World of Coins

Modern European coins except the euro => Scandinavia => Topic started by: Thulium on December 23, 2016, 02:42:05 AM

Title: Analysis: Sweden 1964 5 Öre with "5 Ö in crown"
Post by: Thulium on December 23, 2016, 02:42:05 AM
I recently acquired a very interesting coin from Sweden that’s described either as “50 in crown” or “5 Ö.” in crown. What I find unusual about this variety is how these details are beneath the crown, as shown below compared to a normal 5 Ore coin.

(https://c1.staticflickr.com/1/304/30997948843_37bd3a4bf7_c.jpg)

This coin type is unusual and interesting because the whole design is incuse on the coin. This means the design on the coin die was raised, which makes this variety more difficult to understand. To better visualize what happened, I have created impressions of the crown area in soft rubber for both a normal coin and the 5 Ö. in crown type. These impressions simulate what the relief of the die might look like, to help us better understand the forces involved and the resulting damage that was transferred to the struck coin.

(https://c1.staticflickr.com/1/360/30972999554_ab43acf748_c.jpg)

There are two possible explanations for this variety: the errant 5 Ö. mark was made to the hub, or the damage happened to the die. Since these two scenarios are starkly different, I performed a detailed analysis to better understand the process and rule out what is not supported by evidence.

Explanation 1: the 5 Ö. mark happened to the hub. For this to occur, a raised, reverse-reading punch bearing “5 Ö.” was pressed into the hub before the main design.  The simplified diagram below shows how this might occur in terms of relief to the hub. What I find problematic about this explanation is how the raised design on the hub (same as on the coin) was not affected by the overlap with the 5 Ö. mark--see following diagram.

(https://c1.staticflickr.com/1/723/30997948473_eb0d03b97a.jpg)

As the diagram above shows, if the hub was first struck with 5 Ö., those recessed areas in the hub would produce areas of weaker detail when the hub was made. Below shows the 5 Ö. in yellow, with the red areas where this damage should overlap and result in weaker details--if the damage happened to the hub. However, the red areas show strong details with no loss of relief on the hub and the resulting struck coin. Therefore, I think this explanation is not well-supported by evidence on the coin.

(https://c1.staticflickr.com/1/339/30997948973_3b574d47f6_z.jpg)

The second explanation: the damage happened to the die. For this 5 Ö. design to appear behind the crown, the damage would have to occur after the die was made.  Below, I have diagrammed how this damage might have happened to the die, and how the result might appear on the struck coin.

(https://c1.staticflickr.com/1/687/30997948933_6ac7dee05a_c.jpg)

As diagrammed above, if a clash occurred between the die and a tool bearing a “5 Ö.” mark, it should have both flattened the highest crown details on the die, and caused metal flow into gaps on the die (or pinched raised details on the coin). The animation below compares the crown of the normal die to the one with the “5 Ö.”  Below, I see clear evidence for both flattening and metal flow into gaps on the die, which would suggest the die struck an object which transferred the markings. So, in my opinion, a clash to the die is the better explanation for this unusual variety. 

(https://c1.staticflickr.com/1/393/31807637135_515dc2c75a_o.gif)

This analysis seeks only to explain the physical process involved, rather than specific die-making techniques of the mint at that time. But here is an explanation in Swedish (http://www.falcoin.se/pages/posts/5-oere-1964-med-50-i-kronan-721.php), describing how this variety happened.  However, I was not satisfied by my interpretation of the technical language on that page. Therefore, I focused on what might be the plausible process, rather than specific mint techniques involved.
Title: Re: Analysis: Sweden 1964 5 Öre with "5 Ö in crown"
Post by: Figleaf on January 02, 2017, 01:05:25 PM
Pretty brilliant analysis Thulium. Might I venture that the 5 Ö is a punch normally used to mark the other side of dies, so that minters can see which die they are holding before the mules and errors roll out of the press?

Peter
Title: Re: Analysis: Sweden 1964 5 Öre with "5 Ö in crown"
Post by: FosseWay on January 02, 2017, 06:42:25 PM
I like that explanation. I had previously wondered about this error here (http://www.worldofcoins.eu/forum/index.php/topic,26653.0.html). I also attached somewhere (can't now find it  :-[) an explanation by a Swedish numismatist that IMV didn't explain what happened as convincingly as you have. In both cases, though, the root origin of the 5 Ö mark is as some kind of identifier punch. Sometimes the error is referred to as "50 underneath crown", which I think is wrong. On my example (see link) the dots of the Ö are clearly visible. I don't know whether they are sometimes less clear.
Title: Re: Analysis: Sweden 1964 5 Öre with "5 Ö in crown"
Post by: Thulium on January 02, 2017, 06:54:51 PM
Might I venture that the 5 Ö is a punch normally used to mark the other side of dies, so that minters can see which die they are holding before the mules and errors roll out of the press? Peter

Thanks Peter and FosseWay. :) Creating the crown impressions was an interesting challenge, which I think lends insight into what happened. I agree--a clash of the die with a  5 Ö identifier mark is the most plausible explanation.
Title: Re: Analysis: Sweden 1964 5 Öre with "5 Ö in crown"
Post by: Globetrotter on April 05, 2017, 07:55:40 PM
Hi,

I also have that coin, see below. Thulium's documentation is definitely very nice! Bravo ;D

I think I have some part of Fosseway's missing document, at least the quintessence of it, see below!

Ole
Title: Re: Analysis: Sweden 1964 5 Öre with "5 Ö in crown"
Post by: FosseWay on April 05, 2017, 08:29:24 PM
What still perplexes me is why in that case the 5Ö appears correctly orientated on the coins. If the first stamp in the box was just an identifier with 5Ö and nothing else, you'd expect it to be punched so that it can be read normally by someone taking the dies out of the box. Not, in other words, a mirror image thereof, as a real die would be. But whatever it was, it clearly was mirror-imaged.