Errors explained?

[Rob]

I don't think a weak strike would apply because the shape of the letters is all wrong. With a weak strike you get the detail with a full footprint, but in unusually low relief. This means no fine hair detail for example because the metal wasn't sufficiently forced up to fill the finer voids. The coins struck during WW1 and WW2 do show this characteristic as an attempt was made to extend the life of the dies. Another date which is notoriously weak is 1920 and also 1921 following the change from 925 to 500 silver.

I stick with my original assessment because the legend on any GV penny or halfpenny is flat topped and yet yours has a nicely bevelled high relief verging on the sharp. That is the point which immediately stood out, coupled with the 'moat' surrounding each character.

[Rob]

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

It isn't impossible, but would require the diameter to be of the correct size so that the blank was held securely in the collar. The slightest variation in diameter and you get a noticeable mistrike. This happens when a blank of similar, but not identical dimensions gets thrown into the hopper with the correct blanks. An example is this 1967 florin which weighs 7.78g instead of 11.30g, has only a bare trace of edge milling and is obviously off-centre.

Obverse:

[Rob]

And reverse. The RM suggested it was a Burundi 10Fr flan based on diameter and weight, which means it was actually struck in 1968, not 1967.

As you can see, the detail is slightly weak at the periphery and on the high points, but normal size as a footprint.

Edited April 17, 2013 by Rob

[Sword]

I have dropped a fair number of copper coins into acid over the year (for serious purposes at work and not fooling about). I used concentrated nitric acid which can reduce the weight and size to a fraction within a few minutes.

In this case, it does look like that something has reacted with the coin judging by the shape of the letters and colons in the legend and an oxidising acid seem very plausible to me.

Proving that it is due to acid is of course (very) difficult. You need to be lucky with guessing the concentration of the acid and time scale, etc etc. that might have caused the desired effect.

On a different note, if you have a high grade milled coin (say EF or unc) that is "missing" a letter or has a weak letter in the legend due to say greese, how would that affect its value?

[Gary D]

I have dropped a fair number of copper coins into acid over the year (for serious purposes at work and not fooling about). I used concentrated nitric acid which can reduce the weight and size to a fraction within a few minutes.

In this case, it does look like that something has reacted with the coin judging by the shape of the letters and colons in the legend and an oxidising acid seem very plausible to me.

Proving that it is due to acid is of course (very) difficult. You need to be lucky with guessing the concentration of the acid and time scale, etc etc. that might have caused the desired effect.

On a different note, if you have a high grade milled coin (say EF or unc) that is "missing" a letter or has a weak letter in the legend due to say greese, how would that affect its value?

I would suggest only curiosity value unless it's a very rare coin. It would normally just be a reject.

By the way the coin in my avatar is a classic weak strike due to the wrong sized planchet. I beleive an Irish 6d was used as it is Nickel.

Edited April 18, 2013 by Gary D

[Peckris]

I have dropped a fair number of copper coins into acid over the year (for serious purposes at work and not fooling about). I used concentrated nitric acid which can reduce the weight and size to a fraction within a few minutes.

In this case, it does look like that something has reacted with the coin judging by the shape of the letters and colons in the legend and an oxidising acid seem very plausible to me.

Proving that it is due to acid is of course (very) difficult. You need to be lucky with guessing the concentration of the acid and time scale, etc etc. that might have caused the desired effect.

On a different note, if you have a high grade milled coin (say EF or unc) that is "missing" a letter or has a weak letter in the legend due to say greese, how would that affect its value?

Name your price! Here's my 1964 sixpence...

That well-known variety "I in GRATIA missing" (still trying to get it accepted as a variety - I live in hope)

[Sword]

I have dropped a fair number of copper coins into acid over the year (for serious purposes at work and not fooling about). I used concentrated nitric acid which can reduce the weight and size to a fraction within a few minutes.

In this case, it does look like that something has reacted with the coin judging by the shape of the letters and colons in the legend and an oxidising acid seem very plausible to me.

Proving that it is due to acid is of course (very) difficult. You need to be lucky with guessing the concentration of the acid and time scale, etc etc. that might have caused the desired effect.

On a different note, if you have a high grade milled coin (say EF or unc) that is "missing" a letter or has a weak letter in the legend due to say greese, how would that affect its value?

Name your price! Here's my 1964 sixpence...

That well-known variety "I in GRATIA missing" (still trying to get it accepted as a variety - I live in hope)

Very nice! I can trade you my steel two pence without the copper plating variety for it (I made one sometime ago by leaving a 2p in acid for just the right amount of time and ended up with removing all the copper and without damaging the steel at all)

Seriously, there is obviously a curiosity value as Gary said earlier. If that were to happen to say a unc. young head crown that would otherwise be worth 2K plus, do you also think the value would be reduced significantly. (I don't have any coin like that but is just curious)

[ski]

I think this coin is of weak and/or uneven strikes due to thin flans caused by the use of over-pressed-too-thin sheets of metal.

never mind all the bollox talked about by the experts on this magificent forum.............just wait a frigging minute though......i wasnt there when they rolled the sheet of metal and unevenly/weakly struck this coin.....SO I MUST BE WRONG!!!!!.not really the proof you were looking for.

i bet theres nobody that can give you the "proof" you need in relation to the striking of this coin over more than 75 years ago, or any time it may have been subjected to some chemical treatment since.......but..............theres possibly hundreds of years of experience in handling coins here, many have seen this effect on a coin before and offered theyre opinion on how it may have come about, but hey......what do they know

when you title a post "Errors explained? Opinions as to cause welcomed".....please dont be disappointed if no proof is offered but opinions are.

Edited April 18, 2013 by ski