On a recent road trip to Philadelphia with my family, I attended a behind-the-scenes sneak peek tour of the US Mint, the largest coin manufacturer in the world. The re-designed public tour, which is free, opens July 3, 2012. I was able to also go right down on the factory floor to get an up-close-and-personal look at every stage of the design and manufacturing process at this very historic and important part of our country’s economy. Security is tight, and the public tour does not allow photography, but luckily I had permission to take lots of pictures for you to see here!
This US Mint location makes coins, and is the headquarters of the Mint artists who design all of the other items the Mint offers such as commemorative coins, special collector’s edition coins, and medals.
All of the artists are accomplished sculptors, with strong backgrounds in the fine arts. The technology used to design and refine the concepts for the coins is state-of-the-art, and much of the modeling is done on computer.
Old-school techniques are still relevant though, as seen in these clay models used to make plaster molds for the high tech CNC (Computer Numerical Control) machines that will carve out a master hub with the coin’s design. The plaster model is large, allowing for lots of detail to be worked on in super size form, and the CNC machine then shrinks the design down to the scale that the die will require.
Precision and detail are paramount when the hub is being carved. The master hub is used to make the dies that stamp out each coin. Any flaw, no matter how small, is not acceptable, and each stage is carefully checked and re-checked to make sure everything is perfect.
It’s impressive to see how much of this process is still done by hand, by real humans, even though the high tech machines have a large part as well.
The U.S. Mint uses giant coils of strips of metal about 13 inches wide and 1,500 feet in length to manufacture the nickel, dime, quarter, half-dollar, and dollar. The coils weigh approximately 6,000 pounds each!
Each coil is fed through a blanking press which punches out round discs called blanks.
The leftovers after the blanks are stamped are recycled, and turned into more giant coils of blank metal to make new coins in a continual cycle. (For pennies, the Mint buys blanks ready made from fabricators they supply with copper and zinc.)
After annealing (to soften the metal) and a nice bath to remove the heat scale and discoloration, perfect blanks go through a mill to add a rim to their outside edges. Imperfect ones are recycled, like the scrap from the blanking process.
At the coining press coins are stamped with the dies that were created from the master hubs. After inspection, if they have no imperfections, the coins become legal United States tender.
Finally, the coins are counted and bagged. Pennies aren’t even counted piece by piece, they are put in the large bags and weighed on a giant scale. After all the bagging, counting and weighing is done, the coins are loaded onto trucks and sent out to various Federal Reserve Banks, and eventually end up in your pocket.
The process for special collector’s coins, such as the 3 inch silver bullion US quarter series, is basically the same. Each coin is carefully inspected for flaws, but since they are 3 inches in diameter, they don’t need that strong of a magnification lens!
This design is of Hawaii’s Volcano National Park, and is considered legal United States tender with a face value of 25 cents. Of course, it’s made of 5 ounces of fine silver, so the actual cost if you want to purchase one is currently about $205, so you probably won’t want to use it as change!
Free in Philadelphia: Tour the US Mint
The new public tour would be a fun thing to do with kids in Philly, from preschoolers to teens. While you are not allowed on the factory floor, the gallery level looks down on it from 40 feet in the air, with big clear windows that have a view of everything. There are interactive touchscreens that give in-depth descriptions of what you are looking at, and there are also interesting historical artifacts and interactive exhibits that you can both look at and touch to explore further.
On the Mezzanine level of the public tour there are interesting historical items and more interactive touchscreens. Check out the David Rittenhouse Theater for a short video about the history of the Mint and the establishment of the national coinage system in the fledgling United States of America.
The gift shop has a great selection of neat items that everyone, from serious collectors to kids with a modest allowance, would like. If you can’t get to the shop, or want to get some of those giant silver bullion quarters, you can buy them online directly from the mint.
US Mint in Philadelphia Quick Facts:
- The Mint in Philadelphia is the largest mint in the world and makes 25-30 million coins per day.
- The other three US Mints are in West Point NY, Denver CO and San Francisco CA.
- The US Mint has its own police force, under the jurisdiction of the US Treasury Department.
- All coin and medal designs are authorized by Congress, and must pass several committees before being approved.
- Employees have access to in-house apprentice training in all areas of coin manufacture to gain more skills and career advancement.
- The public tour and exhibit area has been totally redesigned and updated, a process that began over two years ago!
- Public tours are self-guided, and admission is free. No photography is allowed, but you get a great view of the factory floor and interactive exhibits give lots of interesting background and information about coins and coining.
- The website for the US Mint has interesting educational activities and teaching tools.
Go see it!
United States Mint
5th and Arch Streets
151 North Independence Mall East
Philadelphia, PA 19106-1886