The whole team was jammed into one minivan at
8:00 in the morning. We were taking a trip to the
Philadelphia Mint, and everyone was excited. We were all
looking forward to having a tour AND visiting the gift shop,
When we got there, we discovered that the Philadelphia Mint
building covers an entire city block and sits on five acres of land! We
walked up the steps to the building and were met outside by security
people. Moms’ purses were checked and then we all went through a big
Soon we met the man giving us our tour, Mr. Tim Grant,
Exhibits and Public Services. First he explained to our team
coach about what we could take pictures of and what we couldn’t.
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 was a display column filled with whatever
new coin they were making. This time it was Presidential
dollars. When they are done displaying the coin inside the
column, the coins are melted down and the metal is reused.
This surprised us because they look so shiny and bright in the
display column. Presidential dollars are the same size as the
Susan B. Anthony dollar that people didn’t like very much
because it was the same size as a quarter causing much
confusion. This time, they changed the color so that the
difference would be noticeable. The mint
actually sells these coins to Federal Reserve Banks so they have to be
perfect. It costs too much to re-clean and re-polish them even though
they have never been used. When the mint sells coins, they make a
profit. For example: A Presidential dollar costs thirty cents to make
but is sold at its face value of one dollar. The mint is one of the
only government organizations that makes a profit. Last year they made
a profit of 2 billion dollars that was given to the Treasury department.
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
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
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
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.
These are the steps to make a coin:
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
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.
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.
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!
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.
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
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.
Philadelphia Mint antique coin roller and coin press
click here and choose
"Save target as" and download it to play it.
click here and choose
"Save target as" and download it to play it.
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
Our interview with the
Guest Artist who designed the Buffalo nickel