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<p>[QUOTE=&quot;GDJMSP, post: 7496456, member: 112&quot;]C&#039;mon now Mike, that isn&#039;t why planchets are run through the upset mill. If that was the reason all they&#039;d have to do is cut the blanks to whatever diameter they wanted, and skip the upset mill entirely. </p><p><br /></p><p>Planchets are run though the upset mill for one reason and one reason only - it is because that extra metal is needed to form the rim. That&#039;s why they invented the upset process to begin with. If you strike a planchet without it having been run through the upset mill, no rim is ever formed. </p><p><br /></p><p>Now ask yourself a different question. Where does the majority of the metal end up once a coin has been struck ? It&#039;s a really simple question and all you have to do is look at a coin to see the answer. The majority of the metal ends up in the central devices. And that means the majority of the metal flows inwards, not outwards.</p><p><br /></p><p>&nbsp;It&#039;s a combination of things really. The edge of the blank is upset so there is enough metal already there to form the rim. And yes the collar, and the dies, stop and contain the metal at the outer edge so the metal simply cannot flow any further outwards than that. And because the metal is stopped at the outer edge, it is forced to flow inwards towards the central devices. And it has to be forced to flow inwards because if it isn&#039;t the central devices will not strike up.</p><p><br /></p><p>They developed this process because you&#039;re right about one thing, when something is submitted to great pressure the natural tendency is for the material to spread outwards. But to strike up coins they absolutely have to counter that tendency, they have to force the majority of the metal to flow inwards. And that&#039;s exactly what they do with the process that is used.[/QUOTE]</p><p><br /></p>

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