structural weakness due to broken atomic bonds. In effect, you get microscopic fissures on the surface of the flan at the atomic level. It is these points that would be subject to a greater degree of acidic attack because they would allow a deeper penetration of the acid when compared to an unaffected surface which would retain atom to atom to atom bonds in the pattern dictated by the metal concerned. Deeper than normal penetration into the flan surface at the previously stressed points combined with ongoing horizontal chemical reactions in the same manner as would affect the legend, will result in the areas of metal flow being hollowed out at a faster rate than would otherwise be obtained on an intact crystal lattice. Obviously there will be anomalies within the flan and other environmental variables which would result in some inconsistencies, but it shows the overall picture - I hope. It would apply to both silver and base coins equally, but not gold except for the impurities contained within the metal mix.

Edited April 16, 2013 by Rob

[RChris 3]

Thanks for that Rob - although I'm not so well educated as I had to look up what a homogenous crystal lattice is! I respect your opinion and expereince of course, but I'm still not convinced without actually seeing the "acid test" (pun intended) for myself. I have a few thin flan/planchet pennies from different reigns - some with your proposed acid effect but others slightly crisper and without it. Being more practical than academic I assumed that thin blanks are simply the cause of the sheet of metal they are stamped from being rolled beyond the correct thickness. Anyhow, I looked around and found this on the interweb, from a guy who has installed coinage presses, maintained them, worked as a die setter and trained personnel in coining operations. His explanations of causes work for me. http://koinpro.tripod.com/Articles/TrialorWeakStrkMoffatt

[Gary1000 41]

Thanks for that Rob - although I'm not so well educated as I had to look up what a homogenous crystal lattice is! I respect your opinion and expereince of course, but I'm still not convinced without actually seeing the "acid test" (pun intended) for myself. I have a few thin flan/planchet pennies from different reigns - some with your proposed acid effect but others slightly crisper and without it. Being more practical than academic I assumed that thin blanks are simply the cause of the sheet of metal they are stamped from being rolled beyond the correct thickness. Anyhow, I looked around and found this on the interweb, from a guy who has installed coinage presses, maintained them, worked as a die setter and trained personnel in coining operations. His explanations of causes work for me. http://koinpro.tripod.com/Articles/TrialorWeakStrkMoffatt

Your link talks largely about weak strikes, your coin is showing post mint damage whatever the cause.

[RChris 3]

I still don't hear any proof of that though....and he talks about things coming loose in the stamping process, so that's waht this looks like to me. It might also be some kind of mechanical doubling mentioned here; http://jimscoins.com/error_coin_examples.php

[Gary1000 41]

I still don't hear any proof of that though....and he talks about things coming loose in the stamping process, so that's waht this looks like to me. It might also be some kind of mechanical doubling mentioned here; http://jimscoins.com/error_coin_examples.php

Did you pay lots of money for this coin by any chance beings you are happy to ignore the many years of experience on this forum.

[RChris 3]

Not at all Gary - 7 quid..... but I did suspect that might be thought a reason for my reluctance to accept the views of those who've more experience than I. I guess I asked for opinions at the start of this thread and I'm not complaining that's just what I've got - opinions, of which I'm very grateful.

[Coinery 1,153]

I'm still not convinced without actually seeing the "acid test" (pun intended) for myself.

In which case, you're just going to have to get an old car battery and pioneer the experiment yourself, as the only way of seeing the acid test directly is by actually undertaking the study, the results/images of which will be valued on here for certain.

For what it's worth, I believe the appearance of your coin is most definitely the result of Crippen Syndrome.

[RChris 3]

I must be out of my depth here....I just Googled Crippen Syndrome having not a clue what it is - and still can't see how it relates to this. Sorry (there's no emotion for embarrassed or red faced!)

[Coinery 1,153]

I must be out of my depth here....I just Googled Crippen Syndrome having not a clue what it is - and still can't see how it relates to this. Sorry (there's no emotion for embarrassed or red faced!)

Hah, allow me to expand (it was my own attempt at a pun/humour)...Dr Crippen!

[Peckris 579]

Not at all Gary - 7 quid..... but I did suspect that might be thought a reason for my reluctance to accept the views of those who've more experience than I. I guess I asked for opinions at the start of this thread and I'm not complaining that's just what I've got - opinions, of which I'm very grateful.

I have never dissolved a single coin in acid, so I have no personal empirical experience to give you a supremely irrefutable proof. However, I've seen enough alleged acid-damaged coins to now feel competent to express the opinion that IF all those separate and independent acid-damaged coins actually WERE damaged by acid (the lack of empirical proof notwithstanding), then yours falls into the same category. Verum esse ipsum factum.

[declanwmagee 122]

Not at all Gary - 7 quid..... but I did suspect that might be thought a reason for my reluctance to accept the views of those who've more experience than I. I guess I asked for opinions at the start of this thread and I'm not complaining that's just what I've got - opinions, of which I'm very grateful.

I have never dissolved a single coin in acid, so I have no personal empirical experience to give you a supremely irrefutable proof. However, I've seen enough alleged acid-damaged coins to now feel competent to express the opinion that IF all those separate and independent acid-damaged coins actually WERE damaged by acid (the lack of empirical proof notwithstanding), then yours falls into the same category. Verum esse ipsum factum.

Justorum semita lux splendens.

Sorry, that was my school motto...

[Rob 3,152]

Sumus omnes in stercore

That was our class motto.

[Coinery 1,153]

Verum esse ipsum factum.

Justorum semita lux splendens.

Sorry, that was my school motto...

Semper in Excretio, Solum Profundum Variat

Not sure if I've remembered this correctly, but this was on the the wall in Frenchay Main Theatres Recovery...and it was true!

[Red Riley 2]

Ours was; 'Brute aderat forte, Caesar adsum jam. Brute sic in omnibus, Caesar sic intram'

[RChris 3]

I have never dissolved a single coin in acid, so I have no personal empirical experience to give you a supremely irrefutable proof. However, I've seen enough alleged acid-damaged coins to now feel competent to express the opinion that IF all those separate and independent acid-damaged coins actually WERE damaged by acid (the lack of empirical proof notwithstanding), then yours falls into the same category. Verum esse ipsum factum.

So there's alleged, IF and WERE.... still opinion from supposition. I'll really have to ask my mechanic next door neighbour to get me some of that battery acid. Watch this space.

No one has commented on my suggestion of the possibility of weak and/or uneven strikes due to thin flans caused by the use of over-pressed-too-thin sheets of metal. Is that idea impossible?

Numquam credere peritus