Author Topic: Manzhouguo fibercoinage 1944-1945  (Read 10017 times)

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Offline Figleaf

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Re: Manzhouguo fibercoinage 1944-1945
« Reply #30 on: November 08, 2016, 09:33:27 PM »
Fascinating, plasticman. To think that dandelions can actually have some use. For some years now, we are trying NOT to grow dandelions in our garden :), but Murphy's law probably stipulates that those in our garden are the wrong sub-species anyway.

Do your conclusions permit further thought, speculation or even conclusions on why weight and size would be irregular, as Afrasi reported above?

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline MORGENSTERNN

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Re: Manzhouguo fibercoinage 1944-1945
« Reply #31 on: November 17, 2016, 12:39:38 PM »
Hello
I got a 5 fen 1944 WEIGHT 1.21g SIZE 2.01 mm
I will post picture later if needed

Offline plasticman

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Re: Manzhouguo fibercoinage 1944-1945
« Reply #32 on: November 25, 2016, 01:33:46 PM »
I haven't found out any more on the moulding technology which might have been used, all I can go on is the actual coins - the mouldings. So, looking at the dimensions listed here (14 coins inc mine) we find significant variations.   There is a minor variation in diameter of about 5% which you might expect with a metal mould, or set of moulds. The thickest 5 fen was 63% thicker than the thinnest and 37% for the 1 fen. The mass of the 1 fen showed the heaviest some 46% heavier than the lightest with the 5 fen 37% heavier. So, a thicker, heavier coin would result if the material was too stiff (less willing to flow) or the moulding pressure too low or the amount of material used was varying. The ability of the material to be squashed into the mould would be affected by temperature and the actual composition (ratio of rubber to mineral). If the pressure were insufficient, this suggests that it could be a hand operated press but this is very speculative. The 5 fen coins show a bigger variation than the 1 fen, which suggests  that a low pressure technology was used, as a higher pressure would be needed for the larger coins.
I have assumed that the coins were moulded from a dough like consistency material, and not stamped from a sheet because of the thickness variation.
So, based on little evidence apart from a few coins we can speculate that the mouldings were made from a dough-like composition in a relatively low technology manufacturing procedure, but of course other conclusions could be drawn. It would be nice to find non-numismatic items made from the same material

Offline Afrasi

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Re: Manzhouguo fibercoinage 1944-1945
« Reply #33 on: November 25, 2016, 03:21:04 PM »
Thanks for your thoughts!

Offline Figleaf

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Re: Manzhouguo fibercoinage 1944-1945
« Reply #34 on: November 26, 2016, 12:09:35 PM »
Just a little comment on that 5% diameter variation. I measure diameters of all my coins. I regularly find a variation of 0.3 mm (I round off, my electronic callipers give a value in one hundredth mm) among comparable coins. Most coins are between 2 and 3 cm, which would imply a variation closer to 10%.

Here's an example: a series of Russian 2 ruble pieces 2012 for the Napoleonic wars. Diameters range from 22.9 to 23.1 mm and mean and average are 23 mm. Even taking rounding into account, the variation is bound to surpass 5%. However, these coins are metallic. You may see smaller variation when using plastics with metal.

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.