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Shrinking coins
Posted by Edwin Sherman on 10/1/2003, 5:35 am
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Re: Shrinking coins
Posted by Bert Hickman on 10/1/2003, 7:54 am, in reply to "Shrinking coins" Hi Ed, A shrunken coin has the same mass and density as before. I've submitted samples metallurgists for analysis, but I don't have the results as yet. The metal does become work hardened. The coin gets thicker in the process so that the overall volume remains constant. This effect can be seen in Figure 4 of the ErrorWorldNews article: Because the electrical conductivity is highest in the pure copper center, the shrinking forces are strongest in the center layer of clad coins. This results in the less conductive outer clad layers getting pulled along for the ride as the coin's center shrinks radially and teh edge of the coin assumes an "oreo cookie" profile. In some cases the cladding is has hidden manufacturing defects and imperfect bonding. This causes partial separation of the cladding layers, and the resulting force imbalances cause dramatic distortions in the shape of the shrunken coin - see: Thanks for visiting! -- Bert --
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Re: Shrinking coins
Posted by Matt on 7/5/2011, 5:18 pm, in reply to "Re: Shrinking coins"
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Re: Shrinking coins
Posted by Bert Hickman on 7/6/2011, 12:05 am, in reply to "Re: Shrinking coins"
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Re: Shrinking coins
Posted by Mojtaba on 10/29/2004, 8:40 am, in reply to "Re: Shrinking coins"
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Re: Shrinking coins
Posted by Bert Hickman on 10/29/2004, 12:54 pm, in reply to "Re: Shrinking coins" Hi! BTW, my name is Bert ... :^) I don't know exactly how the clad material is actually made (it may in fact be proprietary), but the companies who supply it to the US Mint may be able to answer your question. Olin Brass Posit-Bond® clad metal is used in quarters, dimes and half dollars. Another supplier to the Mint is PMX Industries. You might try asking them: The US Mint also has some information on how coins are made using this material. See: Hoped this helped and good luck! -- Bert --
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