The Philadelphia Mint

Then he showed us coin tanks. The tanks were taller than our waists and hold up to 400,000 pennies or 250,000 quarters. The one we saw was a display case so it only held about one tenth of those amounts but even that’s a lot of money! Now they use vault bags in which all four of us could probably fit!

     There are quite a few artists that work at the mint. They are called engravers because they sketch their ideas for coins and medals and then engrave them in clay molds which are later made in plaster. We saw a lot of these molds while we were there. Sometimes guest artists are asked to create drawings for new coins. It is an honor to have your design chosen. Click here for an interview of a guest artist.
     We saw a reducing machine that was a 100 years old. It was used until six months ago when the mint went digital. All of us wondered why it took so long to do this, but we guessed that the reducing machine worked well enough until then. The reducing machine takes a large model of the coin and copies it to a ‘die’ that is smaller. A large arm on the machine traces the model and a smaller arm mimics the lines and levels onto a small piece of metal, or ‘die’. Once the die has been made, it is used in a coin press. Now the engravers are using a computer to make the ‘die’.
     Then Mr. Grant showed us Peter, the mint eagle that used to have a nest on the first Philadelphia mint. People loved him so much that when he died, they chipped in money to have him stuffed. He has been displayed in the mint for about a hundred years. He is sometimes used as an eagle model for the engravers.
     The Philadelphia mint is the largest mint in the world. It has more coins and medals than anywhere else. Denver is the only other mint, besides Philadelphia, that makes coins. Fort Knox, in Kentucky, is where the United States stores gold. There is about 100 billion dollars in gold there.
     The Philadelphia mint was shut down in 1793 because of the yellow fever epidemic. Animals were used in the coin making process and mosquitoes came in with the animals. Mosquitoes carried and spread yellow fever. They shut the mint down so that mint workers wouldn’t be exposed more to yellow fever.
     All coins and medals are authorized by the United States Congress. When national medals are made, Congress will tell the mint how many need to be ‘struck’. The engravers, and sometimes artists outside of the mint, submit pictures of proposed coins or medals. Congress decides which design will be used. Every U.S. coin has to have “In God We Trust”, “Liberty”, “The United States of America” and “E Pluribus Unum” “out of many, one” on it.
     The mint used to make all of the medal decorations for servicemen like the Congressional Medal of Honor, the Purple Heart, and campaign medals. The mint got too busy to make these anymore so they are made some place else now. If a medal is designed to honor someone, that person gets to keep the original which has about $16,000 of gold in it.
     Next Mr. Grant explained that when state quarters are made, states tell them what symbols they want on the coins and then artists draw them. Also the artists/engravers hide their initials somewhere on the coin. Take out a quarter and see if you can find it.

	The engraver draws the design and makes a clay mold of it. A plaster mold is made from that. The molds are made in reverse, like a mirror image. For example: If there is a face engraved on the die, it will be sunken in instead of sticking out from it the way you would expect a face to be.
	The die (or stamp) is made from that. There will be a die for the front and a die for the back of each coin, done in the reverse. Dies will crack or wear out after awhile and need to be replaced.
	Then a coil of the coin metal (copper, nickel, etc.) is fed into a machine that punches out “blanks”, which is basically a coin with no design. The coils, if rolled out, stretch out five football fields long! The coils are as thick as the coin will be, are about a foot wide, and are made of copper and nickel. The dime, quarter and half dollar have a middle made of copper and an outer layer of copper and nickel. Pennies are made of zinc.
	The blanks go on a conveyor belt leading to a machine that heats them to soften them so they stamp easier. They stay soft enough to stamp for up to 3 days!
	A conveyor belt takes blanks to the other side of the building where they are stamped with a coin press (the die). The coin press has a die for each side of the coin. These are put in the machine so that the coin blank goes through and gets both sides stamped at the same time. The die puts up to 60 tons of pressure on the blank. Each die makes about 1 million pennies. Last year up to 80 thousand dies were made!
	Inspectors will check what comes off the conveyor belt. If the die is worn out they will know by what the coin looks like. If it is starting to crack, there will be lines on the coin. Coins that are not perfect are melted down and reused.
	A machine counts the coins coming out of the coin press.
	Coins are examined under a magnifying glass and are put in plastic fiber bags. Each bag weighs a ton. These bags are weighed and ready for shipment. They are stored in a vault. The bags are shipped out in armored vehicles or unmarked trucks. Police supervise the loading and will travel with the shipment. When the bags reach the Federal Reserve that ordered them, they will be weighed again and compared to the mint weight.

We checked out lots of displays. We saw scales where gold and silver blanks were weighed. We also found out that coins used to be made with smooth edges until people started to shave off some of the gold or silver and then spend the coin. The people would collect all of these shavings and then sell them when they got enough. This put some extra money in a dishonest person’s pocket and caused the mint to put ridges on the edges of coins after that. Ridges can’t easily be carved.

     We were able to look out over the production floor and noticed that most of it was automated and there weren’t that many people who were working even though we were told that 10 million pennies would be made that day. Machines did most of the work.
     We were not able to take production floor pictures because of security reasons. They did not want us to have pictures that might show exits/entrances and window locations.   This was understandable after 9/11. The mint was closed after that and reopened for tours recently. They appear to be doing all they can for people to experience the process of coin making while keeping the building secure.
     It seems that our team is full of shoppers because each and every one of us loved the gift shop! There were bracelets there that were a string of pennies and coin earrings.   They even had piggy bank socks! The Smart Piggy team wanted those but they were for little kids. The mint is missing out on THAT one!
     The best thing about visiting a mint is that you can see just how coins are made. Books explain it, but seeing it is even better! Thank you, Mr. Grant, for the tour of a lifetime! You made the Smart Piggies even smarter!