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Ingots for Coins at Philadelphia Mint

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I found this to be interesting and wonder if all of it/or parts of it, are true:


2002 Blackbook Price Guide 40th Edition

Page 106/How US Coins are Made


Because of the ever increasing demand for coinage, the Mint introduced new time saving steps in its coin minting. Raw metal is cast into giant ingots eighteen feet long, sixteen inches wide and six inches thick, weighing 6,600 pounds. Previously, they had weighed 400 pounds and were sixteen times smaller in measurement. The ingot is rolled red hot and scaled to remove imperfections. It’s then ready for the coins to be stamped; no longer are blanks made and annealed (heated).


The excess metal that is left behind is used to make new ingots in a continuous, never-ending process. The new coins are electronically scanned, counted and automatically bagged. These facilities are in use and the new, ultra-modern Mint in Philadelphia. It has a production capacity of eight billion coins per year and is open to the public.



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It can't be accurate. By 2002 The Philadelphia mint had already shut down and dismantled its foundry. Outside suppliers were providing read to coin cent planchets and strip coils for blanking. They never had the capability of producing the clad ingots and I doubt they ever ran down the clad strip, they just blanked it.


Ingots are not normally rolled red hot because they would transfer that heat to the rollers an cause them to lose their temper and be deformed through use. (In fact in some cases they run a coolant solution over the trip to keep t and the rollers from beoming too hot.) It would be possible to roll them hot if you had a very long rolling mill so the ingot passd each set of roler just once so they had a chance to cool beore the next ingot.


Even so the rolling, blankng, and edge milling work hardens the metal so you woud still need to anneal the planchets before striking. Otherwise you risk less than full strikes without going to higher pressures, premature die failure, and a shortened life for the presses.


It is correct that the bronze and coppernickel ingots were once 400 pound and later they went to a heavier 6600 pound ingot. (Silver and gold ingots never got larger than the 400 pound level.) Then that was cut into halves or thirds part way through the rolling process. (The finished metal coils weigh between 2,200 and 4,000 pound.)

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Thanks Conder, I was suspicious of that read but wanted confirmation. You gave an excellent explaination of the process used today.


Just goes to show how much mis-information is being handed out to the masses!

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